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Diffstat (limited to 'drivers/iio/pressure/zpa2326.c')
| -rw-r--r-- | drivers/iio/pressure/zpa2326.c | 1731 |
1 files changed, 1731 insertions, 0 deletions
diff --git a/drivers/iio/pressure/zpa2326.c b/drivers/iio/pressure/zpa2326.c new file mode 100644 index 000000000..23b4fa81e --- /dev/null +++ b/drivers/iio/pressure/zpa2326.c @@ -0,0 +1,1731 @@ +/* + * Murata ZPA2326 pressure and temperature sensor IIO driver + * + * Copyright (c) 2016 Parrot S.A. + * + * Author: Gregor Boirie <gregor.boirie@parrot.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ + +/** + * DOC: ZPA2326 theory of operations + * + * This driver supports %INDIO_DIRECT_MODE and %INDIO_BUFFER_TRIGGERED IIO + * modes. + * A internal hardware trigger is also implemented to dispatch registered IIO + * trigger consumers upon "sample ready" interrupts. + * + * ZPA2326 hardware supports 2 sampling mode: one shot and continuous. + * + * A complete one shot sampling cycle gets device out of low power mode, + * performs pressure and temperature measurements, then automatically switches + * back to low power mode. It is meant for on demand sampling with optimal power + * saving at the cost of lower sampling rate and higher software overhead. + * This is a natural candidate for IIO read_raw hook implementation + * (%INDIO_DIRECT_MODE). It is also used for triggered buffering support to + * ensure explicit synchronization with external trigger events + * (%INDIO_BUFFER_TRIGGERED). + * + * The continuous mode works according to a periodic hardware measurement + * process continuously pushing samples into an internal hardware FIFO (for + * pressure samples only). Measurement cycle completion may be signaled by a + * "sample ready" interrupt. + * Typical software sequence of operations : + * - get device out of low power mode, + * - setup hardware sampling period, + * - at end of period, upon data ready interrupt: pop pressure samples out of + * hardware FIFO and fetch temperature sample + * - when no longer needed, stop sampling process by putting device into + * low power mode. + * This mode is used to implement %INDIO_BUFFER_TRIGGERED mode if device tree + * declares a valid interrupt line. In this case, the internal hardware trigger + * drives acquisition. + * + * Note that hardware sampling frequency is taken into account only when + * internal hardware trigger is attached as the highest sampling rate seems to + * be the most energy efficient. + * + * TODO: + * preset pressure threshold crossing / IIO events ; + * differential pressure sampling ; + * hardware samples averaging. + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/delay.h> +#include <linux/interrupt.h> +#include <linux/regulator/consumer.h> +#include <linux/pm_runtime.h> +#include <linux/regmap.h> +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/iio/buffer.h> +#include <linux/iio/trigger.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/triggered_buffer.h> +#include "zpa2326.h" + +/* 200 ms should be enough for the longest conversion time in one-shot mode. */ +#define ZPA2326_CONVERSION_JIFFIES (HZ / 5) + +/* There should be a 1 ms delay (Tpup) after getting out of reset. */ +#define ZPA2326_TPUP_USEC_MIN (1000) +#define ZPA2326_TPUP_USEC_MAX (2000) + +/** + * struct zpa2326_frequency - Hardware sampling frequency descriptor + * @hz : Frequency in Hertz. + * @odr: Output Data Rate word as expected by %ZPA2326_CTRL_REG3_REG. + */ +struct zpa2326_frequency { + int hz; + u16 odr; +}; + +/* + * Keep these in strict ascending order: last array entry is expected to + * correspond to the highest sampling frequency. + */ +static const struct zpa2326_frequency zpa2326_sampling_frequencies[] = { + { .hz = 1, .odr = 1 << ZPA2326_CTRL_REG3_ODR_SHIFT }, + { .hz = 5, .odr = 5 << ZPA2326_CTRL_REG3_ODR_SHIFT }, + { .hz = 11, .odr = 6 << ZPA2326_CTRL_REG3_ODR_SHIFT }, + { .hz = 23, .odr = 7 << ZPA2326_CTRL_REG3_ODR_SHIFT }, +}; + +/* Return the highest hardware sampling frequency available. */ +static const struct zpa2326_frequency *zpa2326_highest_frequency(void) +{ + return &zpa2326_sampling_frequencies[ + ARRAY_SIZE(zpa2326_sampling_frequencies) - 1]; +} + +/** + * struct zpa_private - Per-device internal private state + * @timestamp: Buffered samples ready datum. + * @regmap: Underlying I2C / SPI bus adapter used to abstract slave register + * accesses. + * @result: Allows sampling logic to get completion status of operations + * that interrupt handlers perform asynchronously. + * @data_ready: Interrupt handler uses this to wake user context up at sampling + * operation completion. + * @trigger: Optional hardware / interrupt driven trigger used to notify + * external devices a new sample is ready. + * @waken: Flag indicating whether or not device has just been powered on. + * @irq: Optional interrupt line: negative or zero if not declared into + * DT, in which case sampling logic keeps polling status register + * to detect completion. + * @frequency: Current hardware sampling frequency. + * @vref: Power / voltage reference. + * @vdd: Power supply. + */ +struct zpa2326_private { + s64 timestamp; + struct regmap *regmap; + int result; + struct completion data_ready; + struct iio_trigger *trigger; + bool waken; + int irq; + const struct zpa2326_frequency *frequency; + struct regulator *vref; + struct regulator *vdd; +}; + +#define zpa2326_err(idev, fmt, ...) \ + dev_err(idev->dev.parent, fmt "\n", ##__VA_ARGS__) + +#define zpa2326_warn(idev, fmt, ...) \ + dev_warn(idev->dev.parent, fmt "\n", ##__VA_ARGS__) + +#define zpa2326_dbg(idev, fmt, ...) \ + dev_dbg(idev->dev.parent, fmt "\n", ##__VA_ARGS__) + +bool zpa2326_isreg_writeable(struct device *dev, unsigned int reg) +{ + switch (reg) { + case ZPA2326_REF_P_XL_REG: + case ZPA2326_REF_P_L_REG: + case ZPA2326_REF_P_H_REG: + case ZPA2326_RES_CONF_REG: + case ZPA2326_CTRL_REG0_REG: + case ZPA2326_CTRL_REG1_REG: + case ZPA2326_CTRL_REG2_REG: + case ZPA2326_CTRL_REG3_REG: + case ZPA2326_THS_P_LOW_REG: + case ZPA2326_THS_P_HIGH_REG: + return true; + + default: + return false; + } +} +EXPORT_SYMBOL_GPL(zpa2326_isreg_writeable); + +bool zpa2326_isreg_readable(struct device *dev, unsigned int reg) +{ + switch (reg) { + case ZPA2326_REF_P_XL_REG: + case ZPA2326_REF_P_L_REG: + case ZPA2326_REF_P_H_REG: + case ZPA2326_DEVICE_ID_REG: + case ZPA2326_RES_CONF_REG: + case ZPA2326_CTRL_REG0_REG: + case ZPA2326_CTRL_REG1_REG: + case ZPA2326_CTRL_REG2_REG: + case ZPA2326_CTRL_REG3_REG: + case ZPA2326_INT_SOURCE_REG: + case ZPA2326_THS_P_LOW_REG: + case ZPA2326_THS_P_HIGH_REG: + case ZPA2326_STATUS_REG: + case ZPA2326_PRESS_OUT_XL_REG: + case ZPA2326_PRESS_OUT_L_REG: + case ZPA2326_PRESS_OUT_H_REG: + case ZPA2326_TEMP_OUT_L_REG: + case ZPA2326_TEMP_OUT_H_REG: + return true; + + default: + return false; + } +} +EXPORT_SYMBOL_GPL(zpa2326_isreg_readable); + +bool zpa2326_isreg_precious(struct device *dev, unsigned int reg) +{ + switch (reg) { + case ZPA2326_INT_SOURCE_REG: + case ZPA2326_PRESS_OUT_H_REG: + return true; + + default: + return false; + } +} +EXPORT_SYMBOL_GPL(zpa2326_isreg_precious); + +/** + * zpa2326_enable_device() - Enable device, i.e. get out of low power mode. + * @indio_dev: The IIO device associated with the hardware to enable. + * + * Required to access complete register space and to perform any sampling + * or control operations. + * + * Return: Zero when successful, a negative error code otherwise. + */ +static int zpa2326_enable_device(const struct iio_dev *indio_dev) +{ + int err; + + err = regmap_write(((struct zpa2326_private *) + iio_priv(indio_dev))->regmap, + ZPA2326_CTRL_REG0_REG, ZPA2326_CTRL_REG0_ENABLE); + if (err) { + zpa2326_err(indio_dev, "failed to enable device (%d)", err); + return err; + } + + zpa2326_dbg(indio_dev, "enabled"); + + return 0; +} + +/** + * zpa2326_sleep() - Disable device, i.e. switch to low power mode. + * @indio_dev: The IIO device associated with the hardware to disable. + * + * Only %ZPA2326_DEVICE_ID_REG and %ZPA2326_CTRL_REG0_REG registers may be + * accessed once device is in the disabled state. + * + * Return: Zero when successful, a negative error code otherwise. + */ +static int zpa2326_sleep(const struct iio_dev *indio_dev) +{ + int err; + + err = regmap_write(((struct zpa2326_private *) + iio_priv(indio_dev))->regmap, + ZPA2326_CTRL_REG0_REG, 0); + if (err) { + zpa2326_err(indio_dev, "failed to sleep (%d)", err); + return err; + } + + zpa2326_dbg(indio_dev, "sleeping"); + + return 0; +} + +/** + * zpa2326_reset_device() - Reset device to default hardware state. + * @indio_dev: The IIO device associated with the hardware to reset. + * + * Disable sampling and empty hardware FIFO. + * Device must be enabled before reset, i.e. not in low power mode. + * + * Return: Zero when successful, a negative error code otherwise. + */ +static int zpa2326_reset_device(const struct iio_dev *indio_dev) +{ + int err; + + err = regmap_write(((struct zpa2326_private *) + iio_priv(indio_dev))->regmap, + ZPA2326_CTRL_REG2_REG, ZPA2326_CTRL_REG2_SWRESET); + if (err) { + zpa2326_err(indio_dev, "failed to reset device (%d)", err); + return err; + } + + usleep_range(ZPA2326_TPUP_USEC_MIN, ZPA2326_TPUP_USEC_MAX); + + zpa2326_dbg(indio_dev, "reset"); + + return 0; +} + +/** + * zpa2326_start_oneshot() - Start a single sampling cycle, i.e. in one shot + * mode. + * @indio_dev: The IIO device associated with the sampling hardware. + * + * Device must have been previously enabled and configured for one shot mode. + * Device will be switched back to low power mode at end of cycle. + * + * Return: Zero when successful, a negative error code otherwise. + */ +static int zpa2326_start_oneshot(const struct iio_dev *indio_dev) +{ + int err; + + err = regmap_write(((struct zpa2326_private *) + iio_priv(indio_dev))->regmap, + ZPA2326_CTRL_REG0_REG, + ZPA2326_CTRL_REG0_ENABLE | + ZPA2326_CTRL_REG0_ONE_SHOT); + if (err) { + zpa2326_err(indio_dev, "failed to start one shot cycle (%d)", + err); + return err; + } + + zpa2326_dbg(indio_dev, "one shot cycle started"); + + return 0; +} + +/** + * zpa2326_power_on() - Power on device to allow subsequent configuration. + * @indio_dev: The IIO device associated with the sampling hardware. + * @private: Internal private state related to @indio_dev. + * + * Sampling will be disabled, preventing strange things from happening in our + * back. Hardware FIFO content will be cleared. + * When successful, device will be left in the enabled state to allow further + * configuration. + * + * Return: Zero when successful, a negative error code otherwise. + */ +static int zpa2326_power_on(const struct iio_dev *indio_dev, + const struct zpa2326_private *private) +{ + int err; + + err = regulator_enable(private->vref); + if (err) + return err; + + err = regulator_enable(private->vdd); + if (err) + goto vref; + + zpa2326_dbg(indio_dev, "powered on"); + + err = zpa2326_enable_device(indio_dev); + if (err) + goto vdd; + + err = zpa2326_reset_device(indio_dev); + if (err) + goto sleep; + + return 0; + +sleep: + zpa2326_sleep(indio_dev); +vdd: + regulator_disable(private->vdd); +vref: + regulator_disable(private->vref); + + zpa2326_dbg(indio_dev, "powered off"); + + return err; +} + +/** + * zpa2326_power_off() - Power off device, i.e. disable attached power + * regulators. + * @indio_dev: The IIO device associated with the sampling hardware. + * @private: Internal private state related to @indio_dev. + * + * Return: Zero when successful, a negative error code otherwise. + */ +static void zpa2326_power_off(const struct iio_dev *indio_dev, + const struct zpa2326_private *private) +{ + regulator_disable(private->vdd); + regulator_disable(private->vref); + + zpa2326_dbg(indio_dev, "powered off"); +} + +/** + * zpa2326_config_oneshot() - Setup device for one shot / on demand mode. + * @indio_dev: The IIO device associated with the sampling hardware. + * @irq: Optional interrupt line the hardware uses to notify new data + * samples are ready. Negative or zero values indicate no interrupts + * are available, meaning polling is required. + * + * Output Data Rate is configured for the highest possible rate so that + * conversion time and power consumption are reduced to a minimum. + * Note that hardware internal averaging machinery (not implemented in this + * driver) is not applicable in this mode. + * + * Device must have been previously enabled before calling + * zpa2326_config_oneshot(). + * + * Return: Zero when successful, a negative error code otherwise. + */ +static int zpa2326_config_oneshot(const struct iio_dev *indio_dev, + int irq) +{ + struct regmap *regs = ((struct zpa2326_private *) + iio_priv(indio_dev))->regmap; + const struct zpa2326_frequency *freq = zpa2326_highest_frequency(); + int err; + + /* Setup highest available Output Data Rate for one shot mode. */ + err = regmap_write(regs, ZPA2326_CTRL_REG3_REG, freq->odr); + if (err) + return err; + + if (irq > 0) { + /* Request interrupt when new sample is available. */ + err = regmap_write(regs, ZPA2326_CTRL_REG1_REG, + (u8)~ZPA2326_CTRL_REG1_MASK_DATA_READY); + + if (err) { + dev_err(indio_dev->dev.parent, + "failed to setup one shot mode (%d)", err); + return err; + } + } + + zpa2326_dbg(indio_dev, "one shot mode setup @%dHz", freq->hz); + + return 0; +} + +/** + * zpa2326_clear_fifo() - Clear remaining entries in hardware FIFO. + * @indio_dev: The IIO device associated with the sampling hardware. + * @min_count: Number of samples present within hardware FIFO. + * + * @min_count argument is a hint corresponding to the known minimum number of + * samples currently living in the FIFO. This allows to reduce the number of bus + * accesses by skipping status register read operation as long as we know for + * sure there are still entries left. + * + * Return: Zero when successful, a negative error code otherwise. + */ +static int zpa2326_clear_fifo(const struct iio_dev *indio_dev, + unsigned int min_count) +{ + struct regmap *regs = ((struct zpa2326_private *) + iio_priv(indio_dev))->regmap; + int err; + unsigned int val; + + if (!min_count) { + /* + * No hint: read status register to determine whether FIFO is + * empty or not. + */ + err = regmap_read(regs, ZPA2326_STATUS_REG, &val); + + if (err < 0) + goto err; + + if (val & ZPA2326_STATUS_FIFO_E) + /* Fifo is empty: nothing to trash. */ + return 0; + } + + /* Clear FIFO. */ + do { + /* + * A single fetch from pressure MSB register is enough to pop + * values out of FIFO. + */ + err = regmap_read(regs, ZPA2326_PRESS_OUT_H_REG, &val); + if (err < 0) + goto err; + + if (min_count) { + /* + * We know for sure there are at least min_count entries + * left in FIFO. Skip status register read. + */ + min_count--; + continue; + } + + err = regmap_read(regs, ZPA2326_STATUS_REG, &val); + if (err < 0) + goto err; + + } while (!(val & ZPA2326_STATUS_FIFO_E)); + + zpa2326_dbg(indio_dev, "FIFO cleared"); + + return 0; + +err: + zpa2326_err(indio_dev, "failed to clear FIFO (%d)", err); + + return err; +} + +/** + * zpa2326_dequeue_pressure() - Retrieve the most recent pressure sample from + * hardware FIFO. + * @indio_dev: The IIO device associated with the sampling hardware. + * @pressure: Sampled pressure output. + * + * Note that ZPA2326 hardware FIFO stores pressure samples only. + * + * Return: Zero when successful, a negative error code otherwise. + */ +static int zpa2326_dequeue_pressure(const struct iio_dev *indio_dev, + u32 *pressure) +{ + struct regmap *regs = ((struct zpa2326_private *) + iio_priv(indio_dev))->regmap; + unsigned int val; + int err; + int cleared = -1; + + err = regmap_read(regs, ZPA2326_STATUS_REG, &val); + if (err < 0) + return err; + + *pressure = 0; + + if (val & ZPA2326_STATUS_P_OR) { + /* + * Fifo overrun : first sample dequeued from FIFO is the + * newest. + */ + zpa2326_warn(indio_dev, "FIFO overflow"); + + err = regmap_bulk_read(regs, ZPA2326_PRESS_OUT_XL_REG, pressure, + 3); + if (err) + return err; + +#define ZPA2326_FIFO_DEPTH (16U) + /* Hardware FIFO may hold no more than 16 pressure samples. */ + return zpa2326_clear_fifo(indio_dev, ZPA2326_FIFO_DEPTH - 1); + } + + /* + * Fifo has not overflown : retrieve newest sample. We need to pop + * values out until FIFO is empty : last fetched pressure is the newest. + * In nominal cases, we should find a single queued sample only. + */ + do { + err = regmap_bulk_read(regs, ZPA2326_PRESS_OUT_XL_REG, pressure, + 3); + if (err) + return err; + + err = regmap_read(regs, ZPA2326_STATUS_REG, &val); + if (err < 0) + return err; + + cleared++; + } while (!(val & ZPA2326_STATUS_FIFO_E)); + + if (cleared) + /* + * Samples were pushed by hardware during previous rounds but we + * didn't consume them fast enough: inform user. + */ + zpa2326_dbg(indio_dev, "cleared %d FIFO entries", cleared); + + return 0; +} + +/** + * zpa2326_fill_sample_buffer() - Enqueue new channel samples to IIO buffer. + * @indio_dev: The IIO device associated with the sampling hardware. + * @private: Internal private state related to @indio_dev. + * + * Return: Zero when successful, a negative error code otherwise. + */ +static int zpa2326_fill_sample_buffer(struct iio_dev *indio_dev, + const struct zpa2326_private *private) +{ + struct { + u32 pressure; + u16 temperature; + u64 timestamp; + } sample; + int err; + + if (test_bit(0, indio_dev->active_scan_mask)) { + /* Get current pressure from hardware FIFO. */ + err = zpa2326_dequeue_pressure(indio_dev, &sample.pressure); + if (err) { + zpa2326_warn(indio_dev, "failed to fetch pressure (%d)", + err); + return err; + } + } + + if (test_bit(1, indio_dev->active_scan_mask)) { + /* Get current temperature. */ + err = regmap_bulk_read(private->regmap, ZPA2326_TEMP_OUT_L_REG, + &sample.temperature, 2); + if (err) { + zpa2326_warn(indio_dev, + "failed to fetch temperature (%d)", err); + return err; + } + } + + /* + * Now push samples using timestamp stored either : + * - by hardware interrupt handler if interrupt is available: see + * zpa2326_handle_irq(), + * - or oneshot completion polling machinery : see + * zpa2326_trigger_handler(). + */ + zpa2326_dbg(indio_dev, "filling raw samples buffer"); + + iio_push_to_buffers_with_timestamp(indio_dev, &sample, + private->timestamp); + + return 0; +} + +#ifdef CONFIG_PM +static int zpa2326_runtime_suspend(struct device *parent) +{ + const struct iio_dev *indio_dev = dev_get_drvdata(parent); + + if (pm_runtime_autosuspend_expiration(parent)) + /* Userspace changed autosuspend delay. */ + return -EAGAIN; + + zpa2326_power_off(indio_dev, iio_priv(indio_dev)); + + return 0; +} + +static int zpa2326_runtime_resume(struct device *parent) +{ + const struct iio_dev *indio_dev = dev_get_drvdata(parent); + + return zpa2326_power_on(indio_dev, iio_priv(indio_dev)); +} + +const struct dev_pm_ops zpa2326_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, + pm_runtime_force_resume) + SET_RUNTIME_PM_OPS(zpa2326_runtime_suspend, zpa2326_runtime_resume, + NULL) +}; +EXPORT_SYMBOL_GPL(zpa2326_pm_ops); + +/** + * zpa2326_resume() - Request the PM layer to power supply the device. + * @indio_dev: The IIO device associated with the sampling hardware. + * + * Return: + * < 0 - a negative error code meaning failure ; + * 0 - success, device has just been powered up ; + * 1 - success, device was already powered. + */ +static int zpa2326_resume(const struct iio_dev *indio_dev) +{ + int err; + + err = pm_runtime_get_sync(indio_dev->dev.parent); + if (err < 0) { + pm_runtime_put(indio_dev->dev.parent); + return err; + } + + if (err > 0) { + /* + * Device was already power supplied: get it out of low power + * mode and inform caller. + */ + zpa2326_enable_device(indio_dev); + return 1; + } + + /* Inform caller device has just been brought back to life. */ + return 0; +} + +/** + * zpa2326_suspend() - Schedule a power down using autosuspend feature of PM + * layer. + * @indio_dev: The IIO device associated with the sampling hardware. + * + * Device is switched to low power mode at first to save power even when + * attached regulator is a "dummy" one. + */ +static void zpa2326_suspend(struct iio_dev *indio_dev) +{ + struct device *parent = indio_dev->dev.parent; + + zpa2326_sleep(indio_dev); + + pm_runtime_mark_last_busy(parent); + pm_runtime_put_autosuspend(parent); +} + +static void zpa2326_init_runtime(struct device *parent) +{ + pm_runtime_get_noresume(parent); + pm_runtime_set_active(parent); + pm_runtime_enable(parent); + pm_runtime_set_autosuspend_delay(parent, 1000); + pm_runtime_use_autosuspend(parent); + pm_runtime_mark_last_busy(parent); + pm_runtime_put_autosuspend(parent); +} + +static void zpa2326_fini_runtime(struct device *parent) +{ + pm_runtime_disable(parent); + pm_runtime_set_suspended(parent); +} +#else /* !CONFIG_PM */ +static int zpa2326_resume(const struct iio_dev *indio_dev) +{ + zpa2326_enable_device(indio_dev); + + return 0; +} + +static void zpa2326_suspend(struct iio_dev *indio_dev) +{ + zpa2326_sleep(indio_dev); +} + +#define zpa2326_init_runtime(_parent) +#define zpa2326_fini_runtime(_parent) +#endif /* !CONFIG_PM */ + +/** + * zpa2326_handle_irq() - Process hardware interrupts. + * @irq: Interrupt line the hardware uses to notify new data has arrived. + * @data: The IIO device associated with the sampling hardware. + * + * Timestamp buffered samples as soon as possible then schedule threaded bottom + * half. + * + * Return: Always successful. + */ +static irqreturn_t zpa2326_handle_irq(int irq, void *data) +{ + struct iio_dev *indio_dev = data; + + if (iio_buffer_enabled(indio_dev)) { + /* Timestamping needed for buffered sampling only. */ + ((struct zpa2326_private *) + iio_priv(indio_dev))->timestamp = iio_get_time_ns(indio_dev); + } + + return IRQ_WAKE_THREAD; +} + +/** + * zpa2326_handle_threaded_irq() - Interrupt bottom-half handler. + * @irq: Interrupt line the hardware uses to notify new data has arrived. + * @data: The IIO device associated with the sampling hardware. + * + * Mainly ensures interrupt is caused by a real "new sample available" + * condition. This relies upon the ability to perform blocking / sleeping bus + * accesses to slave's registers. This is why zpa2326_handle_threaded_irq() is + * called from within a thread, i.e. not called from hard interrupt context. + * + * When device is using its own internal hardware trigger in continuous sampling + * mode, data are available into hardware FIFO once interrupt has occurred. All + * we have to do is to dispatch the trigger, which in turn will fetch data and + * fill IIO buffer. + * + * When not using its own internal hardware trigger, the device has been + * configured in one-shot mode either by an external trigger or the IIO read_raw + * hook. This means one of the latter is currently waiting for sampling + * completion, in which case we must simply wake it up. + * + * See zpa2326_trigger_handler(). + * + * Return: + * %IRQ_NONE - no consistent interrupt happened ; + * %IRQ_HANDLED - there was new samples available. + */ +static irqreturn_t zpa2326_handle_threaded_irq(int irq, void *data) +{ + struct iio_dev *indio_dev = data; + struct zpa2326_private *priv = iio_priv(indio_dev); + unsigned int val; + bool cont; + irqreturn_t ret = IRQ_NONE; + + /* + * Are we using our own internal trigger in triggered buffer mode, i.e., + * currently working in continuous sampling mode ? + */ + cont = (iio_buffer_enabled(indio_dev) && + iio_trigger_using_own(indio_dev)); + + /* + * Device works according to a level interrupt scheme: reading interrupt + * status de-asserts interrupt line. + */ + priv->result = regmap_read(priv->regmap, ZPA2326_INT_SOURCE_REG, &val); + if (priv->result < 0) { + if (cont) + return IRQ_NONE; + + goto complete; + } + + /* Data ready is the only interrupt source we requested. */ + if (!(val & ZPA2326_INT_SOURCE_DATA_READY)) { + /* + * Interrupt happened but no new sample available: likely caused + * by spurious interrupts, in which case, returning IRQ_NONE + * allows to benefit from the generic spurious interrupts + * handling. + */ + zpa2326_warn(indio_dev, "unexpected interrupt status %02x", + val); + + if (cont) + return IRQ_NONE; + + priv->result = -ENODATA; + goto complete; + } + + /* New sample available: dispatch internal trigger consumers. */ + iio_trigger_poll_chained(priv->trigger); + + if (cont) + /* + * Internal hardware trigger has been scheduled above : it will + * fetch data on its own. + */ + return IRQ_HANDLED; + + ret = IRQ_HANDLED; + +complete: + /* + * Wake up direct or externaly triggered buffer mode waiters: see + * zpa2326_sample_oneshot() and zpa2326_trigger_handler(). + */ + complete(&priv->data_ready); + + return ret; +} + +/** + * zpa2326_wait_oneshot_completion() - Wait for oneshot data ready interrupt. + * @indio_dev: The IIO device associated with the sampling hardware. + * @private: Internal private state related to @indio_dev. + * + * Return: Zero when successful, a negative error code otherwise. + */ +static int zpa2326_wait_oneshot_completion(const struct iio_dev *indio_dev, + struct zpa2326_private *private) +{ + unsigned int val; + long timeout; + + zpa2326_dbg(indio_dev, "waiting for one shot completion interrupt"); + + timeout = wait_for_completion_interruptible_timeout( + &private->data_ready, ZPA2326_CONVERSION_JIFFIES); + if (timeout > 0) + /* + * Interrupt handler completed before timeout: return operation + * status. + */ + return private->result; + + /* Clear all interrupts just to be sure. */ + regmap_read(private->regmap, ZPA2326_INT_SOURCE_REG, &val); + + if (!timeout) { + /* Timed out. */ + zpa2326_warn(indio_dev, "no one shot interrupt occurred (%ld)", + timeout); + return -ETIME; + } + + zpa2326_warn(indio_dev, "wait for one shot interrupt cancelled"); + return -ERESTARTSYS; +} + +static int zpa2326_init_managed_irq(struct device *parent, + struct iio_dev *indio_dev, + struct zpa2326_private *private, + int irq) +{ + int err; + + private->irq = irq; + + if (irq <= 0) { + /* + * Platform declared no interrupt line: device will be polled + * for data availability. + */ + dev_info(parent, "no interrupt found, running in polling mode"); + return 0; + } + + init_completion(&private->data_ready); + + /* Request handler to be scheduled into threaded interrupt context. */ + err = devm_request_threaded_irq(parent, irq, zpa2326_handle_irq, + zpa2326_handle_threaded_irq, + IRQF_TRIGGER_RISING | IRQF_ONESHOT, + dev_name(parent), indio_dev); + if (err) { + dev_err(parent, "failed to request interrupt %d (%d)", irq, + err); + return err; + } + + dev_info(parent, "using interrupt %d", irq); + + return 0; +} + +/** + * zpa2326_poll_oneshot_completion() - Actively poll for one shot data ready. + * @indio_dev: The IIO device associated with the sampling hardware. + * + * Loop over registers content to detect end of sampling cycle. Used when DT + * declared no valid interrupt lines. + * + * Return: Zero when successful, a negative error code otherwise. + */ +static int zpa2326_poll_oneshot_completion(const struct iio_dev *indio_dev) +{ + unsigned long tmout = jiffies + ZPA2326_CONVERSION_JIFFIES; + struct regmap *regs = ((struct zpa2326_private *) + iio_priv(indio_dev))->regmap; + unsigned int val; + int err; + + zpa2326_dbg(indio_dev, "polling for one shot completion"); + + /* + * At least, 100 ms is needed for the device to complete its one-shot + * cycle. + */ + if (msleep_interruptible(100)) + return -ERESTARTSYS; + + /* Poll for conversion completion in hardware. */ + while (true) { + err = regmap_read(regs, ZPA2326_CTRL_REG0_REG, &val); + if (err < 0) + goto err; + + if (!(val & ZPA2326_CTRL_REG0_ONE_SHOT)) + /* One-shot bit self clears at conversion end. */ + break; + + if (time_after(jiffies, tmout)) { + /* Prevent from waiting forever : let's time out. */ + err = -ETIME; + goto err; + } + + usleep_range(10000, 20000); + } + + /* + * In oneshot mode, pressure sample availability guarantees that + * temperature conversion has also completed : just check pressure + * status bit to keep things simple. + */ + err = regmap_read(regs, ZPA2326_STATUS_REG, &val); + if (err < 0) + goto err; + + if (!(val & ZPA2326_STATUS_P_DA)) { + /* No sample available. */ + err = -ENODATA; + goto err; + } + + return 0; + +err: + zpa2326_warn(indio_dev, "failed to poll one shot completion (%d)", err); + + return err; +} + +/** + * zpa2326_fetch_raw_sample() - Retrieve a raw sample and convert it to CPU + * endianness. + * @indio_dev: The IIO device associated with the sampling hardware. + * @type: Type of measurement / channel to fetch from. + * @value: Sample output. + * + * Return: Zero when successful, a negative error code otherwise. + */ +static int zpa2326_fetch_raw_sample(const struct iio_dev *indio_dev, + enum iio_chan_type type, + int *value) +{ + struct regmap *regs = ((struct zpa2326_private *) + iio_priv(indio_dev))->regmap; + int err; + + switch (type) { + case IIO_PRESSURE: + zpa2326_dbg(indio_dev, "fetching raw pressure sample"); + + err = regmap_bulk_read(regs, ZPA2326_PRESS_OUT_XL_REG, value, + 3); + if (err) { + zpa2326_warn(indio_dev, "failed to fetch pressure (%d)", + err); + return err; + } + + /* Pressure is a 24 bits wide little-endian unsigned int. */ + *value = (((u8 *)value)[2] << 16) | (((u8 *)value)[1] << 8) | + ((u8 *)value)[0]; + + return IIO_VAL_INT; + + case IIO_TEMP: + zpa2326_dbg(indio_dev, "fetching raw temperature sample"); + + err = regmap_bulk_read(regs, ZPA2326_TEMP_OUT_L_REG, value, 2); + if (err) { + zpa2326_warn(indio_dev, + "failed to fetch temperature (%d)", err); + return err; + } + + /* Temperature is a 16 bits wide little-endian signed int. */ + *value = (int)le16_to_cpup((__le16 *)value); + + return IIO_VAL_INT; + + default: + return -EINVAL; + } +} + +/** + * zpa2326_sample_oneshot() - Perform a complete one shot sampling cycle. + * @indio_dev: The IIO device associated with the sampling hardware. + * @type: Type of measurement / channel to fetch from. + * @value: Sample output. + * + * Return: Zero when successful, a negative error code otherwise. + */ +static int zpa2326_sample_oneshot(struct iio_dev *indio_dev, + enum iio_chan_type type, + int *value) +{ + int ret; + struct zpa2326_private *priv; + + ret = iio_device_claim_direct_mode(indio_dev); + if (ret) + return ret; + + ret = zpa2326_resume(indio_dev); + if (ret < 0) + goto release; + + priv = iio_priv(indio_dev); + + if (ret > 0) { + /* + * We were already power supplied. Just clear hardware FIFO to + * get rid of samples acquired during previous rounds (if any). + * Sampling operation always generates both temperature and + * pressure samples. The latter are always enqueued into + * hardware FIFO. This may lead to situations were pressure + * samples still sit into FIFO when previous cycle(s) fetched + * temperature data only. + * Hence, we need to clear hardware FIFO content to prevent from + * getting outdated values at the end of current cycle. + */ + if (type == IIO_PRESSURE) { + ret = zpa2326_clear_fifo(indio_dev, 0); + if (ret) + goto suspend; + } + } else { + /* + * We have just been power supplied, i.e. device is in default + * "out of reset" state, meaning we need to reconfigure it + * entirely. + */ + ret = zpa2326_config_oneshot(indio_dev, priv->irq); + if (ret) + goto suspend; + } + + /* Start a sampling cycle in oneshot mode. */ + ret = zpa2326_start_oneshot(indio_dev); + if (ret) + goto suspend; + + /* Wait for sampling cycle to complete. */ + if (priv->irq > 0) + ret = zpa2326_wait_oneshot_completion(indio_dev, priv); + else + ret = zpa2326_poll_oneshot_completion(indio_dev); + + if (ret) + goto suspend; + + /* Retrieve raw sample value and convert it to CPU endianness. */ + ret = zpa2326_fetch_raw_sample(indio_dev, type, value); + +suspend: + zpa2326_suspend(indio_dev); +release: + iio_device_release_direct_mode(indio_dev); + + return ret; +} + +/** + * zpa2326_trigger_handler() - Perform an IIO buffered sampling round in one + * shot mode. + * @irq: The software interrupt assigned to @data + * @data: The IIO poll function dispatched by external trigger our device is + * attached to. + * + * Bottom-half handler called by the IIO trigger to which our device is + * currently attached. Allows us to synchronize this device buffered sampling + * either with external events (such as timer expiration, external device sample + * ready, etc...) or with its own interrupt (internal hardware trigger). + * + * When using an external trigger, basically run the same sequence of operations + * as for zpa2326_sample_oneshot() with the following hereafter. Hardware FIFO + * is not cleared since already done at buffering enable time and samples + * dequeueing always retrieves the most recent value. + * + * Otherwise, when internal hardware trigger has dispatched us, just fetch data + * from hardware FIFO. + * + * Fetched data will pushed unprocessed to IIO buffer since samples conversion + * is delegated to userspace in buffered mode (endianness, etc...). + * + * Return: + * %IRQ_NONE - no consistent interrupt happened ; + * %IRQ_HANDLED - there was new samples available. + */ +static irqreturn_t zpa2326_trigger_handler(int irq, void *data) +{ + struct iio_dev *indio_dev = ((struct iio_poll_func *) + data)->indio_dev; + struct zpa2326_private *priv = iio_priv(indio_dev); + bool cont; + + /* + * We have been dispatched, meaning we are in triggered buffer mode. + * Using our own internal trigger implies we are currently in continuous + * hardware sampling mode. + */ + cont = iio_trigger_using_own(indio_dev); + + if (!cont) { + /* On demand sampling : start a one shot cycle. */ + if (zpa2326_start_oneshot(indio_dev)) + goto out; + + /* Wait for sampling cycle to complete. */ + if (priv->irq <= 0) { + /* No interrupt available: poll for completion. */ + if (zpa2326_poll_oneshot_completion(indio_dev)) + goto out; + + /* Only timestamp sample once it is ready. */ + priv->timestamp = iio_get_time_ns(indio_dev); + } else { + /* Interrupt handlers will timestamp for us. */ + if (zpa2326_wait_oneshot_completion(indio_dev, priv)) + goto out; + } + } + + /* Enqueue to IIO buffer / userspace. */ + zpa2326_fill_sample_buffer(indio_dev, priv); + +out: + if (!cont) + /* Don't switch to low power if sampling continuously. */ + zpa2326_sleep(indio_dev); + + /* Inform attached trigger we are done. */ + iio_trigger_notify_done(indio_dev->trig); + + return IRQ_HANDLED; +} + +/** + * zpa2326_preenable_buffer() - Prepare device for configuring triggered + * sampling + * modes. + * @indio_dev: The IIO device associated with the sampling hardware. + * + * Basically power up device. + * Called with IIO device's lock held. + * + * Return: Zero when successful, a negative error code otherwise. + */ +static int zpa2326_preenable_buffer(struct iio_dev *indio_dev) +{ + int ret = zpa2326_resume(indio_dev); + + if (ret < 0) + return ret; + + /* Tell zpa2326_postenable_buffer() if we have just been powered on. */ + ((struct zpa2326_private *) + iio_priv(indio_dev))->waken = iio_priv(indio_dev); + + return 0; +} + +/** + * zpa2326_postenable_buffer() - Configure device for triggered sampling. + * @indio_dev: The IIO device associated with the sampling hardware. + * + * Basically setup one-shot mode if plugging external trigger. + * Otherwise, let internal trigger configure continuous sampling : + * see zpa2326_set_trigger_state(). + * + * If an error is returned, IIO layer will call our postdisable hook for us, + * i.e. no need to explicitly power device off here. + * Called with IIO device's lock held. + * + * Called with IIO device's lock held. + * + * Return: Zero when successful, a negative error code otherwise. + */ +static int zpa2326_postenable_buffer(struct iio_dev *indio_dev) +{ + const struct zpa2326_private *priv = iio_priv(indio_dev); + int err; + + if (!priv->waken) { + /* + * We were already power supplied. Just clear hardware FIFO to + * get rid of samples acquired during previous rounds (if any). + */ + err = zpa2326_clear_fifo(indio_dev, 0); + if (err) + goto err; + } + + if (!iio_trigger_using_own(indio_dev) && priv->waken) { + /* + * We are using an external trigger and we have just been + * powered up: reconfigure one-shot mode. + */ + err = zpa2326_config_oneshot(indio_dev, priv->irq); + if (err) + goto err; + } + + /* Plug our own trigger event handler. */ + err = iio_triggered_buffer_postenable(indio_dev); + if (err) + goto err; + + return 0; + +err: + zpa2326_err(indio_dev, "failed to enable buffering (%d)", err); + + return err; +} + +static int zpa2326_postdisable_buffer(struct iio_dev *indio_dev) +{ + zpa2326_suspend(indio_dev); + + return 0; +} + +static const struct iio_buffer_setup_ops zpa2326_buffer_setup_ops = { + .preenable = zpa2326_preenable_buffer, + .postenable = zpa2326_postenable_buffer, + .predisable = iio_triggered_buffer_predisable, + .postdisable = zpa2326_postdisable_buffer +}; + +/** + * zpa2326_set_trigger_state() - Start / stop continuous sampling. + * @trig: The trigger being attached to IIO device associated with the sampling + * hardware. + * @state: Tell whether to start (true) or stop (false) + * + * Basically enable / disable hardware continuous sampling mode. + * + * Called with IIO device's lock held at postenable() or predisable() time. + * + * Return: Zero when successful, a negative error code otherwise. + */ +static int zpa2326_set_trigger_state(struct iio_trigger *trig, bool state) +{ + const struct iio_dev *indio_dev = dev_get_drvdata( + trig->dev.parent); + const struct zpa2326_private *priv = iio_priv(indio_dev); + int err; + + if (!state) { + /* + * Switch trigger off : in case of failure, interrupt is left + * disabled in order to prevent handler from accessing released + * resources. + */ + unsigned int val; + + /* + * As device is working in continuous mode, handlers may be + * accessing resources we are currently freeing... + * Prevent this by disabling interrupt handlers and ensure + * the device will generate no more interrupts unless explicitly + * required to, i.e. by restoring back to default one shot mode. + */ + disable_irq(priv->irq); + + /* + * Disable continuous sampling mode to restore settings for + * one shot / direct sampling operations. + */ + err = regmap_write(priv->regmap, ZPA2326_CTRL_REG3_REG, + zpa2326_highest_frequency()->odr); + if (err) + return err; + + /* + * Now that device won't generate interrupts on its own, + * acknowledge any currently active interrupts (may happen on + * rare occasions while stopping continuous mode). + */ + err = regmap_read(priv->regmap, ZPA2326_INT_SOURCE_REG, &val); + if (err < 0) + return err; + + /* + * Re-enable interrupts only if we can guarantee the device will + * generate no more interrupts to prevent handlers from + * accessing released resources. + */ + enable_irq(priv->irq); + + zpa2326_dbg(indio_dev, "continuous mode stopped"); + } else { + /* + * Switch trigger on : start continuous sampling at required + * frequency. + */ + + if (priv->waken) { + /* Enable interrupt if getting out of reset. */ + err = regmap_write(priv->regmap, ZPA2326_CTRL_REG1_REG, + (u8) + ~ZPA2326_CTRL_REG1_MASK_DATA_READY); + if (err) + return err; + } + + /* Enable continuous sampling at specified frequency. */ + err = regmap_write(priv->regmap, ZPA2326_CTRL_REG3_REG, + ZPA2326_CTRL_REG3_ENABLE_MEAS | + priv->frequency->odr); + if (err) + return err; + + zpa2326_dbg(indio_dev, "continuous mode setup @%dHz", + priv->frequency->hz); + } + + return 0; +} + +static const struct iio_trigger_ops zpa2326_trigger_ops = { + .set_trigger_state = zpa2326_set_trigger_state, +}; + +/** + * zpa2326_init_trigger() - Create an interrupt driven / hardware trigger + * allowing to notify external devices a new sample is + * ready. + * @parent: Hardware sampling device @indio_dev is a child of. + * @indio_dev: The IIO device associated with the sampling hardware. + * @private: Internal private state related to @indio_dev. + * @irq: Optional interrupt line the hardware uses to notify new data + * samples are ready. Negative or zero values indicate no interrupts + * are available, meaning polling is required. + * + * Only relevant when DT declares a valid interrupt line. + * + * Return: Zero when successful, a negative error code otherwise. + */ +static int zpa2326_init_managed_trigger(struct device *parent, + struct iio_dev *indio_dev, + struct zpa2326_private *private, + int irq) +{ + struct iio_trigger *trigger; + int ret; + + if (irq <= 0) + return 0; + + trigger = devm_iio_trigger_alloc(parent, "%s-dev%d", + indio_dev->name, indio_dev->id); + if (!trigger) + return -ENOMEM; + + /* Basic setup. */ + trigger->dev.parent = parent; + trigger->ops = &zpa2326_trigger_ops; + + private->trigger = trigger; + + /* Register to triggers space. */ + ret = devm_iio_trigger_register(parent, trigger); + if (ret) + dev_err(parent, "failed to register hardware trigger (%d)", + ret); + + return ret; +} + +static int zpa2326_get_frequency(const struct iio_dev *indio_dev) +{ + return ((struct zpa2326_private *)iio_priv(indio_dev))->frequency->hz; +} + +static int zpa2326_set_frequency(struct iio_dev *indio_dev, int hz) +{ + struct zpa2326_private *priv = iio_priv(indio_dev); + int freq; + int err; + + /* Check if requested frequency is supported. */ + for (freq = 0; freq < ARRAY_SIZE(zpa2326_sampling_frequencies); freq++) + if (zpa2326_sampling_frequencies[freq].hz == hz) + break; + if (freq == ARRAY_SIZE(zpa2326_sampling_frequencies)) + return -EINVAL; + + /* Don't allow changing frequency if buffered sampling is ongoing. */ + err = iio_device_claim_direct_mode(indio_dev); + if (err) + return err; + + priv->frequency = &zpa2326_sampling_frequencies[freq]; + + iio_device_release_direct_mode(indio_dev); + + return 0; +} + +/* Expose supported hardware sampling frequencies (Hz) through sysfs. */ +static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("1 5 11 23"); + +static struct attribute *zpa2326_attributes[] = { + &iio_const_attr_sampling_frequency_available.dev_attr.attr, + NULL +}; + +static const struct attribute_group zpa2326_attribute_group = { + .attrs = zpa2326_attributes, +}; + +static int zpa2326_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, + int *val2, + long mask) +{ + switch (mask) { + case IIO_CHAN_INFO_RAW: + return zpa2326_sample_oneshot(indio_dev, chan->type, val); + + case IIO_CHAN_INFO_SCALE: + switch (chan->type) { + case IIO_PRESSURE: + /* + * Pressure resolution is 1/64 Pascal. Scale to kPascal + * as required by IIO ABI. + */ + *val = 1; + *val2 = 64000; + return IIO_VAL_FRACTIONAL; + + case IIO_TEMP: + /* + * Temperature follows the equation: + * Temp[degC] = Tempcode * 0.00649 - 176.83 + * where: + * Tempcode is composed the raw sampled 16 bits. + * + * Hence, to produce a temperature in milli-degrees + * Celsius according to IIO ABI, we need to apply the + * following equation to raw samples: + * Temp[milli degC] = (Tempcode + Offset) * Scale + * where: + * Offset = -176.83 / 0.00649 + * Scale = 0.00649 * 1000 + */ + *val = 6; + *val2 = 490000; + return IIO_VAL_INT_PLUS_MICRO; + + default: + return -EINVAL; + } + + case IIO_CHAN_INFO_OFFSET: + switch (chan->type) { + case IIO_TEMP: + *val = -17683000; + *val2 = 649; + return IIO_VAL_FRACTIONAL; + + default: + return -EINVAL; + } + + case IIO_CHAN_INFO_SAMP_FREQ: + *val = zpa2326_get_frequency(indio_dev); + return IIO_VAL_INT; + + default: + return -EINVAL; + } +} + +static int zpa2326_write_raw(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + int val, + int val2, + long mask) +{ + if ((mask != IIO_CHAN_INFO_SAMP_FREQ) || val2) + return -EINVAL; + + return zpa2326_set_frequency(indio_dev, val); +} + +static const struct iio_chan_spec zpa2326_channels[] = { + [0] = { + .type = IIO_PRESSURE, + .scan_index = 0, + .scan_type = { + .sign = 'u', + .realbits = 24, + .storagebits = 32, + .endianness = IIO_LE, + }, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_SCALE), + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), + }, + [1] = { + .type = IIO_TEMP, + .scan_index = 1, + .scan_type = { + .sign = 's', + .realbits = 16, + .storagebits = 16, + .endianness = IIO_LE, + }, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_SCALE) | + BIT(IIO_CHAN_INFO_OFFSET), + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), + }, + [2] = IIO_CHAN_SOFT_TIMESTAMP(2), +}; + +static const struct iio_info zpa2326_info = { + .attrs = &zpa2326_attribute_group, + .read_raw = zpa2326_read_raw, + .write_raw = zpa2326_write_raw, +}; + +static struct iio_dev *zpa2326_create_managed_iiodev(struct device *device, + const char *name, + struct regmap *regmap) +{ + struct iio_dev *indio_dev; + + /* Allocate space to hold IIO device internal state. */ + indio_dev = devm_iio_device_alloc(device, + sizeof(struct zpa2326_private)); + if (!indio_dev) + return NULL; + + /* Setup for userspace synchronous on demand sampling. */ + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->dev.parent = device; + indio_dev->channels = zpa2326_channels; + indio_dev->num_channels = ARRAY_SIZE(zpa2326_channels); + indio_dev->name = name; + indio_dev->info = &zpa2326_info; + + return indio_dev; +} + +int zpa2326_probe(struct device *parent, + const char *name, + int irq, + unsigned int hwid, + struct regmap *regmap) +{ + struct iio_dev *indio_dev; + struct zpa2326_private *priv; + int err; + unsigned int id; + + indio_dev = zpa2326_create_managed_iiodev(parent, name, regmap); + if (!indio_dev) + return -ENOMEM; + + priv = iio_priv(indio_dev); + + priv->vref = devm_regulator_get(parent, "vref"); + if (IS_ERR(priv->vref)) + return PTR_ERR(priv->vref); + + priv->vdd = devm_regulator_get(parent, "vdd"); + if (IS_ERR(priv->vdd)) + return PTR_ERR(priv->vdd); + + /* Set default hardware sampling frequency to highest rate supported. */ + priv->frequency = zpa2326_highest_frequency(); + + /* + * Plug device's underlying bus abstraction : this MUST be set before + * registering interrupt handlers since an interrupt might happen if + * power up sequence is not properly applied. + */ + priv->regmap = regmap; + + err = devm_iio_triggered_buffer_setup(parent, indio_dev, NULL, + zpa2326_trigger_handler, + &zpa2326_buffer_setup_ops); + if (err) + return err; + + err = zpa2326_init_managed_trigger(parent, indio_dev, priv, irq); + if (err) + return err; + + err = zpa2326_init_managed_irq(parent, indio_dev, priv, irq); + if (err) + return err; + + /* Power up to check device ID and perform initial hardware setup. */ + err = zpa2326_power_on(indio_dev, priv); + if (err) + return err; + + /* Read id register to check we are talking to the right slave. */ + err = regmap_read(regmap, ZPA2326_DEVICE_ID_REG, &id); + if (err) + goto sleep; + + if (id != hwid) { + dev_err(parent, "found device with unexpected id %02x", id); + err = -ENODEV; + goto sleep; + } + + err = zpa2326_config_oneshot(indio_dev, irq); + if (err) + goto sleep; + + /* Setup done : go sleeping. Device will be awaken upon user request. */ + err = zpa2326_sleep(indio_dev); + if (err) + goto poweroff; + + dev_set_drvdata(parent, indio_dev); + + zpa2326_init_runtime(parent); + + err = iio_device_register(indio_dev); + if (err) { + zpa2326_fini_runtime(parent); + goto poweroff; + } + + return 0; + +sleep: + /* Put to sleep just in case power regulators are "dummy" ones. */ + zpa2326_sleep(indio_dev); +poweroff: + zpa2326_power_off(indio_dev, priv); + + return err; +} +EXPORT_SYMBOL_GPL(zpa2326_probe); + +void zpa2326_remove(const struct device *parent) +{ + struct iio_dev *indio_dev = dev_get_drvdata(parent); + + iio_device_unregister(indio_dev); + zpa2326_fini_runtime(indio_dev->dev.parent); + zpa2326_sleep(indio_dev); + zpa2326_power_off(indio_dev, iio_priv(indio_dev)); +} +EXPORT_SYMBOL_GPL(zpa2326_remove); + +MODULE_AUTHOR("Gregor Boirie <gregor.boirie@parrot.com>"); +MODULE_DESCRIPTION("Core driver for Murata ZPA2326 pressure sensor"); +MODULE_LICENSE("GPL v2"); |