Merge tag 'staging-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging

Pull staging and IIO updates from Greg KH:
 "Here is the big staging and IIO driver pull request for 4.9-rc1.

  There are a lot of patches in here, the majority due to the
  drivers/staging/greybus/ subsystem being merged in with full
  development history that went back a few years, in order to preserve
  the work that those developers did over time.

  Lots and lots of tiny cleanups happened in the tree as well, due to
  the Outreachy application process and lots of other developers showing
  up for the first time to clean code up.  Along with those changes, we
  deleted a wireless driver, and added a raspberrypi driver (currently
  marked broken), and lots of new iio drivers.

  Overall the tree still shrunk with more lines removed than added,
  about 10 thousand lines removed in total. Full details are in the very
  long shortlog below.

  All of this has been in the linux-next tree with no issues. There will
  be some merge problems with other subsystem trees, but those are all
  minor problems and shouldn't be hard to work out when they happen
  (MAINTAINERS and some lustre build problems with the IB tree)"

And furter from me asking for clarification about greybus:
 "Right now there is a phone from Motorola shipping with this code (a
  slightly older version, but the same tree), so even though Ara is not
  alive in the same form, the functionality is happening. We are working
  with the developers of that phone to merge the newer stuff in with
  their fork so they can use the upstream version in future versions of
  their phone product line.

  Toshiba has at least one chip shipping in their catalog that
  needs/uses this protocol over a Unipro link, and rumor has it that
  there might be more in the future.

  There are also other users of the greybus protocols, there is a talk
  next week at ELC that shows how it is being used across a network
  connection to control a device, and previous ELC talks have showed the
  protocol stack being used over USB to drive embedded Linux boards.
  I've also talked to some people who are starting to work to add a host
  controller driver to control arduinos as the greybus PHY protocols are
  very useful to control a serial/i2c/spio/whatever device across a
  random physical link, as it is a way to have a self-describing device
  be attached to a host without needing manual configuration.

  So yes, people are using it, and there is still the chance that it
  will show up in a phone/laptop/tablet/whatever from Google in the
  future as well, the tech isn't dead, even if the original large phone
  project happens to be"

* tag 'staging-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (3703 commits)
  Staging: fbtft: Fix bug in fbtft-core
  staging: rtl8188eu: fix double unlock error in rtw_resume_process()
  staging:r8188eu: remove GEN_MLME_EXT_HANDLER macro
  staging:r8188eu: remove GEN_DRV_CMD_HANDLER macro
  staging:r8188eu: remove GEN_EVT_CODE macro
  staging:r8188eu: remove GEN_CMD_CODE macro
  staging:r8188eu: remove pkt_newalloc member of the recv_buf structure
  staging:r8188eu: remove rtw_handle_dualmac declaration
  staging:r8188eu: remove (RGTRY|BSSID)_(OFT|SZ) macros
  staging:r8188eu: change rtl8188e_process_phy_info function argument type
  Staging: fsl-mc: Remove blank lines
  Staging: fsl-mc: Fix unaligned * in block comments
  Staging: comedi: Align the * in block comments
  Staging : ks7010 : Fix block comments warninig
  Staging: vt6655: Remove explicit NULL comparison using Coccinelle
  staging: rtl8188eu: core: rtw_xmit: Use macros instead of constants
  staging: rtl8188eu: core: rtw_xmit: Move constant of the right side
  staging: dgnc: Fix lines longer than 80 characters
  Staging: dgnc: constify attribute_group structures
  Staging: most: hdm-dim2: constify attribute_group structures
  ...

7 files changed, 2053 insertions, 4 deletions

diff --git a/drivers/iio/pressure/Kconfig b/drivers/iio/pressure/Kconfig
index 7fa65ab664fb..15cd416365c1 100644
--- a/drivers/iio/pressure/Kconfig
+++ b/drivers/iio/pressure/Kconfig
@@ -185,4 +185,26 @@ config HP206C
 	  This driver can also be built as a module. If so, the module will
 	  be called hp206c.
 
+config ZPA2326
+	tristate "Murata ZPA2326 pressure sensor driver"
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	select REGMAP
+	select ZPA2326_I2C if I2C
+	select ZPA2326_SPI if SPI_MASTER
+	help
+	  Say Y here to build support for the Murata ZPA2326 pressure and
+	  temperature sensor.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called zpa2326.
+
+config ZPA2326_I2C
+	tristate
+	select REGMAP_I2C
+
+config ZPA2326_SPI
+	tristate
+	select REGMAP_SPI
+
 endmenu
diff --git a/drivers/iio/pressure/Makefile b/drivers/iio/pressure/Makefile
index 7f395bed5e88..fff77185a5cc 100644
--- a/drivers/iio/pressure/Makefile
+++ b/drivers/iio/pressure/Makefile
@@ -22,6 +22,9 @@ st_pressure-y := st_pressure_core.o
 st_pressure-$(CONFIG_IIO_BUFFER) += st_pressure_buffer.o
 obj-$(CONFIG_T5403) += t5403.o
 obj-$(CONFIG_HP206C) += hp206c.o
+obj-$(CONFIG_ZPA2326) += zpa2326.o
+obj-$(CONFIG_ZPA2326_I2C) += zpa2326_i2c.o
+obj-$(CONFIG_ZPA2326_SPI) += zpa2326_spi.o
 
 obj-$(CONFIG_IIO_ST_PRESS_I2C) += st_pressure_i2c.o
 obj-$(CONFIG_IIO_ST_PRESS_SPI) += st_pressure_spi.o
diff --git a/drivers/iio/pressure/ms5611_core.c b/drivers/iio/pressure/ms5611_core.c
index feb41f82c64a..a74ed1f0c880 100644
--- a/drivers/iio/pressure/ms5611_core.c
+++ b/drivers/iio/pressure/ms5611_core.c
@@ -416,8 +416,7 @@ static int ms5611_init(struct iio_dev *indio_dev)
 	return 0;
 
 err_regulator_disable:
-	if (!IS_ERR_OR_NULL(st->vdd))
-		regulator_disable(st->vdd);
+	regulator_disable(st->vdd);
 	return ret;
 }
 
@@ -425,8 +424,7 @@ static void ms5611_fini(const struct iio_dev *indio_dev)
 {
 	const struct ms5611_state *st = iio_priv(indio_dev);
 
-	if (!IS_ERR_OR_NULL(st->vdd))
-		regulator_disable(st->vdd);
+	regulator_disable(st->vdd);
 }
 
 int ms5611_probe(struct iio_dev *indio_dev, struct device *dev,
diff --git a/drivers/iio/pressure/zpa2326.c b/drivers/iio/pressure/zpa2326.c
new file mode 100644
index 000000000000..19d2eb46fda6
--- /dev/null
+++ b/drivers/iio/pressure/zpa2326.c
@@ -0,0 +1,1735 @@
+/*
+ * 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, _format, _arg...) \
+	dev_err(_idev->dev.parent, _format, ##_arg)
+
+#define zpa2326_warn(_idev, _format, _arg...) \
+	dev_warn(_idev->dev.parent, _format, ##_arg)
+
+#ifdef DEBUG
+#define zpa2326_dbg(_idev, _format, _arg...) \
+	dev_dbg(_idev->dev.parent, _format, ##_arg)
+#else
+#define zpa2326_dbg(_idev, _format, _arg...)
+#endif
+
+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)
+		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 = (struct iio_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 = (struct iio_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)
+{
+	int          ret;
+	unsigned int val;
+
+	zpa2326_dbg(indio_dev, "waiting for one shot completion interrupt");
+
+	ret = wait_for_completion_interruptible_timeout(
+		&private->data_ready, ZPA2326_CONVERSION_JIFFIES);
+	if (ret > 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 (!ret)
+		/* Timed out. */
+		ret = -ETIME;
+
+	if (ret != -ERESTARTSYS)
+		zpa2326_warn(indio_dev, "no one shot interrupt occurred (%d)",
+			     ret);
+
+	return ret;
+}
+
+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 = {
+	.owner             = THIS_MODULE,
+	.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 = {
+	.driver_module = THIS_MODULE,
+	.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");
diff --git a/drivers/iio/pressure/zpa2326.h b/drivers/iio/pressure/zpa2326.h
new file mode 100644
index 000000000000..05d3e1e3a449
--- /dev/null
+++ b/drivers/iio/pressure/zpa2326.h
@@ -0,0 +1,89 @@
+/*
+ * 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.
+ */
+
+#ifndef _ZPA2326_H
+#define _ZPA2326_H
+
+/* Register map. */
+#define ZPA2326_REF_P_XL_REG              (0x8)
+#define ZPA2326_REF_P_L_REG               (0x9)
+#define ZPA2326_REF_P_H_REG               (0xa)
+#define ZPA2326_DEVICE_ID_REG             (0xf)
+#define ZPA2326_DEVICE_ID                 (0xb9)
+#define ZPA2326_RES_CONF_REG              (0x10)
+#define ZPA2326_CTRL_REG0_REG             (0x20)
+#define ZPA2326_CTRL_REG0_ONE_SHOT        BIT(0)
+#define ZPA2326_CTRL_REG0_ENABLE          BIT(1)
+#define ZPA2326_CTRL_REG1_REG             (0x21)
+#define ZPA2326_CTRL_REG1_MASK_DATA_READY BIT(2)
+#define ZPA2326_CTRL_REG2_REG             (0x22)
+#define ZPA2326_CTRL_REG2_SWRESET         BIT(2)
+#define ZPA2326_CTRL_REG3_REG             (0x23)
+#define ZPA2326_CTRL_REG3_ODR_SHIFT       (4)
+#define ZPA2326_CTRL_REG3_ENABLE_MEAS     BIT(7)
+#define ZPA2326_INT_SOURCE_REG            (0x24)
+#define ZPA2326_INT_SOURCE_DATA_READY     BIT(2)
+#define ZPA2326_THS_P_LOW_REG             (0x25)
+#define ZPA2326_THS_P_HIGH_REG            (0x26)
+#define ZPA2326_STATUS_REG                (0x27)
+#define ZPA2326_STATUS_P_DA               BIT(1)
+#define ZPA2326_STATUS_FIFO_E             BIT(2)
+#define ZPA2326_STATUS_P_OR               BIT(5)
+#define ZPA2326_PRESS_OUT_XL_REG          (0x28)
+#define ZPA2326_PRESS_OUT_L_REG           (0x29)
+#define ZPA2326_PRESS_OUT_H_REG           (0x2a)
+#define ZPA2326_TEMP_OUT_L_REG            (0x2b)
+#define ZPA2326_TEMP_OUT_H_REG            (0x2c)
+
+struct device;
+struct regmap;
+
+bool zpa2326_isreg_writeable(struct device *dev, unsigned int reg);
+bool zpa2326_isreg_readable(struct device *dev, unsigned int reg);
+bool zpa2326_isreg_precious(struct device *dev, unsigned int reg);
+
+/**
+ * zpa2326_probe() - Instantiate and register core ZPA2326 IIO device
+ * @parent: Hardware sampling device the created IIO device will be a child of.
+ * @name:   Arbitrary name to identify the device.
+ * @irq:    Interrupt line, negative if none.
+ * @hwid:   Expected device hardware id.
+ * @regmap: Registers map used to abstract underlying bus accesses.
+ *
+ * Return: Zero when successful, a negative error code otherwise.
+ */
+int zpa2326_probe(struct device        *parent,
+		  const char           *name,
+		  int                   irq,
+		  unsigned int          hwid,
+		  struct regmap        *regmap);
+
+/**
+ * zpa2326_remove() - Unregister and destroy core ZPA2326 IIO device.
+ * @parent: Hardware sampling device the IIO device to remove is a child of.
+ */
+void zpa2326_remove(const struct device *parent);
+
+#ifdef CONFIG_PM
+#include <linux/pm.h>
+extern const struct dev_pm_ops zpa2326_pm_ops;
+#define ZPA2326_PM_OPS (&zpa2326_pm_ops)
+#else
+#define ZPA2326_PM_OPS (NULL)
+#endif
+
+#endif
diff --git a/drivers/iio/pressure/zpa2326_i2c.c b/drivers/iio/pressure/zpa2326_i2c.c
new file mode 100644
index 000000000000..e4d27dd4493a
--- /dev/null
+++ b/drivers/iio/pressure/zpa2326_i2c.c
@@ -0,0 +1,99 @@
+/*
+ * Murata ZPA2326 I2C pressure and temperature sensor 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.
+ */
+
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/i2c.h>
+#include <linux/of_device.h>
+#include "zpa2326.h"
+
+/*
+ * read_flag_mask:
+ *   - address bit 7 must be set to request a register read operation
+ */
+static const struct regmap_config zpa2326_regmap_i2c_config = {
+	.reg_bits       = 8,
+	.val_bits       = 8,
+	.writeable_reg  = zpa2326_isreg_writeable,
+	.readable_reg   = zpa2326_isreg_readable,
+	.precious_reg   = zpa2326_isreg_precious,
+	.max_register   = ZPA2326_TEMP_OUT_H_REG,
+	.read_flag_mask = BIT(7),
+	.cache_type     = REGCACHE_NONE,
+};
+
+static unsigned int zpa2326_i2c_hwid(const struct i2c_client *client)
+{
+#define ZPA2326_SA0(_addr)          (_addr & BIT(0))
+#define ZPA2326_DEVICE_ID_SA0_SHIFT (1)
+
+	/* Identification register bit 1 mirrors device address bit 0. */
+	return (ZPA2326_DEVICE_ID |
+		(ZPA2326_SA0(client->addr) << ZPA2326_DEVICE_ID_SA0_SHIFT));
+}
+
+static int zpa2326_probe_i2c(struct i2c_client          *client,
+			     const struct i2c_device_id *i2c_id)
+{
+	struct regmap *regmap;
+
+	regmap = devm_regmap_init_i2c(client, &zpa2326_regmap_i2c_config);
+	if (IS_ERR(regmap)) {
+		dev_err(&client->dev, "failed to init registers map");
+		return PTR_ERR(regmap);
+	}
+
+	return zpa2326_probe(&client->dev, i2c_id->name, client->irq,
+			     zpa2326_i2c_hwid(client), regmap);
+}
+
+static int zpa2326_remove_i2c(struct i2c_client *client)
+{
+	zpa2326_remove(&client->dev);
+
+	return 0;
+}
+
+static const struct i2c_device_id zpa2326_i2c_ids[] = {
+	{ "zpa2326", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, zpa2326_i2c_ids);
+
+#if defined(CONFIG_OF)
+static const struct of_device_id zpa2326_i2c_matches[] = {
+	{ .compatible = "murata,zpa2326" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, zpa2326_i2c_matches);
+#endif
+
+static struct i2c_driver zpa2326_i2c_driver = {
+	.driver = {
+		.name           = "zpa2326-i2c",
+		.of_match_table = of_match_ptr(zpa2326_i2c_matches),
+		.pm             = ZPA2326_PM_OPS,
+	},
+	.probe    = zpa2326_probe_i2c,
+	.remove   = zpa2326_remove_i2c,
+	.id_table = zpa2326_i2c_ids,
+};
+module_i2c_driver(zpa2326_i2c_driver);
+
+MODULE_AUTHOR("Gregor Boirie <gregor.boirie@parrot.com>");
+MODULE_DESCRIPTION("I2C driver for Murata ZPA2326 pressure sensor");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/pressure/zpa2326_spi.c b/drivers/iio/pressure/zpa2326_spi.c
new file mode 100644
index 000000000000..bd2c1c319fca
--- /dev/null
+++ b/drivers/iio/pressure/zpa2326_spi.c
@@ -0,0 +1,103 @@
+/*
+ * Murata ZPA2326 SPI pressure and temperature sensor 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.
+ */
+
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+#include <linux/of_device.h>
+#include "zpa2326.h"
+
+/*
+ * read_flag_mask:
+ *   - address bit 7 must be set to request a register read operation
+ *   - address bit 6 must be set to request register address auto increment
+ */
+static const struct regmap_config zpa2326_regmap_spi_config = {
+	.reg_bits       = 8,
+	.val_bits       = 8,
+	.writeable_reg  = zpa2326_isreg_writeable,
+	.readable_reg   = zpa2326_isreg_readable,
+	.precious_reg   = zpa2326_isreg_precious,
+	.max_register   = ZPA2326_TEMP_OUT_H_REG,
+	.read_flag_mask = BIT(7) | BIT(6),
+	.cache_type     = REGCACHE_NONE,
+};
+
+static int zpa2326_probe_spi(struct spi_device *spi)
+{
+	struct regmap *regmap;
+	int            err;
+
+	regmap = devm_regmap_init_spi(spi, &zpa2326_regmap_spi_config);
+	if (IS_ERR(regmap)) {
+		dev_err(&spi->dev, "failed to init registers map");
+		return PTR_ERR(regmap);
+	}
+
+	/*
+	 * Enforce SPI slave settings to prevent from DT misconfiguration.
+	 *
+	 * Clock is idle high. Sampling happens on trailing edge, i.e., rising
+	 * edge. Maximum bus frequency is 1 MHz. Registers are 8 bits wide.
+	 */
+	spi->mode = SPI_MODE_3;
+	spi->max_speed_hz = min(spi->max_speed_hz, 1000000U);
+	spi->bits_per_word = 8;
+	err = spi_setup(spi);
+	if (err < 0)
+		return err;
+
+	return zpa2326_probe(&spi->dev, spi_get_device_id(spi)->name,
+			     spi->irq, ZPA2326_DEVICE_ID, regmap);
+}
+
+static int zpa2326_remove_spi(struct spi_device *spi)
+{
+	zpa2326_remove(&spi->dev);
+
+	return 0;
+}
+
+static const struct spi_device_id zpa2326_spi_ids[] = {
+	{ "zpa2326", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(spi, zpa2326_spi_ids);
+
+#if defined(CONFIG_OF)
+static const struct of_device_id zpa2326_spi_matches[] = {
+	{ .compatible = "murata,zpa2326" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, zpa2326_spi_matches);
+#endif
+
+static struct spi_driver zpa2326_spi_driver = {
+	.driver = {
+		.name           = "zpa2326-spi",
+		.of_match_table = of_match_ptr(zpa2326_spi_matches),
+		.pm             = ZPA2326_PM_OPS,
+	},
+	.probe    = zpa2326_probe_spi,
+	.remove   = zpa2326_remove_spi,
+	.id_table = zpa2326_spi_ids,
+};
+module_spi_driver(zpa2326_spi_driver);
+
+MODULE_AUTHOR("Gregor Boirie <gregor.boirie@parrot.com>");
+MODULE_DESCRIPTION("SPI driver for Murata ZPA2326 pressure sensor");
+MODULE_LICENSE("GPL v2");