2 * Murata ZPA2326 pressure and temperature sensor IIO driver
4 * Copyright (c) 2016 Parrot S.A.
6 * Author: Gregor Boirie <gregor.boirie@parrot.com>
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 as published by
10 * the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
19 * DOC: ZPA2326 theory of operations
21 * This driver supports %INDIO_DIRECT_MODE and %INDIO_BUFFER_TRIGGERED IIO
23 * A internal hardware trigger is also implemented to dispatch registered IIO
24 * trigger consumers upon "sample ready" interrupts.
26 * ZPA2326 hardware supports 2 sampling mode: one shot and continuous.
28 * A complete one shot sampling cycle gets device out of low power mode,
29 * performs pressure and temperature measurements, then automatically switches
30 * back to low power mode. It is meant for on demand sampling with optimal power
31 * saving at the cost of lower sampling rate and higher software overhead.
32 * This is a natural candidate for IIO read_raw hook implementation
33 * (%INDIO_DIRECT_MODE). It is also used for triggered buffering support to
34 * ensure explicit synchronization with external trigger events
35 * (%INDIO_BUFFER_TRIGGERED).
37 * The continuous mode works according to a periodic hardware measurement
38 * process continuously pushing samples into an internal hardware FIFO (for
39 * pressure samples only). Measurement cycle completion may be signaled by a
40 * "sample ready" interrupt.
41 * Typical software sequence of operations :
42 * - get device out of low power mode,
43 * - setup hardware sampling period,
44 * - at end of period, upon data ready interrupt: pop pressure samples out of
45 * hardware FIFO and fetch temperature sample
46 * - when no longer needed, stop sampling process by putting device into
48 * This mode is used to implement %INDIO_BUFFER_TRIGGERED mode if device tree
49 * declares a valid interrupt line. In this case, the internal hardware trigger
52 * Note that hardware sampling frequency is taken into account only when
53 * internal hardware trigger is attached as the highest sampling rate seems to
54 * be the most energy efficient.
57 * preset pressure threshold crossing / IIO events ;
58 * differential pressure sampling ;
59 * hardware samples averaging.
62 #include <linux/module.h>
63 #include <linux/kernel.h>
64 #include <linux/delay.h>
65 #include <linux/interrupt.h>
66 #include <linux/regulator/consumer.h>
67 #include <linux/pm_runtime.h>
68 #include <linux/regmap.h>
69 #include <linux/iio/iio.h>
70 #include <linux/iio/sysfs.h>
71 #include <linux/iio/buffer.h>
72 #include <linux/iio/trigger.h>
73 #include <linux/iio/trigger_consumer.h>
74 #include <linux/iio/triggered_buffer.h>
77 /* 200 ms should be enough for the longest conversion time in one-shot mode. */
78 #define ZPA2326_CONVERSION_JIFFIES (HZ / 5)
80 /* There should be a 1 ms delay (Tpup) after getting out of reset. */
81 #define ZPA2326_TPUP_USEC_MIN (1000)
82 #define ZPA2326_TPUP_USEC_MAX (2000)
85 * struct zpa2326_frequency - Hardware sampling frequency descriptor
86 * @hz : Frequency in Hertz.
87 * @odr: Output Data Rate word as expected by %ZPA2326_CTRL_REG3_REG.
89 struct zpa2326_frequency {
95 * Keep these in strict ascending order: last array entry is expected to
96 * correspond to the highest sampling frequency.
98 static const struct zpa2326_frequency zpa2326_sampling_frequencies[] = {
99 { .hz = 1, .odr = 1 << ZPA2326_CTRL_REG3_ODR_SHIFT },
100 { .hz = 5, .odr = 5 << ZPA2326_CTRL_REG3_ODR_SHIFT },
101 { .hz = 11, .odr = 6 << ZPA2326_CTRL_REG3_ODR_SHIFT },
102 { .hz = 23, .odr = 7 << ZPA2326_CTRL_REG3_ODR_SHIFT },
105 /* Return the highest hardware sampling frequency available. */
106 static const struct zpa2326_frequency *zpa2326_highest_frequency(void)
108 return &zpa2326_sampling_frequencies[
109 ARRAY_SIZE(zpa2326_sampling_frequencies) - 1];
113 * struct zpa_private - Per-device internal private state
114 * @timestamp: Buffered samples ready datum.
115 * @regmap: Underlying I2C / SPI bus adapter used to abstract slave register
117 * @result: Allows sampling logic to get completion status of operations
118 * that interrupt handlers perform asynchronously.
119 * @data_ready: Interrupt handler uses this to wake user context up at sampling
120 * operation completion.
121 * @trigger: Optional hardware / interrupt driven trigger used to notify
122 * external devices a new sample is ready.
123 * @waken: Flag indicating whether or not device has just been powered on.
124 * @irq: Optional interrupt line: negative or zero if not declared into
125 * DT, in which case sampling logic keeps polling status register
126 * to detect completion.
127 * @frequency: Current hardware sampling frequency.
128 * @vref: Power / voltage reference.
129 * @vdd: Power supply.
131 struct zpa2326_private {
133 struct regmap *regmap;
135 struct completion data_ready;
136 struct iio_trigger *trigger;
139 const struct zpa2326_frequency *frequency;
140 struct regulator *vref;
141 struct regulator *vdd;
144 #define zpa2326_err(idev, fmt, ...) \
145 dev_err(idev->dev.parent, fmt "\n", ##__VA_ARGS__)
147 #define zpa2326_warn(idev, fmt, ...) \
148 dev_warn(idev->dev.parent, fmt "\n", ##__VA_ARGS__)
150 #define zpa2326_dbg(idev, fmt, ...) \
151 dev_dbg(idev->dev.parent, fmt "\n", ##__VA_ARGS__)
153 bool zpa2326_isreg_writeable(struct device *dev, unsigned int reg)
156 case ZPA2326_REF_P_XL_REG:
157 case ZPA2326_REF_P_L_REG:
158 case ZPA2326_REF_P_H_REG:
159 case ZPA2326_RES_CONF_REG:
160 case ZPA2326_CTRL_REG0_REG:
161 case ZPA2326_CTRL_REG1_REG:
162 case ZPA2326_CTRL_REG2_REG:
163 case ZPA2326_CTRL_REG3_REG:
164 case ZPA2326_THS_P_LOW_REG:
165 case ZPA2326_THS_P_HIGH_REG:
172 EXPORT_SYMBOL_GPL(zpa2326_isreg_writeable);
174 bool zpa2326_isreg_readable(struct device *dev, unsigned int reg)
177 case ZPA2326_REF_P_XL_REG:
178 case ZPA2326_REF_P_L_REG:
179 case ZPA2326_REF_P_H_REG:
180 case ZPA2326_DEVICE_ID_REG:
181 case ZPA2326_RES_CONF_REG:
182 case ZPA2326_CTRL_REG0_REG:
183 case ZPA2326_CTRL_REG1_REG:
184 case ZPA2326_CTRL_REG2_REG:
185 case ZPA2326_CTRL_REG3_REG:
186 case ZPA2326_INT_SOURCE_REG:
187 case ZPA2326_THS_P_LOW_REG:
188 case ZPA2326_THS_P_HIGH_REG:
189 case ZPA2326_STATUS_REG:
190 case ZPA2326_PRESS_OUT_XL_REG:
191 case ZPA2326_PRESS_OUT_L_REG:
192 case ZPA2326_PRESS_OUT_H_REG:
193 case ZPA2326_TEMP_OUT_L_REG:
194 case ZPA2326_TEMP_OUT_H_REG:
201 EXPORT_SYMBOL_GPL(zpa2326_isreg_readable);
203 bool zpa2326_isreg_precious(struct device *dev, unsigned int reg)
206 case ZPA2326_INT_SOURCE_REG:
207 case ZPA2326_PRESS_OUT_H_REG:
214 EXPORT_SYMBOL_GPL(zpa2326_isreg_precious);
217 * zpa2326_enable_device() - Enable device, i.e. get out of low power mode.
218 * @indio_dev: The IIO device associated with the hardware to enable.
220 * Required to access complete register space and to perform any sampling
221 * or control operations.
223 * Return: Zero when successful, a negative error code otherwise.
225 static int zpa2326_enable_device(const struct iio_dev *indio_dev)
229 err = regmap_write(((struct zpa2326_private *)
230 iio_priv(indio_dev))->regmap,
231 ZPA2326_CTRL_REG0_REG, ZPA2326_CTRL_REG0_ENABLE);
233 zpa2326_err(indio_dev, "failed to enable device (%d)", err);
237 zpa2326_dbg(indio_dev, "enabled");
243 * zpa2326_sleep() - Disable device, i.e. switch to low power mode.
244 * @indio_dev: The IIO device associated with the hardware to disable.
246 * Only %ZPA2326_DEVICE_ID_REG and %ZPA2326_CTRL_REG0_REG registers may be
247 * accessed once device is in the disabled state.
249 * Return: Zero when successful, a negative error code otherwise.
251 static int zpa2326_sleep(const struct iio_dev *indio_dev)
255 err = regmap_write(((struct zpa2326_private *)
256 iio_priv(indio_dev))->regmap,
257 ZPA2326_CTRL_REG0_REG, 0);
259 zpa2326_err(indio_dev, "failed to sleep (%d)", err);
263 zpa2326_dbg(indio_dev, "sleeping");
269 * zpa2326_reset_device() - Reset device to default hardware state.
270 * @indio_dev: The IIO device associated with the hardware to reset.
272 * Disable sampling and empty hardware FIFO.
273 * Device must be enabled before reset, i.e. not in low power mode.
275 * Return: Zero when successful, a negative error code otherwise.
277 static int zpa2326_reset_device(const struct iio_dev *indio_dev)
281 err = regmap_write(((struct zpa2326_private *)
282 iio_priv(indio_dev))->regmap,
283 ZPA2326_CTRL_REG2_REG, ZPA2326_CTRL_REG2_SWRESET);
285 zpa2326_err(indio_dev, "failed to reset device (%d)", err);
289 usleep_range(ZPA2326_TPUP_USEC_MIN, ZPA2326_TPUP_USEC_MAX);
291 zpa2326_dbg(indio_dev, "reset");
297 * zpa2326_start_oneshot() - Start a single sampling cycle, i.e. in one shot
299 * @indio_dev: The IIO device associated with the sampling hardware.
301 * Device must have been previously enabled and configured for one shot mode.
302 * Device will be switched back to low power mode at end of cycle.
304 * Return: Zero when successful, a negative error code otherwise.
306 static int zpa2326_start_oneshot(const struct iio_dev *indio_dev)
310 err = regmap_write(((struct zpa2326_private *)
311 iio_priv(indio_dev))->regmap,
312 ZPA2326_CTRL_REG0_REG,
313 ZPA2326_CTRL_REG0_ENABLE |
314 ZPA2326_CTRL_REG0_ONE_SHOT);
316 zpa2326_err(indio_dev, "failed to start one shot cycle (%d)",
321 zpa2326_dbg(indio_dev, "one shot cycle started");
327 * zpa2326_power_on() - Power on device to allow subsequent configuration.
328 * @indio_dev: The IIO device associated with the sampling hardware.
329 * @private: Internal private state related to @indio_dev.
331 * Sampling will be disabled, preventing strange things from happening in our
332 * back. Hardware FIFO content will be cleared.
333 * When successful, device will be left in the enabled state to allow further
336 * Return: Zero when successful, a negative error code otherwise.
338 static int zpa2326_power_on(const struct iio_dev *indio_dev,
339 const struct zpa2326_private *private)
343 err = regulator_enable(private->vref);
347 err = regulator_enable(private->vdd);
351 zpa2326_dbg(indio_dev, "powered on");
353 err = zpa2326_enable_device(indio_dev);
357 err = zpa2326_reset_device(indio_dev);
364 zpa2326_sleep(indio_dev);
366 regulator_disable(private->vdd);
368 regulator_disable(private->vref);
370 zpa2326_dbg(indio_dev, "powered off");
376 * zpa2326_power_off() - Power off device, i.e. disable attached power
378 * @indio_dev: The IIO device associated with the sampling hardware.
379 * @private: Internal private state related to @indio_dev.
381 * Return: Zero when successful, a negative error code otherwise.
383 static void zpa2326_power_off(const struct iio_dev *indio_dev,
384 const struct zpa2326_private *private)
386 regulator_disable(private->vdd);
387 regulator_disable(private->vref);
389 zpa2326_dbg(indio_dev, "powered off");
393 * zpa2326_config_oneshot() - Setup device for one shot / on demand mode.
394 * @indio_dev: The IIO device associated with the sampling hardware.
395 * @irq: Optional interrupt line the hardware uses to notify new data
396 * samples are ready. Negative or zero values indicate no interrupts
397 * are available, meaning polling is required.
399 * Output Data Rate is configured for the highest possible rate so that
400 * conversion time and power consumption are reduced to a minimum.
401 * Note that hardware internal averaging machinery (not implemented in this
402 * driver) is not applicable in this mode.
404 * Device must have been previously enabled before calling
405 * zpa2326_config_oneshot().
407 * Return: Zero when successful, a negative error code otherwise.
409 static int zpa2326_config_oneshot(const struct iio_dev *indio_dev,
412 struct regmap *regs = ((struct zpa2326_private *)
413 iio_priv(indio_dev))->regmap;
414 const struct zpa2326_frequency *freq = zpa2326_highest_frequency();
417 /* Setup highest available Output Data Rate for one shot mode. */
418 err = regmap_write(regs, ZPA2326_CTRL_REG3_REG, freq->odr);
423 /* Request interrupt when new sample is available. */
424 err = regmap_write(regs, ZPA2326_CTRL_REG1_REG,
425 (u8)~ZPA2326_CTRL_REG1_MASK_DATA_READY);
428 dev_err(indio_dev->dev.parent,
429 "failed to setup one shot mode (%d)", err);
434 zpa2326_dbg(indio_dev, "one shot mode setup @%dHz", freq->hz);
440 * zpa2326_clear_fifo() - Clear remaining entries in hardware FIFO.
441 * @indio_dev: The IIO device associated with the sampling hardware.
442 * @min_count: Number of samples present within hardware FIFO.
444 * @min_count argument is a hint corresponding to the known minimum number of
445 * samples currently living in the FIFO. This allows to reduce the number of bus
446 * accesses by skipping status register read operation as long as we know for
447 * sure there are still entries left.
449 * Return: Zero when successful, a negative error code otherwise.
451 static int zpa2326_clear_fifo(const struct iio_dev *indio_dev,
452 unsigned int min_count)
454 struct regmap *regs = ((struct zpa2326_private *)
455 iio_priv(indio_dev))->regmap;
461 * No hint: read status register to determine whether FIFO is
464 err = regmap_read(regs, ZPA2326_STATUS_REG, &val);
469 if (val & ZPA2326_STATUS_FIFO_E)
470 /* Fifo is empty: nothing to trash. */
477 * A single fetch from pressure MSB register is enough to pop
478 * values out of FIFO.
480 err = regmap_read(regs, ZPA2326_PRESS_OUT_H_REG, &val);
486 * We know for sure there are at least min_count entries
487 * left in FIFO. Skip status register read.
493 err = regmap_read(regs, ZPA2326_STATUS_REG, &val);
497 } while (!(val & ZPA2326_STATUS_FIFO_E));
499 zpa2326_dbg(indio_dev, "FIFO cleared");
504 zpa2326_err(indio_dev, "failed to clear FIFO (%d)", err);
510 * zpa2326_dequeue_pressure() - Retrieve the most recent pressure sample from
512 * @indio_dev: The IIO device associated with the sampling hardware.
513 * @pressure: Sampled pressure output.
515 * Note that ZPA2326 hardware FIFO stores pressure samples only.
517 * Return: Zero when successful, a negative error code otherwise.
519 static int zpa2326_dequeue_pressure(const struct iio_dev *indio_dev,
522 struct regmap *regs = ((struct zpa2326_private *)
523 iio_priv(indio_dev))->regmap;
528 err = regmap_read(regs, ZPA2326_STATUS_REG, &val);
534 if (val & ZPA2326_STATUS_P_OR) {
536 * Fifo overrun : first sample dequeued from FIFO is the
539 zpa2326_warn(indio_dev, "FIFO overflow");
541 err = regmap_bulk_read(regs, ZPA2326_PRESS_OUT_XL_REG, pressure,
546 #define ZPA2326_FIFO_DEPTH (16U)
547 /* Hardware FIFO may hold no more than 16 pressure samples. */
548 return zpa2326_clear_fifo(indio_dev, ZPA2326_FIFO_DEPTH - 1);
552 * Fifo has not overflown : retrieve newest sample. We need to pop
553 * values out until FIFO is empty : last fetched pressure is the newest.
554 * In nominal cases, we should find a single queued sample only.
557 err = regmap_bulk_read(regs, ZPA2326_PRESS_OUT_XL_REG, pressure,
562 err = regmap_read(regs, ZPA2326_STATUS_REG, &val);
567 } while (!(val & ZPA2326_STATUS_FIFO_E));
571 * Samples were pushed by hardware during previous rounds but we
572 * didn't consume them fast enough: inform user.
574 zpa2326_dbg(indio_dev, "cleared %d FIFO entries", cleared);
580 * zpa2326_fill_sample_buffer() - Enqueue new channel samples to IIO buffer.
581 * @indio_dev: The IIO device associated with the sampling hardware.
582 * @private: Internal private state related to @indio_dev.
584 * Return: Zero when successful, a negative error code otherwise.
586 static int zpa2326_fill_sample_buffer(struct iio_dev *indio_dev,
587 const struct zpa2326_private *private)
596 if (test_bit(0, indio_dev->active_scan_mask)) {
597 /* Get current pressure from hardware FIFO. */
598 err = zpa2326_dequeue_pressure(indio_dev, &sample.pressure);
600 zpa2326_warn(indio_dev, "failed to fetch pressure (%d)",
606 if (test_bit(1, indio_dev->active_scan_mask)) {
607 /* Get current temperature. */
608 err = regmap_bulk_read(private->regmap, ZPA2326_TEMP_OUT_L_REG,
609 &sample.temperature, 2);
611 zpa2326_warn(indio_dev,
612 "failed to fetch temperature (%d)", err);
618 * Now push samples using timestamp stored either :
619 * - by hardware interrupt handler if interrupt is available: see
620 * zpa2326_handle_irq(),
621 * - or oneshot completion polling machinery : see
622 * zpa2326_trigger_handler().
624 zpa2326_dbg(indio_dev, "filling raw samples buffer");
626 iio_push_to_buffers_with_timestamp(indio_dev, &sample,
633 static int zpa2326_runtime_suspend(struct device *parent)
635 const struct iio_dev *indio_dev = dev_get_drvdata(parent);
637 if (pm_runtime_autosuspend_expiration(parent))
638 /* Userspace changed autosuspend delay. */
641 zpa2326_power_off(indio_dev, iio_priv(indio_dev));
646 static int zpa2326_runtime_resume(struct device *parent)
648 const struct iio_dev *indio_dev = dev_get_drvdata(parent);
650 return zpa2326_power_on(indio_dev, iio_priv(indio_dev));
653 const struct dev_pm_ops zpa2326_pm_ops = {
654 SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
655 pm_runtime_force_resume)
656 SET_RUNTIME_PM_OPS(zpa2326_runtime_suspend, zpa2326_runtime_resume,
659 EXPORT_SYMBOL_GPL(zpa2326_pm_ops);
662 * zpa2326_resume() - Request the PM layer to power supply the device.
663 * @indio_dev: The IIO device associated with the sampling hardware.
666 * < 0 - a negative error code meaning failure ;
667 * 0 - success, device has just been powered up ;
668 * 1 - success, device was already powered.
670 static int zpa2326_resume(const struct iio_dev *indio_dev)
674 err = pm_runtime_get_sync(indio_dev->dev.parent);
676 pm_runtime_put(indio_dev->dev.parent);
682 * Device was already power supplied: get it out of low power
683 * mode and inform caller.
685 zpa2326_enable_device(indio_dev);
689 /* Inform caller device has just been brought back to life. */
694 * zpa2326_suspend() - Schedule a power down using autosuspend feature of PM
696 * @indio_dev: The IIO device associated with the sampling hardware.
698 * Device is switched to low power mode at first to save power even when
699 * attached regulator is a "dummy" one.
701 static void zpa2326_suspend(struct iio_dev *indio_dev)
703 struct device *parent = indio_dev->dev.parent;
705 zpa2326_sleep(indio_dev);
707 pm_runtime_mark_last_busy(parent);
708 pm_runtime_put_autosuspend(parent);
711 static void zpa2326_init_runtime(struct device *parent)
713 pm_runtime_get_noresume(parent);
714 pm_runtime_set_active(parent);
715 pm_runtime_enable(parent);
716 pm_runtime_set_autosuspend_delay(parent, 1000);
717 pm_runtime_use_autosuspend(parent);
718 pm_runtime_mark_last_busy(parent);
719 pm_runtime_put_autosuspend(parent);
722 static void zpa2326_fini_runtime(struct device *parent)
724 pm_runtime_disable(parent);
725 pm_runtime_set_suspended(parent);
727 #else /* !CONFIG_PM */
728 static int zpa2326_resume(const struct iio_dev *indio_dev)
730 zpa2326_enable_device(indio_dev);
735 static void zpa2326_suspend(struct iio_dev *indio_dev)
737 zpa2326_sleep(indio_dev);
740 #define zpa2326_init_runtime(_parent)
741 #define zpa2326_fini_runtime(_parent)
742 #endif /* !CONFIG_PM */
745 * zpa2326_handle_irq() - Process hardware interrupts.
746 * @irq: Interrupt line the hardware uses to notify new data has arrived.
747 * @data: The IIO device associated with the sampling hardware.
749 * Timestamp buffered samples as soon as possible then schedule threaded bottom
752 * Return: Always successful.
754 static irqreturn_t zpa2326_handle_irq(int irq, void *data)
756 struct iio_dev *indio_dev = data;
758 if (iio_buffer_enabled(indio_dev)) {
759 /* Timestamping needed for buffered sampling only. */
760 ((struct zpa2326_private *)
761 iio_priv(indio_dev))->timestamp = iio_get_time_ns(indio_dev);
764 return IRQ_WAKE_THREAD;
768 * zpa2326_handle_threaded_irq() - Interrupt bottom-half handler.
769 * @irq: Interrupt line the hardware uses to notify new data has arrived.
770 * @data: The IIO device associated with the sampling hardware.
772 * Mainly ensures interrupt is caused by a real "new sample available"
773 * condition. This relies upon the ability to perform blocking / sleeping bus
774 * accesses to slave's registers. This is why zpa2326_handle_threaded_irq() is
775 * called from within a thread, i.e. not called from hard interrupt context.
777 * When device is using its own internal hardware trigger in continuous sampling
778 * mode, data are available into hardware FIFO once interrupt has occurred. All
779 * we have to do is to dispatch the trigger, which in turn will fetch data and
782 * When not using its own internal hardware trigger, the device has been
783 * configured in one-shot mode either by an external trigger or the IIO read_raw
784 * hook. This means one of the latter is currently waiting for sampling
785 * completion, in which case we must simply wake it up.
787 * See zpa2326_trigger_handler().
790 * %IRQ_NONE - no consistent interrupt happened ;
791 * %IRQ_HANDLED - there was new samples available.
793 static irqreturn_t zpa2326_handle_threaded_irq(int irq, void *data)
795 struct iio_dev *indio_dev = data;
796 struct zpa2326_private *priv = iio_priv(indio_dev);
799 irqreturn_t ret = IRQ_NONE;
802 * Are we using our own internal trigger in triggered buffer mode, i.e.,
803 * currently working in continuous sampling mode ?
805 cont = (iio_buffer_enabled(indio_dev) &&
806 iio_trigger_using_own(indio_dev));
809 * Device works according to a level interrupt scheme: reading interrupt
810 * status de-asserts interrupt line.
812 priv->result = regmap_read(priv->regmap, ZPA2326_INT_SOURCE_REG, &val);
813 if (priv->result < 0) {
820 /* Data ready is the only interrupt source we requested. */
821 if (!(val & ZPA2326_INT_SOURCE_DATA_READY)) {
823 * Interrupt happened but no new sample available: likely caused
824 * by spurious interrupts, in which case, returning IRQ_NONE
825 * allows to benefit from the generic spurious interrupts
828 zpa2326_warn(indio_dev, "unexpected interrupt status %02x",
834 priv->result = -ENODATA;
838 /* New sample available: dispatch internal trigger consumers. */
839 iio_trigger_poll_chained(priv->trigger);
843 * Internal hardware trigger has been scheduled above : it will
844 * fetch data on its own.
852 * Wake up direct or externaly triggered buffer mode waiters: see
853 * zpa2326_sample_oneshot() and zpa2326_trigger_handler().
855 complete(&priv->data_ready);
861 * zpa2326_wait_oneshot_completion() - Wait for oneshot data ready interrupt.
862 * @indio_dev: The IIO device associated with the sampling hardware.
863 * @private: Internal private state related to @indio_dev.
865 * Return: Zero when successful, a negative error code otherwise.
867 static int zpa2326_wait_oneshot_completion(const struct iio_dev *indio_dev,
868 struct zpa2326_private *private)
873 zpa2326_dbg(indio_dev, "waiting for one shot completion interrupt");
875 timeout = wait_for_completion_interruptible_timeout(
876 &private->data_ready, ZPA2326_CONVERSION_JIFFIES);
879 * Interrupt handler completed before timeout: return operation
882 return private->result;
884 /* Clear all interrupts just to be sure. */
885 regmap_read(private->regmap, ZPA2326_INT_SOURCE_REG, &val);
889 zpa2326_warn(indio_dev, "no one shot interrupt occurred (%ld)",
894 zpa2326_warn(indio_dev, "wait for one shot interrupt cancelled");
898 static int zpa2326_init_managed_irq(struct device *parent,
899 struct iio_dev *indio_dev,
900 struct zpa2326_private *private,
909 * Platform declared no interrupt line: device will be polled
910 * for data availability.
912 dev_info(parent, "no interrupt found, running in polling mode");
916 init_completion(&private->data_ready);
918 /* Request handler to be scheduled into threaded interrupt context. */
919 err = devm_request_threaded_irq(parent, irq, zpa2326_handle_irq,
920 zpa2326_handle_threaded_irq,
921 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
922 dev_name(parent), indio_dev);
924 dev_err(parent, "failed to request interrupt %d (%d)", irq,
929 dev_info(parent, "using interrupt %d", irq);
935 * zpa2326_poll_oneshot_completion() - Actively poll for one shot data ready.
936 * @indio_dev: The IIO device associated with the sampling hardware.
938 * Loop over registers content to detect end of sampling cycle. Used when DT
939 * declared no valid interrupt lines.
941 * Return: Zero when successful, a negative error code otherwise.
943 static int zpa2326_poll_oneshot_completion(const struct iio_dev *indio_dev)
945 unsigned long tmout = jiffies + ZPA2326_CONVERSION_JIFFIES;
946 struct regmap *regs = ((struct zpa2326_private *)
947 iio_priv(indio_dev))->regmap;
951 zpa2326_dbg(indio_dev, "polling for one shot completion");
954 * At least, 100 ms is needed for the device to complete its one-shot
957 if (msleep_interruptible(100))
960 /* Poll for conversion completion in hardware. */
962 err = regmap_read(regs, ZPA2326_CTRL_REG0_REG, &val);
966 if (!(val & ZPA2326_CTRL_REG0_ONE_SHOT))
967 /* One-shot bit self clears at conversion end. */
970 if (time_after(jiffies, tmout)) {
971 /* Prevent from waiting forever : let's time out. */
976 usleep_range(10000, 20000);
980 * In oneshot mode, pressure sample availability guarantees that
981 * temperature conversion has also completed : just check pressure
982 * status bit to keep things simple.
984 err = regmap_read(regs, ZPA2326_STATUS_REG, &val);
988 if (!(val & ZPA2326_STATUS_P_DA)) {
989 /* No sample available. */
997 zpa2326_warn(indio_dev, "failed to poll one shot completion (%d)", err);
1003 * zpa2326_fetch_raw_sample() - Retrieve a raw sample and convert it to CPU
1005 * @indio_dev: The IIO device associated with the sampling hardware.
1006 * @type: Type of measurement / channel to fetch from.
1007 * @value: Sample output.
1009 * Return: Zero when successful, a negative error code otherwise.
1011 static int zpa2326_fetch_raw_sample(const struct iio_dev *indio_dev,
1012 enum iio_chan_type type,
1015 struct regmap *regs = ((struct zpa2326_private *)
1016 iio_priv(indio_dev))->regmap;
1021 zpa2326_dbg(indio_dev, "fetching raw pressure sample");
1023 err = regmap_bulk_read(regs, ZPA2326_PRESS_OUT_XL_REG, value,
1026 zpa2326_warn(indio_dev, "failed to fetch pressure (%d)",
1031 /* Pressure is a 24 bits wide little-endian unsigned int. */
1032 *value = (((u8 *)value)[2] << 16) | (((u8 *)value)[1] << 8) |
1038 zpa2326_dbg(indio_dev, "fetching raw temperature sample");
1040 err = regmap_bulk_read(regs, ZPA2326_TEMP_OUT_L_REG, value, 2);
1042 zpa2326_warn(indio_dev,
1043 "failed to fetch temperature (%d)", err);
1047 /* Temperature is a 16 bits wide little-endian signed int. */
1048 *value = (int)le16_to_cpup((__le16 *)value);
1058 * zpa2326_sample_oneshot() - Perform a complete one shot sampling cycle.
1059 * @indio_dev: The IIO device associated with the sampling hardware.
1060 * @type: Type of measurement / channel to fetch from.
1061 * @value: Sample output.
1063 * Return: Zero when successful, a negative error code otherwise.
1065 static int zpa2326_sample_oneshot(struct iio_dev *indio_dev,
1066 enum iio_chan_type type,
1070 struct zpa2326_private *priv;
1072 ret = iio_device_claim_direct_mode(indio_dev);
1076 ret = zpa2326_resume(indio_dev);
1080 priv = iio_priv(indio_dev);
1084 * We were already power supplied. Just clear hardware FIFO to
1085 * get rid of samples acquired during previous rounds (if any).
1086 * Sampling operation always generates both temperature and
1087 * pressure samples. The latter are always enqueued into
1088 * hardware FIFO. This may lead to situations were pressure
1089 * samples still sit into FIFO when previous cycle(s) fetched
1090 * temperature data only.
1091 * Hence, we need to clear hardware FIFO content to prevent from
1092 * getting outdated values at the end of current cycle.
1094 if (type == IIO_PRESSURE) {
1095 ret = zpa2326_clear_fifo(indio_dev, 0);
1101 * We have just been power supplied, i.e. device is in default
1102 * "out of reset" state, meaning we need to reconfigure it
1105 ret = zpa2326_config_oneshot(indio_dev, priv->irq);
1110 /* Start a sampling cycle in oneshot mode. */
1111 ret = zpa2326_start_oneshot(indio_dev);
1115 /* Wait for sampling cycle to complete. */
1117 ret = zpa2326_wait_oneshot_completion(indio_dev, priv);
1119 ret = zpa2326_poll_oneshot_completion(indio_dev);
1124 /* Retrieve raw sample value and convert it to CPU endianness. */
1125 ret = zpa2326_fetch_raw_sample(indio_dev, type, value);
1128 zpa2326_suspend(indio_dev);
1130 iio_device_release_direct_mode(indio_dev);
1136 * zpa2326_trigger_handler() - Perform an IIO buffered sampling round in one
1138 * @irq: The software interrupt assigned to @data
1139 * @data: The IIO poll function dispatched by external trigger our device is
1142 * Bottom-half handler called by the IIO trigger to which our device is
1143 * currently attached. Allows us to synchronize this device buffered sampling
1144 * either with external events (such as timer expiration, external device sample
1145 * ready, etc...) or with its own interrupt (internal hardware trigger).
1147 * When using an external trigger, basically run the same sequence of operations
1148 * as for zpa2326_sample_oneshot() with the following hereafter. Hardware FIFO
1149 * is not cleared since already done at buffering enable time and samples
1150 * dequeueing always retrieves the most recent value.
1152 * Otherwise, when internal hardware trigger has dispatched us, just fetch data
1153 * from hardware FIFO.
1155 * Fetched data will pushed unprocessed to IIO buffer since samples conversion
1156 * is delegated to userspace in buffered mode (endianness, etc...).
1159 * %IRQ_NONE - no consistent interrupt happened ;
1160 * %IRQ_HANDLED - there was new samples available.
1162 static irqreturn_t zpa2326_trigger_handler(int irq, void *data)
1164 struct iio_dev *indio_dev = ((struct iio_poll_func *)
1166 struct zpa2326_private *priv = iio_priv(indio_dev);
1170 * We have been dispatched, meaning we are in triggered buffer mode.
1171 * Using our own internal trigger implies we are currently in continuous
1172 * hardware sampling mode.
1174 cont = iio_trigger_using_own(indio_dev);
1177 /* On demand sampling : start a one shot cycle. */
1178 if (zpa2326_start_oneshot(indio_dev))
1181 /* Wait for sampling cycle to complete. */
1182 if (priv->irq <= 0) {
1183 /* No interrupt available: poll for completion. */
1184 if (zpa2326_poll_oneshot_completion(indio_dev))
1187 /* Only timestamp sample once it is ready. */
1188 priv->timestamp = iio_get_time_ns(indio_dev);
1190 /* Interrupt handlers will timestamp for us. */
1191 if (zpa2326_wait_oneshot_completion(indio_dev, priv))
1196 /* Enqueue to IIO buffer / userspace. */
1197 zpa2326_fill_sample_buffer(indio_dev, priv);
1201 /* Don't switch to low power if sampling continuously. */
1202 zpa2326_sleep(indio_dev);
1204 /* Inform attached trigger we are done. */
1205 iio_trigger_notify_done(indio_dev->trig);
1211 * zpa2326_preenable_buffer() - Prepare device for configuring triggered
1214 * @indio_dev: The IIO device associated with the sampling hardware.
1216 * Basically power up device.
1217 * Called with IIO device's lock held.
1219 * Return: Zero when successful, a negative error code otherwise.
1221 static int zpa2326_preenable_buffer(struct iio_dev *indio_dev)
1223 int ret = zpa2326_resume(indio_dev);
1228 /* Tell zpa2326_postenable_buffer() if we have just been powered on. */
1229 ((struct zpa2326_private *)
1230 iio_priv(indio_dev))->waken = iio_priv(indio_dev);
1236 * zpa2326_postenable_buffer() - Configure device for triggered sampling.
1237 * @indio_dev: The IIO device associated with the sampling hardware.
1239 * Basically setup one-shot mode if plugging external trigger.
1240 * Otherwise, let internal trigger configure continuous sampling :
1241 * see zpa2326_set_trigger_state().
1243 * If an error is returned, IIO layer will call our postdisable hook for us,
1244 * i.e. no need to explicitly power device off here.
1245 * Called with IIO device's lock held.
1247 * Called with IIO device's lock held.
1249 * Return: Zero when successful, a negative error code otherwise.
1251 static int zpa2326_postenable_buffer(struct iio_dev *indio_dev)
1253 const struct zpa2326_private *priv = iio_priv(indio_dev);
1258 * We were already power supplied. Just clear hardware FIFO to
1259 * get rid of samples acquired during previous rounds (if any).
1261 err = zpa2326_clear_fifo(indio_dev, 0);
1266 if (!iio_trigger_using_own(indio_dev) && priv->waken) {
1268 * We are using an external trigger and we have just been
1269 * powered up: reconfigure one-shot mode.
1271 err = zpa2326_config_oneshot(indio_dev, priv->irq);
1276 /* Plug our own trigger event handler. */
1277 err = iio_triggered_buffer_postenable(indio_dev);
1284 zpa2326_err(indio_dev, "failed to enable buffering (%d)", err);
1289 static int zpa2326_postdisable_buffer(struct iio_dev *indio_dev)
1291 zpa2326_suspend(indio_dev);
1296 static const struct iio_buffer_setup_ops zpa2326_buffer_setup_ops = {
1297 .preenable = zpa2326_preenable_buffer,
1298 .postenable = zpa2326_postenable_buffer,
1299 .predisable = iio_triggered_buffer_predisable,
1300 .postdisable = zpa2326_postdisable_buffer
1304 * zpa2326_set_trigger_state() - Start / stop continuous sampling.
1305 * @trig: The trigger being attached to IIO device associated with the sampling
1307 * @state: Tell whether to start (true) or stop (false)
1309 * Basically enable / disable hardware continuous sampling mode.
1311 * Called with IIO device's lock held at postenable() or predisable() time.
1313 * Return: Zero when successful, a negative error code otherwise.
1315 static int zpa2326_set_trigger_state(struct iio_trigger *trig, bool state)
1317 const struct iio_dev *indio_dev = dev_get_drvdata(
1319 const struct zpa2326_private *priv = iio_priv(indio_dev);
1324 * Switch trigger off : in case of failure, interrupt is left
1325 * disabled in order to prevent handler from accessing released
1331 * As device is working in continuous mode, handlers may be
1332 * accessing resources we are currently freeing...
1333 * Prevent this by disabling interrupt handlers and ensure
1334 * the device will generate no more interrupts unless explicitly
1335 * required to, i.e. by restoring back to default one shot mode.
1337 disable_irq(priv->irq);
1340 * Disable continuous sampling mode to restore settings for
1341 * one shot / direct sampling operations.
1343 err = regmap_write(priv->regmap, ZPA2326_CTRL_REG3_REG,
1344 zpa2326_highest_frequency()->odr);
1349 * Now that device won't generate interrupts on its own,
1350 * acknowledge any currently active interrupts (may happen on
1351 * rare occasions while stopping continuous mode).
1353 err = regmap_read(priv->regmap, ZPA2326_INT_SOURCE_REG, &val);
1358 * Re-enable interrupts only if we can guarantee the device will
1359 * generate no more interrupts to prevent handlers from
1360 * accessing released resources.
1362 enable_irq(priv->irq);
1364 zpa2326_dbg(indio_dev, "continuous mode stopped");
1367 * Switch trigger on : start continuous sampling at required
1372 /* Enable interrupt if getting out of reset. */
1373 err = regmap_write(priv->regmap, ZPA2326_CTRL_REG1_REG,
1375 ~ZPA2326_CTRL_REG1_MASK_DATA_READY);
1380 /* Enable continuous sampling at specified frequency. */
1381 err = regmap_write(priv->regmap, ZPA2326_CTRL_REG3_REG,
1382 ZPA2326_CTRL_REG3_ENABLE_MEAS |
1383 priv->frequency->odr);
1387 zpa2326_dbg(indio_dev, "continuous mode setup @%dHz",
1388 priv->frequency->hz);
1394 static const struct iio_trigger_ops zpa2326_trigger_ops = {
1395 .set_trigger_state = zpa2326_set_trigger_state,
1399 * zpa2326_init_trigger() - Create an interrupt driven / hardware trigger
1400 * allowing to notify external devices a new sample is
1402 * @parent: Hardware sampling device @indio_dev is a child of.
1403 * @indio_dev: The IIO device associated with the sampling hardware.
1404 * @private: Internal private state related to @indio_dev.
1405 * @irq: Optional interrupt line the hardware uses to notify new data
1406 * samples are ready. Negative or zero values indicate no interrupts
1407 * are available, meaning polling is required.
1409 * Only relevant when DT declares a valid interrupt line.
1411 * Return: Zero when successful, a negative error code otherwise.
1413 static int zpa2326_init_managed_trigger(struct device *parent,
1414 struct iio_dev *indio_dev,
1415 struct zpa2326_private *private,
1418 struct iio_trigger *trigger;
1424 trigger = devm_iio_trigger_alloc(parent, "%s-dev%d",
1425 indio_dev->name, indio_dev->id);
1430 trigger->dev.parent = parent;
1431 trigger->ops = &zpa2326_trigger_ops;
1433 private->trigger = trigger;
1435 /* Register to triggers space. */
1436 ret = devm_iio_trigger_register(parent, trigger);
1438 dev_err(parent, "failed to register hardware trigger (%d)",
1444 static int zpa2326_get_frequency(const struct iio_dev *indio_dev)
1446 return ((struct zpa2326_private *)iio_priv(indio_dev))->frequency->hz;
1449 static int zpa2326_set_frequency(struct iio_dev *indio_dev, int hz)
1451 struct zpa2326_private *priv = iio_priv(indio_dev);
1455 /* Check if requested frequency is supported. */
1456 for (freq = 0; freq < ARRAY_SIZE(zpa2326_sampling_frequencies); freq++)
1457 if (zpa2326_sampling_frequencies[freq].hz == hz)
1459 if (freq == ARRAY_SIZE(zpa2326_sampling_frequencies))
1462 /* Don't allow changing frequency if buffered sampling is ongoing. */
1463 err = iio_device_claim_direct_mode(indio_dev);
1467 priv->frequency = &zpa2326_sampling_frequencies[freq];
1469 iio_device_release_direct_mode(indio_dev);
1474 /* Expose supported hardware sampling frequencies (Hz) through sysfs. */
1475 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("1 5 11 23");
1477 static struct attribute *zpa2326_attributes[] = {
1478 &iio_const_attr_sampling_frequency_available.dev_attr.attr,
1482 static const struct attribute_group zpa2326_attribute_group = {
1483 .attrs = zpa2326_attributes,
1486 static int zpa2326_read_raw(struct iio_dev *indio_dev,
1487 struct iio_chan_spec const *chan,
1493 case IIO_CHAN_INFO_RAW:
1494 return zpa2326_sample_oneshot(indio_dev, chan->type, val);
1496 case IIO_CHAN_INFO_SCALE:
1497 switch (chan->type) {
1500 * Pressure resolution is 1/64 Pascal. Scale to kPascal
1501 * as required by IIO ABI.
1505 return IIO_VAL_FRACTIONAL;
1509 * Temperature follows the equation:
1510 * Temp[degC] = Tempcode * 0.00649 - 176.83
1512 * Tempcode is composed the raw sampled 16 bits.
1514 * Hence, to produce a temperature in milli-degrees
1515 * Celsius according to IIO ABI, we need to apply the
1516 * following equation to raw samples:
1517 * Temp[milli degC] = (Tempcode + Offset) * Scale
1519 * Offset = -176.83 / 0.00649
1520 * Scale = 0.00649 * 1000
1524 return IIO_VAL_INT_PLUS_MICRO;
1530 case IIO_CHAN_INFO_OFFSET:
1531 switch (chan->type) {
1535 return IIO_VAL_FRACTIONAL;
1541 case IIO_CHAN_INFO_SAMP_FREQ:
1542 *val = zpa2326_get_frequency(indio_dev);
1550 static int zpa2326_write_raw(struct iio_dev *indio_dev,
1551 const struct iio_chan_spec *chan,
1556 if ((mask != IIO_CHAN_INFO_SAMP_FREQ) || val2)
1559 return zpa2326_set_frequency(indio_dev, val);
1562 static const struct iio_chan_spec zpa2326_channels[] = {
1564 .type = IIO_PRESSURE,
1570 .endianness = IIO_LE,
1572 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
1573 BIT(IIO_CHAN_INFO_SCALE),
1574 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
1583 .endianness = IIO_LE,
1585 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
1586 BIT(IIO_CHAN_INFO_SCALE) |
1587 BIT(IIO_CHAN_INFO_OFFSET),
1588 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
1590 [2] = IIO_CHAN_SOFT_TIMESTAMP(2),
1593 static const struct iio_info zpa2326_info = {
1594 .attrs = &zpa2326_attribute_group,
1595 .read_raw = zpa2326_read_raw,
1596 .write_raw = zpa2326_write_raw,
1599 static struct iio_dev *zpa2326_create_managed_iiodev(struct device *device,
1601 struct regmap *regmap)
1603 struct iio_dev *indio_dev;
1605 /* Allocate space to hold IIO device internal state. */
1606 indio_dev = devm_iio_device_alloc(device,
1607 sizeof(struct zpa2326_private));
1611 /* Setup for userspace synchronous on demand sampling. */
1612 indio_dev->modes = INDIO_DIRECT_MODE;
1613 indio_dev->dev.parent = device;
1614 indio_dev->channels = zpa2326_channels;
1615 indio_dev->num_channels = ARRAY_SIZE(zpa2326_channels);
1616 indio_dev->name = name;
1617 indio_dev->info = &zpa2326_info;
1622 int zpa2326_probe(struct device *parent,
1626 struct regmap *regmap)
1628 struct iio_dev *indio_dev;
1629 struct zpa2326_private *priv;
1633 indio_dev = zpa2326_create_managed_iiodev(parent, name, regmap);
1637 priv = iio_priv(indio_dev);
1639 priv->vref = devm_regulator_get(parent, "vref");
1640 if (IS_ERR(priv->vref))
1641 return PTR_ERR(priv->vref);
1643 priv->vdd = devm_regulator_get(parent, "vdd");
1644 if (IS_ERR(priv->vdd))
1645 return PTR_ERR(priv->vdd);
1647 /* Set default hardware sampling frequency to highest rate supported. */
1648 priv->frequency = zpa2326_highest_frequency();
1651 * Plug device's underlying bus abstraction : this MUST be set before
1652 * registering interrupt handlers since an interrupt might happen if
1653 * power up sequence is not properly applied.
1655 priv->regmap = regmap;
1657 err = devm_iio_triggered_buffer_setup(parent, indio_dev, NULL,
1658 zpa2326_trigger_handler,
1659 &zpa2326_buffer_setup_ops);
1663 err = zpa2326_init_managed_trigger(parent, indio_dev, priv, irq);
1667 err = zpa2326_init_managed_irq(parent, indio_dev, priv, irq);
1671 /* Power up to check device ID and perform initial hardware setup. */
1672 err = zpa2326_power_on(indio_dev, priv);
1676 /* Read id register to check we are talking to the right slave. */
1677 err = regmap_read(regmap, ZPA2326_DEVICE_ID_REG, &id);
1682 dev_err(parent, "found device with unexpected id %02x", id);
1687 err = zpa2326_config_oneshot(indio_dev, irq);
1691 /* Setup done : go sleeping. Device will be awaken upon user request. */
1692 err = zpa2326_sleep(indio_dev);
1696 dev_set_drvdata(parent, indio_dev);
1698 zpa2326_init_runtime(parent);
1700 err = iio_device_register(indio_dev);
1702 zpa2326_fini_runtime(parent);
1709 /* Put to sleep just in case power regulators are "dummy" ones. */
1710 zpa2326_sleep(indio_dev);
1712 zpa2326_power_off(indio_dev, priv);
1716 EXPORT_SYMBOL_GPL(zpa2326_probe);
1718 void zpa2326_remove(const struct device *parent)
1720 struct iio_dev *indio_dev = dev_get_drvdata(parent);
1722 iio_device_unregister(indio_dev);
1723 zpa2326_fini_runtime(indio_dev->dev.parent);
1724 zpa2326_sleep(indio_dev);
1725 zpa2326_power_off(indio_dev, iio_priv(indio_dev));
1727 EXPORT_SYMBOL_GPL(zpa2326_remove);
1729 MODULE_AUTHOR("Gregor Boirie <gregor.boirie@parrot.com>");
1730 MODULE_DESCRIPTION("Core driver for Murata ZPA2326 pressure sensor");
1731 MODULE_LICENSE("GPL v2");