iio: health: Add driver for the TI AFE4404 heart monitor

Add driver for the TI AFE4404 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.

Datasheet: http://www.ti.com/product/AFE4404/datasheet

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

1 files changed, 679 insertions, 0 deletions

diff --git a/drivers/iio/health/afe4404.c b/drivers/iio/health/afe4404.c
new file mode 100644
index 000000000000..0759268f37e0
--- /dev/null
+++ b/drivers/iio/health/afe4404.c
@@ -0,0 +1,679 @@
+/*
+ * AFE4404 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/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/regmap.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 AFE4404_DRIVER_NAME		"afe4404"
+
+/* AFE4404 registers */
+#define AFE4404_TIA_GAIN_SEP		0x20
+#define AFE4404_TIA_GAIN		0x21
+#define AFE4404_PROG_TG_STC		0x34
+#define AFE4404_PROG_TG_ENDC		0x35
+#define AFE4404_LED3LEDSTC		0x36
+#define AFE4404_LED3LEDENDC		0x37
+#define AFE4404_CLKDIV_PRF		0x39
+#define AFE4404_OFFDAC			0x3a
+#define AFE4404_DEC			0x3d
+#define AFE4404_AVG_LED2_ALED2VAL	0x3f
+#define AFE4404_AVG_LED1_ALED1VAL	0x40
+
+/* AFE4404 GAIN register fields */
+#define AFE4404_TIA_GAIN_RES_MASK	GENMASK(2, 0)
+#define AFE4404_TIA_GAIN_RES_SHIFT	0
+#define AFE4404_TIA_GAIN_CAP_MASK	GENMASK(5, 3)
+#define AFE4404_TIA_GAIN_CAP_SHIFT	3
+
+/* AFE4404 LEDCNTRL register fields */
+#define AFE4404_LEDCNTRL_ILED1_MASK	GENMASK(5, 0)
+#define AFE4404_LEDCNTRL_ILED1_SHIFT	0
+#define AFE4404_LEDCNTRL_ILED2_MASK	GENMASK(11, 6)
+#define AFE4404_LEDCNTRL_ILED2_SHIFT	6
+#define AFE4404_LEDCNTRL_ILED3_MASK	GENMASK(17, 12)
+#define AFE4404_LEDCNTRL_ILED3_SHIFT	12
+
+/* AFE4404 CONTROL2 register fields */
+#define AFE440X_CONTROL2_ILED_2X_MASK	BIT(17)
+#define AFE440X_CONTROL2_ILED_2X_SHIFT	17
+
+/* AFE4404 CONTROL3 register fields */
+#define AFE440X_CONTROL3_OSC_ENABLE	BIT(9)
+
+/* AFE4404 OFFDAC register current fields */
+#define AFE4404_OFFDAC_CURR_LED1_MASK	GENMASK(9, 5)
+#define AFE4404_OFFDAC_CURR_LED1_SHIFT	5
+#define AFE4404_OFFDAC_CURR_LED2_MASK	GENMASK(19, 15)
+#define AFE4404_OFFDAC_CURR_LED2_SHIFT	15
+#define AFE4404_OFFDAC_CURR_LED3_MASK	GENMASK(4, 0)
+#define AFE4404_OFFDAC_CURR_LED3_SHIFT	0
+#define AFE4404_OFFDAC_CURR_ALED1_MASK	GENMASK(14, 10)
+#define AFE4404_OFFDAC_CURR_ALED1_SHIFT	10
+#define AFE4404_OFFDAC_CURR_ALED2_MASK	GENMASK(4, 0)
+#define AFE4404_OFFDAC_CURR_ALED2_SHIFT	0
+
+/* AFE4404 NULL fields */
+#define NULL_MASK	0
+#define NULL_SHIFT	0
+
+/* AFE4404 TIA_GAIN_CAP values */
+#define AFE4404_TIA_GAIN_CAP_5_P	0x0
+#define AFE4404_TIA_GAIN_CAP_2_5_P	0x1
+#define AFE4404_TIA_GAIN_CAP_10_P	0x2
+#define AFE4404_TIA_GAIN_CAP_7_5_P	0x3
+#define AFE4404_TIA_GAIN_CAP_20_P	0x4
+#define AFE4404_TIA_GAIN_CAP_17_5_P	0x5
+#define AFE4404_TIA_GAIN_CAP_25_P	0x6
+#define AFE4404_TIA_GAIN_CAP_22_5_P	0x7
+
+/* AFE4404 TIA_GAIN_RES values */
+#define AFE4404_TIA_GAIN_RES_500_K	0x0
+#define AFE4404_TIA_GAIN_RES_250_K	0x1
+#define AFE4404_TIA_GAIN_RES_100_K	0x2
+#define AFE4404_TIA_GAIN_RES_50_K	0x3
+#define AFE4404_TIA_GAIN_RES_25_K	0x4
+#define AFE4404_TIA_GAIN_RES_10_K	0x5
+#define AFE4404_TIA_GAIN_RES_1_M	0x6
+#define AFE4404_TIA_GAIN_RES_2_M	0x7
+
+/**
+ * struct afe4404_data
+ * @dev - Device structure
+ * @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 afe4404_data {
+	struct device *dev;
+	struct regmap *regmap;
+	struct regulator *regulator;
+	struct iio_trigger *trig;
+	int irq;
+};
+
+enum afe4404_chan_id {
+	LED1,
+	ALED1,
+	LED2,
+	ALED2,
+	LED3,
+	LED1_ALED1,
+	LED2_ALED2,
+	ILED1,
+	ILED2,
+	ILED3,
+};
+
+static const struct afe440x_reg_info afe4404_reg_info[] = {
+	[LED1] = AFE440X_REG_INFO(AFE440X_LED1VAL, AFE4404_OFFDAC, AFE4404_OFFDAC_CURR_LED1),
+	[ALED1] = AFE440X_REG_INFO(AFE440X_ALED1VAL, AFE4404_OFFDAC, AFE4404_OFFDAC_CURR_ALED1),
+	[LED2] = AFE440X_REG_INFO(AFE440X_LED2VAL, AFE4404_OFFDAC, AFE4404_OFFDAC_CURR_LED2),
+	[ALED2] = AFE440X_REG_INFO(AFE440X_ALED2VAL, AFE4404_OFFDAC, AFE4404_OFFDAC_CURR_ALED2),
+	[LED3] = 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, AFE4404_LEDCNTRL_ILED1),
+	[ILED2] = AFE440X_REG_INFO(AFE440X_LEDCNTRL, 0, AFE4404_LEDCNTRL_ILED2),
+	[ILED3] = AFE440X_REG_INFO(AFE440X_LEDCNTRL, 0, AFE4404_LEDCNTRL_ILED3),
+};
+
+static const struct iio_chan_spec afe4404_channels[] = {
+	/* ADC values */
+	AFE440X_INTENSITY_CHAN(LED1, "led1", BIT(IIO_CHAN_INFO_OFFSET)),
+	AFE440X_INTENSITY_CHAN(ALED1, "led1_ambient", BIT(IIO_CHAN_INFO_OFFSET)),
+	AFE440X_INTENSITY_CHAN(LED2, "led2", BIT(IIO_CHAN_INFO_OFFSET)),
+	AFE440X_INTENSITY_CHAN(ALED2, "led2_ambient", BIT(IIO_CHAN_INFO_OFFSET)),
+	AFE440X_INTENSITY_CHAN(LED3, "led3", BIT(IIO_CHAN_INFO_OFFSET)),
+	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"),
+	AFE440X_CURRENT_CHAN(ILED3, "led3"),
+};
+
+static const struct afe440x_val_table afe4404_res_table[] = {
+	{ .integer = 500000, .fract = 0 },
+	{ .integer = 250000, .fract = 0 },
+	{ .integer = 100000, .fract = 0 },
+	{ .integer = 50000, .fract = 0 },
+	{ .integer = 25000, .fract = 0 },
+	{ .integer = 10000, .fract = 0 },
+	{ .integer = 1000000, .fract = 0 },
+	{ .integer = 2000000, .fract = 0 },
+};
+AFE440X_TABLE_ATTR(tia_resistance_available, afe4404_res_table);
+
+static const struct afe440x_val_table afe4404_cap_table[] = {
+	{ .integer = 0, .fract = 5000 },
+	{ .integer = 0, .fract = 2500 },
+	{ .integer = 0, .fract = 10000 },
+	{ .integer = 0, .fract = 7500 },
+	{ .integer = 0, .fract = 20000 },
+	{ .integer = 0, .fract = 17500 },
+	{ .integer = 0, .fract = 25000 },
+	{ .integer = 0, .fract = 22500 },
+};
+AFE440X_TABLE_ATTR(tia_capacitance_available, afe4404_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 afe4404_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 afe4404_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, AFE4404_TIA_GAIN_SEP, AFE440X_TIAGAIN_ENSEPGAIN, SIMPLE, NULL, 0);
+
+static AFE440X_ATTR(tia_resistance1, AFE4404_TIA_GAIN, AFE4404_TIA_GAIN_RES, RESISTANCE, afe4404_res_table, ARRAY_SIZE(afe4404_res_table));
+static AFE440X_ATTR(tia_capacitance1, AFE4404_TIA_GAIN, AFE4404_TIA_GAIN_CAP, CAPACITANCE, afe4404_cap_table, ARRAY_SIZE(afe4404_cap_table));
+
+static AFE440X_ATTR(tia_resistance2, AFE4404_TIA_GAIN_SEP, AFE4404_TIA_GAIN_RES, RESISTANCE, afe4404_res_table, ARRAY_SIZE(afe4404_res_table));
+static AFE440X_ATTR(tia_capacitance2, AFE4404_TIA_GAIN_SEP, AFE4404_TIA_GAIN_CAP, CAPACITANCE, afe4404_cap_table, ARRAY_SIZE(afe4404_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 afe4404_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val, int *val2, long mask)
+{
+	struct afe4404_data *afe = iio_priv(indio_dev);
+	const struct afe440x_reg_info reg_info = afe4404_reg_info[chan->address];
+	int ret;
+
+	switch (chan->type) {
+	case IIO_INTENSITY:
+		switch (mask) {
+		case IIO_CHAN_INFO_RAW:
+			ret = regmap_read(afe->regmap, 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 afe4404_write_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int val, int val2, long mask)
+{
+	struct afe4404_data *afe = iio_priv(indio_dev);
+	const struct afe440x_reg_info reg_info = afe4404_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 afe4404_iio_info = {
+	.attrs = &afe440x_attribute_group,
+	.read_raw = afe4404_read_raw,
+	.write_raw = afe4404_write_raw,
+	.driver_module = THIS_MODULE,
+};
+
+static irqreturn_t afe4404_trigger_handler(int irq, void *private)
+{
+	struct iio_poll_func *pf = private;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct afe4404_data *afe = iio_priv(indio_dev);
+	int ret, bit, i = 0;
+	s32 buffer[10];
+
+	for_each_set_bit(bit, indio_dev->active_scan_mask,
+			 indio_dev->masklength) {
+		ret = regmap_read(afe->regmap, afe4404_reg_info[bit].reg,
+				  &buffer[i++]);
+		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 afe4404_trigger_ops = {
+	.owner = THIS_MODULE,
+};
+
+/* Default timings from data-sheet */
+#define AFE4404_TIMING_PAIRS			\
+	{ AFE440X_PRPCOUNT,	39999	},	\
+	{ AFE440X_LED2LEDSTC,	0	},	\
+	{ AFE440X_LED2LEDENDC,	398	},	\
+	{ AFE440X_LED2STC,	80	},	\
+	{ AFE440X_LED2ENDC,	398	},	\
+	{ AFE440X_ADCRSTSTCT0,	5600	},	\
+	{ AFE440X_ADCRSTENDCT0,	5606	},	\
+	{ AFE440X_LED2CONVST,	5607	},	\
+	{ AFE440X_LED2CONVEND,	6066	},	\
+	{ AFE4404_LED3LEDSTC,	400	},	\
+	{ AFE4404_LED3LEDENDC,	798	},	\
+	{ AFE440X_ALED2STC,	480	},	\
+	{ AFE440X_ALED2ENDC,	798	},	\
+	{ AFE440X_ADCRSTSTCT1,	6068	},	\
+	{ AFE440X_ADCRSTENDCT1,	6074	},	\
+	{ AFE440X_ALED2CONVST,	6075	},	\
+	{ AFE440X_ALED2CONVEND,	6534	},	\
+	{ AFE440X_LED1LEDSTC,	800	},	\
+	{ AFE440X_LED1LEDENDC,	1198	},	\
+	{ AFE440X_LED1STC,	880	},	\
+	{ AFE440X_LED1ENDC,	1198	},	\
+	{ AFE440X_ADCRSTSTCT2,	6536	},	\
+	{ AFE440X_ADCRSTENDCT2,	6542	},	\
+	{ AFE440X_LED1CONVST,	6543	},	\
+	{ AFE440X_LED1CONVEND,	7003	},	\
+	{ AFE440X_ALED1STC,	1280	},	\
+	{ AFE440X_ALED1ENDC,	1598	},	\
+	{ AFE440X_ADCRSTSTCT3,	7005	},	\
+	{ AFE440X_ADCRSTENDCT3,	7011	},	\
+	{ AFE440X_ALED1CONVST,	7012	},	\
+	{ AFE440X_ALED1CONVEND,	7471	},	\
+	{ AFE440X_PDNCYCLESTC,	7671	},	\
+	{ AFE440X_PDNCYCLEENDC,	39199	}
+
+static const struct reg_sequence afe4404_reg_sequences[] = {
+	AFE4404_TIMING_PAIRS,
+	{ AFE440X_CONTROL1, AFE440X_CONTROL1_TIMEREN },
+	{ AFE4404_TIA_GAIN, AFE4404_TIA_GAIN_RES_50_K },
+	{ AFE440X_LEDCNTRL, (0xf << AFE4404_LEDCNTRL_ILED1_SHIFT) |
+			    (0x3 << AFE4404_LEDCNTRL_ILED2_SHIFT) |
+			    (0x3 << AFE4404_LEDCNTRL_ILED3_SHIFT) },
+	{ AFE440X_CONTROL2, AFE440X_CONTROL3_OSC_ENABLE	},
+};
+
+static const struct regmap_range afe4404_yes_ranges[] = {
+	regmap_reg_range(AFE440X_LED2VAL, AFE440X_LED1_ALED1VAL),
+	regmap_reg_range(AFE4404_AVG_LED2_ALED2VAL, AFE4404_AVG_LED1_ALED1VAL),
+};
+
+static const struct regmap_access_table afe4404_volatile_table = {
+	.yes_ranges = afe4404_yes_ranges,
+	.n_yes_ranges = ARRAY_SIZE(afe4404_yes_ranges),
+};
+
+static const struct regmap_config afe4404_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 24,
+
+	.max_register = AFE4404_AVG_LED1_ALED1VAL,
+	.cache_type = REGCACHE_RBTREE,
+	.volatile_table = &afe4404_volatile_table,
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id afe4404_of_match[] = {
+	{ .compatible = "ti,afe4404", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, afe4404_of_match);
+#endif
+
+static int afe4404_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct afe4404_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 afe4404_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct afe4404_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(afe4404_pm_ops, afe4404_suspend, afe4404_resume);
+
+static int afe4404_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct iio_dev *indio_dev;
+	struct afe4404_data *afe;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*afe));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	afe = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+
+	afe->dev = &client->dev;
+	afe->irq = client->irq;
+
+	afe->regmap = devm_regmap_init_i2c(client, &afe4404_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 disable_reg;
+	}
+
+	ret = regmap_multi_reg_write(afe->regmap, afe4404_reg_sequences,
+				     ARRAY_SIZE(afe4404_reg_sequences));
+	if (ret) {
+		dev_err(afe->dev, "Unable to set register defaults\n");
+		goto disable_reg;
+	}
+
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->dev.parent = afe->dev;
+	indio_dev->channels = afe4404_channels;
+	indio_dev->num_channels = ARRAY_SIZE(afe4404_channels);
+	indio_dev->name = AFE4404_DRIVER_NAME;
+	indio_dev->info = &afe4404_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 disable_reg;
+		}
+
+		iio_trigger_set_drvdata(afe->trig, indio_dev);
+
+		afe->trig->ops = &afe4404_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 disable_reg;
+		}
+
+		ret = devm_request_threaded_irq(afe->dev, afe->irq,
+						iio_trigger_generic_data_rdy_poll,
+						NULL, IRQF_ONESHOT,
+						AFE4404_DRIVER_NAME,
+						afe->trig);
+		if (ret) {
+			dev_err(afe->dev, "Unable to request IRQ\n");
+			goto disable_reg;
+		}
+	}
+
+	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
+					 afe4404_trigger_handler, NULL);
+	if (ret) {
+		dev_err(afe->dev, "Unable to setup buffer\n");
+		goto unregister_trigger;
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(afe->dev, "Unable to register IIO device\n");
+		goto unregister_triggered_buffer;
+	}
+
+	return 0;
+
+unregister_triggered_buffer:
+	iio_triggered_buffer_cleanup(indio_dev);
+unregister_trigger:
+	if (afe->irq > 0)
+		iio_trigger_unregister(afe->trig);
+disable_reg:
+	regulator_disable(afe->regulator);
+
+	return ret;
+}
+
+static int afe4404_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct afe4404_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 i2c_device_id afe4404_ids[] = {
+	{ "afe4404", 0 },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(i2c, afe4404_ids);
+
+static struct i2c_driver afe4404_i2c_driver = {
+	.driver = {
+		.name = AFE4404_DRIVER_NAME,
+		.of_match_table = of_match_ptr(afe4404_of_match),
+		.pm = &afe4404_pm_ops,
+	},
+	.probe = afe4404_probe,
+	.remove = afe4404_remove,
+	.id_table = afe4404_ids,
+};
+module_i2c_driver(afe4404_i2c_driver);
+
+MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
+MODULE_DESCRIPTION("TI AFE4404 Heart Rate and Pulse Oximeter");
+MODULE_LICENSE("GPL v2");