1 // SPDX-License-Identifier: GPL-2.0-only
5 // Copyright (C) 2019-2020 Glider bv
7 #define DRV_NAME "gpio-aggregator"
8 #define pr_fmt(fmt) DRV_NAME ": " fmt
10 #include <linux/bitmap.h>
11 #include <linux/bitops.h>
12 #include <linux/ctype.h>
13 #include <linux/gpio.h>
14 #include <linux/gpio/consumer.h>
15 #include <linux/gpio/driver.h>
16 #include <linux/gpio/machine.h>
17 #include <linux/idr.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/mutex.h>
21 #include <linux/overflow.h>
22 #include <linux/platform_device.h>
23 #include <linux/spinlock.h>
24 #include <linux/string.h>
28 * GPIO Aggregator sysfs interface
31 struct gpio_aggregator {
32 struct gpiod_lookup_table *lookups;
33 struct platform_device *pdev;
37 static DEFINE_MUTEX(gpio_aggregator_lock); /* protects idr */
38 static DEFINE_IDR(gpio_aggregator_idr);
40 static char *get_arg(char **args)
44 start = skip_spaces(*args);
50 end = strchr(++start, '"');
52 return ERR_PTR(-EINVAL);
55 for (end = start; *end && !isspace(*end); end++) ;
65 static bool isrange(const char *s)
69 if (IS_ERR_OR_NULL(s))
73 n = strspn(s, "0123456789");
93 static int aggr_add_gpio(struct gpio_aggregator *aggr, const char *key,
94 int hwnum, unsigned int *n)
96 struct gpiod_lookup_table *lookups;
98 lookups = krealloc(aggr->lookups, struct_size(lookups, table, *n + 2),
104 (struct gpiod_lookup)GPIO_LOOKUP_IDX(key, hwnum, NULL, *n, 0);
107 memset(&lookups->table[*n], 0, sizeof(lookups->table[*n]));
109 aggr->lookups = lookups;
113 static int aggr_parse(struct gpio_aggregator *aggr)
115 char *args = aggr->args;
116 unsigned long *bitmap;
117 unsigned int i, n = 0;
118 char *name, *offsets;
121 bitmap = bitmap_alloc(ARCH_NR_GPIOS, GFP_KERNEL);
125 for (name = get_arg(&args), offsets = get_arg(&args); name;
126 offsets = get_arg(&args)) {
128 pr_err("Cannot get GPIO specifier: %pe\n", name);
129 error = PTR_ERR(name);
133 if (!isrange(offsets)) {
134 /* Named GPIO line */
135 error = aggr_add_gpio(aggr, name, U16_MAX, &n);
143 /* GPIO chip + offset(s) */
144 error = bitmap_parselist(offsets, bitmap, ARCH_NR_GPIOS);
146 pr_err("Cannot parse %s: %d\n", offsets, error);
150 for_each_set_bit(i, bitmap, ARCH_NR_GPIOS) {
151 error = aggr_add_gpio(aggr, name, i, &n);
156 name = get_arg(&args);
160 pr_err("No GPIOs specified\n");
169 static ssize_t new_device_store(struct device_driver *driver, const char *buf,
172 struct gpio_aggregator *aggr;
173 struct platform_device *pdev;
176 /* kernfs guarantees string termination, so count + 1 is safe */
177 aggr = kzalloc(sizeof(*aggr) + count + 1, GFP_KERNEL);
181 memcpy(aggr->args, buf, count + 1);
183 aggr->lookups = kzalloc(struct_size(aggr->lookups, table, 1),
185 if (!aggr->lookups) {
190 mutex_lock(&gpio_aggregator_lock);
191 id = idr_alloc(&gpio_aggregator_idr, aggr, 0, 0, GFP_KERNEL);
192 mutex_unlock(&gpio_aggregator_lock);
199 aggr->lookups->dev_id = kasprintf(GFP_KERNEL, "%s.%d", DRV_NAME, id);
200 if (!aggr->lookups->dev_id) {
205 res = aggr_parse(aggr);
209 gpiod_add_lookup_table(aggr->lookups);
211 pdev = platform_device_register_simple(DRV_NAME, id, NULL, 0);
221 gpiod_remove_lookup_table(aggr->lookups);
223 kfree(aggr->lookups->dev_id);
225 mutex_lock(&gpio_aggregator_lock);
226 idr_remove(&gpio_aggregator_idr, id);
227 mutex_unlock(&gpio_aggregator_lock);
229 kfree(aggr->lookups);
235 static DRIVER_ATTR_WO(new_device);
237 static void gpio_aggregator_free(struct gpio_aggregator *aggr)
239 platform_device_unregister(aggr->pdev);
240 gpiod_remove_lookup_table(aggr->lookups);
241 kfree(aggr->lookups->dev_id);
242 kfree(aggr->lookups);
246 static ssize_t delete_device_store(struct device_driver *driver,
247 const char *buf, size_t count)
249 struct gpio_aggregator *aggr;
253 if (!str_has_prefix(buf, DRV_NAME "."))
256 error = kstrtouint(buf + strlen(DRV_NAME "."), 10, &id);
260 mutex_lock(&gpio_aggregator_lock);
261 aggr = idr_remove(&gpio_aggregator_idr, id);
262 mutex_unlock(&gpio_aggregator_lock);
266 gpio_aggregator_free(aggr);
269 static DRIVER_ATTR_WO(delete_device);
271 static struct attribute *gpio_aggregator_attrs[] = {
272 &driver_attr_new_device.attr,
273 &driver_attr_delete_device.attr,
276 ATTRIBUTE_GROUPS(gpio_aggregator);
278 static int __exit gpio_aggregator_idr_remove(int id, void *p, void *data)
280 gpio_aggregator_free(p);
284 static void __exit gpio_aggregator_remove_all(void)
286 mutex_lock(&gpio_aggregator_lock);
287 idr_for_each(&gpio_aggregator_idr, gpio_aggregator_idr_remove, NULL);
288 idr_destroy(&gpio_aggregator_idr);
289 mutex_unlock(&gpio_aggregator_lock);
297 struct gpiochip_fwd {
298 struct gpio_chip chip;
299 struct gpio_desc **descs;
301 struct mutex mlock; /* protects tmp[] if can_sleep */
302 spinlock_t slock; /* protects tmp[] if !can_sleep */
304 unsigned long tmp[]; /* values and descs for multiple ops */
307 static int gpio_fwd_get_direction(struct gpio_chip *chip, unsigned int offset)
309 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
311 return gpiod_get_direction(fwd->descs[offset]);
314 static int gpio_fwd_direction_input(struct gpio_chip *chip, unsigned int offset)
316 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
318 return gpiod_direction_input(fwd->descs[offset]);
321 static int gpio_fwd_direction_output(struct gpio_chip *chip,
322 unsigned int offset, int value)
324 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
326 return gpiod_direction_output(fwd->descs[offset], value);
329 static int gpio_fwd_get(struct gpio_chip *chip, unsigned int offset)
331 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
333 return chip->can_sleep ? gpiod_get_value_cansleep(fwd->descs[offset])
334 : gpiod_get_value(fwd->descs[offset]);
337 static int gpio_fwd_get_multiple(struct gpiochip_fwd *fwd, unsigned long *mask,
340 struct gpio_desc **descs;
341 unsigned long *values;
342 unsigned int i, j = 0;
345 /* Both values bitmap and desc pointers are stored in tmp[] */
346 values = &fwd->tmp[0];
347 descs = (void *)&fwd->tmp[BITS_TO_LONGS(fwd->chip.ngpio)];
349 bitmap_clear(values, 0, fwd->chip.ngpio);
350 for_each_set_bit(i, mask, fwd->chip.ngpio)
351 descs[j++] = fwd->descs[i];
353 if (fwd->chip.can_sleep)
354 error = gpiod_get_array_value_cansleep(j, descs, NULL, values);
356 error = gpiod_get_array_value(j, descs, NULL, values);
361 for_each_set_bit(i, mask, fwd->chip.ngpio)
362 __assign_bit(i, bits, test_bit(j++, values));
367 static int gpio_fwd_get_multiple_locked(struct gpio_chip *chip,
368 unsigned long *mask, unsigned long *bits)
370 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
374 if (chip->can_sleep) {
375 mutex_lock(&fwd->mlock);
376 error = gpio_fwd_get_multiple(fwd, mask, bits);
377 mutex_unlock(&fwd->mlock);
379 spin_lock_irqsave(&fwd->slock, flags);
380 error = gpio_fwd_get_multiple(fwd, mask, bits);
381 spin_unlock_irqrestore(&fwd->slock, flags);
387 static void gpio_fwd_set(struct gpio_chip *chip, unsigned int offset, int value)
389 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
392 gpiod_set_value_cansleep(fwd->descs[offset], value);
394 gpiod_set_value(fwd->descs[offset], value);
397 static void gpio_fwd_set_multiple(struct gpiochip_fwd *fwd, unsigned long *mask,
400 struct gpio_desc **descs;
401 unsigned long *values;
402 unsigned int i, j = 0;
404 /* Both values bitmap and desc pointers are stored in tmp[] */
405 values = &fwd->tmp[0];
406 descs = (void *)&fwd->tmp[BITS_TO_LONGS(fwd->chip.ngpio)];
408 for_each_set_bit(i, mask, fwd->chip.ngpio) {
409 __assign_bit(j, values, test_bit(i, bits));
410 descs[j++] = fwd->descs[i];
413 if (fwd->chip.can_sleep)
414 gpiod_set_array_value_cansleep(j, descs, NULL, values);
416 gpiod_set_array_value(j, descs, NULL, values);
419 static void gpio_fwd_set_multiple_locked(struct gpio_chip *chip,
420 unsigned long *mask, unsigned long *bits)
422 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
425 if (chip->can_sleep) {
426 mutex_lock(&fwd->mlock);
427 gpio_fwd_set_multiple(fwd, mask, bits);
428 mutex_unlock(&fwd->mlock);
430 spin_lock_irqsave(&fwd->slock, flags);
431 gpio_fwd_set_multiple(fwd, mask, bits);
432 spin_unlock_irqrestore(&fwd->slock, flags);
436 static int gpio_fwd_set_config(struct gpio_chip *chip, unsigned int offset,
437 unsigned long config)
439 struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
441 return gpiod_set_config(fwd->descs[offset], config);
445 * gpiochip_fwd_create() - Create a new GPIO forwarder
446 * @dev: Parent device pointer
447 * @ngpios: Number of GPIOs in the forwarder.
448 * @descs: Array containing the GPIO descriptors to forward to.
449 * This array must contain @ngpios entries, and must not be deallocated
450 * before the forwarder has been destroyed again.
452 * This function creates a new gpiochip, which forwards all GPIO operations to
453 * the passed GPIO descriptors.
455 * Return: An opaque object pointer, or an ERR_PTR()-encoded negative error
458 static struct gpiochip_fwd *gpiochip_fwd_create(struct device *dev,
460 struct gpio_desc *descs[])
462 const char *label = dev_name(dev);
463 struct gpiochip_fwd *fwd;
464 struct gpio_chip *chip;
468 fwd = devm_kzalloc(dev, struct_size(fwd, tmp,
469 BITS_TO_LONGS(ngpios) + ngpios), GFP_KERNEL);
471 return ERR_PTR(-ENOMEM);
476 * If any of the GPIO lines are sleeping, then the entire forwarder
478 * If any of the chips support .set_config(), then the forwarder will
479 * support setting configs.
481 for (i = 0; i < ngpios; i++) {
482 struct gpio_chip *parent = gpiod_to_chip(descs[i]);
484 dev_dbg(dev, "%u => gpio-%d\n", i, desc_to_gpio(descs[i]));
486 if (gpiod_cansleep(descs[i]))
487 chip->can_sleep = true;
488 if (parent && parent->set_config)
489 chip->set_config = gpio_fwd_set_config;
494 chip->owner = THIS_MODULE;
495 chip->get_direction = gpio_fwd_get_direction;
496 chip->direction_input = gpio_fwd_direction_input;
497 chip->direction_output = gpio_fwd_direction_output;
498 chip->get = gpio_fwd_get;
499 chip->get_multiple = gpio_fwd_get_multiple_locked;
500 chip->set = gpio_fwd_set;
501 chip->set_multiple = gpio_fwd_set_multiple_locked;
503 chip->ngpio = ngpios;
507 mutex_init(&fwd->mlock);
509 spin_lock_init(&fwd->slock);
511 error = devm_gpiochip_add_data(dev, chip, fwd);
513 return ERR_PTR(error);
520 * GPIO Aggregator platform device
523 static int gpio_aggregator_probe(struct platform_device *pdev)
525 struct device *dev = &pdev->dev;
526 struct gpio_desc **descs;
527 struct gpiochip_fwd *fwd;
530 n = gpiod_count(dev, NULL);
534 descs = devm_kmalloc_array(dev, n, sizeof(*descs), GFP_KERNEL);
538 for (i = 0; i < n; i++) {
539 descs[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
540 if (IS_ERR(descs[i]))
541 return PTR_ERR(descs[i]);
544 fwd = gpiochip_fwd_create(dev, n, descs);
548 platform_set_drvdata(pdev, fwd);
553 static const struct of_device_id gpio_aggregator_dt_ids[] = {
555 * Add GPIO-operated devices controlled from userspace below,
556 * or use "driver_override" in sysfs
560 MODULE_DEVICE_TABLE(of, gpio_aggregator_dt_ids);
563 static struct platform_driver gpio_aggregator_driver = {
564 .probe = gpio_aggregator_probe,
567 .groups = gpio_aggregator_groups,
568 .of_match_table = of_match_ptr(gpio_aggregator_dt_ids),
572 static int __init gpio_aggregator_init(void)
574 return platform_driver_register(&gpio_aggregator_driver);
576 module_init(gpio_aggregator_init);
578 static void __exit gpio_aggregator_exit(void)
580 gpio_aggregator_remove_all();
581 platform_driver_unregister(&gpio_aggregator_driver);
583 module_exit(gpio_aggregator_exit);
585 MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
586 MODULE_DESCRIPTION("GPIO Aggregator");
587 MODULE_LICENSE("GPL v2");