[PATCH 2/3] iio: adc: add driver support for AD5940

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The AD5940 is a high precision, low power analog front end (AFE)
designed for portable applications that require high precision,
electrochemical-based measurement techniques, such as amper-
ometric, voltammetric, or impedance measurements.

Datasheet:
Link: https://www.analog.com/media/en/technical-documentation/data-sheets/AD5940.pdf

Signed-off-by: Song Qiang <songqiang1304521@xxxxxxxxx>
---
 .../ABI/testing/sysfs-bus-iio-adc-ad5940      |   7 +
 drivers/iio/adc/Kconfig                       |  10 +
 drivers/iio/adc/Makefile                      |   1 +
 drivers/iio/adc/ad5940.c                      | 679 ++++++++++++++++++
 4 files changed, 697 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-adc-ad5940
 create mode 100644 drivers/iio/adc/ad5940.c

diff --git a/Documentation/ABI/testing/sysfs-bus-iio-adc-ad5940 b/Documentation/ABI/testing/sysfs-bus-iio-adc-ad5940
new file mode 100644
index 000000000000..839644ffbd9b
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-iio-adc-ad5940
@@ -0,0 +1,7 @@
+What:		/sys/bus/iio/devices/iio:deviceX/events/in_voltageY-voltageZ_name
+Date:		June 2019
+KernelVersion:	4.14.5
+Contact:	songqiang1304521@xxxxxxxxx
+Description:
+		Channel name assigned in devicetree, used to tell userspace
+		users which channel this is.
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index f0af3a42f53c..345f934d3444 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -11,6 +11,16 @@ config AD_SIGMA_DELTA
 	select IIO_BUFFER
 	select IIO_TRIGGERED_BUFFER
 
+config AD5940
+	tristate "Analog Devices AD5940 ADC Driver"
+	depends on SPI
+	help
+	  Say yes here to build support for the ADC part of Analog Devices
+	  analog front end AD5940.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ad5940.
+
 config AD7124
 	tristate "Analog Devices AD7124 and similar sigma-delta ADCs driver"
 	depends on SPI_MASTER
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index ef9cc485fb67..ac52d1b6f3fb 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -5,6 +5,7 @@
 
 # When adding new entries keep the list in alphabetical order
 obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
+obj-$(CONFIG_AD5940) += ad5940.o
 obj-$(CONFIG_AD7124) += ad7124.o
 obj-$(CONFIG_AD7266) += ad7266.o
 obj-$(CONFIG_AD7291) += ad7291.o
diff --git a/drivers/iio/adc/ad5940.c b/drivers/iio/adc/ad5940.c
new file mode 100644
index 000000000000..57f737edca36
--- /dev/null
+++ b/drivers/iio/adc/ad5940.c
@@ -0,0 +1,679 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AD5940 SPI ADC driver
+ *
+ * Copyright (C) 2019 Song Qiang <songqiang1304521@xxxxxxxxx>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bsearch.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of_irq.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+
+#include <linux/iio/iio.h>
+
+#define AD5940_CHANNEL_AINP_MSK		GENMASK(5, 0)
+#define AD5940_CHANNEL_AINP(x)		FIELD_PREP(AD5940_CHANNEL_AINP_MSK, x)
+#define AD5940_CHANNEL_AINN_MSK		GENMASK(12, 8)
+#define AD5940_CHANNEL_AINN(x)		FIELD_PREP(AD5940_CHANNEL_AINN_MSK, x)
+
+#define AD5940_CHANNEL_NAME		0
+
+#define AD5940_SPICMD_SETADDR		0x20
+#define AD5940_SPICMD_READREG		0x6d
+#define AD5940_SPICMD_WRITEREG		0x2d
+#define AD5940_SPICMD_READFIFO		0x5f
+
+#define AD5940_REG_AFECON		0x00002000
+#define AD5940_AFECON_ADCCONV_MSK	BIT(8)
+#define AD5940_AFECON_ADCCONV_EN	FIELD_PREP(AD5940_AFECON_ADCCONV_MSK, 1)
+#define AD5940_AFECON_ADCCONV_DIS	FIELD_PREP(AD5940_AFECON_ADCCONV_MSK, 0)
+#define AD5940_AFECON_ADCEN_MSK		BIT(7)
+#define AD5940_AFECON_ADCEN		FIELD_PREP(AD5940_AFECON_ADCEN_MSK, 1)
+
+#define AD5940_REG_ADCDAT		0x00002074
+#define AD5940_REG_DFTREAL		0x00002078
+#define AD5940_REG_DFTIMAG		0x0000207C
+#define AD5940_REG_SINC2DAT		0x00002080
+#define AD5940_REG_TEMPSENSDAT		0x00002084
+#define AD5940_REG_STATSMEAN		0x000021C8
+#define AD5940_REG_STATSVAR		0x000021C0
+
+#define AD5940_REG_INTCPOL		0x00003000 /* Interrupt Polarity. */
+#define AD5940_INTCPOL_MSK		BIT(0)
+#define AD5940_INTCPOL_POS		FIELD_PREP(AD5940_INTCPOL_MSK, 1)
+#define AD5940_INTCPOL_NEG		FIELD_PREP(AD5940_INTCPOL_MSK, 0)
+#define AD5940_REG_INTCLR		0x00003004
+
+#define AD5940_REG_PMBW			0x000022F0
+#define	AD5940_PMBW_SYSHS_MSK		BIT(0)
+#define	AD5940_PMBW_HP			FIELD_PREP(AD5940_PMBW_SYSHS_MSK, 1)
+#define	AD5940_PMBW_LP			FIELD_PREP(AD5940_PMBW_SYSHS_MSK, 0)
+#define AD5940_PMBW_SYSBW_MSK		GENMASK(3, 2)
+#define	AD5940_PMBW_BWNA		FIELD_PREP(AD5940_PMBW_SYSBW_MSK, 0)
+#define	AD5940_PMBW_BW50		FIELD_PREP(AD5940_PMBW_SYSBW_MSK, 1)
+#define	AD5940_PMBW_BW100		FIELD_PREP(AD5940_PMBW_SYSBW_MSK, 2)
+#define	AD5940_PMBW_BW250		FIELD_PREP(AD5940_PMBW_SYSBW_MSK, 3)
+
+#define AD5940_REG_ADCCON		0x000021A8
+#define AD5940_ADCCON_PGA_MSK		GENMASK(18, 16)
+#define AD5940_ADCCON_PGA_1		FIELD_PREP(AD5940_ADCCON_PGA_MSK, 0)
+#define AD5940_ADCCON_PGA_1P5		FIELD_PREP(AD5940_ADCCON_PGA_MSK, 1)
+#define AD5940_ADCCON_PGA_2		FIELD_PREP(AD5940_ADCCON_PGA_MSK, 2)
+#define AD5940_ADCCON_PGA_4		FIELD_PREP(AD5940_ADCCON_PGA_MSK, 3)
+#define AD5940_ADCCON_PGA_9		FIELD_PREP(AD5940_ADCCON_PGA_MSK, 4)
+#define AD5940_ADCCON_MUX_MSK		(GENMASK(12, 8) | GENMASK(5, 0))
+
+#define AD5940_REG_INTCLR		0x00003004
+#define AD5940_REG_INTCSEL0		0x00003008
+#define AD5940_INTC_BRK			BIT(31)
+#define AD5940_INTC_OUTLIER		BIT(29)
+#define AD5940_INTC_FIFO_UNDERFLOW	BIT(27)
+#define AD5940_INTC_FIFO_OVERFLOW	BIT(26)
+#define AD5940_INTC_FIFO_THRESHOLD	BIT(25)
+#define AD5940_INTC_FIFO_EMPTY		BIT(24)
+#define AD5940_INTC_FIFO_FULL		BIT(23)
+#define AD5940_INTC_SEQ_TO_ERR		BIT(17)
+#define AD5940_INTC_SEQ_TO_FINISH	BIT(16)
+#define AD5940_INTC_SEQ_END		BIT(15)
+#define AD5940_INTC_BL_DONE		BIT(13)
+#define AD5940_INTC_IRQ_3		BIT(12)
+#define AD5940_INTC_IRQ_2		BIT(11)
+#define AD5940_INTC_IRQ_1		BIT(10)
+#define AD5940_INTC_IRQ_0		BIT(9)
+#define AD5940_INTC_VAR			BIT(8)
+#define AD5940_INTC_MEAN		BIT(7)
+#define AD5940_INTC_ADC_DELTA_FAIL	BIT(6)
+#define AD5940_INTC_ADC_MAX_FAIL	BIT(5)
+#define AD5940_INTC_ADC_MIN_FAIL	BIT(4)
+#define AD5940_INTC_TEMP		BIT(3)
+#define AD5940_INTC_SINC2		BIT(2)
+#define AD5940_INTC_DFT			BIT(1)
+#define AD5940_INTC_ADC			BIT(0)
+
+#define AD5940_REG_GP0CON		0x00000000
+#define AD5940_GP0CON_3_MSK		GENMASK(7, 6)
+#define AD5940_GP0CON_3_INT		FIELD_PREP(AD5940_GP0CON_3_MSK, 3)
+#define AD5940_GP0CON_6_MSK		GENMASK(13, 12)
+#define AD5940_GP0CON_6_INT		FIELD_PREP(AD5940_GP0CON_6_MSK, 3)
+
+#define AD5940_REG_GP0OEN		0x00000004
+
+#define AD5940_AFECON_CHIPID		0x00000404
+#define AD5940_CHIPID			0x5502
+
+struct ad5940_channel_config {
+	u32 ain;
+	const char *channel_name;
+};
+
+struct ad5940_state {
+	struct spi_device *spi;
+	/* This mutex is for protecting the SPI command sequences. */
+	struct mutex lock;
+
+	struct completion complete;
+	u32 conversion_time;
+
+	u8 n_input;
+	u8 p_input;
+
+	struct regulator *vref;
+	int vref_mv;
+
+	int num_channels;
+	struct ad5940_channel_config *channel_config;
+	union {
+		__be32 d32;
+		u8 d8[5];
+	} data ____cacheline_aligned;
+};
+
+static int ad5940_set_addr(struct ad5940_state *st, u16 addr)
+{
+	st->data.d8[0] = AD5940_SPICMD_SETADDR;
+	st->data.d8[1] = (addr >> 8) & 0xff;
+	st->data.d8[2] = addr & 0xff;
+
+	return spi_write(st->spi, st->data.d8, 3);
+}
+
+static int ad5940_read_reg(struct ad5940_state *st, u16 addr, u32 *data)
+{
+	int rx_len;
+	u8 shift;
+	int ret;
+
+	ret = ad5940_set_addr(st, addr);
+	if (ret < 0)
+		return ret;
+
+	if ((addr >= 0x1000) && (addr <= 0x3014))
+		rx_len = 4;
+	else
+		rx_len = 2;
+
+	st->data.d8[0] = AD5940_SPICMD_READREG;
+	st->data.d8[1] = 0;
+	shift = 32 - (8 * rx_len);
+
+	ret = spi_write_then_read(st->spi, st->data.d8, 2, &st->data.d32,
+				  rx_len);
+	if (ret < 0)
+		return ret;
+
+	*data = be32_to_cpu(st->data.d32) >> shift;
+
+	return 0;
+}
+
+static int ad5940_write_reg(struct ad5940_state *st, u16 addr, u32 data)
+{
+	int tx_len;
+	int ret;
+
+	ret = ad5940_set_addr(st, addr);
+	if (ret < 0)
+		return ret;
+
+	st->data.d8[0] = AD5940_SPICMD_WRITEREG;
+	if ((addr >= 0x1000) && (addr <= 0x3014)) {
+		st->data.d8[1] = (data >> 24) & 0xff;
+		st->data.d8[2] = (data >> 16) & 0xff;
+		st->data.d8[3] = (data >> 8) & 0xff;
+		st->data.d8[4] = data & 0xff;
+		tx_len = 5;
+	} else {
+		st->data.d8[1] = (data >> 8) & 0xff;
+		st->data.d8[2] = data & 0xff;
+		tx_len = 3;
+	}
+
+	return spi_write(st->spi, st->data.d8, tx_len);
+}
+
+static int ad5940_write_reg_mask(struct ad5940_state *st, u16 addr,
+				 u32 mask, u32 data)
+{
+	u32 temp;
+	int ret;
+
+	ret = ad5940_read_reg(st, addr, &temp);
+	if (ret < 0)
+		return ret;
+
+	temp &= ~mask;
+	temp |= data;
+
+	return ad5940_write_reg(st, addr, temp);
+}
+
+static ssize_t ad5940_read_info(struct iio_dev *indio_dev,
+				uintptr_t private,
+				const struct iio_chan_spec *chan,
+				char *buf)
+{
+	struct ad5940_state *st = iio_priv(indio_dev);
+
+	switch ((u32)private) {
+	case AD5940_CHANNEL_NAME:
+		return sprintf(buf, "%s\n",
+			st->channel_config[chan->address].channel_name);
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_chan_spec_ext_info ad4590_ext_info[] = {
+	{
+		.name = "name",
+		.read = ad5940_read_info,
+		.private = AD5940_CHANNEL_NAME,
+		.shared = IIO_SEPARATE,
+	},
+	{ },
+};
+
+static const struct iio_chan_spec ad5940_channel_template = {
+	.type = IIO_VOLTAGE,
+	.differential = 1,
+	.indexed = 1,
+	.ext_info = ad4590_ext_info,
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+};
+
+static int ad5940_clear_ready(struct ad5940_state *st)
+{
+	int ret;
+
+	ret = ad5940_write_reg_mask(st, AD5940_REG_AFECON,
+				    AD5940_AFECON_ADCCONV_MSK,
+				    AD5940_AFECON_ADCCONV_DIS);
+	if (ret < 0)
+		return ret;
+
+	return ad5940_write_reg(st, AD5940_REG_INTCLR, AD5940_INTC_ADC);
+}
+
+static irqreturn_t ad5940_irq_handler(int irq, void *private)
+{
+	struct ad5940_state *st = private;
+	int ret;
+
+	ret = ad5940_clear_ready(st);
+	if (ret < 0)
+		return ret;
+
+	complete(&st->complete);
+
+	return IRQ_HANDLED;
+}
+
+static int ad5940_scan_direct(struct ad5940_state *st, u32 mux, int *val)
+{
+	int ret;
+	u32 result;
+
+	mutex_lock(&st->lock);
+	ret = ad5940_write_reg_mask(st, AD5940_REG_ADCCON,
+				    AD5940_ADCCON_MUX_MSK, mux);
+	if (ret < 0)
+		goto unlock_return;
+
+	reinit_completion(&st->complete);
+	ret = ad5940_write_reg_mask(st, AD5940_REG_AFECON,
+				    AD5940_AFECON_ADCCONV_MSK,
+				    AD5940_AFECON_ADCCONV_EN);
+	if (ret < 0)
+		goto unlock_return;
+
+	ret = wait_for_completion_timeout(&st->complete,
+					  msecs_to_jiffies(1000));
+	if (!ret) {
+		ad5940_clear_ready(st);
+		ret = -ETIMEDOUT;
+		goto unlock_return;
+	}
+
+	ret = ad5940_read_reg(st, AD5940_REG_ADCDAT, &result);
+	mutex_unlock(&st->lock);
+	if (ret < 0)
+		return ret;
+	*val = result & 0xffff;
+
+	return 0;
+
+unlock_return:
+	mutex_unlock(&st->lock);
+	return ret;
+}
+
+static int ad5940_read_raw(struct iio_dev *indio_dev,
+	const struct iio_chan_spec *chan, int *val, int *val2, long info)
+{
+	struct ad5940_state *st = iio_priv(indio_dev);
+	int ret;
+
+	switch (info) {
+	case IIO_CHAN_INFO_RAW:
+		ret = ad5940_scan_direct(st,
+				st->channel_config[chan->address].ain,
+				val);
+		if (ret < 0)
+			return ret;
+		else
+			return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = st->vref_mv;
+		*val2 = 16;
+		return IIO_VAL_FRACTIONAL_LOG2;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info ad5940_info = {
+	.read_raw = &ad5940_read_raw,
+};
+
+int cmp_u8(const void *a, const void *b)
+{
+	return (*(u8 *)a - *(u8 *)b);
+}
+
+static int ad5940_check_channel_indexes(struct device *dev, u32 *ain)
+{
+	const u8 channel_p[] = {
+		0, 1, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 18, 19,
+		20, 22, 23, 24, 25, 26, 31, 33, 35, 36
+	};
+	const u8 channel_n[] = {
+		0, 1, 2, 4, 5, 6, 7, 10, 11, 12, 14, 16, 17, 20
+	};
+	u8 *index;
+
+	index = (u8 *) bsearch(&ain[0], channel_p, ARRAY_SIZE(channel_p),
+				sizeof(u8), cmp_u8);
+	if (!index) {
+		dev_err(dev, "Positive input index not found.\n");
+		return -EINVAL;
+	}
+
+	index = (u8 *) bsearch(&ain[1], channel_n, ARRAY_SIZE(channel_n),
+				sizeof(u8), cmp_u8);
+	if (!index) {
+		dev_err(dev, "negtive input index not found.\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int ad5940_of_parse_channel_config(struct iio_dev *indio_dev,
+					  struct device_node *np)
+{
+	struct ad5940_state *st = iio_priv(indio_dev);
+	struct iio_chan_spec *chan;
+	struct device_node *child;
+	u32 channel, ain[2];
+	int ret;
+
+	st->num_channels = of_get_available_child_count(np);
+	if (!st->num_channels) {
+		dev_err(indio_dev->dev.parent, "no channel children\n");
+		return -ENODEV;
+	}
+
+	chan = devm_kcalloc(indio_dev->dev.parent, st->num_channels,
+			    sizeof(*chan), GFP_KERNEL);
+	if (!chan)
+		return -ENOMEM;
+
+	st->channel_config = devm_kcalloc(indio_dev->dev.parent,
+					  st->num_channels,
+					  sizeof(*st->channel_config),
+					  GFP_KERNEL);
+	if (!st->channel_config)
+		return -ENOMEM;
+
+	indio_dev->channels = chan;
+	indio_dev->num_channels = st->num_channels;
+
+	for_each_available_child_of_node(np, child) {
+		ret = of_property_read_u32(child, "reg", &channel);
+		if (ret)
+			goto err;
+
+		ret = of_property_read_u32_array(child, "diff-channels",
+						 ain, 2);
+		if (ret)
+			goto err;
+
+		ret = of_property_read_string(child, "channel-name",
+				&st->channel_config[channel].channel_name);
+		if (ret)
+			st->channel_config[channel].channel_name = "none-name";
+
+		ret = ad5940_check_channel_indexes(indio_dev->dev.parent, ain);
+		if (ret) {
+			dev_err(indio_dev->dev.parent,
+				"some input channel index does not exist: %d, %d, %d",
+				channel, ain[0], ain[1]);
+			goto err;
+		}
+
+		st->channel_config[channel].ain = AD5940_CHANNEL_AINP(ain[0]) |
+						  AD5940_CHANNEL_AINN(ain[1]);
+
+		*chan = ad5940_channel_template;
+		chan->address = channel;
+		chan->scan_index = channel;
+		chan->channel = ain[0];
+		chan->channel2 = ain[1];
+
+		chan++;
+	}
+
+	return 0;
+err:
+	of_node_put(child);
+
+	return ret;
+}
+
+static int ad5940_config_polarity(struct ad5940_state *st, u32 polarity)
+{
+	u32 val;
+
+	if (polarity == IRQF_TRIGGER_RISING)
+		val = AD5940_INTCPOL_POS;
+	else
+		val = AD5940_INTCPOL_NEG;
+
+	return ad5940_write_reg_mask(st, AD5940_REG_INTCPOL,
+				     AD5940_INTCPOL_MSK, val);
+}
+
+static int ad5940_config_int_io(struct ad5940_state *st, u8 int_io)
+{
+	int ret = 0;
+
+	if (int_io == 3)
+		ret = ad5940_write_reg_mask(st, AD5940_REG_GP0CON,
+					    AD5940_GP0CON_3_MSK,
+					    AD5940_GP0CON_3_INT);
+	else if (int_io == 6)
+		ret = ad5940_write_reg_mask(st, AD5940_REG_GP0CON,
+					    AD5940_GP0CON_6_MSK,
+					    AD5940_GP0CON_6_INT);
+	if (ret < 0)
+		return ret;
+
+	return  ad5940_write_reg(st, AD5940_REG_GP0OEN, BIT(int_io));
+}
+
+static const u32 ad5940_powerup_setting[][2] = {
+	{ 0x0908, 0x02c9 },
+	{ 0x0c08, 0x206c },
+	{ 0x21f0, 0x0010 },
+	{ 0x0410, 0x02c9 },
+	{ 0x0a28, 0x0009 },
+	{ 0x238c, 0x0104 },
+	{ 0x0a04, 0x4859 },
+	{ 0x0a04, 0xf27b },
+	{ 0x0a00, 0x8009 },
+	{ 0x22f0, 0x0000 },
+	{ 0x2230, 0xde87a5af },
+	{ 0x2250, 0x103f },
+	{ 0x22b0, 0x203c },
+	{ 0x2230, 0xde87a5a0 },
+};
+
+static int ad5940_setup(struct ad5940_state *st, u8 int_io)
+{
+	u32 chip_id;
+	int ret;
+	u8 i;
+
+	for (i = 0; i < ARRAY_SIZE(ad5940_powerup_setting); i++) {
+		ret = ad5940_write_reg(st, ad5940_powerup_setting[i][0],
+				       ad5940_powerup_setting[i][1]);
+		if (ret < 0)
+			return ret;
+	}
+
+	ret = ad5940_read_reg(st, AD5940_AFECON_CHIPID, &chip_id);
+	if (ret < 0)
+		return ret;
+	if (chip_id != AD5940_CHIPID) {
+		dev_err(&st->spi->dev, "Wrong chip ID with 0x%x.", chip_id);
+		return -ENXIO;
+	}
+	dev_info(&st->spi->dev, "Found ad5940");
+
+	ret = ad5940_write_reg(st, AD5940_REG_PMBW,
+			       AD5940_PMBW_LP | AD5940_PMBW_BW250);
+	if (ret < 0)
+		return ret;
+
+	ret = ad5940_config_int_io(st, int_io);
+	if (ret < 0)
+		return ret;
+
+	ret = ad5940_clear_ready(st);
+	if (ret < 0)
+		return ret;
+
+	ret = ad5940_write_reg(st, AD5940_REG_INTCSEL0, AD5940_INTC_ADC);
+	if (ret < 0)
+		return ret;
+
+	ret = ad5940_write_reg_mask(st, AD5940_REG_ADCCON,
+				    AD5940_ADCCON_PGA_MSK,
+				    AD5940_ADCCON_PGA_1);
+	if (ret < 0)
+		return ret;
+
+	return ad5940_write_reg_mask(st, AD5940_REG_AFECON,
+				     AD5940_AFECON_ADCEN_MSK,
+				     AD5940_AFECON_ADCEN);
+}
+
+static void ad5940_regulator_disable(void *data)
+{
+	struct ad5940_state *st = data;
+
+	regulator_disable(st->vref);
+}
+
+static inline int ad5940_check_int_io(u32 io, struct device *dev)
+{
+	static const u8 int_io[3] = {0, 3, 6};
+	u8 *p;
+
+	p = bsearch(&io, int_io, 3, sizeof(u8), cmp_u8);
+	if (!p) {
+		dev_err(dev, "interrupt output pin not valid,");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int ad5940_probe(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev;
+	struct ad5940_state *st;
+	u32 trig_type;
+	int vref_uv = 0;
+	u32 int_io;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+
+	ret = device_property_read_u32(&spi->dev, "adi,interrupt-io", &int_io);
+	if (ret) {
+		dev_err(&spi->dev,
+			"reading dt property 'adi,interrupt-io' failed.");
+		return -EINVAL;
+	}
+
+	st->spi = spi;
+
+	trig_type = irq_get_trigger_type(spi->irq);
+	if (trig_type != IRQF_TRIGGER_RISING &&
+	    trig_type != IRQF_TRIGGER_FALLING) {
+		dev_err(&spi->dev, "trigger type must be rising or falling.");
+		return -EINVAL;
+	}
+	ret = ad5940_config_polarity(st, trig_type);
+	if (ret < 0) {
+		dev_err(&spi->dev, "config polarity failed.");
+		return ret;
+	}
+
+	ret = ad5940_check_int_io(int_io, &spi->dev);
+	if (ret < 0)
+		return ret;
+
+	st->vref = devm_regulator_get_optional(&spi->dev, "vref");
+	if (!IS_ERR(st->vref)) {
+		ret = regulator_enable(st->vref);
+		if (ret) {
+			dev_err(&spi->dev, "Failed to enbale specified vref supply.\n");
+			return ret;
+		}
+
+		ret = devm_add_action_or_reset(&spi->dev,
+				ad5940_regulator_disable, st);
+		if (ret) {
+			regulator_disable(st->vref);
+			return ret;
+		}
+
+		ret = regulator_get_voltage(st->vref);
+		if (ret < 0)
+			return ret;
+
+		vref_uv = ret;
+	}
+
+	if (vref_uv)
+		st->vref_mv = vref_uv / 1000;
+	else
+		st->vref_mv = 1820;
+
+	indio_dev->dev.parent = &spi->dev;
+	indio_dev->dev.of_node = spi->dev.of_node;
+	indio_dev->name = spi->dev.of_node->name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &ad5940_info;
+
+	ret = ad5940_of_parse_channel_config(indio_dev, spi->dev.of_node);
+	if (ret < 0)
+		return ret;
+
+	init_completion(&st->complete);
+
+	ret = ad5940_setup(st, int_io);
+	if (ret)
+		return ret;
+
+	ret = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
+					ad5940_irq_handler,
+					trig_type | IRQF_ONESHOT,
+					dev_name(&spi->dev), st);
+	if (ret < 0)
+		return ret;
+
+	return devm_iio_device_register(&spi->dev, indio_dev);
+}
+
+static const struct of_device_id ad5940_dt_match[] = {
+	{ .compatible = "adi,ad5940" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ad5940_spi_ids);
+
+static struct spi_driver ad5940_driver = {
+	.driver = {
+		.name = "ad5940",
+		.of_match_table = ad5940_dt_match,
+	},
+	.probe = ad5940_probe,
+};
+module_spi_driver(ad5940_driver);
+
+MODULE_AUTHOR("Song Qiang <songqiang1304521@xxxxxxxxx>");
+MODULE_DESCRIPTION("Analog Device AD5940 ADC driver");
+MODULE_LICENSE("GPL");
-- 
2.17.1




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