iio: health: Add driver for the TI AFE4403 heart monitor

Add driver for the TI AFE4403 heart rate monitor and pulse oximeter.
This device detects reflected LED light fluctuations and presents an ADC
value to the user space for further signal processing.

Data sheet located here:
http://www.ti.com/product/AFE4403/datasheet

Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

3 files changed, 721 insertions, 0 deletions

diff --git a/drivers/iio/health/Kconfig b/drivers/iio/health/Kconfig
index 632a14b7dd6f..f0c19779ac27 100644
--- a/drivers/iio/health/Kconfig
+++ b/drivers/iio/health/Kconfig
@@ -7,6 +7,18 @@ menu "Health Sensors"
 
 menu "Heart Rate Monitors"
 
+config AFE4403
+	tristate "TI AFE4403 Heart Rate Monitor"
+	depends on SPI_MASTER
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	help
+	  Say yes to choose the Texas Instruments AFE4403
+	  heart rate monitor and low-cost pulse oximeter.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called afe4403.
+
 config AFE4404
 	tristate "TI AFE4404 heart rate and pulse oximeter sensor"
 	depends on I2C
diff --git a/drivers/iio/health/Makefile b/drivers/iio/health/Makefile
index b37c0d5e07b8..9955a2ae8df1 100644
--- a/drivers/iio/health/Makefile
+++ b/drivers/iio/health/Makefile
@@ -4,5 +4,6 @@
 
 # When adding new entries keep the list in alphabetical order
 
+obj-$(CONFIG_AFE4403)		+= afe4403.o
 obj-$(CONFIG_AFE4404)		+= afe4404.o
 obj-$(CONFIG_MAX30100)		+= max30100.o
diff --git a/drivers/iio/health/afe4403.c b/drivers/iio/health/afe4403.c
new file mode 100644
index 000000000000..91c046e40d2f
--- /dev/null
+++ b/drivers/iio/health/afe4403.c
@@ -0,0 +1,708 @@
+/*
+ * AFE4403 Heart Rate Monitors and Low-Cost Pulse Oximeters
+ *
+ * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/
+ *	Andrew F. Davis <afd@ti.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/device.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+#include <linux/sysfs.h>
+#include <linux/regulator/consumer.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+
+#include "afe440x.h"
+
+#define AFE4403_DRIVER_NAME		"afe4403"
+
+/* AFE4403 Registers */
+#define AFE4403_TIAGAIN			0x20
+#define AFE4403_TIA_AMB_GAIN		0x21
+
+/* AFE4403 GAIN register fields */
+#define AFE4403_TIAGAIN_RES_MASK	GENMASK(2, 0)
+#define AFE4403_TIAGAIN_RES_SHIFT	0
+#define AFE4403_TIAGAIN_CAP_MASK	GENMASK(7, 3)
+#define AFE4403_TIAGAIN_CAP_SHIFT	3
+
+/* AFE4403 LEDCNTRL register fields */
+#define AFE440X_LEDCNTRL_LED1_MASK		GENMASK(15, 8)
+#define AFE440X_LEDCNTRL_LED1_SHIFT		8
+#define AFE440X_LEDCNTRL_LED2_MASK		GENMASK(7, 0)
+#define AFE440X_LEDCNTRL_LED2_SHIFT		0
+#define AFE440X_LEDCNTRL_LED_RANGE_MASK		GENMASK(17, 16)
+#define AFE440X_LEDCNTRL_LED_RANGE_SHIFT	16
+
+/* AFE4403 CONTROL2 register fields */
+#define AFE440X_CONTROL2_PWR_DWN_TX	BIT(2)
+#define AFE440X_CONTROL2_EN_SLOW_DIAG	BIT(8)
+#define AFE440X_CONTROL2_DIAG_OUT_TRI	BIT(10)
+#define AFE440X_CONTROL2_TX_BRDG_MOD	BIT(11)
+#define AFE440X_CONTROL2_TX_REF_MASK	GENMASK(18, 17)
+#define AFE440X_CONTROL2_TX_REF_SHIFT	17
+
+/* AFE4404 NULL fields */
+#define NULL_MASK	0
+#define NULL_SHIFT	0
+
+/* AFE4403 LEDCNTRL values */
+#define AFE440X_LEDCNTRL_RANGE_TX_HALF	0x1
+#define AFE440X_LEDCNTRL_RANGE_TX_FULL	0x2
+#define AFE440X_LEDCNTRL_RANGE_TX_OFF	0x3
+
+/* AFE4403 CONTROL2 values */
+#define AFE440X_CONTROL2_TX_REF_025	0x0
+#define AFE440X_CONTROL2_TX_REF_050	0x1
+#define AFE440X_CONTROL2_TX_REF_100	0x2
+#define AFE440X_CONTROL2_TX_REF_075	0x3
+
+/* AFE4403 CONTROL3 values */
+#define AFE440X_CONTROL3_CLK_DIV_2	0x0
+#define AFE440X_CONTROL3_CLK_DIV_4	0x2
+#define AFE440X_CONTROL3_CLK_DIV_6	0x3
+#define AFE440X_CONTROL3_CLK_DIV_8	0x4
+#define AFE440X_CONTROL3_CLK_DIV_12	0x5
+#define AFE440X_CONTROL3_CLK_DIV_1	0x7
+
+/* AFE4403 TIAGAIN_CAP values */
+#define AFE4403_TIAGAIN_CAP_5_P		0x0
+#define AFE4403_TIAGAIN_CAP_10_P	0x1
+#define AFE4403_TIAGAIN_CAP_20_P	0x2
+#define AFE4403_TIAGAIN_CAP_30_P	0x3
+#define AFE4403_TIAGAIN_CAP_55_P	0x8
+#define AFE4403_TIAGAIN_CAP_155_P	0x10
+
+/* AFE4403 TIAGAIN_RES values */
+#define AFE4403_TIAGAIN_RES_500_K	0x0
+#define AFE4403_TIAGAIN_RES_250_K	0x1
+#define AFE4403_TIAGAIN_RES_100_K	0x2
+#define AFE4403_TIAGAIN_RES_50_K	0x3
+#define AFE4403_TIAGAIN_RES_25_K	0x4
+#define AFE4403_TIAGAIN_RES_10_K	0x5
+#define AFE4403_TIAGAIN_RES_1_M		0x6
+#define AFE4403_TIAGAIN_RES_NONE	0x7
+
+/**
+ * struct afe4403_data
+ * @dev - Device structure
+ * @spi - SPI device handle
+ * @regmap - Register map of the device
+ * @regulator - Pointer to the regulator for the IC
+ * @trig - IIO trigger for this device
+ * @irq - ADC_RDY line interrupt number
+ */
+struct afe4403_data {
+	struct device *dev;
+	struct spi_device *spi;
+	struct regmap *regmap;
+	struct regulator *regulator;
+	struct iio_trigger *trig;
+	int irq;
+};
+
+enum afe4403_chan_id {
+	LED1,
+	ALED1,
+	LED2,
+	ALED2,
+	LED1_ALED1,
+	LED2_ALED2,
+	ILED1,
+	ILED2,
+};
+
+static const struct afe440x_reg_info afe4403_reg_info[] = {
+	[LED1] = AFE440X_REG_INFO(AFE440X_LED1VAL, 0, NULL),
+	[ALED1] = AFE440X_REG_INFO(AFE440X_ALED1VAL, 0, NULL),
+	[LED2] = AFE440X_REG_INFO(AFE440X_LED2VAL, 0, NULL),
+	[ALED2] = AFE440X_REG_INFO(AFE440X_ALED2VAL, 0, NULL),
+	[LED1_ALED1] = AFE440X_REG_INFO(AFE440X_LED1_ALED1VAL, 0, NULL),
+	[LED2_ALED2] = AFE440X_REG_INFO(AFE440X_LED2_ALED2VAL, 0, NULL),
+	[ILED1] = AFE440X_REG_INFO(AFE440X_LEDCNTRL, 0, AFE440X_LEDCNTRL_LED1),
+	[ILED2] = AFE440X_REG_INFO(AFE440X_LEDCNTRL, 0, AFE440X_LEDCNTRL_LED2),
+};
+
+static const struct iio_chan_spec afe4403_channels[] = {
+	/* ADC values */
+	AFE440X_INTENSITY_CHAN(LED1, "led1", 0),
+	AFE440X_INTENSITY_CHAN(ALED1, "led1_ambient", 0),
+	AFE440X_INTENSITY_CHAN(LED2, "led2", 0),
+	AFE440X_INTENSITY_CHAN(ALED2, "led2_ambient", 0),
+	AFE440X_INTENSITY_CHAN(LED1_ALED1, "led1-led1_ambient", 0),
+	AFE440X_INTENSITY_CHAN(LED2_ALED2, "led2-led2_ambient", 0),
+	/* LED current */
+	AFE440X_CURRENT_CHAN(ILED1, "led1"),
+	AFE440X_CURRENT_CHAN(ILED2, "led2"),
+};
+
+static const struct afe440x_val_table afe4403_res_table[] = {
+	{ 500000 }, { 250000 }, { 100000 }, { 50000 },
+	{ 25000 }, { 10000 }, { 1000000 }, { 0 },
+};
+AFE440X_TABLE_ATTR(tia_resistance_available, afe4403_res_table);
+
+static const struct afe440x_val_table afe4403_cap_table[] = {
+	{ 0, 5000 }, { 0, 10000 }, { 0, 20000 }, { 0, 25000 },
+	{ 0, 30000 }, { 0, 35000 }, { 0, 45000 }, { 0, 50000 },
+	{ 0, 55000 }, { 0, 60000 }, { 0, 70000 }, { 0, 75000 },
+	{ 0, 80000 }, { 0, 85000 }, { 0, 95000 }, { 0, 100000 },
+	{ 0, 155000 }, { 0, 160000 }, { 0, 170000 }, { 0, 175000 },
+	{ 0, 180000 }, { 0, 185000 }, { 0, 195000 }, { 0, 200000 },
+	{ 0, 205000 }, { 0, 210000 }, { 0, 220000 }, { 0, 225000 },
+	{ 0, 230000 }, { 0, 235000 }, { 0, 245000 }, { 0, 250000 },
+};
+AFE440X_TABLE_ATTR(tia_capacitance_available, afe4403_cap_table);
+
+static ssize_t afe440x_show_register(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct afe4403_data *afe = iio_priv(indio_dev);
+	struct afe440x_attr *afe440x_attr = to_afe440x_attr(attr);
+	unsigned int reg_val, type;
+	int vals[2];
+	int ret, val_len;
+
+	ret = regmap_read(afe->regmap, afe440x_attr->reg, &reg_val);
+	if (ret)
+		return ret;
+
+	reg_val &= afe440x_attr->mask;
+	reg_val >>= afe440x_attr->shift;
+
+	switch (afe440x_attr->type) {
+	case SIMPLE:
+		type = IIO_VAL_INT;
+		val_len = 1;
+		vals[0] = reg_val;
+		break;
+	case RESISTANCE:
+	case CAPACITANCE:
+		type = IIO_VAL_INT_PLUS_MICRO;
+		val_len = 2;
+		if (reg_val < afe440x_attr->table_size) {
+			vals[0] = afe440x_attr->val_table[reg_val].integer;
+			vals[1] = afe440x_attr->val_table[reg_val].fract;
+			break;
+		}
+		return -EINVAL;
+	default:
+		return -EINVAL;
+	}
+
+	return iio_format_value(buf, type, val_len, vals);
+}
+
+static ssize_t afe440x_store_register(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t count)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct afe4403_data *afe = iio_priv(indio_dev);
+	struct afe440x_attr *afe440x_attr = to_afe440x_attr(attr);
+	int val, integer, fract, ret;
+
+	ret = iio_str_to_fixpoint(buf, 100000, &integer, &fract);
+	if (ret)
+		return ret;
+
+	switch (afe440x_attr->type) {
+	case SIMPLE:
+		val = integer;
+		break;
+	case RESISTANCE:
+	case CAPACITANCE:
+		for (val = 0; val < afe440x_attr->table_size; val++)
+			if (afe440x_attr->val_table[val].integer == integer &&
+			    afe440x_attr->val_table[val].fract == fract)
+				break;
+		if (val == afe440x_attr->table_size)
+			return -EINVAL;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = regmap_update_bits(afe->regmap, afe440x_attr->reg,
+				 afe440x_attr->mask,
+				 (val << afe440x_attr->shift));
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static AFE440X_ATTR(tia_separate_en, AFE4403_TIAGAIN, AFE440X_TIAGAIN_ENSEPGAIN, SIMPLE, NULL, 0);
+
+static AFE440X_ATTR(tia_resistance1, AFE4403_TIAGAIN, AFE4403_TIAGAIN_RES, RESISTANCE, afe4403_res_table, ARRAY_SIZE(afe4403_res_table));
+static AFE440X_ATTR(tia_capacitance1, AFE4403_TIAGAIN, AFE4403_TIAGAIN_CAP, CAPACITANCE, afe4403_cap_table, ARRAY_SIZE(afe4403_cap_table));
+
+static AFE440X_ATTR(tia_resistance2, AFE4403_TIA_AMB_GAIN, AFE4403_TIAGAIN_RES, RESISTANCE, afe4403_res_table, ARRAY_SIZE(afe4403_res_table));
+static AFE440X_ATTR(tia_capacitance2, AFE4403_TIA_AMB_GAIN, AFE4403_TIAGAIN_RES, CAPACITANCE, afe4403_cap_table, ARRAY_SIZE(afe4403_cap_table));
+
+static struct attribute *afe440x_attributes[] = {
+	&afe440x_attr_tia_separate_en.dev_attr.attr,
+	&afe440x_attr_tia_resistance1.dev_attr.attr,
+	&afe440x_attr_tia_capacitance1.dev_attr.attr,
+	&afe440x_attr_tia_resistance2.dev_attr.attr,
+	&afe440x_attr_tia_capacitance2.dev_attr.attr,
+	&dev_attr_tia_resistance_available.attr,
+	&dev_attr_tia_capacitance_available.attr,
+	NULL
+};
+
+static const struct attribute_group afe440x_attribute_group = {
+	.attrs = afe440x_attributes
+};
+
+static int afe4403_read(struct afe4403_data *afe, unsigned int reg, u32 *val)
+{
+	u8 tx[4] = {AFE440X_CONTROL0, 0x0, 0x0, AFE440X_CONTROL0_READ};
+	u8 rx[3];
+	int ret;
+
+	/* Enable reading from the device */
+	ret = spi_write_then_read(afe->spi, tx, 4, NULL, 0);
+	if (ret)
+		return ret;
+
+	ret = spi_write_then_read(afe->spi, &reg, 1, rx, 3);
+	if (ret)
+		return ret;
+
+	*val = (rx[0] << 16) |
+		(rx[1] << 8) |
+		(rx[2]);
+
+	/* Disable reading from the device */
+	tx[3] = AFE440X_CONTROL0_WRITE;
+	ret = spi_write_then_read(afe->spi, tx, 4, NULL, 0);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int afe4403_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val, int *val2, long mask)
+{
+	struct afe4403_data *afe = iio_priv(indio_dev);
+	const struct afe440x_reg_info reg_info = afe4403_reg_info[chan->address];
+	int ret;
+
+	switch (chan->type) {
+	case IIO_INTENSITY:
+		switch (mask) {
+		case IIO_CHAN_INFO_RAW:
+			ret = afe4403_read(afe, reg_info.reg, val);
+			if (ret)
+				return ret;
+			return IIO_VAL_INT;
+		case IIO_CHAN_INFO_OFFSET:
+			ret = regmap_read(afe->regmap, reg_info.offreg,
+					  val);
+			if (ret)
+				return ret;
+			*val &= reg_info.mask;
+			*val >>= reg_info.shift;
+			return IIO_VAL_INT;
+		}
+		break;
+	case IIO_CURRENT:
+		switch (mask) {
+		case IIO_CHAN_INFO_RAW:
+			ret = regmap_read(afe->regmap, reg_info.reg, val);
+			if (ret)
+				return ret;
+			*val &= reg_info.mask;
+			*val >>= reg_info.shift;
+			return IIO_VAL_INT;
+		case IIO_CHAN_INFO_SCALE:
+			*val = 0;
+			*val2 = 800000;
+			return IIO_VAL_INT_PLUS_MICRO;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+
+static int afe4403_write_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int val, int val2, long mask)
+{
+	struct afe4403_data *afe = iio_priv(indio_dev);
+	const struct afe440x_reg_info reg_info = afe4403_reg_info[chan->address];
+
+	switch (chan->type) {
+	case IIO_INTENSITY:
+		switch (mask) {
+		case IIO_CHAN_INFO_OFFSET:
+			return regmap_update_bits(afe->regmap,
+				reg_info.offreg,
+				reg_info.mask,
+				(val << reg_info.shift));
+		}
+		break;
+	case IIO_CURRENT:
+		switch (mask) {
+		case IIO_CHAN_INFO_RAW:
+			return regmap_update_bits(afe->regmap,
+				reg_info.reg,
+				reg_info.mask,
+				(val << reg_info.shift));
+		}
+		break;
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+
+static const struct iio_info afe4403_iio_info = {
+	.attrs = &afe440x_attribute_group,
+	.read_raw = afe4403_read_raw,
+	.write_raw = afe4403_write_raw,
+	.driver_module = THIS_MODULE,
+};
+
+static irqreturn_t afe4403_trigger_handler(int irq, void *private)
+{
+	struct iio_poll_func *pf = private;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct afe4403_data *afe = iio_priv(indio_dev);
+	int ret, bit, i = 0;
+	s32 buffer[8];
+	u8 tx[4] = {AFE440X_CONTROL0, 0x0, 0x0, AFE440X_CONTROL0_READ};
+	u8 rx[3];
+
+	/* Enable reading from the device */
+	ret = spi_write_then_read(afe->spi, tx, 4, NULL, 0);
+	if (ret)
+		goto err;
+
+	for_each_set_bit(bit, indio_dev->active_scan_mask,
+			 indio_dev->masklength) {
+		ret = spi_write_then_read(afe->spi,
+					  &afe4403_reg_info[bit].reg, 1,
+					  rx, 3);
+		if (ret)
+			goto err;
+
+		buffer[i++] = (rx[0] << 16) |
+				(rx[1] << 8) |
+				(rx[2]);
+	}
+
+	/* Disable reading from the device */
+	tx[3] = AFE440X_CONTROL0_WRITE;
+	ret = spi_write_then_read(afe->spi, tx, 4, NULL, 0);
+	if (ret)
+		goto err;
+
+	iio_push_to_buffers_with_timestamp(indio_dev, buffer, pf->timestamp);
+err:
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static const struct iio_trigger_ops afe4403_trigger_ops = {
+	.owner = THIS_MODULE,
+};
+
+#define AFE4403_TIMING_PAIRS			\
+	{ AFE440X_LED2STC,	0x000050 },	\
+	{ AFE440X_LED2ENDC,	0x0003e7 },	\
+	{ AFE440X_LED1LEDSTC,	0x0007d0 },	\
+	{ AFE440X_LED1LEDENDC,	0x000bb7 },	\
+	{ AFE440X_ALED2STC,	0x000438 },	\
+	{ AFE440X_ALED2ENDC,	0x0007cf },	\
+	{ AFE440X_LED1STC,	0x000820 },	\
+	{ AFE440X_LED1ENDC,	0x000bb7 },	\
+	{ AFE440X_LED2LEDSTC,	0x000000 },	\
+	{ AFE440X_LED2LEDENDC,	0x0003e7 },	\
+	{ AFE440X_ALED1STC,	0x000c08 },	\
+	{ AFE440X_ALED1ENDC,	0x000f9f },	\
+	{ AFE440X_LED2CONVST,	0x0003ef },	\
+	{ AFE440X_LED2CONVEND,	0x0007cf },	\
+	{ AFE440X_ALED2CONVST,	0x0007d7 },	\
+	{ AFE440X_ALED2CONVEND,	0x000bb7 },	\
+	{ AFE440X_LED1CONVST,	0x000bbf },	\
+	{ AFE440X_LED1CONVEND,	0x009c3f },	\
+	{ AFE440X_ALED1CONVST,	0x000fa7 },	\
+	{ AFE440X_ALED1CONVEND,	0x001387 },	\
+	{ AFE440X_ADCRSTSTCT0,	0x0003e8 },	\
+	{ AFE440X_ADCRSTENDCT0,	0x0003eb },	\
+	{ AFE440X_ADCRSTSTCT1,	0x0007d0 },	\
+	{ AFE440X_ADCRSTENDCT1,	0x0007d3 },	\
+	{ AFE440X_ADCRSTSTCT2,	0x000bb8 },	\
+	{ AFE440X_ADCRSTENDCT2,	0x000bbb },	\
+	{ AFE440X_ADCRSTSTCT3,	0x000fa0 },	\
+	{ AFE440X_ADCRSTENDCT3,	0x000fa3 },	\
+	{ AFE440X_PRPCOUNT,	0x009c3f },	\
+	{ AFE440X_PDNCYCLESTC,	0x001518 },	\
+	{ AFE440X_PDNCYCLEENDC,	0x00991f }
+
+static const struct reg_sequence afe4403_reg_sequences[] = {
+	AFE4403_TIMING_PAIRS,
+	{ AFE440X_CONTROL1, AFE440X_CONTROL1_TIMEREN | 0x000007},
+	{ AFE4403_TIA_AMB_GAIN, AFE4403_TIAGAIN_RES_1_M },
+	{ AFE440X_LEDCNTRL, (0x14 << AFE440X_LEDCNTRL_LED1_SHIFT) |
+			    (0x14 << AFE440X_LEDCNTRL_LED2_SHIFT) },
+	{ AFE440X_CONTROL2, AFE440X_CONTROL2_TX_REF_050 <<
+			    AFE440X_CONTROL2_TX_REF_SHIFT },
+};
+
+static const struct regmap_range afe4403_yes_ranges[] = {
+	regmap_reg_range(AFE440X_LED2VAL, AFE440X_LED1_ALED1VAL),
+};
+
+static const struct regmap_access_table afe4403_volatile_table = {
+	.yes_ranges = afe4403_yes_ranges,
+	.n_yes_ranges = ARRAY_SIZE(afe4403_yes_ranges),
+};
+
+static const struct regmap_config afe4403_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 24,
+
+	.max_register = AFE440X_PDNCYCLEENDC,
+	.cache_type = REGCACHE_RBTREE,
+	.volatile_table = &afe4403_volatile_table,
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id afe4403_of_match[] = {
+	{ .compatible = "ti,afe4403", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, afe4403_of_match);
+#endif
+
+static int afe4403_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct afe4403_data *afe = iio_priv(indio_dev);
+	int ret;
+
+	ret = regmap_update_bits(afe->regmap, AFE440X_CONTROL2,
+				 AFE440X_CONTROL2_PDN_AFE,
+				 AFE440X_CONTROL2_PDN_AFE);
+	if (ret)
+		return ret;
+
+	ret = regulator_disable(afe->regulator);
+	if (ret) {
+		dev_err(dev, "Unable to disable regulator\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int afe4403_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct afe4403_data *afe = iio_priv(indio_dev);
+	int ret;
+
+	ret = regulator_enable(afe->regulator);
+	if (ret) {
+		dev_err(dev, "Unable to enable regulator\n");
+		return ret;
+	}
+
+	ret = regmap_update_bits(afe->regmap, AFE440X_CONTROL2,
+				 AFE440X_CONTROL2_PDN_AFE, 0);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(afe4403_pm_ops, afe4403_suspend, afe4403_resume);
+
+static int afe4403_probe(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev;
+	struct afe4403_data *afe;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*afe));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	afe = iio_priv(indio_dev);
+	spi_set_drvdata(spi, indio_dev);
+
+	afe->dev = &spi->dev;
+	afe->spi = spi;
+	afe->irq = spi->irq;
+
+	afe->regmap = devm_regmap_init_spi(spi, &afe4403_regmap_config);
+	if (IS_ERR(afe->regmap)) {
+		dev_err(afe->dev, "Unable to allocate register map\n");
+		return PTR_ERR(afe->regmap);
+	}
+
+	afe->regulator = devm_regulator_get(afe->dev, "tx_sup");
+	if (IS_ERR(afe->regulator)) {
+		dev_err(afe->dev, "Unable to get regulator\n");
+		return PTR_ERR(afe->regulator);
+	}
+	ret = regulator_enable(afe->regulator);
+	if (ret) {
+		dev_err(afe->dev, "Unable to enable regulator\n");
+		return ret;
+	}
+
+	ret = regmap_write(afe->regmap, AFE440X_CONTROL0,
+			   AFE440X_CONTROL0_SW_RESET);
+	if (ret) {
+		dev_err(afe->dev, "Unable to reset device\n");
+		goto err_disable_reg;
+	}
+
+	ret = regmap_multi_reg_write(afe->regmap, afe4403_reg_sequences,
+				     ARRAY_SIZE(afe4403_reg_sequences));
+	if (ret) {
+		dev_err(afe->dev, "Unable to set register defaults\n");
+		goto err_disable_reg;
+	}
+
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->dev.parent = afe->dev;
+	indio_dev->channels = afe4403_channels;
+	indio_dev->num_channels = ARRAY_SIZE(afe4403_channels);
+	indio_dev->name = AFE4403_DRIVER_NAME;
+	indio_dev->info = &afe4403_iio_info;
+
+	if (afe->irq > 0) {
+		afe->trig = devm_iio_trigger_alloc(afe->dev,
+						   "%s-dev%d",
+						   indio_dev->name,
+						   indio_dev->id);
+		if (!afe->trig) {
+			dev_err(afe->dev, "Unable to allocate IIO trigger\n");
+			ret = -ENOMEM;
+			goto err_disable_reg;
+		}
+
+		iio_trigger_set_drvdata(afe->trig, indio_dev);
+
+		afe->trig->ops = &afe4403_trigger_ops;
+		afe->trig->dev.parent = afe->dev;
+
+		ret = iio_trigger_register(afe->trig);
+		if (ret) {
+			dev_err(afe->dev, "Unable to register IIO trigger\n");
+			goto err_disable_reg;
+		}
+
+		ret = devm_request_threaded_irq(afe->dev, afe->irq,
+						iio_trigger_generic_data_rdy_poll,
+						NULL, IRQF_ONESHOT,
+						AFE4403_DRIVER_NAME,
+						afe->trig);
+		if (ret) {
+			dev_err(afe->dev, "Unable to request IRQ\n");
+			goto err_trig;
+		}
+	}
+
+	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
+					 afe4403_trigger_handler, NULL);
+	if (ret) {
+		dev_err(afe->dev, "Unable to setup buffer\n");
+		goto err_trig;
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(afe->dev, "Unable to register IIO device\n");
+		goto err_buff;
+	}
+
+	return 0;
+
+err_buff:
+	iio_triggered_buffer_cleanup(indio_dev);
+err_trig:
+	if (afe->irq > 0)
+		iio_trigger_unregister(afe->trig);
+err_disable_reg:
+	regulator_disable(afe->regulator);
+
+	return ret;
+}
+
+static int afe4403_remove(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev = spi_get_drvdata(spi);
+	struct afe4403_data *afe = iio_priv(indio_dev);
+	int ret;
+
+	iio_device_unregister(indio_dev);
+
+	iio_triggered_buffer_cleanup(indio_dev);
+
+	if (afe->irq > 0)
+		iio_trigger_unregister(afe->trig);
+
+	ret = regulator_disable(afe->regulator);
+	if (ret) {
+		dev_err(afe->dev, "Unable to disable regulator\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct spi_device_id afe4403_ids[] = {
+	{ "afe4403", 0 },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(spi, afe4403_ids);
+
+static struct spi_driver afe4403_spi_driver = {
+	.driver = {
+		.name = AFE4403_DRIVER_NAME,
+		.of_match_table = of_match_ptr(afe4403_of_match),
+		.pm = &afe4403_pm_ops,
+	},
+	.probe = afe4403_probe,
+	.remove = afe4403_remove,
+	.id_table = afe4403_ids,
+};
+module_spi_driver(afe4403_spi_driver);
+
+MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
+MODULE_DESCRIPTION("TI AFE4403 Heart Rate and Pulse Oximeter");
+MODULE_LICENSE("GPL v2");