4 * Copyright (C) 2005 David Brownell
5 * Copyright (C) 2008 Secret Lab Technologies Ltd.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
18 #include <linux/kernel.h>
19 #include <linux/device.h>
20 #include <linux/init.h>
21 #include <linux/cache.h>
22 #include <linux/dma-mapping.h>
23 #include <linux/dmaengine.h>
24 #include <linux/mutex.h>
25 #include <linux/of_device.h>
26 #include <linux/of_irq.h>
27 #include <linux/clk/clk-conf.h>
28 #include <linux/slab.h>
29 #include <linux/mod_devicetable.h>
30 #include <linux/spi/spi.h>
31 #include <linux/of_gpio.h>
32 #include <linux/pm_runtime.h>
33 #include <linux/pm_domain.h>
34 #include <linux/export.h>
35 #include <linux/sched/rt.h>
36 #include <linux/delay.h>
37 #include <linux/kthread.h>
38 #include <linux/ioport.h>
39 #include <linux/acpi.h>
41 #define CREATE_TRACE_POINTS
42 #include <trace/events/spi.h>
44 static void spidev_release(struct device *dev)
46 struct spi_device *spi = to_spi_device(dev);
48 /* spi masters may cleanup for released devices */
49 if (spi->master->cleanup)
50 spi->master->cleanup(spi);
52 spi_master_put(spi->master);
57 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
59 const struct spi_device *spi = to_spi_device(dev);
62 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
66 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
68 static DEVICE_ATTR_RO(modalias);
70 #define SPI_STATISTICS_ATTRS(field, file) \
71 static ssize_t spi_master_##field##_show(struct device *dev, \
72 struct device_attribute *attr, \
75 struct spi_master *master = container_of(dev, \
76 struct spi_master, dev); \
77 return spi_statistics_##field##_show(&master->statistics, buf); \
79 static struct device_attribute dev_attr_spi_master_##field = { \
80 .attr = { .name = file, .mode = S_IRUGO }, \
81 .show = spi_master_##field##_show, \
83 static ssize_t spi_device_##field##_show(struct device *dev, \
84 struct device_attribute *attr, \
87 struct spi_device *spi = container_of(dev, \
88 struct spi_device, dev); \
89 return spi_statistics_##field##_show(&spi->statistics, buf); \
91 static struct device_attribute dev_attr_spi_device_##field = { \
92 .attr = { .name = file, .mode = S_IRUGO }, \
93 .show = spi_device_##field##_show, \
96 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string) \
97 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
100 unsigned long flags; \
102 spin_lock_irqsave(&stat->lock, flags); \
103 len = sprintf(buf, format_string, stat->field); \
104 spin_unlock_irqrestore(&stat->lock, flags); \
107 SPI_STATISTICS_ATTRS(name, file)
109 #define SPI_STATISTICS_SHOW(field, format_string) \
110 SPI_STATISTICS_SHOW_NAME(field, __stringify(field), \
111 field, format_string)
113 SPI_STATISTICS_SHOW(messages, "%lu");
114 SPI_STATISTICS_SHOW(transfers, "%lu");
115 SPI_STATISTICS_SHOW(errors, "%lu");
116 SPI_STATISTICS_SHOW(timedout, "%lu");
118 SPI_STATISTICS_SHOW(spi_sync, "%lu");
119 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
120 SPI_STATISTICS_SHOW(spi_async, "%lu");
122 SPI_STATISTICS_SHOW(bytes, "%llu");
123 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
124 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
126 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number) \
127 SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index, \
128 "transfer_bytes_histo_" number, \
129 transfer_bytes_histo[index], "%lu")
130 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0, "0-1");
131 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1, "2-3");
132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2, "4-7");
133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3, "8-15");
134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4, "16-31");
135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5, "32-63");
136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6, "64-127");
137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7, "128-255");
138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8, "256-511");
139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9, "512-1023");
140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
146 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
148 static struct attribute *spi_dev_attrs[] = {
149 &dev_attr_modalias.attr,
153 static const struct attribute_group spi_dev_group = {
154 .attrs = spi_dev_attrs,
157 static struct attribute *spi_device_statistics_attrs[] = {
158 &dev_attr_spi_device_messages.attr,
159 &dev_attr_spi_device_transfers.attr,
160 &dev_attr_spi_device_errors.attr,
161 &dev_attr_spi_device_timedout.attr,
162 &dev_attr_spi_device_spi_sync.attr,
163 &dev_attr_spi_device_spi_sync_immediate.attr,
164 &dev_attr_spi_device_spi_async.attr,
165 &dev_attr_spi_device_bytes.attr,
166 &dev_attr_spi_device_bytes_rx.attr,
167 &dev_attr_spi_device_bytes_tx.attr,
168 &dev_attr_spi_device_transfer_bytes_histo0.attr,
169 &dev_attr_spi_device_transfer_bytes_histo1.attr,
170 &dev_attr_spi_device_transfer_bytes_histo2.attr,
171 &dev_attr_spi_device_transfer_bytes_histo3.attr,
172 &dev_attr_spi_device_transfer_bytes_histo4.attr,
173 &dev_attr_spi_device_transfer_bytes_histo5.attr,
174 &dev_attr_spi_device_transfer_bytes_histo6.attr,
175 &dev_attr_spi_device_transfer_bytes_histo7.attr,
176 &dev_attr_spi_device_transfer_bytes_histo8.attr,
177 &dev_attr_spi_device_transfer_bytes_histo9.attr,
178 &dev_attr_spi_device_transfer_bytes_histo10.attr,
179 &dev_attr_spi_device_transfer_bytes_histo11.attr,
180 &dev_attr_spi_device_transfer_bytes_histo12.attr,
181 &dev_attr_spi_device_transfer_bytes_histo13.attr,
182 &dev_attr_spi_device_transfer_bytes_histo14.attr,
183 &dev_attr_spi_device_transfer_bytes_histo15.attr,
184 &dev_attr_spi_device_transfer_bytes_histo16.attr,
188 static const struct attribute_group spi_device_statistics_group = {
189 .name = "statistics",
190 .attrs = spi_device_statistics_attrs,
193 static const struct attribute_group *spi_dev_groups[] = {
195 &spi_device_statistics_group,
199 static struct attribute *spi_master_statistics_attrs[] = {
200 &dev_attr_spi_master_messages.attr,
201 &dev_attr_spi_master_transfers.attr,
202 &dev_attr_spi_master_errors.attr,
203 &dev_attr_spi_master_timedout.attr,
204 &dev_attr_spi_master_spi_sync.attr,
205 &dev_attr_spi_master_spi_sync_immediate.attr,
206 &dev_attr_spi_master_spi_async.attr,
207 &dev_attr_spi_master_bytes.attr,
208 &dev_attr_spi_master_bytes_rx.attr,
209 &dev_attr_spi_master_bytes_tx.attr,
210 &dev_attr_spi_master_transfer_bytes_histo0.attr,
211 &dev_attr_spi_master_transfer_bytes_histo1.attr,
212 &dev_attr_spi_master_transfer_bytes_histo2.attr,
213 &dev_attr_spi_master_transfer_bytes_histo3.attr,
214 &dev_attr_spi_master_transfer_bytes_histo4.attr,
215 &dev_attr_spi_master_transfer_bytes_histo5.attr,
216 &dev_attr_spi_master_transfer_bytes_histo6.attr,
217 &dev_attr_spi_master_transfer_bytes_histo7.attr,
218 &dev_attr_spi_master_transfer_bytes_histo8.attr,
219 &dev_attr_spi_master_transfer_bytes_histo9.attr,
220 &dev_attr_spi_master_transfer_bytes_histo10.attr,
221 &dev_attr_spi_master_transfer_bytes_histo11.attr,
222 &dev_attr_spi_master_transfer_bytes_histo12.attr,
223 &dev_attr_spi_master_transfer_bytes_histo13.attr,
224 &dev_attr_spi_master_transfer_bytes_histo14.attr,
225 &dev_attr_spi_master_transfer_bytes_histo15.attr,
226 &dev_attr_spi_master_transfer_bytes_histo16.attr,
230 static const struct attribute_group spi_master_statistics_group = {
231 .name = "statistics",
232 .attrs = spi_master_statistics_attrs,
235 static const struct attribute_group *spi_master_groups[] = {
236 &spi_master_statistics_group,
240 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
241 struct spi_transfer *xfer,
242 struct spi_master *master)
245 int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
250 spin_lock_irqsave(&stats->lock, flags);
253 stats->transfer_bytes_histo[l2len]++;
255 stats->bytes += xfer->len;
256 if ((xfer->tx_buf) &&
257 (xfer->tx_buf != master->dummy_tx))
258 stats->bytes_tx += xfer->len;
259 if ((xfer->rx_buf) &&
260 (xfer->rx_buf != master->dummy_rx))
261 stats->bytes_rx += xfer->len;
263 spin_unlock_irqrestore(&stats->lock, flags);
265 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
267 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
268 * and the sysfs version makes coldplug work too.
271 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
272 const struct spi_device *sdev)
274 while (id->name[0]) {
275 if (!strcmp(sdev->modalias, id->name))
282 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
284 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
286 return spi_match_id(sdrv->id_table, sdev);
288 EXPORT_SYMBOL_GPL(spi_get_device_id);
290 static int spi_match_device(struct device *dev, struct device_driver *drv)
292 const struct spi_device *spi = to_spi_device(dev);
293 const struct spi_driver *sdrv = to_spi_driver(drv);
295 /* Attempt an OF style match */
296 if (of_driver_match_device(dev, drv))
300 if (acpi_driver_match_device(dev, drv))
304 return !!spi_match_id(sdrv->id_table, spi);
306 return strcmp(spi->modalias, drv->name) == 0;
309 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
311 const struct spi_device *spi = to_spi_device(dev);
314 rc = acpi_device_uevent_modalias(dev, env);
318 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
322 struct bus_type spi_bus_type = {
324 .dev_groups = spi_dev_groups,
325 .match = spi_match_device,
326 .uevent = spi_uevent,
328 EXPORT_SYMBOL_GPL(spi_bus_type);
331 static int spi_drv_probe(struct device *dev)
333 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
334 struct spi_device *spi = to_spi_device(dev);
337 ret = of_clk_set_defaults(dev->of_node, false);
342 spi->irq = of_irq_get(dev->of_node, 0);
343 if (spi->irq == -EPROBE_DEFER)
344 return -EPROBE_DEFER;
349 ret = dev_pm_domain_attach(dev, true);
350 if (ret != -EPROBE_DEFER) {
351 ret = sdrv->probe(spi);
353 dev_pm_domain_detach(dev, true);
359 static int spi_drv_remove(struct device *dev)
361 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
364 ret = sdrv->remove(to_spi_device(dev));
365 dev_pm_domain_detach(dev, true);
370 static void spi_drv_shutdown(struct device *dev)
372 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
374 sdrv->shutdown(to_spi_device(dev));
378 * __spi_register_driver - register a SPI driver
379 * @owner: owner module of the driver to register
380 * @sdrv: the driver to register
383 * Return: zero on success, else a negative error code.
385 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
387 sdrv->driver.owner = owner;
388 sdrv->driver.bus = &spi_bus_type;
390 sdrv->driver.probe = spi_drv_probe;
392 sdrv->driver.remove = spi_drv_remove;
394 sdrv->driver.shutdown = spi_drv_shutdown;
395 return driver_register(&sdrv->driver);
397 EXPORT_SYMBOL_GPL(__spi_register_driver);
399 /*-------------------------------------------------------------------------*/
401 /* SPI devices should normally not be created by SPI device drivers; that
402 * would make them board-specific. Similarly with SPI master drivers.
403 * Device registration normally goes into like arch/.../mach.../board-YYY.c
404 * with other readonly (flashable) information about mainboard devices.
408 struct list_head list;
409 struct spi_board_info board_info;
412 static LIST_HEAD(board_list);
413 static LIST_HEAD(spi_master_list);
416 * Used to protect add/del opertion for board_info list and
417 * spi_master list, and their matching process
419 static DEFINE_MUTEX(board_lock);
422 * Prevents addition of devices with same chip select and
423 * addition of devices below an unregistering controller.
425 static DEFINE_MUTEX(spi_add_lock);
428 * spi_alloc_device - Allocate a new SPI device
429 * @master: Controller to which device is connected
432 * Allows a driver to allocate and initialize a spi_device without
433 * registering it immediately. This allows a driver to directly
434 * fill the spi_device with device parameters before calling
435 * spi_add_device() on it.
437 * Caller is responsible to call spi_add_device() on the returned
438 * spi_device structure to add it to the SPI master. If the caller
439 * needs to discard the spi_device without adding it, then it should
440 * call spi_dev_put() on it.
442 * Return: a pointer to the new device, or NULL.
444 struct spi_device *spi_alloc_device(struct spi_master *master)
446 struct spi_device *spi;
448 if (!spi_master_get(master))
451 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
453 spi_master_put(master);
457 spi->master = master;
458 spi->dev.parent = &master->dev;
459 spi->dev.bus = &spi_bus_type;
460 spi->dev.release = spidev_release;
461 spi->cs_gpio = -ENOENT;
463 spin_lock_init(&spi->statistics.lock);
465 device_initialize(&spi->dev);
468 EXPORT_SYMBOL_GPL(spi_alloc_device);
470 static void spi_dev_set_name(struct spi_device *spi)
472 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
475 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
479 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
483 static int spi_dev_check(struct device *dev, void *data)
485 struct spi_device *spi = to_spi_device(dev);
486 struct spi_device *new_spi = data;
488 if (spi->master == new_spi->master &&
489 spi->chip_select == new_spi->chip_select)
495 * spi_add_device - Add spi_device allocated with spi_alloc_device
496 * @spi: spi_device to register
498 * Companion function to spi_alloc_device. Devices allocated with
499 * spi_alloc_device can be added onto the spi bus with this function.
501 * Return: 0 on success; negative errno on failure
503 int spi_add_device(struct spi_device *spi)
505 struct spi_master *master = spi->master;
506 struct device *dev = master->dev.parent;
509 /* Chipselects are numbered 0..max; validate. */
510 if (spi->chip_select >= master->num_chipselect) {
511 dev_err(dev, "cs%d >= max %d\n",
513 master->num_chipselect);
517 /* Set the bus ID string */
518 spi_dev_set_name(spi);
520 /* We need to make sure there's no other device with this
521 * chipselect **BEFORE** we call setup(), else we'll trash
522 * its configuration. Lock against concurrent add() calls.
524 mutex_lock(&spi_add_lock);
526 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
528 dev_err(dev, "chipselect %d already in use\n",
533 /* Controller may unregister concurrently */
534 if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
535 !device_is_registered(&master->dev)) {
540 if (master->cs_gpios)
541 spi->cs_gpio = master->cs_gpios[spi->chip_select];
543 /* Drivers may modify this initial i/o setup, but will
544 * normally rely on the device being setup. Devices
545 * using SPI_CS_HIGH can't coexist well otherwise...
547 status = spi_setup(spi);
549 dev_err(dev, "can't setup %s, status %d\n",
550 dev_name(&spi->dev), status);
554 /* Device may be bound to an active driver when this returns */
555 status = device_add(&spi->dev);
557 dev_err(dev, "can't add %s, status %d\n",
558 dev_name(&spi->dev), status);
560 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
563 mutex_unlock(&spi_add_lock);
566 EXPORT_SYMBOL_GPL(spi_add_device);
569 * spi_new_device - instantiate one new SPI device
570 * @master: Controller to which device is connected
571 * @chip: Describes the SPI device
574 * On typical mainboards, this is purely internal; and it's not needed
575 * after board init creates the hard-wired devices. Some development
576 * platforms may not be able to use spi_register_board_info though, and
577 * this is exported so that for example a USB or parport based adapter
578 * driver could add devices (which it would learn about out-of-band).
580 * Return: the new device, or NULL.
582 struct spi_device *spi_new_device(struct spi_master *master,
583 struct spi_board_info *chip)
585 struct spi_device *proxy;
588 /* NOTE: caller did any chip->bus_num checks necessary.
590 * Also, unless we change the return value convention to use
591 * error-or-pointer (not NULL-or-pointer), troubleshootability
592 * suggests syslogged diagnostics are best here (ugh).
595 proxy = spi_alloc_device(master);
599 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
601 proxy->chip_select = chip->chip_select;
602 proxy->max_speed_hz = chip->max_speed_hz;
603 proxy->mode = chip->mode;
604 proxy->irq = chip->irq;
605 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
606 proxy->dev.platform_data = (void *) chip->platform_data;
607 proxy->controller_data = chip->controller_data;
608 proxy->controller_state = NULL;
610 status = spi_add_device(proxy);
618 EXPORT_SYMBOL_GPL(spi_new_device);
620 static void spi_match_master_to_boardinfo(struct spi_master *master,
621 struct spi_board_info *bi)
623 struct spi_device *dev;
625 if (master->bus_num != bi->bus_num)
628 dev = spi_new_device(master, bi);
630 dev_err(master->dev.parent, "can't create new device for %s\n",
635 * spi_register_board_info - register SPI devices for a given board
636 * @info: array of chip descriptors
637 * @n: how many descriptors are provided
640 * Board-specific early init code calls this (probably during arch_initcall)
641 * with segments of the SPI device table. Any device nodes are created later,
642 * after the relevant parent SPI controller (bus_num) is defined. We keep
643 * this table of devices forever, so that reloading a controller driver will
644 * not make Linux forget about these hard-wired devices.
646 * Other code can also call this, e.g. a particular add-on board might provide
647 * SPI devices through its expansion connector, so code initializing that board
648 * would naturally declare its SPI devices.
650 * The board info passed can safely be __initdata ... but be careful of
651 * any embedded pointers (platform_data, etc), they're copied as-is.
653 * Return: zero on success, else a negative error code.
655 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
657 struct boardinfo *bi;
663 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
667 for (i = 0; i < n; i++, bi++, info++) {
668 struct spi_master *master;
670 memcpy(&bi->board_info, info, sizeof(*info));
671 mutex_lock(&board_lock);
672 list_add_tail(&bi->list, &board_list);
673 list_for_each_entry(master, &spi_master_list, list)
674 spi_match_master_to_boardinfo(master, &bi->board_info);
675 mutex_unlock(&board_lock);
681 /*-------------------------------------------------------------------------*/
683 static void spi_set_cs(struct spi_device *spi, bool enable)
685 if (spi->mode & SPI_CS_HIGH)
688 if (gpio_is_valid(spi->cs_gpio))
689 gpio_set_value(spi->cs_gpio, !enable);
690 else if (spi->master->set_cs)
691 spi->master->set_cs(spi, !enable);
694 #ifdef CONFIG_HAS_DMA
695 static int spi_map_buf(struct spi_master *master, struct device *dev,
696 struct sg_table *sgt, void *buf, size_t len,
697 enum dma_data_direction dir)
699 const bool vmalloced_buf = is_vmalloc_addr(buf);
702 struct page *vm_page;
708 desc_len = PAGE_SIZE;
709 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
711 desc_len = master->max_dma_len;
712 sgs = DIV_ROUND_UP(len, desc_len);
715 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
719 for (i = 0; i < sgs; i++) {
723 * Next scatterlist entry size is the minimum between
724 * the desc_len and the remaining buffer length that
727 min = min_t(size_t, desc_len,
729 PAGE_SIZE - offset_in_page(buf)));
730 vm_page = vmalloc_to_page(buf);
735 sg_set_page(&sgt->sgl[i], vm_page,
736 min, offset_in_page(buf));
738 min = min_t(size_t, len, desc_len);
740 sg_set_buf(&sgt->sgl[i], sg_buf, min);
748 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
761 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
762 struct sg_table *sgt, enum dma_data_direction dir)
764 if (sgt->orig_nents) {
765 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
770 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
772 struct device *tx_dev, *rx_dev;
773 struct spi_transfer *xfer;
776 if (!master->can_dma)
780 tx_dev = master->dma_tx->device->dev;
782 tx_dev = &master->dev;
785 rx_dev = master->dma_rx->device->dev;
787 rx_dev = &master->dev;
789 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
790 if (!master->can_dma(master, msg->spi, xfer))
793 if (xfer->tx_buf != NULL) {
794 ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
795 (void *)xfer->tx_buf, xfer->len,
801 if (xfer->rx_buf != NULL) {
802 ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
803 xfer->rx_buf, xfer->len,
806 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
813 master->cur_msg_mapped = true;
818 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
820 struct spi_transfer *xfer;
821 struct device *tx_dev, *rx_dev;
823 if (!master->cur_msg_mapped || !master->can_dma)
827 tx_dev = master->dma_tx->device->dev;
829 tx_dev = &master->dev;
832 rx_dev = master->dma_rx->device->dev;
834 rx_dev = &master->dev;
836 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
837 if (!master->can_dma(master, msg->spi, xfer))
840 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
841 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
846 #else /* !CONFIG_HAS_DMA */
847 static inline int __spi_map_msg(struct spi_master *master,
848 struct spi_message *msg)
853 static inline int __spi_unmap_msg(struct spi_master *master,
854 struct spi_message *msg)
858 #endif /* !CONFIG_HAS_DMA */
860 static inline int spi_unmap_msg(struct spi_master *master,
861 struct spi_message *msg)
863 struct spi_transfer *xfer;
865 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
867 * Restore the original value of tx_buf or rx_buf if they are
870 if (xfer->tx_buf == master->dummy_tx)
872 if (xfer->rx_buf == master->dummy_rx)
876 return __spi_unmap_msg(master, msg);
879 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
881 struct spi_transfer *xfer;
883 unsigned int max_tx, max_rx;
885 if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
889 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
890 if ((master->flags & SPI_MASTER_MUST_TX) &&
892 max_tx = max(xfer->len, max_tx);
893 if ((master->flags & SPI_MASTER_MUST_RX) &&
895 max_rx = max(xfer->len, max_rx);
899 tmp = krealloc(master->dummy_tx, max_tx,
900 GFP_KERNEL | GFP_DMA);
903 master->dummy_tx = tmp;
904 memset(tmp, 0, max_tx);
908 tmp = krealloc(master->dummy_rx, max_rx,
909 GFP_KERNEL | GFP_DMA);
912 master->dummy_rx = tmp;
915 if (max_tx || max_rx) {
916 list_for_each_entry(xfer, &msg->transfers,
921 xfer->tx_buf = master->dummy_tx;
923 xfer->rx_buf = master->dummy_rx;
928 return __spi_map_msg(master, msg);
932 * spi_transfer_one_message - Default implementation of transfer_one_message()
934 * This is a standard implementation of transfer_one_message() for
935 * drivers which impelment a transfer_one() operation. It provides
936 * standard handling of delays and chip select management.
938 static int spi_transfer_one_message(struct spi_master *master,
939 struct spi_message *msg)
941 struct spi_transfer *xfer;
942 bool keep_cs = false;
944 unsigned long ms = 1;
945 struct spi_statistics *statm = &master->statistics;
946 struct spi_statistics *stats = &msg->spi->statistics;
948 spi_set_cs(msg->spi, true);
950 SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
951 SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
953 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
954 trace_spi_transfer_start(msg, xfer);
956 spi_statistics_add_transfer_stats(statm, xfer, master);
957 spi_statistics_add_transfer_stats(stats, xfer, master);
959 if (xfer->tx_buf || xfer->rx_buf) {
960 reinit_completion(&master->xfer_completion);
962 ret = master->transfer_one(master, msg->spi, xfer);
964 SPI_STATISTICS_INCREMENT_FIELD(statm,
966 SPI_STATISTICS_INCREMENT_FIELD(stats,
968 dev_err(&msg->spi->dev,
969 "SPI transfer failed: %d\n", ret);
975 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
976 ms += ms + 100; /* some tolerance */
978 ms = wait_for_completion_timeout(&master->xfer_completion,
979 msecs_to_jiffies(ms));
983 SPI_STATISTICS_INCREMENT_FIELD(statm,
985 SPI_STATISTICS_INCREMENT_FIELD(stats,
987 dev_err(&msg->spi->dev,
988 "SPI transfer timed out\n");
989 msg->status = -ETIMEDOUT;
993 dev_err(&msg->spi->dev,
994 "Bufferless transfer has length %u\n",
998 trace_spi_transfer_stop(msg, xfer);
1000 if (msg->status != -EINPROGRESS)
1003 if (xfer->delay_usecs)
1004 udelay(xfer->delay_usecs);
1006 if (xfer->cs_change) {
1007 if (list_is_last(&xfer->transfer_list,
1011 spi_set_cs(msg->spi, false);
1013 spi_set_cs(msg->spi, true);
1017 msg->actual_length += xfer->len;
1021 if (ret != 0 || !keep_cs)
1022 spi_set_cs(msg->spi, false);
1024 if (msg->status == -EINPROGRESS)
1027 if (msg->status && master->handle_err)
1028 master->handle_err(master, msg);
1030 spi_finalize_current_message(master);
1036 * spi_finalize_current_transfer - report completion of a transfer
1037 * @master: the master reporting completion
1039 * Called by SPI drivers using the core transfer_one_message()
1040 * implementation to notify it that the current interrupt driven
1041 * transfer has finished and the next one may be scheduled.
1043 void spi_finalize_current_transfer(struct spi_master *master)
1045 complete(&master->xfer_completion);
1047 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1050 * __spi_pump_messages - function which processes spi message queue
1051 * @master: master to process queue for
1052 * @in_kthread: true if we are in the context of the message pump thread
1054 * This function checks if there is any spi message in the queue that
1055 * needs processing and if so call out to the driver to initialize hardware
1056 * and transfer each message.
1058 * Note that it is called both from the kthread itself and also from
1059 * inside spi_sync(); the queue extraction handling at the top of the
1060 * function should deal with this safely.
1062 static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
1064 unsigned long flags;
1065 bool was_busy = false;
1069 spin_lock_irqsave(&master->queue_lock, flags);
1071 /* Make sure we are not already running a message */
1072 if (master->cur_msg) {
1073 spin_unlock_irqrestore(&master->queue_lock, flags);
1077 /* If another context is idling the device then defer */
1078 if (master->idling) {
1079 queue_kthread_work(&master->kworker, &master->pump_messages);
1080 spin_unlock_irqrestore(&master->queue_lock, flags);
1084 /* Check if the queue is idle */
1085 if (list_empty(&master->queue) || !master->running) {
1086 if (!master->busy) {
1087 spin_unlock_irqrestore(&master->queue_lock, flags);
1091 /* Only do teardown in the thread */
1093 queue_kthread_work(&master->kworker,
1094 &master->pump_messages);
1095 spin_unlock_irqrestore(&master->queue_lock, flags);
1099 master->busy = false;
1100 master->idling = true;
1101 spin_unlock_irqrestore(&master->queue_lock, flags);
1103 kfree(master->dummy_rx);
1104 master->dummy_rx = NULL;
1105 kfree(master->dummy_tx);
1106 master->dummy_tx = NULL;
1107 if (master->unprepare_transfer_hardware &&
1108 master->unprepare_transfer_hardware(master))
1109 dev_err(&master->dev,
1110 "failed to unprepare transfer hardware\n");
1111 if (master->auto_runtime_pm) {
1112 pm_runtime_mark_last_busy(master->dev.parent);
1113 pm_runtime_put_autosuspend(master->dev.parent);
1115 trace_spi_master_idle(master);
1117 spin_lock_irqsave(&master->queue_lock, flags);
1118 master->idling = false;
1119 spin_unlock_irqrestore(&master->queue_lock, flags);
1123 /* Extract head of queue */
1125 list_first_entry(&master->queue, struct spi_message, queue);
1127 list_del_init(&master->cur_msg->queue);
1131 master->busy = true;
1132 spin_unlock_irqrestore(&master->queue_lock, flags);
1134 if (!was_busy && master->auto_runtime_pm) {
1135 ret = pm_runtime_get_sync(master->dev.parent);
1137 dev_err(&master->dev, "Failed to power device: %d\n",
1144 trace_spi_master_busy(master);
1146 if (!was_busy && master->prepare_transfer_hardware) {
1147 ret = master->prepare_transfer_hardware(master);
1149 dev_err(&master->dev,
1150 "failed to prepare transfer hardware\n");
1152 if (master->auto_runtime_pm)
1153 pm_runtime_put(master->dev.parent);
1158 trace_spi_message_start(master->cur_msg);
1160 if (master->prepare_message) {
1161 ret = master->prepare_message(master, master->cur_msg);
1163 dev_err(&master->dev,
1164 "failed to prepare message: %d\n", ret);
1165 master->cur_msg->status = ret;
1166 spi_finalize_current_message(master);
1169 master->cur_msg_prepared = true;
1172 ret = spi_map_msg(master, master->cur_msg);
1174 master->cur_msg->status = ret;
1175 spi_finalize_current_message(master);
1179 ret = master->transfer_one_message(master, master->cur_msg);
1181 dev_err(&master->dev,
1182 "failed to transfer one message from queue\n");
1188 * spi_pump_messages - kthread work function which processes spi message queue
1189 * @work: pointer to kthread work struct contained in the master struct
1191 static void spi_pump_messages(struct kthread_work *work)
1193 struct spi_master *master =
1194 container_of(work, struct spi_master, pump_messages);
1196 __spi_pump_messages(master, true);
1199 static int spi_init_queue(struct spi_master *master)
1201 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1203 master->running = false;
1204 master->busy = false;
1206 init_kthread_worker(&master->kworker);
1207 master->kworker_task = kthread_run(kthread_worker_fn,
1208 &master->kworker, "%s",
1209 dev_name(&master->dev));
1210 if (IS_ERR(master->kworker_task)) {
1211 dev_err(&master->dev, "failed to create message pump task\n");
1212 return PTR_ERR(master->kworker_task);
1214 init_kthread_work(&master->pump_messages, spi_pump_messages);
1217 * Master config will indicate if this controller should run the
1218 * message pump with high (realtime) priority to reduce the transfer
1219 * latency on the bus by minimising the delay between a transfer
1220 * request and the scheduling of the message pump thread. Without this
1221 * setting the message pump thread will remain at default priority.
1224 dev_info(&master->dev,
1225 "will run message pump with realtime priority\n");
1226 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
1233 * spi_get_next_queued_message() - called by driver to check for queued
1235 * @master: the master to check for queued messages
1237 * If there are more messages in the queue, the next message is returned from
1240 * Return: the next message in the queue, else NULL if the queue is empty.
1242 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1244 struct spi_message *next;
1245 unsigned long flags;
1247 /* get a pointer to the next message, if any */
1248 spin_lock_irqsave(&master->queue_lock, flags);
1249 next = list_first_entry_or_null(&master->queue, struct spi_message,
1251 spin_unlock_irqrestore(&master->queue_lock, flags);
1255 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1258 * spi_finalize_current_message() - the current message is complete
1259 * @master: the master to return the message to
1261 * Called by the driver to notify the core that the message in the front of the
1262 * queue is complete and can be removed from the queue.
1264 void spi_finalize_current_message(struct spi_master *master)
1266 struct spi_message *mesg;
1267 unsigned long flags;
1270 spin_lock_irqsave(&master->queue_lock, flags);
1271 mesg = master->cur_msg;
1272 spin_unlock_irqrestore(&master->queue_lock, flags);
1274 spi_unmap_msg(master, mesg);
1276 if (master->cur_msg_prepared && master->unprepare_message) {
1277 ret = master->unprepare_message(master, mesg);
1279 dev_err(&master->dev,
1280 "failed to unprepare message: %d\n", ret);
1284 spin_lock_irqsave(&master->queue_lock, flags);
1285 master->cur_msg = NULL;
1286 master->cur_msg_prepared = false;
1287 queue_kthread_work(&master->kworker, &master->pump_messages);
1288 spin_unlock_irqrestore(&master->queue_lock, flags);
1290 trace_spi_message_done(mesg);
1294 mesg->complete(mesg->context);
1296 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1298 static int spi_start_queue(struct spi_master *master)
1300 unsigned long flags;
1302 spin_lock_irqsave(&master->queue_lock, flags);
1304 if (master->running || master->busy) {
1305 spin_unlock_irqrestore(&master->queue_lock, flags);
1309 master->running = true;
1310 master->cur_msg = NULL;
1311 spin_unlock_irqrestore(&master->queue_lock, flags);
1313 queue_kthread_work(&master->kworker, &master->pump_messages);
1318 static int spi_stop_queue(struct spi_master *master)
1320 unsigned long flags;
1321 unsigned limit = 500;
1324 spin_lock_irqsave(&master->queue_lock, flags);
1327 * This is a bit lame, but is optimized for the common execution path.
1328 * A wait_queue on the master->busy could be used, but then the common
1329 * execution path (pump_messages) would be required to call wake_up or
1330 * friends on every SPI message. Do this instead.
1332 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1333 spin_unlock_irqrestore(&master->queue_lock, flags);
1334 usleep_range(10000, 11000);
1335 spin_lock_irqsave(&master->queue_lock, flags);
1338 if (!list_empty(&master->queue) || master->busy)
1341 master->running = false;
1343 spin_unlock_irqrestore(&master->queue_lock, flags);
1346 dev_warn(&master->dev,
1347 "could not stop message queue\n");
1353 static int spi_destroy_queue(struct spi_master *master)
1357 ret = spi_stop_queue(master);
1360 * flush_kthread_worker will block until all work is done.
1361 * If the reason that stop_queue timed out is that the work will never
1362 * finish, then it does no good to call flush/stop thread, so
1366 dev_err(&master->dev, "problem destroying queue\n");
1370 flush_kthread_worker(&master->kworker);
1371 kthread_stop(master->kworker_task);
1376 static int __spi_queued_transfer(struct spi_device *spi,
1377 struct spi_message *msg,
1380 struct spi_master *master = spi->master;
1381 unsigned long flags;
1383 spin_lock_irqsave(&master->queue_lock, flags);
1385 if (!master->running) {
1386 spin_unlock_irqrestore(&master->queue_lock, flags);
1389 msg->actual_length = 0;
1390 msg->status = -EINPROGRESS;
1392 list_add_tail(&msg->queue, &master->queue);
1393 if (!master->busy && need_pump)
1394 queue_kthread_work(&master->kworker, &master->pump_messages);
1396 spin_unlock_irqrestore(&master->queue_lock, flags);
1401 * spi_queued_transfer - transfer function for queued transfers
1402 * @spi: spi device which is requesting transfer
1403 * @msg: spi message which is to handled is queued to driver queue
1405 * Return: zero on success, else a negative error code.
1407 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1409 return __spi_queued_transfer(spi, msg, true);
1412 static int spi_master_initialize_queue(struct spi_master *master)
1416 master->transfer = spi_queued_transfer;
1417 if (!master->transfer_one_message)
1418 master->transfer_one_message = spi_transfer_one_message;
1420 /* Initialize and start queue */
1421 ret = spi_init_queue(master);
1423 dev_err(&master->dev, "problem initializing queue\n");
1424 goto err_init_queue;
1426 master->queued = true;
1427 ret = spi_start_queue(master);
1429 dev_err(&master->dev, "problem starting queue\n");
1430 goto err_start_queue;
1436 spi_destroy_queue(master);
1441 /*-------------------------------------------------------------------------*/
1443 #if defined(CONFIG_OF)
1444 static struct spi_device *
1445 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1447 struct spi_device *spi;
1451 /* Alloc an spi_device */
1452 spi = spi_alloc_device(master);
1454 dev_err(&master->dev, "spi_device alloc error for %s\n",
1460 /* Select device driver */
1461 rc = of_modalias_node(nc, spi->modalias,
1462 sizeof(spi->modalias));
1464 dev_err(&master->dev, "cannot find modalias for %s\n",
1469 /* Device address */
1470 rc = of_property_read_u32(nc, "reg", &value);
1472 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1476 spi->chip_select = value;
1478 /* Mode (clock phase/polarity/etc.) */
1479 if (of_find_property(nc, "spi-cpha", NULL))
1480 spi->mode |= SPI_CPHA;
1481 if (of_find_property(nc, "spi-cpol", NULL))
1482 spi->mode |= SPI_CPOL;
1483 if (of_find_property(nc, "spi-cs-high", NULL))
1484 spi->mode |= SPI_CS_HIGH;
1485 if (of_find_property(nc, "spi-3wire", NULL))
1486 spi->mode |= SPI_3WIRE;
1487 if (of_find_property(nc, "spi-lsb-first", NULL))
1488 spi->mode |= SPI_LSB_FIRST;
1490 /* Device DUAL/QUAD mode */
1491 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1496 spi->mode |= SPI_TX_DUAL;
1499 spi->mode |= SPI_TX_QUAD;
1502 dev_warn(&master->dev,
1503 "spi-tx-bus-width %d not supported\n",
1509 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1514 spi->mode |= SPI_RX_DUAL;
1517 spi->mode |= SPI_RX_QUAD;
1520 dev_warn(&master->dev,
1521 "spi-rx-bus-width %d not supported\n",
1528 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1530 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1534 spi->max_speed_hz = value;
1536 /* Store a pointer to the node in the device structure */
1538 spi->dev.of_node = nc;
1540 /* Register the new device */
1541 rc = spi_add_device(spi);
1543 dev_err(&master->dev, "spi_device register error %s\n",
1556 * of_register_spi_devices() - Register child devices onto the SPI bus
1557 * @master: Pointer to spi_master device
1559 * Registers an spi_device for each child node of master node which has a 'reg'
1562 static void of_register_spi_devices(struct spi_master *master)
1564 struct spi_device *spi;
1565 struct device_node *nc;
1567 if (!master->dev.of_node)
1570 for_each_available_child_of_node(master->dev.of_node, nc) {
1571 spi = of_register_spi_device(master, nc);
1573 dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1578 static void of_register_spi_devices(struct spi_master *master) { }
1582 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1584 struct spi_device *spi = data;
1586 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1587 struct acpi_resource_spi_serialbus *sb;
1589 sb = &ares->data.spi_serial_bus;
1590 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1591 spi->chip_select = sb->device_selection;
1592 spi->max_speed_hz = sb->connection_speed;
1594 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1595 spi->mode |= SPI_CPHA;
1596 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1597 spi->mode |= SPI_CPOL;
1598 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1599 spi->mode |= SPI_CS_HIGH;
1601 } else if (spi->irq < 0) {
1604 if (acpi_dev_resource_interrupt(ares, 0, &r))
1608 /* Always tell the ACPI core to skip this resource */
1612 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1613 void *data, void **return_value)
1615 struct spi_master *master = data;
1616 struct list_head resource_list;
1617 struct acpi_device *adev;
1618 struct spi_device *spi;
1621 if (acpi_bus_get_device(handle, &adev))
1623 if (acpi_bus_get_status(adev) || !adev->status.present)
1626 spi = spi_alloc_device(master);
1628 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1629 dev_name(&adev->dev));
1630 return AE_NO_MEMORY;
1633 ACPI_COMPANION_SET(&spi->dev, adev);
1636 INIT_LIST_HEAD(&resource_list);
1637 ret = acpi_dev_get_resources(adev, &resource_list,
1638 acpi_spi_add_resource, spi);
1639 acpi_dev_free_resource_list(&resource_list);
1641 if (ret < 0 || !spi->max_speed_hz) {
1646 adev->power.flags.ignore_parent = true;
1647 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1648 if (spi_add_device(spi)) {
1649 adev->power.flags.ignore_parent = false;
1650 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1651 dev_name(&adev->dev));
1658 static void acpi_register_spi_devices(struct spi_master *master)
1663 handle = ACPI_HANDLE(master->dev.parent);
1667 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1668 acpi_spi_add_device, NULL,
1670 if (ACPI_FAILURE(status))
1671 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1674 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1675 #endif /* CONFIG_ACPI */
1677 static void spi_master_release(struct device *dev)
1679 struct spi_master *master;
1681 master = container_of(dev, struct spi_master, dev);
1685 static struct class spi_master_class = {
1686 .name = "spi_master",
1687 .owner = THIS_MODULE,
1688 .dev_release = spi_master_release,
1689 .dev_groups = spi_master_groups,
1694 * spi_alloc_master - allocate SPI master controller
1695 * @dev: the controller, possibly using the platform_bus
1696 * @size: how much zeroed driver-private data to allocate; the pointer to this
1697 * memory is in the driver_data field of the returned device,
1698 * accessible with spi_master_get_devdata().
1699 * Context: can sleep
1701 * This call is used only by SPI master controller drivers, which are the
1702 * only ones directly touching chip registers. It's how they allocate
1703 * an spi_master structure, prior to calling spi_register_master().
1705 * This must be called from context that can sleep.
1707 * The caller is responsible for assigning the bus number and initializing
1708 * the master's methods before calling spi_register_master(); and (after errors
1709 * adding the device) calling spi_master_put() to prevent a memory leak.
1711 * Return: the SPI master structure on success, else NULL.
1713 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1715 struct spi_master *master;
1720 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1724 device_initialize(&master->dev);
1725 master->bus_num = -1;
1726 master->num_chipselect = 1;
1727 master->dev.class = &spi_master_class;
1728 master->dev.parent = dev;
1729 spi_master_set_devdata(master, &master[1]);
1733 EXPORT_SYMBOL_GPL(spi_alloc_master);
1735 static void devm_spi_release_master(struct device *dev, void *master)
1737 spi_master_put(*(struct spi_master **)master);
1741 * devm_spi_alloc_master - resource-managed spi_alloc_master()
1742 * @dev: physical device of SPI master
1743 * @size: how much zeroed driver-private data to allocate
1744 * Context: can sleep
1746 * Allocate an SPI master and automatically release a reference on it
1747 * when @dev is unbound from its driver. Drivers are thus relieved from
1748 * having to call spi_master_put().
1750 * The arguments to this function are identical to spi_alloc_master().
1752 * Return: the SPI master structure on success, else NULL.
1754 struct spi_master *devm_spi_alloc_master(struct device *dev, unsigned int size)
1756 struct spi_master **ptr, *master;
1758 ptr = devres_alloc(devm_spi_release_master, sizeof(*ptr),
1763 master = spi_alloc_master(dev, size);
1765 master->devm_allocated = true;
1767 devres_add(dev, ptr);
1774 EXPORT_SYMBOL_GPL(devm_spi_alloc_master);
1777 static int of_spi_register_master(struct spi_master *master)
1780 struct device_node *np = master->dev.of_node;
1785 nb = of_gpio_named_count(np, "cs-gpios");
1786 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1788 /* Return error only for an incorrectly formed cs-gpios property */
1789 if (nb == 0 || nb == -ENOENT)
1794 cs = devm_kzalloc(&master->dev,
1795 sizeof(int) * master->num_chipselect,
1797 master->cs_gpios = cs;
1799 if (!master->cs_gpios)
1802 for (i = 0; i < master->num_chipselect; i++)
1805 for (i = 0; i < nb; i++)
1806 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1811 static int of_spi_register_master(struct spi_master *master)
1818 * spi_register_master - register SPI master controller
1819 * @master: initialized master, originally from spi_alloc_master()
1820 * Context: can sleep
1822 * SPI master controllers connect to their drivers using some non-SPI bus,
1823 * such as the platform bus. The final stage of probe() in that code
1824 * includes calling spi_register_master() to hook up to this SPI bus glue.
1826 * SPI controllers use board specific (often SOC specific) bus numbers,
1827 * and board-specific addressing for SPI devices combines those numbers
1828 * with chip select numbers. Since SPI does not directly support dynamic
1829 * device identification, boards need configuration tables telling which
1830 * chip is at which address.
1832 * This must be called from context that can sleep. It returns zero on
1833 * success, else a negative error code (dropping the master's refcount).
1834 * After a successful return, the caller is responsible for calling
1835 * spi_unregister_master().
1837 * Return: zero on success, else a negative error code.
1839 int spi_register_master(struct spi_master *master)
1841 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1842 struct device *dev = master->dev.parent;
1843 struct boardinfo *bi;
1844 int status = -ENODEV;
1850 status = of_spi_register_master(master);
1854 /* even if it's just one always-selected device, there must
1855 * be at least one chipselect
1857 if (master->num_chipselect == 0)
1860 if ((master->bus_num < 0) && master->dev.of_node)
1861 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1863 /* convention: dynamically assigned bus IDs count down from the max */
1864 if (master->bus_num < 0) {
1865 /* FIXME switch to an IDR based scheme, something like
1866 * I2C now uses, so we can't run out of "dynamic" IDs
1868 master->bus_num = atomic_dec_return(&dyn_bus_id);
1872 INIT_LIST_HEAD(&master->queue);
1873 spin_lock_init(&master->queue_lock);
1874 spin_lock_init(&master->bus_lock_spinlock);
1875 mutex_init(&master->bus_lock_mutex);
1876 master->bus_lock_flag = 0;
1877 init_completion(&master->xfer_completion);
1878 if (!master->max_dma_len)
1879 master->max_dma_len = INT_MAX;
1881 /* register the device, then userspace will see it.
1882 * registration fails if the bus ID is in use.
1884 dev_set_name(&master->dev, "spi%u", master->bus_num);
1885 status = device_add(&master->dev);
1888 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1889 dynamic ? " (dynamic)" : "");
1891 /* If we're using a queued driver, start the queue */
1892 if (master->transfer)
1893 dev_info(dev, "master is unqueued, this is deprecated\n");
1895 status = spi_master_initialize_queue(master);
1897 device_del(&master->dev);
1901 /* add statistics */
1902 spin_lock_init(&master->statistics.lock);
1904 mutex_lock(&board_lock);
1905 list_add_tail(&master->list, &spi_master_list);
1906 list_for_each_entry(bi, &board_list, list)
1907 spi_match_master_to_boardinfo(master, &bi->board_info);
1908 mutex_unlock(&board_lock);
1910 /* Register devices from the device tree and ACPI */
1911 of_register_spi_devices(master);
1912 acpi_register_spi_devices(master);
1916 EXPORT_SYMBOL_GPL(spi_register_master);
1918 static void devm_spi_unregister(struct device *dev, void *res)
1920 spi_unregister_master(*(struct spi_master **)res);
1924 * dev_spi_register_master - register managed SPI master controller
1925 * @dev: device managing SPI master
1926 * @master: initialized master, originally from spi_alloc_master()
1927 * Context: can sleep
1929 * Register a SPI device as with spi_register_master() which will
1930 * automatically be unregister
1932 * Return: zero on success, else a negative error code.
1934 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1936 struct spi_master **ptr;
1939 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1943 ret = spi_register_master(master);
1946 devres_add(dev, ptr);
1953 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1955 static int __unregister(struct device *dev, void *null)
1957 spi_unregister_device(to_spi_device(dev));
1962 * spi_unregister_master - unregister SPI master controller
1963 * @master: the master being unregistered
1964 * Context: can sleep
1966 * This call is used only by SPI master controller drivers, which are the
1967 * only ones directly touching chip registers.
1969 * This must be called from context that can sleep.
1971 void spi_unregister_master(struct spi_master *master)
1973 /* Prevent addition of new devices, unregister existing ones */
1974 if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
1975 mutex_lock(&spi_add_lock);
1977 device_for_each_child(&master->dev, NULL, __unregister);
1979 if (master->queued) {
1980 if (spi_destroy_queue(master))
1981 dev_err(&master->dev, "queue remove failed\n");
1984 mutex_lock(&board_lock);
1985 list_del(&master->list);
1986 mutex_unlock(&board_lock);
1988 device_del(&master->dev);
1990 /* Release the last reference on the master if its driver
1991 * has not yet been converted to devm_spi_alloc_master().
1993 if (!master->devm_allocated)
1994 put_device(&master->dev);
1996 if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
1997 mutex_unlock(&spi_add_lock);
1999 EXPORT_SYMBOL_GPL(spi_unregister_master);
2001 int spi_master_suspend(struct spi_master *master)
2005 /* Basically no-ops for non-queued masters */
2006 if (!master->queued)
2009 ret = spi_stop_queue(master);
2011 dev_err(&master->dev, "queue stop failed\n");
2015 EXPORT_SYMBOL_GPL(spi_master_suspend);
2017 int spi_master_resume(struct spi_master *master)
2021 if (!master->queued)
2024 ret = spi_start_queue(master);
2026 dev_err(&master->dev, "queue restart failed\n");
2030 EXPORT_SYMBOL_GPL(spi_master_resume);
2032 static int __spi_master_match(struct device *dev, const void *data)
2034 struct spi_master *m;
2035 const u16 *bus_num = data;
2037 m = container_of(dev, struct spi_master, dev);
2038 return m->bus_num == *bus_num;
2042 * spi_busnum_to_master - look up master associated with bus_num
2043 * @bus_num: the master's bus number
2044 * Context: can sleep
2046 * This call may be used with devices that are registered after
2047 * arch init time. It returns a refcounted pointer to the relevant
2048 * spi_master (which the caller must release), or NULL if there is
2049 * no such master registered.
2051 * Return: the SPI master structure on success, else NULL.
2053 struct spi_master *spi_busnum_to_master(u16 bus_num)
2056 struct spi_master *master = NULL;
2058 dev = class_find_device(&spi_master_class, NULL, &bus_num,
2059 __spi_master_match);
2061 master = container_of(dev, struct spi_master, dev);
2062 /* reference got in class_find_device */
2065 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2068 /*-------------------------------------------------------------------------*/
2070 /* Core methods for SPI master protocol drivers. Some of the
2071 * other core methods are currently defined as inline functions.
2074 static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2076 if (master->bits_per_word_mask) {
2077 /* Only 32 bits fit in the mask */
2078 if (bits_per_word > 32)
2080 if (!(master->bits_per_word_mask &
2081 SPI_BPW_MASK(bits_per_word)))
2089 * spi_setup - setup SPI mode and clock rate
2090 * @spi: the device whose settings are being modified
2091 * Context: can sleep, and no requests are queued to the device
2093 * SPI protocol drivers may need to update the transfer mode if the
2094 * device doesn't work with its default. They may likewise need
2095 * to update clock rates or word sizes from initial values. This function
2096 * changes those settings, and must be called from a context that can sleep.
2097 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2098 * effect the next time the device is selected and data is transferred to
2099 * or from it. When this function returns, the spi device is deselected.
2101 * Note that this call will fail if the protocol driver specifies an option
2102 * that the underlying controller or its driver does not support. For
2103 * example, not all hardware supports wire transfers using nine bit words,
2104 * LSB-first wire encoding, or active-high chipselects.
2106 * Return: zero on success, else a negative error code.
2108 int spi_setup(struct spi_device *spi)
2110 unsigned bad_bits, ugly_bits;
2113 /* check mode to prevent that DUAL and QUAD set at the same time
2115 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2116 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2118 "setup: can not select dual and quad at the same time\n");
2121 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2123 if ((spi->mode & SPI_3WIRE) && (spi->mode &
2124 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2126 /* help drivers fail *cleanly* when they need options
2127 * that aren't supported with their current master
2129 bad_bits = spi->mode & ~spi->master->mode_bits;
2130 ugly_bits = bad_bits &
2131 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2134 "setup: ignoring unsupported mode bits %x\n",
2136 spi->mode &= ~ugly_bits;
2137 bad_bits &= ~ugly_bits;
2140 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2145 if (!spi->bits_per_word)
2146 spi->bits_per_word = 8;
2148 status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2152 if (!spi->max_speed_hz)
2153 spi->max_speed_hz = spi->master->max_speed_hz;
2155 if (spi->master->setup)
2156 status = spi->master->setup(spi);
2158 spi_set_cs(spi, false);
2160 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2161 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2162 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2163 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2164 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2165 (spi->mode & SPI_LOOP) ? "loopback, " : "",
2166 spi->bits_per_word, spi->max_speed_hz,
2171 EXPORT_SYMBOL_GPL(spi_setup);
2173 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2175 struct spi_master *master = spi->master;
2176 struct spi_transfer *xfer;
2179 if (list_empty(&message->transfers))
2182 /* Half-duplex links include original MicroWire, and ones with
2183 * only one data pin like SPI_3WIRE (switches direction) or where
2184 * either MOSI or MISO is missing. They can also be caused by
2185 * software limitations.
2187 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2188 || (spi->mode & SPI_3WIRE)) {
2189 unsigned flags = master->flags;
2191 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2192 if (xfer->rx_buf && xfer->tx_buf)
2194 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2196 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2202 * Set transfer bits_per_word and max speed as spi device default if
2203 * it is not set for this transfer.
2204 * Set transfer tx_nbits and rx_nbits as single transfer default
2205 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2207 message->frame_length = 0;
2208 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2209 message->frame_length += xfer->len;
2210 if (!xfer->bits_per_word)
2211 xfer->bits_per_word = spi->bits_per_word;
2213 if (!xfer->speed_hz)
2214 xfer->speed_hz = spi->max_speed_hz;
2215 if (!xfer->speed_hz)
2216 xfer->speed_hz = master->max_speed_hz;
2218 if (master->max_speed_hz &&
2219 xfer->speed_hz > master->max_speed_hz)
2220 xfer->speed_hz = master->max_speed_hz;
2222 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2226 * SPI transfer length should be multiple of SPI word size
2227 * where SPI word size should be power-of-two multiple
2229 if (xfer->bits_per_word <= 8)
2231 else if (xfer->bits_per_word <= 16)
2236 /* No partial transfers accepted */
2237 if (xfer->len % w_size)
2240 if (xfer->speed_hz && master->min_speed_hz &&
2241 xfer->speed_hz < master->min_speed_hz)
2244 if (xfer->tx_buf && !xfer->tx_nbits)
2245 xfer->tx_nbits = SPI_NBITS_SINGLE;
2246 if (xfer->rx_buf && !xfer->rx_nbits)
2247 xfer->rx_nbits = SPI_NBITS_SINGLE;
2248 /* check transfer tx/rx_nbits:
2249 * 1. check the value matches one of single, dual and quad
2250 * 2. check tx/rx_nbits match the mode in spi_device
2253 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2254 xfer->tx_nbits != SPI_NBITS_DUAL &&
2255 xfer->tx_nbits != SPI_NBITS_QUAD)
2257 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2258 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2260 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2261 !(spi->mode & SPI_TX_QUAD))
2264 /* check transfer rx_nbits */
2266 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2267 xfer->rx_nbits != SPI_NBITS_DUAL &&
2268 xfer->rx_nbits != SPI_NBITS_QUAD)
2270 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2271 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2273 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2274 !(spi->mode & SPI_RX_QUAD))
2279 message->status = -EINPROGRESS;
2284 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2286 struct spi_master *master = spi->master;
2290 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2291 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2293 trace_spi_message_submit(message);
2295 return master->transfer(spi, message);
2299 * spi_async - asynchronous SPI transfer
2300 * @spi: device with which data will be exchanged
2301 * @message: describes the data transfers, including completion callback
2302 * Context: any (irqs may be blocked, etc)
2304 * This call may be used in_irq and other contexts which can't sleep,
2305 * as well as from task contexts which can sleep.
2307 * The completion callback is invoked in a context which can't sleep.
2308 * Before that invocation, the value of message->status is undefined.
2309 * When the callback is issued, message->status holds either zero (to
2310 * indicate complete success) or a negative error code. After that
2311 * callback returns, the driver which issued the transfer request may
2312 * deallocate the associated memory; it's no longer in use by any SPI
2313 * core or controller driver code.
2315 * Note that although all messages to a spi_device are handled in
2316 * FIFO order, messages may go to different devices in other orders.
2317 * Some device might be higher priority, or have various "hard" access
2318 * time requirements, for example.
2320 * On detection of any fault during the transfer, processing of
2321 * the entire message is aborted, and the device is deselected.
2322 * Until returning from the associated message completion callback,
2323 * no other spi_message queued to that device will be processed.
2324 * (This rule applies equally to all the synchronous transfer calls,
2325 * which are wrappers around this core asynchronous primitive.)
2327 * Return: zero on success, else a negative error code.
2329 int spi_async(struct spi_device *spi, struct spi_message *message)
2331 struct spi_master *master = spi->master;
2333 unsigned long flags;
2335 ret = __spi_validate(spi, message);
2339 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2341 if (master->bus_lock_flag)
2344 ret = __spi_async(spi, message);
2346 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2350 EXPORT_SYMBOL_GPL(spi_async);
2353 * spi_async_locked - version of spi_async with exclusive bus usage
2354 * @spi: device with which data will be exchanged
2355 * @message: describes the data transfers, including completion callback
2356 * Context: any (irqs may be blocked, etc)
2358 * This call may be used in_irq and other contexts which can't sleep,
2359 * as well as from task contexts which can sleep.
2361 * The completion callback is invoked in a context which can't sleep.
2362 * Before that invocation, the value of message->status is undefined.
2363 * When the callback is issued, message->status holds either zero (to
2364 * indicate complete success) or a negative error code. After that
2365 * callback returns, the driver which issued the transfer request may
2366 * deallocate the associated memory; it's no longer in use by any SPI
2367 * core or controller driver code.
2369 * Note that although all messages to a spi_device are handled in
2370 * FIFO order, messages may go to different devices in other orders.
2371 * Some device might be higher priority, or have various "hard" access
2372 * time requirements, for example.
2374 * On detection of any fault during the transfer, processing of
2375 * the entire message is aborted, and the device is deselected.
2376 * Until returning from the associated message completion callback,
2377 * no other spi_message queued to that device will be processed.
2378 * (This rule applies equally to all the synchronous transfer calls,
2379 * which are wrappers around this core asynchronous primitive.)
2381 * Return: zero on success, else a negative error code.
2383 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2385 struct spi_master *master = spi->master;
2387 unsigned long flags;
2389 ret = __spi_validate(spi, message);
2393 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2395 ret = __spi_async(spi, message);
2397 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2402 EXPORT_SYMBOL_GPL(spi_async_locked);
2405 /*-------------------------------------------------------------------------*/
2407 /* Utility methods for SPI master protocol drivers, layered on
2408 * top of the core. Some other utility methods are defined as
2412 static void spi_complete(void *arg)
2417 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2420 DECLARE_COMPLETION_ONSTACK(done);
2422 struct spi_master *master = spi->master;
2423 unsigned long flags;
2425 status = __spi_validate(spi, message);
2429 message->complete = spi_complete;
2430 message->context = &done;
2433 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2434 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2437 mutex_lock(&master->bus_lock_mutex);
2439 /* If we're not using the legacy transfer method then we will
2440 * try to transfer in the calling context so special case.
2441 * This code would be less tricky if we could remove the
2442 * support for driver implemented message queues.
2444 if (master->transfer == spi_queued_transfer) {
2445 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2447 trace_spi_message_submit(message);
2449 status = __spi_queued_transfer(spi, message, false);
2451 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2453 status = spi_async_locked(spi, message);
2457 mutex_unlock(&master->bus_lock_mutex);
2460 /* Push out the messages in the calling context if we
2463 if (master->transfer == spi_queued_transfer) {
2464 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2465 spi_sync_immediate);
2466 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2467 spi_sync_immediate);
2468 __spi_pump_messages(master, false);
2471 wait_for_completion(&done);
2472 status = message->status;
2474 message->context = NULL;
2479 * spi_sync - blocking/synchronous SPI data transfers
2480 * @spi: device with which data will be exchanged
2481 * @message: describes the data transfers
2482 * Context: can sleep
2484 * This call may only be used from a context that may sleep. The sleep
2485 * is non-interruptible, and has no timeout. Low-overhead controller
2486 * drivers may DMA directly into and out of the message buffers.
2488 * Note that the SPI device's chip select is active during the message,
2489 * and then is normally disabled between messages. Drivers for some
2490 * frequently-used devices may want to minimize costs of selecting a chip,
2491 * by leaving it selected in anticipation that the next message will go
2492 * to the same chip. (That may increase power usage.)
2494 * Also, the caller is guaranteeing that the memory associated with the
2495 * message will not be freed before this call returns.
2497 * Return: zero on success, else a negative error code.
2499 int spi_sync(struct spi_device *spi, struct spi_message *message)
2501 return __spi_sync(spi, message, 0);
2503 EXPORT_SYMBOL_GPL(spi_sync);
2506 * spi_sync_locked - version of spi_sync with exclusive bus usage
2507 * @spi: device with which data will be exchanged
2508 * @message: describes the data transfers
2509 * Context: can sleep
2511 * This call may only be used from a context that may sleep. The sleep
2512 * is non-interruptible, and has no timeout. Low-overhead controller
2513 * drivers may DMA directly into and out of the message buffers.
2515 * This call should be used by drivers that require exclusive access to the
2516 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2517 * be released by a spi_bus_unlock call when the exclusive access is over.
2519 * Return: zero on success, else a negative error code.
2521 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2523 return __spi_sync(spi, message, 1);
2525 EXPORT_SYMBOL_GPL(spi_sync_locked);
2528 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2529 * @master: SPI bus master that should be locked for exclusive bus access
2530 * Context: can sleep
2532 * This call may only be used from a context that may sleep. The sleep
2533 * is non-interruptible, and has no timeout.
2535 * This call should be used by drivers that require exclusive access to the
2536 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2537 * exclusive access is over. Data transfer must be done by spi_sync_locked
2538 * and spi_async_locked calls when the SPI bus lock is held.
2540 * Return: always zero.
2542 int spi_bus_lock(struct spi_master *master)
2544 unsigned long flags;
2546 mutex_lock(&master->bus_lock_mutex);
2548 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2549 master->bus_lock_flag = 1;
2550 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2552 /* mutex remains locked until spi_bus_unlock is called */
2556 EXPORT_SYMBOL_GPL(spi_bus_lock);
2559 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2560 * @master: SPI bus master that was locked for exclusive bus access
2561 * Context: can sleep
2563 * This call may only be used from a context that may sleep. The sleep
2564 * is non-interruptible, and has no timeout.
2566 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2569 * Return: always zero.
2571 int spi_bus_unlock(struct spi_master *master)
2573 master->bus_lock_flag = 0;
2575 mutex_unlock(&master->bus_lock_mutex);
2579 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2581 /* portable code must never pass more than 32 bytes */
2582 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2587 * spi_write_then_read - SPI synchronous write followed by read
2588 * @spi: device with which data will be exchanged
2589 * @txbuf: data to be written (need not be dma-safe)
2590 * @n_tx: size of txbuf, in bytes
2591 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2592 * @n_rx: size of rxbuf, in bytes
2593 * Context: can sleep
2595 * This performs a half duplex MicroWire style transaction with the
2596 * device, sending txbuf and then reading rxbuf. The return value
2597 * is zero for success, else a negative errno status code.
2598 * This call may only be used from a context that may sleep.
2600 * Parameters to this routine are always copied using a small buffer;
2601 * portable code should never use this for more than 32 bytes.
2602 * Performance-sensitive or bulk transfer code should instead use
2603 * spi_{async,sync}() calls with dma-safe buffers.
2605 * Return: zero on success, else a negative error code.
2607 int spi_write_then_read(struct spi_device *spi,
2608 const void *txbuf, unsigned n_tx,
2609 void *rxbuf, unsigned n_rx)
2611 static DEFINE_MUTEX(lock);
2614 struct spi_message message;
2615 struct spi_transfer x[2];
2618 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2619 * copying here, (as a pure convenience thing), but we can
2620 * keep heap costs out of the hot path unless someone else is
2621 * using the pre-allocated buffer or the transfer is too large.
2623 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2624 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2625 GFP_KERNEL | GFP_DMA);
2632 spi_message_init(&message);
2633 memset(x, 0, sizeof(x));
2636 spi_message_add_tail(&x[0], &message);
2640 spi_message_add_tail(&x[1], &message);
2643 memcpy(local_buf, txbuf, n_tx);
2644 x[0].tx_buf = local_buf;
2645 x[1].rx_buf = local_buf + n_tx;
2648 status = spi_sync(spi, &message);
2650 memcpy(rxbuf, x[1].rx_buf, n_rx);
2652 if (x[0].tx_buf == buf)
2653 mutex_unlock(&lock);
2659 EXPORT_SYMBOL_GPL(spi_write_then_read);
2661 /*-------------------------------------------------------------------------*/
2663 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
2664 static int __spi_of_device_match(struct device *dev, void *data)
2666 return dev->of_node == data;
2669 /* must call put_device() when done with returned spi_device device */
2670 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
2672 struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
2673 __spi_of_device_match);
2674 return dev ? to_spi_device(dev) : NULL;
2677 static int __spi_of_master_match(struct device *dev, const void *data)
2679 return dev->of_node == data;
2682 /* the spi masters are not using spi_bus, so we find it with another way */
2683 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
2687 dev = class_find_device(&spi_master_class, NULL, node,
2688 __spi_of_master_match);
2692 /* reference got in class_find_device */
2693 return container_of(dev, struct spi_master, dev);
2696 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
2699 struct of_reconfig_data *rd = arg;
2700 struct spi_master *master;
2701 struct spi_device *spi;
2703 switch (of_reconfig_get_state_change(action, arg)) {
2704 case OF_RECONFIG_CHANGE_ADD:
2705 master = of_find_spi_master_by_node(rd->dn->parent);
2707 return NOTIFY_OK; /* not for us */
2709 spi = of_register_spi_device(master, rd->dn);
2710 put_device(&master->dev);
2713 pr_err("%s: failed to create for '%s'\n",
2714 __func__, rd->dn->full_name);
2715 return notifier_from_errno(PTR_ERR(spi));
2719 case OF_RECONFIG_CHANGE_REMOVE:
2720 /* find our device by node */
2721 spi = of_find_spi_device_by_node(rd->dn);
2723 return NOTIFY_OK; /* no? not meant for us */
2725 /* unregister takes one ref away */
2726 spi_unregister_device(spi);
2728 /* and put the reference of the find */
2729 put_device(&spi->dev);
2736 static struct notifier_block spi_of_notifier = {
2737 .notifier_call = of_spi_notify,
2739 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2740 extern struct notifier_block spi_of_notifier;
2741 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2743 static int __init spi_init(void)
2747 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2753 status = bus_register(&spi_bus_type);
2757 status = class_register(&spi_master_class);
2761 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2762 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
2767 bus_unregister(&spi_bus_type);
2775 /* board_info is normally registered in arch_initcall(),
2776 * but even essential drivers wait till later
2778 * REVISIT only boardinfo really needs static linking. the rest (device and
2779 * driver registration) _could_ be dynamically linked (modular) ... costs
2780 * include needing to have boardinfo data structures be much more public.
2782 postcore_initcall(spi_init);