[PATCH v2 1/2] iio: adc: driver for texas instruments ads7142

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This is an iio driver for
 Texas Instruments ADS7142 dual-channel, programmable sensor monitor.

All of the data buffer modes, supported by the device are selectable
 over sysfs:
  /sys/bus/iio/devices/iio:deviceX/buffer_mode

Data buffer operation modes:
  - start_burst:
    In triggered buffer preenable hook: not relevant.
    In trigger handler: the driver selects the autonomous monitoring
      (see chapter 7.4.3 in datasheet) operation mode,
	  configures the channels in sequencer as specified by
      sysfs(scan_elements/in_voltageY_en),
	  sets the data buffer mode to "Start Burst Mode",
      then starts the conversion.
    In irq handler: the driver pushes the conversion results received
      from the device to the buffer,
      then restarts the conversion like in trigger handler.
    Both IRQ and trigger are required to support this mode.
    See chapter 7.4.3.2.1 "Autonomous Mode with Start Burst"
    in datasheet.
  - stop_burst:
    In triggered buffer preenable hook: the driver selects the
      autonomous monitoring (see chapter 7.4.3 in datasheet)
      operation mode,
      configures the channels in sequencer as
      specified by sysfs(scan_elements/in_voltageY_en),
	  sets the data buffer mode to "Stop Burst Mode",
      then starts the conversion.
    In trigger handler: the driver pushes the conversion results received
      from the device to the buffer,
	  then restarts the conversion like in preenable hook.
    In irq handler: not relevant.
    Trigger is required to support this mode.
    See chapter 7.4.3.2.2 "Autonomous Mode with Stop Burst"
    in datasheet.
  - pre_alert:
    In triggered buffer preenable hook: the driver selects the autonomous
      monitoring (see chapter 7.4.3 in datasheet) operation mode,
      configures the channels in sequencer
        as specified by sysfs(scan_elements/in_voltageY_en),
      configures the digital window comparator and alert flags,
	  sets the data buffer mode to "Pre Alert Data Mode",
      then starts the conversion.
    In trigger handler: not relevant.
    In irq handler: the driver pushes the conversion results received
      from the device to the buffer,
      then restarts the conversion like in preenable hook.
    IRQ is required to support this mode.
    See chapter 7.4.3.1.1 "Autonomous Mode with Pre Alert Data"
    in datasheet
  - post_alert:
    The operations are same like in pre_alert mode,
      except the data buffer mode selection, the selected mode is
      "Post Alert Data Mode".
    See chapter 7.4.3.1.2 "Autonomous Mode with Post Alert Data"
    in datasheet

The in_voltageY_raw can be used, if the buffering mode is not enabled
 in sysfs(buffer/enable).
 The driver initiates a single conversion in the device for each
 read request(in_voltageY_raw).
 This is a one-shot conversion.
 See chapter 7.4.2.2 "Manual Mode with AUTO Sequence" in datasheet.

Datasheet: https://www.ti.com/lit/ds/symlink/ads7142.pdf

Signed-off-by: Jozsef Horvath <info@xxxxxxxxxxx>
---

changes v1
  - All of the buffer opertaion modes
    (pre_alert, post_alert, start_burst, stop_burst)
	are added
  - Added triggered buffer
  - Added buffer operation mode selection sysfs support
  - Redundant parameters (ti,threshold-rising, etc.)
    are removed
  - Supply name changed(vref -> avdd)
  - Added dvdd supply
  - Added device sampling rate calculation
  - Use device-managed functions for regulator, iio device register
    and triggered buffer

changes v2
  - Unreachable statements removed
  - ti_ads7142_buffered_setup_and_start returns without error when
    pre/post alert mode is selected, but no thresh_{rising/falling}
    enabled on any channel. Fixed with return -EINVAL in the case above.
  - Stylistical changes
  - devm_regulator_get return value error/NULL handling.
  - "ti,prealert-count" parameter added, just for completeness.
---
 .../ABI/testing/sysfs-bus-iio-adc-ti-ads7142  |   11 +
 MAINTAINERS                                   |    7 +
 drivers/iio/adc/Kconfig                       |   13 +
 drivers/iio/adc/Makefile                      |    1 +
 drivers/iio/adc/ti-ads7142.c                  | 1461 +++++++++++++++++
 5 files changed, 1493 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-adc-ti-ads7142
 create mode 100644 drivers/iio/adc/ti-ads7142.c

diff --git a/Documentation/ABI/testing/sysfs-bus-iio-adc-ti-ads7142 b/Documentation/ABI/testing/sysfs-bus-iio-adc-ti-ads7142
new file mode 100644
index 000000000000..485017235f4a
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-iio-adc-ti-ads7142
@@ -0,0 +1,11 @@
+What:		/sys/bus/iio/devices/iio:deviceX/buffer_mode_available
+Date:		May 2021
+KernelVersion:	5.13
+Contact:	info@xxxxxxxxxxx
+Description: 	List all available buffer_mode settings.
+
+What:		/sys/bus/iio/devices/iio:deviceX/buffer_mode
+Date:		May 2021
+KernelVersion:	5.13
+Contact:	info@xxxxxxxxxxx
+Description: 	Sets up the device data buffer mode.
diff --git a/MAINTAINERS b/MAINTAINERS
index 6582d19cdf7a..97922bffd766 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18086,6 +18086,13 @@ T:	git git://github.com/czankel/xtensa-linux.git
 F:	arch/xtensa/
 F:	drivers/irqchip/irq-xtensa-*
 
+TEXAS INSTRUMENTS ADS7142 ADC DRIVER
+M:	Jozsef Horvath <info@xxxxxxxxxxx>
+S:	Maintained
+F:	Documentation/ABI/testing/sysfs-bus-iio-adc-ti-ads7142
+F:	Documentation/devicetree/bindings/iio/adc/ti,ads7142.yaml
+F:	drivers/iio/adc/ti-ads7142.c
+
 TEXAS INSTRUMENTS ASoC DRIVERS
 M:	Peter Ujfalusi <peter.ujfalusi@xxxxxxxxx>
 L:	alsa-devel@xxxxxxxxxxxxxxxx (moderated for non-subscribers)
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index db0c8fb60515..6c34ede355e4 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -1111,6 +1111,19 @@ config TI_ADS1015
 	  This driver can also be built as a module. If so, the module will be
 	  called ti-ads1015.
 
+config TI_ADS7142
+	tristate "Texas Instruments ADS7142 ADC driver"
+	depends on I2C
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	help
+	  This driver is for Texas Instruments ADS7142 Nanopower,
+	   Dual-Channel, Programmable Sensor Monitor.
+	  Say 'Y' here if you wish to use it.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ti-ads7142.
+
 config TI_ADS7950
 	tristate "Texas Instruments ADS7950 ADC driver"
 	depends on SPI && GPIOLIB
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index f70d877c555a..486ca7f4037e 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -99,6 +99,7 @@ obj-$(CONFIG_TI_ADC108S102) += ti-adc108s102.o
 obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o
 obj-$(CONFIG_TI_ADC161S626) += ti-adc161s626.o
 obj-$(CONFIG_TI_ADS1015) += ti-ads1015.o
+obj-$(CONFIG_TI_ADS7142) += ti-ads7142.o
 obj-$(CONFIG_TI_ADS7950) += ti-ads7950.o
 obj-$(CONFIG_TI_ADS8344) += ti-ads8344.o
 obj-$(CONFIG_TI_ADS8688) += ti-ads8688.o
diff --git a/drivers/iio/adc/ti-ads7142.c b/drivers/iio/adc/ti-ads7142.c
new file mode 100644
index 000000000000..a0828ee7f013
--- /dev/null
+++ b/drivers/iio/adc/ti-ads7142.c
@@ -0,0 +1,1461 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 Jozsef Horvath <info@xxxxxxxxxxx>
+ *
+ */
+#include <linux/i2c.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/events.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+#define TI_ADS7142_NAME					"ads7142"
+
+#define TI_ADS7142_DATA_VALID_TIMEOUT			100
+
+/* Opcodes for commands */
+/* General */
+#define TI_ADS7142_OC_GENERAL				0x00
+/* Single Register Read */
+#define TI_ADS7142_OC_SINGLE_REG_READ			0x10
+/* Single Register Write */
+#define TI_ADS7142_OC_SINGLE_REG_WRITE			0x08
+/* Single Bit Set */
+#define TI_ADS7142_OC_SET_BIT				0x18
+/* Single Bit Clear */
+#define TI_ADS7142_OC_CLEAR_BIT				0x20
+/* Block Register Read */
+#define TI_ADS7142_OC_BLOCK_READ			0x30
+/* Block Register Write */
+#define TI_ADS7142_OC_BLOCK_WRITE			0x28
+
+/* Registers */
+/* Reset registers */
+#define TI_ADS7142_WKEY					0x17
+#define TI_ADS7142_DEVICE_RESET				0x14
+/* Functional mode select registers */
+#define TI_ADS7142_OFFSET_CAL				0x15
+#define TI_ADS7142_OPMODE_SEL				0x1C
+#define TI_ADS7142_OPMODE_SEL_MANUALCH0			(0)
+#define TI_ADS7142_OPMODE_SEL_MANUALSEQ			(4)
+#define TI_ADS7142_OPMODE_SEL_MONITORING		(6)
+#define TI_ADS7142_OPMODE_SEL_HIGHPREC			(7)
+#define TI_ADS7142_OPMODE_STATUS			0x00
+#define TI_ADS7142_OPMODE_STATUS_OPMODE_MSK		(3)
+#define TI_ADS7142_OPMODE_STATUS_OPMODE_MANUAL		(0)
+#define TI_ADS7142_OPMODE_STATUS_OPMODE_AUTO		(2)
+#define TI_ADS7142_OPMODE_STATUS_OPMODE_HIGHPREC	(3)
+#define TI_ADS7142_OPMODE_STATUS_HS_MODE		BIT(2)
+
+/* Input config register */
+#define TI_ADS7142_CH_INPUT_CFG				0x24
+#define TI_ADS7142_CH_INPUT_CFG_TCSE			(0)
+#define TI_ADS7142_CH_INPUT_CFG_SCSE			(1)
+#define TI_ADS7142_CH_INPUT_CFG_SCPD			(2)
+/* Analog mux and sequencer registers */
+#define TI_ADS7142_AUTO_SEQ_CHEN			0x20
+#define TI_ADS7142_AUTO_SEQ_CHEN_CH0			BIT(0)
+#define TI_ADS7142_AUTO_SEQ_CHEN_CH1			BIT(1)
+#define TI_ADS7142_START_SEQUENCE			0x1E
+#define TI_ADS7142_START_SEQUENCE_SEQ_START		BIT(0)
+#define TI_ADS7142_ABORT_SEQUENCE			0x1F
+#define TI_ADS7142_ABORT_SEQUENCE_SEQ_ABORT		BIT(0)
+#define TI_ADS7142_SEQUENCE_STATUS			0x04
+#define TI_ADS7142_SEQUENCE_STATUS_SEQ_ERR_ST_MSK	(0x06)
+#define TI_ADS7142_SEQUENCE_STATUS_SEQ_DISABLED		(0x00)
+#define TI_ADS7142_SEQUENCE_STATUS_SEQ_ENABLED		(0x02)
+#define TI_ADS7142_SEQUENCE_STATUS_SEQ_ERROR		(0x06)
+/* Oscillator and timing control registers */
+#define TI_ADS7142_OSC_SEL				0x18
+#define TI_ADS7142_OSC_SEL_HSZ_LP			BIT(0)
+#define TI_ADS7142_NCLK_SEL				0x19
+#define TI_ADS7142_NCLK_SEL_MSK				0xFF
+/* Data buffer control register */
+#define TI_ADS7142_DATA_BUFFER_OPMODE			0x2C
+#define TI_ADS7142_DATA_BUFFER_OPMODE_STOP_BURST	(0)
+#define TI_ADS7142_DATA_BUFFER_OPMODE_START_BURST	(1)
+#define TI_ADS7142_DATA_BUFFER_OPMODE_PRE_ALERT		(4)
+#define TI_ADS7142_DATA_BUFFER_OPMODE_POST_ALERT	(6)
+#define TI_ADS7142_DOUT_FORMAT_CFG			0x28
+#define TI_ADS7142_DOUT_FORMAT_CFG_12B			(0)
+#define TI_ADS7142_DOUT_FORMAT_CFG_12BCH		(1)
+#define TI_ADS7142_DOUT_FORMAT_CFG_12BCHDV		(2)
+#define TI_ADS7142_DATA_BUFFER_STATUS			0x01
+/* Accumulator control register */
+#define TI_ADS7142_ACC_EN				0x30
+#define TI_ADS7142_ACC_CH0_LSB				0x08
+#define TI_ADS7142_ACC_CH0_MSB				0x09
+#define TI_ADS7142_ACC_CH1_LSB				0x0A
+#define TI_ADS7142_ACC_CH1_MSB				0x0B
+#define TI_ADS7142_ACC_STATUS				0x02
+/* Digital window comparator registers */
+#define TI_ADS7142_ALERT_DWC_EN				0x37
+#define TI_ADS7142_ALERT_DWC_EN_BLOCK_EN		BIT(0)
+#define TI_ADS7142_ALERT_CHEN				0x34
+#define TI_ADS7142_DWC_HTH_CH0_LSB			0x38
+#define TI_ADS7142_DWC_HTH_CH0_MSB			0x39
+#define TI_ADS7142_DWC_LTH_CH0_LSB			0x3A
+#define TI_ADS7142_DWC_LTH_CH0_MSB			0x3B
+#define TI_ADS7142_DWC_HYS_CH0				0x40
+#define TI_ADS7142_DWC_HTH_CH1_LSB			0x3C
+#define TI_ADS7142_DWC_HTH_CH1_MSB			0x3D
+#define TI_ADS7142_DWC_LTH_CH1_LSB			0x3E
+#define TI_ADS7142_DWC_LTH_CH1_MSB			0x3F
+#define TI_ADS7142_DWC_HYS_CH1				0x41
+#define TI_ADS7142_PRE_ALT_EVT_CNT			0x36
+#define TI_ADS7142_PRE_ALT_EVT_CNT_MSK			0x0F
+#define TI_ADS7142_ALT_TRIG_CHID			0x03
+#define TI_ADS7142_ALT_LOW_FLAGS			0x0C
+#define TI_ADS7142_ALT_LOW_FLAGS_CH0			BIT(0)
+#define TI_ADS7142_ALT_LOW_FLAGS_CH1			BIT(1)
+#define TI_ADS7142_ALT_HIGH_FLAGS			0x0E
+#define TI_ADS7142_ALT_HIGH_FLAGS_CH0			BIT(0)
+#define TI_ADS7142_ALT_HIGH_FLAGS_CH1			BIT(1)
+
+#define TI_ADS7142_THRESHOLD_MSK			0xFFF
+#define TI_ADS7142_HYSTERESIS_MSK			0x3F
+
+#define TI_ADS7142_HSO_FREQ				20000000
+#define TI_ADS7142_HSO_NCLK_MIN				21
+#define TI_ADS7142_HSO_NCLK_MAX				255
+#define TI_ADS7142_HSO_MIN_SS				78431
+#define TI_ADS7142_HSO_MAX_SS				952380
+#define TI_ADS7142_LPO_FREQ				10504
+#define TI_ADS7142_LPO_NCLK_MIN				18
+#define TI_ADS7142_LPO_NCLK_MAX				255
+#define TI_ADS7142_LPO_MIN_SS				42
+#define TI_ADS7142_LPO_MAX_SS				583
+
+#define TI_ADS7142_CHANNEL_COUNT			2
+
+#define TI_ADS7142_PROP_REG				"reg"
+#define TI_ADS7142_PROP_PREALERT_COUNT			"ti,prealert-count"
+
+struct ti_ads7142_channel_config {
+	bool alert_low;
+	bool alert_high;
+	int high_threshold;
+	int low_threshold;
+	int hysteresis;
+};
+
+struct ti_ads7142_channel {
+	struct ti_ads7142_channel_config config;
+	u32 channel;
+};
+
+struct ti_ads7142_config {
+	bool osc_sel;
+	u32 n_clk;
+	u32 prealert_count;
+	int buffer_mode;
+};
+
+struct ti_ads7142_priv {
+	struct mutex lock; /* For syncing access to device */
+	struct regulator *avdd;
+	struct regulator *dvdd;
+	struct ti_ads7142_config config;
+	struct ti_ads7142_channel *channels;
+	bool irq_present;
+	bool monitor_pending;
+	u16 scan_data[TI_ADS7142_CHANNEL_COUNT] ____cacheline_aligned;
+};
+
+static const struct iio_event_spec ti_ads7142_events[] = {
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE)
+				| BIT(IIO_EV_INFO_ENABLE),
+	}, {
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_FALLING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE)
+				| BIT(IIO_EV_INFO_ENABLE),
+	}, {
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_EITHER,
+		.mask_separate = BIT(IIO_EV_INFO_HYSTERESIS),
+	},
+};
+
+static const struct iio_chan_spec ti_ads7142_channel_template = {
+	.type = IIO_VOLTAGE,
+	.scan_type = {
+		.sign = 'u',
+		.realbits = 12,
+		.storagebits = 16,
+		.endianness = IIO_CPU,
+	},
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+	.event_spec = ti_ads7142_events,
+	.num_event_specs = ARRAY_SIZE(ti_ads7142_events),
+	.indexed = 1,
+};
+
+static const char * const ti_ads7142_ain_names[] = {
+	"AIN0",
+	"AIN1",
+};
+
+#define TI_ADS7142_BUFFM_NONE				0
+#define TI_ADS7142_BUFFM_STOP_BURST			1
+#define TI_ADS7142_BUFFM_START_BURST			2
+#define TI_ADS7142_BUFFM_PRE_ALERT			3
+#define TI_ADS7142_BUFFM_POST_ALERT			4
+static const char * const ti_ads7142_buffer_modes[] = {
+	[TI_ADS7142_BUFFM_NONE]		= "none",
+	[TI_ADS7142_BUFFM_STOP_BURST]	= "stop_burst",
+	[TI_ADS7142_BUFFM_START_BURST]	= "start_burst",
+	[TI_ADS7142_BUFFM_PRE_ALERT]	= "pre_alert",
+	[TI_ADS7142_BUFFM_POST_ALERT]	= "post_alert"
+};
+
+static int ti_ads7142_reg_write(const struct i2c_client *client, u8 reg,
+				u8 data)
+{
+	u8 buf[3] = { TI_ADS7142_OC_SINGLE_REG_WRITE, reg, data };
+	int ret;
+
+	ret = i2c_master_send(client, buf, sizeof(buf));
+	if (ret >= 0 && ret != sizeof(buf))
+		ret = -EIO;
+
+	return ret == sizeof(buf) ? 0 : ret;
+}
+
+static int ti_ads7142_reg_read(const struct i2c_client *client, u8 reg,
+			       u8 *data)
+{
+	u8 buf[2] = { TI_ADS7142_OC_SINGLE_REG_READ, reg };
+	struct i2c_msg msg[2] = {
+		{
+			.addr = client->addr,
+			.len = sizeof(buf),
+			.buf = buf,
+		},
+		{
+			.addr = client->addr,
+			.flags = I2C_M_RD,
+			.len = 1,
+			.buf = data,
+		}
+	};
+	int ret;
+
+	ret = i2c_transfer(client->adapter, msg, 2);
+	if (ret >= 0 && ret != ARRAY_SIZE(msg))
+		ret = -EIO;
+
+	return ret == ARRAY_SIZE(msg) ? 0 : ret;
+}
+
+static int ti_ads7142_data_buffer_read(const struct i2c_client *client,
+				       int length, void *data)
+{
+	int ret;
+
+	ret = i2c_master_recv(client, data, length);
+	if (ret >= 0 && ret != length)
+		ret = -EIO;
+
+	return ret == length ? 0 : ret;
+}
+
+static int ti_ads7142_soft_reset(const struct i2c_client *client)
+{
+	u8 buf[2] = { TI_ADS7142_OC_GENERAL, 0x06 };
+	int ret;
+
+	ret = i2c_master_send(client, buf, sizeof(buf));
+	if (ret >= 0 && ret != sizeof(buf))
+		ret = -EIO;
+
+	return ret == sizeof(buf) ? 0 : ret;
+}
+
+static struct ti_ads7142_channel *ti_ads7142_address2channel(struct iio_dev *indio_dev,
+							     int address)
+{
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+	int i;
+
+	for (i = 0; i < indio_dev->num_channels; i++) {
+		if (address == priv->channels[i].channel)
+			return &priv->channels[i];
+	}
+	return NULL;
+}
+
+static int ti_ads7142_sequence_start(struct iio_dev *indio_dev)
+{
+	struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
+
+	return ti_ads7142_reg_write(client, TI_ADS7142_START_SEQUENCE,
+				    TI_ADS7142_START_SEQUENCE_SEQ_START);
+}
+
+static int ti_ads7142_sequence_abort(struct iio_dev *indio_dev)
+{
+	struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
+
+	return ti_ads7142_reg_write(client, TI_ADS7142_ABORT_SEQUENCE,
+				    TI_ADS7142_ABORT_SEQUENCE_SEQ_ABORT);
+}
+
+static int ti_ads7142_osc_set(struct iio_dev *indio_dev)
+{
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+	struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
+	int ret;
+
+	ret = ti_ads7142_reg_write(client, TI_ADS7142_OSC_SEL,
+				   priv->config.osc_sel ? TI_ADS7142_OSC_SEL_HSZ_LP : 0);
+	if (ret)
+		return ret;
+
+	return ti_ads7142_reg_write(client, TI_ADS7142_NCLK_SEL,
+				    priv->config.n_clk);
+}
+
+static int ti_ads7142_input_cfg_set(struct iio_dev *indio_dev)
+{
+	struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
+
+	return ti_ads7142_reg_write(client, TI_ADS7142_CH_INPUT_CFG,
+				    TI_ADS7142_CH_INPUT_CFG_TCSE);
+}
+
+static int ti_ads7142_dout_format_set(struct iio_dev *indio_dev)
+{
+	struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
+
+	return ti_ads7142_reg_write(client, TI_ADS7142_DOUT_FORMAT_CFG,
+				    TI_ADS7142_DOUT_FORMAT_CFG_12BCHDV);
+}
+
+static int ti_ads7142_osc_calc_set(struct iio_dev *indio_dev, int request)
+{
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+	bool osc_sel;
+	u32 osc_freq;
+
+	if (request <= TI_ADS7142_LPO_MAX_SS) {
+		osc_sel = true;
+		if (request < TI_ADS7142_LPO_MIN_SS)
+			request = TI_ADS7142_LPO_MIN_SS;
+		osc_freq = TI_ADS7142_LPO_FREQ;
+	} else {
+		osc_sel = false;
+		if (request < TI_ADS7142_HSO_MIN_SS)
+			request = TI_ADS7142_HSO_MIN_SS;
+		if (request > TI_ADS7142_HSO_MAX_SS)
+			request = TI_ADS7142_HSO_MAX_SS;
+		osc_freq = TI_ADS7142_HSO_FREQ;
+	}
+
+	priv->config.osc_sel = osc_sel;
+	priv->config.n_clk = (osc_freq / request) & TI_ADS7142_NCLK_SEL_MSK;
+	return 0;
+}
+
+static int ti_ads7142_osc_calc_get(struct iio_dev *indio_dev, int *result)
+{
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+	u32 n_clk;
+	u32 osc_freq;
+
+	if (priv->config.osc_sel) {
+		// Low power oscillator
+		n_clk = priv->config.n_clk;
+		if (n_clk < TI_ADS7142_LPO_NCLK_MIN)
+			n_clk = TI_ADS7142_LPO_NCLK_MIN;
+		if (n_clk > TI_ADS7142_LPO_NCLK_MAX)
+			n_clk = TI_ADS7142_LPO_NCLK_MAX;
+		osc_freq = TI_ADS7142_LPO_FREQ;
+	} else {
+		// High speed oscillator
+		n_clk = priv->config.n_clk;
+		if (n_clk < TI_ADS7142_HSO_NCLK_MIN)
+			n_clk = TI_ADS7142_HSO_NCLK_MIN;
+		if (n_clk > TI_ADS7142_HSO_NCLK_MAX)
+			n_clk = TI_ADS7142_HSO_NCLK_MAX;
+		osc_freq = TI_ADS7142_HSO_FREQ;
+	}
+	*result = osc_freq / n_clk;
+	return 0;
+}
+
+static int ti_ads7142_hth_set(struct iio_dev *indio_dev, int channel,
+			      int threshold)
+{
+	struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
+	int ret;
+
+	if (threshold < 0 || threshold > TI_ADS7142_THRESHOLD_MSK)
+		return -EINVAL;
+
+	ret = ti_ads7142_reg_write(client,
+				   TI_ADS7142_DWC_HTH_CH0_LSB + channel * 4,
+				   threshold & 0xFF);
+	if (ret)
+		return ret;
+
+	ret = ti_ads7142_reg_write(client,
+				   TI_ADS7142_DWC_HTH_CH0_MSB + channel * 4,
+				   (threshold >> 8) & 0xF);
+	return ret;
+}
+
+static int ti_ads7142_lth_set(struct iio_dev *indio_dev, int channel,
+			      int threshold)
+{
+	struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
+	int ret;
+
+	if (threshold < 0 || threshold > TI_ADS7142_THRESHOLD_MSK)
+		return -EINVAL;
+
+	ret = ti_ads7142_reg_write(client,
+				   TI_ADS7142_DWC_LTH_CH0_LSB + channel * 4,
+				   threshold & 0xFF);
+	if (ret)
+		return ret;
+
+	ret = ti_ads7142_reg_write(client,
+				   TI_ADS7142_DWC_LTH_CH0_MSB + channel * 4,
+				   (threshold >> 8) & 0xF);
+	return ret;
+}
+
+static int ti_ads7142_hys_set(struct iio_dev *indio_dev, int channel,
+			      int hysteresis)
+{
+	struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
+	int ret;
+
+	if (hysteresis < 0 || hysteresis > TI_ADS7142_HYSTERESIS_MSK)
+		return -EINVAL;
+
+	ret = ti_ads7142_reg_write(client, TI_ADS7142_DWC_HYS_CH0 + channel,
+				   hysteresis & TI_ADS7142_HYSTERESIS_MSK);
+	return ret;
+}
+
+static int ti_ads7142_buffered_setup_and_start(struct iio_dev *indio_dev)
+{
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+	struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
+	struct ti_ads7142_channel *channel;
+	int i;
+	u8 alert_ch = 0;
+	u8 buffer_op_mode;
+	u8 seq_channels = 0;
+	int ret;
+
+	if (!priv->config.buffer_mode)
+		return 0;
+
+	priv->monitor_pending = false;
+
+	ret = ti_ads7142_sequence_abort(indio_dev);
+	if (ret)
+		return ret;
+
+	ret = ti_ads7142_osc_set(indio_dev);
+	if (ret)
+		return ret;
+
+	ret = ti_ads7142_input_cfg_set(indio_dev);
+	if (ret)
+		return ret;
+
+	ret = ti_ads7142_dout_format_set(indio_dev);
+	if (ret)
+		return ret;
+
+	switch (priv->config.buffer_mode) {
+	case TI_ADS7142_BUFFM_STOP_BURST:
+		buffer_op_mode = TI_ADS7142_DATA_BUFFER_OPMODE_STOP_BURST;
+		break;
+	case TI_ADS7142_BUFFM_START_BURST:
+		buffer_op_mode = TI_ADS7142_DATA_BUFFER_OPMODE_START_BURST;
+		break;
+	case TI_ADS7142_BUFFM_PRE_ALERT:
+		buffer_op_mode = TI_ADS7142_DATA_BUFFER_OPMODE_PRE_ALERT;
+		break;
+	case TI_ADS7142_BUFFM_POST_ALERT:
+		buffer_op_mode = TI_ADS7142_DATA_BUFFER_OPMODE_POST_ALERT;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = ti_ads7142_reg_write(client, TI_ADS7142_DATA_BUFFER_OPMODE,
+				   buffer_op_mode);
+	if (ret)
+		return ret;
+
+	ret = ti_ads7142_reg_write(client, TI_ADS7142_OPMODE_SEL,
+				   TI_ADS7142_OPMODE_SEL_MONITORING);
+	if (ret)
+		return ret;
+
+	for_each_set_bit(i, indio_dev->active_scan_mask,
+			 indio_dev->masklength) {
+		seq_channels |= 1 << i;
+	}
+
+	ret = ti_ads7142_reg_write(client, TI_ADS7142_AUTO_SEQ_CHEN,
+				   seq_channels);
+	if (ret)
+		return ret;
+
+	if (priv->config.buffer_mode < TI_ADS7142_BUFFM_PRE_ALERT)
+		goto seq_start;
+
+	/*
+	 * Pre and post alert settings
+	 */
+	ret = ti_ads7142_reg_write(client, TI_ADS7142_PRE_ALT_EVT_CNT,
+				   priv->config.prealert_count &
+				   TI_ADS7142_PRE_ALT_EVT_CNT_MSK);
+	if (ret)
+		return ret;
+
+	ret = ti_ads7142_reg_write(client, TI_ADS7142_ALT_LOW_FLAGS,
+				   TI_ADS7142_ALT_LOW_FLAGS_CH0
+				   | TI_ADS7142_ALT_LOW_FLAGS_CH1);
+	if (ret)
+		return ret;
+
+	ret = ti_ads7142_reg_write(client, TI_ADS7142_ALT_HIGH_FLAGS,
+				   TI_ADS7142_ALT_HIGH_FLAGS_CH0
+				   | TI_ADS7142_ALT_HIGH_FLAGS_CH1);
+	if (ret)
+		return ret;
+
+	for_each_set_bit(i, indio_dev->active_scan_mask,
+			 indio_dev->masklength) {
+		channel = ti_ads7142_address2channel(indio_dev, i);
+		if (!channel)
+			return -ENODEV;
+
+		ret = ti_ads7142_hth_set(indio_dev, channel->channel,
+					 channel->config.high_threshold);
+		if (ret)
+			return ret;
+
+		ret = ti_ads7142_lth_set(indio_dev, channel->channel,
+					 channel->config.low_threshold);
+		if (ret)
+			return ret;
+
+		ret = ti_ads7142_hys_set(indio_dev, channel->channel,
+					 channel->config.hysteresis);
+		if (ret)
+			return ret;
+
+		if (channel->config.alert_low ||
+		    channel->config.alert_high) {
+			alert_ch |= 1 << channel->channel;
+		}
+	}
+
+	/*
+	 * This means no threshold enabled for any channel.
+	 * In Pre/Post alert mode this state is invalid.
+	 */
+	if (!alert_ch)
+		return -EINVAL;
+
+	ret = ti_ads7142_reg_write(client, TI_ADS7142_ALERT_DWC_EN,
+				   alert_ch ? TI_ADS7142_ALERT_DWC_EN_BLOCK_EN : 0);
+	if (ret)
+		return ret;
+
+	ret = ti_ads7142_reg_write(client, TI_ADS7142_ALERT_CHEN,
+				   alert_ch);
+	if (ret)
+		return ret;
+
+seq_start:
+	ret = ti_ads7142_sequence_start(indio_dev);
+	priv->monitor_pending = !ret;
+
+	return ret;
+}
+
+static int ti_ads7142_buffered_collect(struct iio_dev *indio_dev,
+				       int *channel_collected)
+{
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+	struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
+	int scan_channel_count;
+	int have_valid_data;
+	int data_valid;
+	u16 data_buffer;
+	u16 buffer[TI_ADS7142_CHANNEL_COUNT];
+	u8 seq_channels = 0;
+	int channel_address;
+	int value;
+	int i, j;
+	int ret;
+
+	scan_channel_count = bitmap_weight(indio_dev->active_scan_mask,
+					   indio_dev->masklength);
+	if (!scan_channel_count)
+		return -EINVAL;
+
+	for_each_set_bit(i, indio_dev->active_scan_mask,
+			 indio_dev->masklength) {
+		seq_channels |= 1 << i;
+	}
+
+	do {
+		memset(priv->scan_data, 0x00, indio_dev->scan_bytes);
+		have_valid_data = 0;
+		for (i = 0; i < scan_channel_count; i++) {
+			ret = ti_ads7142_data_buffer_read(client,
+							  sizeof(data_buffer),
+							  &data_buffer);
+			if (ret)
+				return ret;
+			data_buffer = be16_to_cpu(data_buffer);
+			data_valid = data_buffer & 1;
+			if (!data_valid) {
+				ret = -ENOENT;
+				break;
+			}
+
+			channel_address = (data_buffer >> 1) & 0x7;
+			if (!(seq_channels & 1 << channel_address)) {
+				dev_err(indio_dev->dev.parent,
+					"%s: invalid channel address(%d)",
+					__func__, channel_address);
+				return -EIO;
+			}
+
+			value = data_buffer >> 4;
+			buffer[channel_address] = value;
+			have_valid_data = 1;
+			if (channel_collected)
+				*channel_collected |= 1 << channel_address;
+		}
+
+		if (!have_valid_data)
+			continue;
+
+		j = 0;
+		for_each_set_bit(i, indio_dev->active_scan_mask,
+				 indio_dev->masklength) {
+			priv->scan_data[j] = buffer[i];
+			j++;
+		}
+		iio_push_to_buffers_with_timestamp(indio_dev, priv->scan_data,
+						   iio_get_time_ns(indio_dev));
+	} while (data_valid);
+
+	return ret;
+}
+
+static int ti_ads7142_buffered_abort(struct iio_dev *indio_dev)
+{
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+	int ret;
+
+	ret = ti_ads7142_sequence_abort(indio_dev);
+	if (!ret)
+		priv->monitor_pending = false;
+
+	return ret;
+}
+
+static int ti_ads7142_manual_read(struct iio_dev *indio_dev,
+				  int address, int *val)
+{
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+	struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
+	u16 data_buffer;
+	int ret;
+
+	mutex_lock(&priv->lock);
+	ret = ti_ads7142_sequence_abort(indio_dev);
+	if (ret)
+		goto final;
+
+	ret = ti_ads7142_osc_set(indio_dev);
+	if (ret)
+		goto final;
+
+	ret = ti_ads7142_input_cfg_set(indio_dev);
+	if (ret)
+		goto final;
+
+	ret = ti_ads7142_dout_format_set(indio_dev);
+	if (ret)
+		goto final;
+
+	ret = ti_ads7142_reg_write(client, TI_ADS7142_OPMODE_SEL,
+				   TI_ADS7142_OPMODE_SEL_MANUALSEQ);
+	if (ret)
+		goto final;
+
+	ret = ti_ads7142_reg_write(client, TI_ADS7142_AUTO_SEQ_CHEN,
+				   1 << address);
+	if (ret)
+		goto final;
+
+	ret = ti_ads7142_sequence_start(indio_dev);
+	if (ret)
+		goto final;
+
+	ret = ti_ads7142_data_buffer_read(client, sizeof(data_buffer),
+					  &data_buffer);
+	if (ret)
+		goto abort;
+
+	*val = (be16_to_cpu(data_buffer) >> 4);
+
+abort:
+	ret = ti_ads7142_sequence_abort(indio_dev);
+final:
+	mutex_unlock(&priv->lock);
+	return ret;
+}
+
+static irqreturn_t ti_ads7142_ist(int irq, void *dev_id)
+{
+	struct iio_dev *indio_dev = dev_id;
+	struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+	struct ti_ads7142_channel *channel;
+	u8 low_flags;
+	u8 high_flags;
+	u8 seq_st;
+	int i;
+	int ret;
+	int channel_collected;
+	s64 timestamp = iio_get_time_ns(indio_dev);
+
+	mutex_lock(&priv->lock);
+	if (!priv->config.buffer_mode || !priv->monitor_pending) {
+		mutex_unlock(&priv->lock);
+		return IRQ_NONE;
+	}
+
+	/*
+	 * BUSY/PDY fires when the sequence stopped in
+	 * trigger handler(ti_ads7142_trigger_handler),
+	 * if buffer mode is stop_burst, all the required
+	 * operations are in trigger handler, so irq handler
+	 * simple returns at this point.
+	 */
+	if (priv->config.buffer_mode == TI_ADS7142_BUFFM_STOP_BURST) {
+		mutex_unlock(&priv->lock);
+		return IRQ_NONE;
+	}
+
+	ret = ti_ads7142_reg_read(client, TI_ADS7142_SEQUENCE_STATUS, &seq_st);
+	if (ret) {
+		dev_err(indio_dev->dev.parent,
+			"%s: SEQUENCE_STATUS reg read error(%i)",
+			__func__, ret);
+		goto err_unlock;
+	}
+
+	if ((seq_st & TI_ADS7142_SEQUENCE_STATUS_SEQ_ERR_ST_MSK)
+	    != TI_ADS7142_SEQUENCE_STATUS_SEQ_ENABLED) {
+		dev_err(indio_dev->dev.parent,
+			"%s: SEQUENCE_STATUS error(%i)",
+			__func__, seq_st);
+		goto err_unlock;
+	}
+
+	ret = ti_ads7142_reg_read(client, TI_ADS7142_ALT_LOW_FLAGS,
+				  &low_flags);
+	if (ret) {
+		dev_err(indio_dev->dev.parent,
+			"%s: ALT_LOW_FLAGS reg read error(%i)",
+			__func__, ret);
+		goto err_unlock;
+	}
+
+	ret = ti_ads7142_reg_read(client, TI_ADS7142_ALT_HIGH_FLAGS,
+				  &high_flags);
+	if (ret) {
+		dev_err(indio_dev->dev.parent,
+			"%s: ALT_HIGH_FLAGS reg read error(%i)",
+			__func__, ret);
+		goto err_unlock;
+	}
+
+	ret = ti_ads7142_sequence_abort(indio_dev);
+	if (ret)
+		goto err_unlock;
+
+	priv->monitor_pending = false;
+
+	channel_collected = 0;
+	ret = ti_ads7142_buffered_collect(indio_dev, &channel_collected);
+	if (ret && ret != -ENOENT) {
+		dev_err(indio_dev->dev.parent,
+			"%s: error(%d) when collecting result for %s mode",
+			__func__, ret,
+			ti_ads7142_buffer_modes[priv->config.buffer_mode]);
+		goto err_unlock;
+	}
+
+	if (!channel_collected)
+		goto out_unlock;
+
+	if (priv->config.buffer_mode < TI_ADS7142_BUFFM_PRE_ALERT)
+		goto out_unlock;
+
+	for_each_set_bit(i, indio_dev->active_scan_mask,
+			 indio_dev->masklength) {
+		channel = ti_ads7142_address2channel(indio_dev, i);
+		if (!channel)
+			goto err_unlock;
+
+		if (!(channel_collected & (1 << channel->channel)))
+			continue;
+		if (channel->config.alert_low &&
+		    (low_flags & (1 << channel->channel))) {
+			iio_push_event(indio_dev,
+				       IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE,
+							    i,
+							    IIO_EV_TYPE_THRESH,
+							    IIO_EV_DIR_FALLING),
+				       timestamp);
+		}
+
+		if (channel->config.alert_high &&
+		    (high_flags & (1 << channel->channel))) {
+			iio_push_event(indio_dev,
+				       IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE,
+							    i,
+							    IIO_EV_TYPE_THRESH,
+							    IIO_EV_DIR_RISING),
+				       timestamp);
+		}
+	}
+
+out_unlock:
+	if (priv->config.buffer_mode >= TI_ADS7142_BUFFM_PRE_ALERT) {
+		ret = ti_ads7142_buffered_setup_and_start(indio_dev);
+		if (ret) {
+			dev_err(indio_dev->dev.parent,
+				"%s: error(%d) when starting %s mode",
+				__func__, ret,
+				ti_ads7142_buffer_modes[priv->config.buffer_mode]);
+			goto err_unlock;
+		}
+	}
+	mutex_unlock(&priv->lock);
+	return IRQ_HANDLED;
+
+err_unlock:
+	mutex_unlock(&priv->lock);
+	return IRQ_NONE;
+}
+
+static int ti_ads7142_read_raw(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       int *val, int *val2, long info)
+{
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+	int ret;
+
+	switch (info) {
+	case IIO_CHAN_INFO_RAW:
+		if (iio_buffer_enabled(indio_dev))
+			return -EBUSY;
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
+		ret = ti_ads7142_manual_read(indio_dev, chan->address,
+					     val);
+		if (!ret)
+			ret = IIO_VAL_INT;
+		iio_device_release_direct_mode(indio_dev);
+		return ret;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		ti_ads7142_osc_calc_get(indio_dev, val);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		if (!priv->avdd)
+			return -EINVAL;
+
+		*val = regulator_get_voltage(priv->avdd) / 1000;
+		*val2 = (1 << chan->scan_type.realbits) - 1;
+		return IIO_VAL_FRACTIONAL;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ti_ads7142_write_raw(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan,
+				int val, int val2, long mask)
+{
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		return ti_ads7142_osc_calc_set(indio_dev, val);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ti_ads7142_read_event_value(struct iio_dev *indio_dev,
+				       const struct iio_chan_spec *chan,
+				       enum iio_event_type type,
+				       enum iio_event_direction dir,
+				       enum iio_event_info info,
+				       int *val, int *val2)
+{
+	struct ti_ads7142_channel *channel;
+
+	channel = ti_ads7142_address2channel(indio_dev, chan->address);
+	if (!channel)
+		return -ENODEV;
+
+	switch (info) {
+	case IIO_EV_INFO_VALUE:
+		if (dir == IIO_EV_DIR_RISING)
+			*val = channel->config.high_threshold;
+		else
+			*val = channel->config.low_threshold;
+		return IIO_VAL_INT;
+	case IIO_EV_INFO_HYSTERESIS:
+		*val = channel->config.hysteresis;
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ti_ads7142_write_event_value(struct iio_dev *indio_dev,
+					const struct iio_chan_spec *chan,
+					enum iio_event_type type,
+					enum iio_event_direction dir,
+					enum iio_event_info info,
+					int val, int val2)
+{
+	struct ti_ads7142_channel *channel;
+
+	channel = ti_ads7142_address2channel(indio_dev, chan->address);
+	if (!channel)
+		return -ENODEV;
+
+	switch (info) {
+	case IIO_EV_INFO_VALUE:
+		if (val < 0 || val > TI_ADS7142_THRESHOLD_MSK)
+			return -EINVAL;
+
+		if (dir == IIO_EV_DIR_RISING)
+			channel->config.high_threshold = val;
+		else
+			channel->config.low_threshold = val;
+		return 0;
+	case IIO_EV_INFO_HYSTERESIS:
+		if (val < 0 || val > TI_ADS7142_HYSTERESIS_MSK)
+			return -EINVAL;
+
+		channel->config.hysteresis = val;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ti_ads7142_read_event_config(struct iio_dev *indio_dev,
+					const struct iio_chan_spec *chan,
+					enum iio_event_type type,
+					enum iio_event_direction dir)
+{
+	struct ti_ads7142_channel *channel;
+
+	if (type != IIO_EV_TYPE_THRESH)
+		return -EINVAL;
+
+	channel = ti_ads7142_address2channel(indio_dev, chan->address);
+	if (!channel)
+		return -ENODEV;
+
+	if (dir == IIO_EV_DIR_RISING)
+		return channel->config.alert_high ? 1 : 0;
+
+	return channel->config.alert_low ? 1 : 0;
+}
+
+static int ti_ads7142_write_event_config(struct iio_dev *indio_dev,
+					 const struct iio_chan_spec *chan,
+					 enum iio_event_type type,
+					 enum iio_event_direction dir,
+					 int state)
+{
+	struct ti_ads7142_channel *channel;
+
+	if (type != IIO_EV_TYPE_THRESH)
+		return -EINVAL;
+
+	channel = ti_ads7142_address2channel(indio_dev, chan->address);
+	if (!channel)
+		return -ENODEV;
+
+	if (dir == IIO_EV_DIR_RISING)
+		channel->config.alert_high = state;
+	else
+		channel->config.alert_low = state;
+
+	return 0;
+}
+
+static const struct iio_info ti_ads7142_iio_info = {
+	.read_raw		= ti_ads7142_read_raw,
+	.write_raw		= ti_ads7142_write_raw,
+	.read_event_value	= ti_ads7142_read_event_value,
+	.write_event_value	= ti_ads7142_write_event_value,
+	.read_event_config	= ti_ads7142_read_event_config,
+	.write_event_config	= ti_ads7142_write_event_config,
+};
+
+static int ti_ads7142_triggered_buffer_preenable(struct iio_dev *indio_dev)
+{
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+	int ret;
+
+	if (!priv->config.buffer_mode)
+		return -EINVAL;
+
+	/*
+	 * Start/stop burst buffer modes requires trigger
+	 */
+	if (priv->config.buffer_mode <= TI_ADS7142_BUFFM_START_BURST &&
+	    !indio_dev->trig) {
+		dev_err(indio_dev->dev.parent,
+			"%s: Start/stop burst buffer modes requires trigger",
+			__func__);
+		return -EINVAL;
+	}
+
+	/*
+	 * Start burst and pre/post alert modes requires irq
+	 */
+	if (priv->config.buffer_mode >= TI_ADS7142_BUFFM_START_BURST &&
+	    !priv->irq_present) {
+		dev_err(indio_dev->dev.parent,
+			"%s: Start burst and pre/post alert modes requires irq",
+			__func__);
+		return -EINVAL;
+	}
+
+	mutex_lock(&priv->lock);
+	/*
+	 * Start burst mode started in trigger handler.
+	 * Sequencer aborted here, just for safe.
+	 */
+	if (priv->config.buffer_mode == TI_ADS7142_BUFFM_START_BURST)
+		ret = ti_ads7142_buffered_abort(indio_dev);
+	else
+		ret = ti_ads7142_buffered_setup_and_start(indio_dev);
+	mutex_unlock(&priv->lock);
+
+	return ret;
+}
+
+static int ti_ads7142_triggered_buffer_predisable(struct iio_dev *indio_dev)
+{
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+	int ret = 0;
+
+	mutex_lock(&priv->lock);
+	ti_ads7142_buffered_abort(indio_dev);
+	mutex_unlock(&priv->lock);
+
+	return ret;
+}
+
+static const struct iio_buffer_setup_ops ti_ads7142_triggered_buffer_ops = {
+	.preenable = &ti_ads7142_triggered_buffer_preenable,
+	.predisable = &ti_ads7142_triggered_buffer_predisable,
+};
+
+static irqreturn_t ti_ads7142_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+	int ret = 0;
+
+	mutex_lock(&priv->lock);
+	if (priv->config.buffer_mode == TI_ADS7142_BUFFM_STOP_BURST) {
+		ret = ti_ads7142_buffered_abort(indio_dev);
+		if (ret) {
+			dev_err(indio_dev->dev.parent,
+				"%s: error(%d) when aborting in %s mode",
+				__func__, ret,
+				ti_ads7142_buffer_modes[priv->config.buffer_mode]);
+			goto err_unlock;
+		}
+
+		ret = ti_ads7142_buffered_collect(indio_dev, NULL);
+		if (ret && ret != -ENOENT) {
+			dev_err(indio_dev->dev.parent,
+				"%s: error(%d) when collecting result for %s mode",
+				__func__, ret,
+				ti_ads7142_buffer_modes[priv->config.buffer_mode]);
+			goto err_unlock;
+		}
+	}
+	if (priv->config.buffer_mode == TI_ADS7142_BUFFM_START_BURST ||
+	    priv->config.buffer_mode == TI_ADS7142_BUFFM_STOP_BURST) {
+		ret = ti_ads7142_buffered_setup_and_start(indio_dev);
+		if (ret) {
+			dev_err(indio_dev->dev.parent,
+				"%s: error(%d) when starting %s mode",
+				__func__, ret,
+				ti_ads7142_buffer_modes[priv->config.buffer_mode]);
+			goto err_unlock;
+		}
+	}
+
+	mutex_unlock(&priv->lock);
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+
+err_unlock:
+	mutex_unlock(&priv->lock);
+	return IRQ_NONE;
+}
+
+static int ti_ads7142_get_buffer_mode(struct iio_dev *indio_dev,
+				      const struct iio_chan_spec *chan)
+{
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+
+	return priv->config.buffer_mode;
+}
+
+static int ti_ads7142_set_buffer_mode(struct iio_dev *indio_dev,
+				      const struct iio_chan_spec *chan,
+				      unsigned int mode)
+{
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+	int ret;
+
+	if (mode > TI_ADS7142_BUFFM_STOP_BURST && !priv->irq_present) {
+		dev_err(indio_dev->dev.parent,
+			"%s: no irq(BUSY/RDY) specified, mode %s is not supported",
+			__func__, ti_ads7142_buffer_modes[mode]);
+		return -EINVAL;
+	}
+
+	ret = iio_device_claim_direct_mode(indio_dev);
+	if (ret)
+		return ret;
+
+	priv->config.buffer_mode = mode;
+	iio_device_release_direct_mode(indio_dev);
+	return 0;
+}
+
+static const struct iio_enum ti_ads7142_buffer_modes_enum = {
+	.items = ti_ads7142_buffer_modes,
+	.num_items = ARRAY_SIZE(ti_ads7142_buffer_modes),
+	.get = ti_ads7142_get_buffer_mode,
+	.set = ti_ads7142_set_buffer_mode,
+};
+
+static const struct iio_chan_spec_ext_info ti_ads7142_ext_info[] = {
+	IIO_ENUM("buffer_mode", IIO_SHARED_BY_ALL,
+		 &ti_ads7142_buffer_modes_enum),
+	{
+		.name = "buffer_mode_available",
+		.shared = IIO_SHARED_BY_ALL,
+		.read = iio_enum_available_read,
+		.private = (uintptr_t)&ti_ads7142_buffer_modes_enum,
+	},
+	{ }
+};
+
+static int ti_ads7142_parse_channel_config(struct device *dev,
+					   struct iio_dev *indio_dev)
+{
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+	struct fwnode_handle *channel_node;
+	struct iio_chan_spec *iio_channels;
+	struct iio_chan_spec *iio_channel;
+	struct ti_ads7142_channel *ads_channel;
+	int channel_index = 0;
+	int channel_count;
+	int ret;
+
+	channel_count = device_get_child_node_count(dev);
+	if (!channel_count) {
+		dev_err(dev, "%s: there is no channel definition",
+			__func__);
+		return -ENODEV;
+	}
+
+	if (channel_count > TI_ADS7142_CHANNEL_COUNT) {
+		dev_err(dev, "%s: invalid number(%d) of channel definitions",
+			__func__, channel_count);
+		return -ENODEV;
+	}
+
+	priv->channels = devm_kcalloc(dev, channel_count,
+				      sizeof(*priv->channels),
+				      GFP_KERNEL);
+	if (!priv->channels)
+		return -ENOMEM;
+
+	indio_dev->num_channels = channel_count;
+	iio_channels = devm_kcalloc(dev, channel_count, sizeof(*iio_channels),
+				    GFP_KERNEL);
+	if (!iio_channels)
+		return -ENOMEM;
+
+	indio_dev->channels = iio_channels;
+
+	device_for_each_child_node(dev, channel_node) {
+		ads_channel = &priv->channels[channel_index];
+
+		ret = fwnode_property_read_u32(channel_node,
+					       TI_ADS7142_PROP_REG,
+					       &ads_channel->channel);
+		if (ret) {
+			dev_err(dev, "%s: %s parameter error(%d)",
+				__func__, TI_ADS7142_PROP_REG, ret);
+			fwnode_handle_put(channel_node);
+			return ret;
+		}
+
+		iio_channels[channel_index] = ti_ads7142_channel_template;
+		iio_channel = &iio_channels[channel_index];
+		iio_channel->datasheet_name = ti_ads7142_ain_names[ads_channel->channel];
+		if (priv->avdd)
+			iio_channel->info_mask_separate |= BIT(IIO_CHAN_INFO_SCALE);
+		iio_channel->address = ads_channel->channel;
+		iio_channel->scan_index = ads_channel->channel;
+		iio_channel->channel = ads_channel->channel;
+		iio_channel->ext_info = ti_ads7142_ext_info;
+
+		ads_channel->config.high_threshold = TI_ADS7142_THRESHOLD_MSK;
+		channel_index++;
+	}
+
+	return 0;
+}
+
+static int ti_ads7142_parse_config(struct device *dev,
+				   struct iio_dev *indio_dev)
+{
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+	int ret;
+
+	ret = device_property_read_u32(dev, TI_ADS7142_PROP_PREALERT_COUNT,
+				       &priv->config.prealert_count);
+	if (ret)
+		priv->config.prealert_count = 0;
+
+	return ti_ads7142_parse_channel_config(dev, indio_dev);
+}
+
+static void ti_ads7142_regulator_disable(void *data)
+{
+	if (data)
+		regulator_disable(data);
+}
+
+static int ti_ads7142_probe(struct i2c_client *client,
+			    const struct i2c_device_id *id)
+{
+	struct iio_dev *indio_dev;
+	struct ti_ads7142_priv *priv;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*priv));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, indio_dev);
+	priv = iio_priv(indio_dev);
+
+	/**
+	 * starting from v5.9-rc1 iio_device_alloc
+	 *  sets indio_dev->dev.parent, but older versions not :(
+	 **/
+	if (!indio_dev->dev.parent)
+		indio_dev->dev.parent = &client->dev;
+	indio_dev->name = TI_ADS7142_NAME;
+	indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
+	indio_dev->info = &ti_ads7142_iio_info;
+
+	priv->avdd = devm_regulator_get(&client->dev, "avdd");
+	if (IS_ERR(priv->avdd))
+		return PTR_ERR(priv->avdd);
+
+	if (priv->avdd) {
+		ret = regulator_enable(priv->avdd);
+		if (ret)
+			return ret;
+
+		ret = devm_add_action_or_reset(&client->dev,
+					       ti_ads7142_regulator_disable,
+					       priv->avdd);
+		if (ret)
+			return ret;
+	}
+
+	priv->dvdd = devm_regulator_get(&client->dev, "dvdd");
+	if (IS_ERR(priv->dvdd))
+		return PTR_ERR(priv->dvdd);
+
+	if (priv->dvdd) {
+		ret = regulator_enable(priv->dvdd);
+		if (ret)
+			return ret;
+
+		ret = devm_add_action_or_reset(&client->dev,
+					       ti_ads7142_regulator_disable,
+					       priv->dvdd);
+		if (ret)
+			return ret;
+	}
+
+	ret = ti_ads7142_soft_reset(client);
+	if (ret)
+		return ret;
+
+	ret = ti_ads7142_parse_config(&client->dev, indio_dev);
+	if (ret)
+		return ret;
+
+	mutex_init(&priv->lock);
+
+	if (client->irq) {
+		ret = devm_request_threaded_irq(&client->dev, client->irq,
+						NULL, ti_ads7142_ist,
+						IRQF_ONESHOT | IRQF_SHARED,
+						dev_name(&client->dev),
+						indio_dev);
+		if (ret) {
+			dev_err(&client->dev, "Unable to request IRQ %i",
+				client->irq);
+			return ret;
+		}
+		priv->irq_present = true;
+	}
+
+	ret = devm_iio_triggered_buffer_setup(&client->dev,
+					      indio_dev,
+					      &iio_pollfunc_store_time,
+					      &ti_ads7142_trigger_handler,
+					      &ti_ads7142_triggered_buffer_ops);
+	if (ret)
+		return ret;
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static int __maybe_unused ti_ads7142_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+
+	mutex_lock(&priv->lock);
+	do {
+		/*
+		 * Keep all regulators on when the device in autonomous
+		 *  monitoring mode.
+		 * The device can wake up the system with ALERT pin
+		 */
+		if (priv->monitor_pending &&
+		    (priv->config.buffer_mode == TI_ADS7142_BUFFM_PRE_ALERT ||
+		     priv->config.buffer_mode == TI_ADS7142_BUFFM_POST_ALERT))
+			continue;
+
+		if (priv->avdd)
+			regulator_disable(priv->avdd);
+		if (priv->dvdd)
+			regulator_disable(priv->dvdd);
+	} while (0);
+	mutex_unlock(&priv->lock);
+
+	return 0;
+}
+
+static int __maybe_unused ti_ads7142_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct ti_ads7142_priv *priv = iio_priv(indio_dev);
+	int ret = 0;
+
+	mutex_lock(&priv->lock);
+	do {
+		/*
+		 * Nothing to do when the device in autonomous monitoring mode.
+		 */
+		if (priv->monitor_pending &&
+		    (priv->config.buffer_mode == TI_ADS7142_BUFFM_PRE_ALERT ||
+		     priv->config.buffer_mode == TI_ADS7142_BUFFM_POST_ALERT))
+			continue;
+
+		if (priv->avdd) {
+			ret = regulator_enable(priv->avdd);
+			if (ret)
+				continue;
+		}
+		if (priv->dvdd) {
+			ret = regulator_enable(priv->dvdd);
+			if (ret)
+				continue;
+		}
+	} while (0);
+	mutex_unlock(&priv->lock);
+
+	return ret;
+}
+
+static SIMPLE_DEV_PM_OPS(ti_ads7142_pm_ops, ti_ads7142_suspend,
+			 ti_ads7142_resume);
+
+static const struct i2c_device_id ti_ads7142_id[] = {
+	{ TI_ADS7142_NAME, 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ti_ads7142_id);
+
+static const struct of_device_id ti_ads7142_of_match[] = {
+	{ .compatible = "ti,ads7142" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, ti_ads7142_of_match);
+
+static struct i2c_driver ti_ads7142_driver = {
+	.driver = {
+		.name = TI_ADS7142_NAME,
+		.of_match_table = ti_ads7142_of_match,
+		.pm = &ti_ads7142_pm_ops,
+	},
+	.probe		= ti_ads7142_probe,
+	.id_table	= ti_ads7142_id,
+};
+
+module_i2c_driver(ti_ads7142_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jozsef Horvath <info@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("Texas Instruments ADS7142 ADC driver");
-- 
2.17.1





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