iio: light: add support for TI's opt3001 light sensor

TI's opt3001 light sensor is a simple and yet powerful
little device. The device provides 99% IR rejection,
automatic full-scale, very low power consumption and
measurements from 0.01 to 83k lux.

This patch adds support for that device using the IIO
framework.

See http://www.ti.com/product/opt3001 for more information.
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Andreas Dannenberg <dannenberg@ti.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/light/Kconfig

@@ -209,6 +209,16 @@ config LTR501
 	 This driver can also be built as a module.  If so, the module
          will be called ltr501.
 
+config OPT3001
+	tristate "Texas Instruments OPT3001 Light Sensor"
+	depends on I2C
+	help
+	  If you say Y or M here, you get support for Texas Instruments
+	  OPT3001 Ambient Light Sensor.
+
+	  If built as a dynamically linked module, it will be called
+	  opt3001.
+
 config STK3310
 	tristate "STK3310 ALS and proximity sensor"
 	depends on I2C

drivers/iio/light/Makefile

@@ -19,6 +19,7 @@ obj-$(CONFIG_ISL29125)		+= isl29125.o
 obj-$(CONFIG_JSA1212)		+= jsa1212.o
 obj-$(CONFIG_SENSORS_LM3533)	+= lm3533-als.o
 obj-$(CONFIG_LTR501)		+= ltr501.o
+obj-$(CONFIG_OPT3001)		+= opt3001.o
 obj-$(CONFIG_RPR0521)		+= rpr0521.o
 obj-$(CONFIG_SENSORS_TSL2563)	+= tsl2563.o
 obj-$(CONFIG_STK3310)          += stk3310.o

drivers/iio/light/opt3001.c

+/**
+ * opt3001.c - Texas Instruments OPT3001 Light Sensor
+ *
+ * Copyright (C) 2014 Texas Instruments Incorporated - http://www.ti.com
+ *
+ * Author: Andreas Dannenberg <dannenberg@ti.com>
+ * Based on previous work from: Felipe Balbi <balbi@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 of the License
+ * 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/bitops.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include <linux/iio/events.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define OPT3001_RESULT		0x00
+#define OPT3001_CONFIGURATION	0x01
+#define OPT3001_LOW_LIMIT	0x02
+#define OPT3001_HIGH_LIMIT	0x03
+#define OPT3001_MANUFACTURER_ID	0x7e
+#define OPT3001_DEVICE_ID	0x7f
+
+#define OPT3001_CONFIGURATION_RN_MASK	(0xf << 12)
+#define OPT3001_CONFIGURATION_RN_AUTO	(0xc << 12)
+
+#define OPT3001_CONFIGURATION_CT	BIT(11)
+
+#define OPT3001_CONFIGURATION_M_MASK	(3 << 9)
+#define OPT3001_CONFIGURATION_M_SHUTDOWN (0 << 9)
+#define OPT3001_CONFIGURATION_M_SINGLE	(1 << 9)
+#define OPT3001_CONFIGURATION_M_CONTINUOUS (2 << 9) /* also 3 << 9 */
+
+#define OPT3001_CONFIGURATION_OVF	BIT(8)
+#define OPT3001_CONFIGURATION_CRF	BIT(7)
+#define OPT3001_CONFIGURATION_FH	BIT(6)
+#define OPT3001_CONFIGURATION_FL	BIT(5)
+#define OPT3001_CONFIGURATION_L		BIT(4)
+#define OPT3001_CONFIGURATION_POL	BIT(3)
+#define OPT3001_CONFIGURATION_ME	BIT(2)
+
+#define OPT3001_CONFIGURATION_FC_MASK	(3 << 0)
+
+/* The end-of-conversion enable is located in the low-limit register */
+#define OPT3001_LOW_LIMIT_EOC_ENABLE	0xc000
+
+#define OPT3001_REG_EXPONENT(n)		((n) >> 12)
+#define OPT3001_REG_MANTISSA(n)		((n) & 0xfff)
+
+/*
+ * Time to wait for conversion result to be ready. The device datasheet
+ * worst-case max value is 880ms. Add some slack to be on the safe side.
+ */
+#define OPT3001_RESULT_READY_TIMEOUT	msecs_to_jiffies(1000)
+
+struct opt3001 {
+	struct i2c_client	*client;
+	struct device		*dev;
+
+	struct mutex		lock;
+	u16			ok_to_ignore_lock:1;
+	u16			result_ready:1;
+	wait_queue_head_t	result_ready_queue;
+	u16			result;
+
+	u32			int_time;
+	u32			mode;
+
+	u16			high_thresh_mantissa;
+	u16			low_thresh_mantissa;
+
+	u8			high_thresh_exp;
+	u8			low_thresh_exp;
+};
+
+struct opt3001_scale {
+	int	val;
+	int	val2;
+};
+
+static const struct opt3001_scale opt3001_scales[] = {
+	{
+		.val = 40,
+		.val2 = 950000,
+	},
+	{
+		.val = 81,
+		.val2 = 900000,
+	},
+	{
+		.val = 163,
+		.val2 = 800000,
+	},
+	{
+		.val = 327,
+		.val2 = 600000,
+	},
+	{
+		.val = 655,
+		.val2 = 200000,
+	},
+	{
+		.val = 1310,
+		.val2 = 400000,
+	},
+	{
+		.val = 2620,
+		.val2 = 800000,
+	},
+	{
+		.val = 5241,
+		.val2 = 600000,
+	},
+	{
+		.val = 10483,
+		.val2 = 200000,
+	},
+	{
+		.val = 20966,
+		.val2 = 400000,
+	},
+	{
+		.val = 83865,
+		.val2 = 600000,
+	},
+};
+
+static int opt3001_find_scale(const struct opt3001 *opt, int val,
+		int val2, u8 *exponent)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(opt3001_scales); i++) {
+		const struct opt3001_scale *scale = &opt3001_scales[i];
+
+		/*
+		 * Combine the integer and micro parts for comparison
+		 * purposes. Use milli lux precision to avoid 32-bit integer
+		 * overflows.
+		 */
+		if ((val * 1000 + val2 / 1000) <=
+				(scale->val * 1000 + scale->val2 / 1000)) {
+			*exponent = i;
+			return 0;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static void opt3001_to_iio_ret(struct opt3001 *opt, u8 exponent,
+		u16 mantissa, int *val, int *val2)
+{
+	int lux;
+
+	lux = 10 * (mantissa << exponent);
+	*val = lux / 1000;
+	*val2 = (lux - (*val * 1000)) * 1000;
+}
+
+static void opt3001_set_mode(struct opt3001 *opt, u16 *reg, u16 mode)
+{
+	*reg &= ~OPT3001_CONFIGURATION_M_MASK;
+	*reg |= mode;
+	opt->mode = mode;
+}
+
+static IIO_CONST_ATTR_INT_TIME_AVAIL("0.1 0.8");
+
+static struct attribute *opt3001_attributes[] = {
+	&iio_const_attr_integration_time_available.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group opt3001_attribute_group = {
+	.attrs = opt3001_attributes,
+};
+
+static const struct iio_event_spec opt3001_event_spec[] = {
+	{
+		.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),
+	},
+};
+
+static const struct iio_chan_spec opt3001_channels[] = {
+	{
+		.type = IIO_LIGHT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
+				BIT(IIO_CHAN_INFO_INT_TIME),
+		.event_spec = opt3001_event_spec,
+		.num_event_specs = ARRAY_SIZE(opt3001_event_spec),
+	},
+	IIO_CHAN_SOFT_TIMESTAMP(1),
+};
+
+static int opt3001_get_lux(struct opt3001 *opt, int *val, int *val2)
+{
+	int ret;
+	u16 mantissa;
+	u16 reg;
+	u8 exponent;
+	u16 value;
+
+	/*
+	 * Enable the end-of-conversion interrupt mechanism. Note that doing
+	 * so will overwrite the low-level limit value however we will restore
+	 * this value later on.
+	 */
+	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_LOW_LIMIT,
+			OPT3001_LOW_LIMIT_EOC_ENABLE);
+	if (ret < 0) {
+		dev_err(opt->dev, "failed to write register %02x\n",
+				OPT3001_LOW_LIMIT);
+		return ret;
+	}
+
+	/* Reset data-ready indicator flag (will be set in the IRQ routine) */
+	opt->result_ready = false;
+
+	/* Allow IRQ to access the device despite lock being set */
+	opt->ok_to_ignore_lock = true;
+
+	/* Configure for single-conversion mode and start a new conversion */
+	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
+	if (ret < 0) {
+		dev_err(opt->dev, "failed to read register %02x\n",
+				OPT3001_CONFIGURATION);
+		goto err;
+	}
+
+	reg = ret;
+	opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SINGLE);
+
+	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
+			reg);
+	if (ret < 0) {
+		dev_err(opt->dev, "failed to write register %02x\n",
+				OPT3001_CONFIGURATION);
+		goto err;
+	}
+
+	/* Wait for the IRQ to indicate the conversion is complete */
+	ret = wait_event_timeout(opt->result_ready_queue, opt->result_ready,
+			OPT3001_RESULT_READY_TIMEOUT);
+
+err:
+	/* Disallow IRQ to access the device while lock is active */
+	opt->ok_to_ignore_lock = false;
+
+	if (ret == 0)
+		return -ETIMEDOUT;
+	else if (ret < 0)
+		return ret;
+
+	/*
+	 * Disable the end-of-conversion interrupt mechanism by restoring the
+	 * low-level limit value (clearing OPT3001_LOW_LIMIT_EOC_ENABLE). Note
+	 * that selectively clearing those enable bits would affect the actual
+	 * limit value due to bit-overlap and therefore can't be done.
+	 */
+	value = (opt->low_thresh_exp << 12) | opt->low_thresh_mantissa;
+	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_LOW_LIMIT,
+			value);
+	if (ret < 0) {
+		dev_err(opt->dev, "failed to write register %02x\n",
+				OPT3001_LOW_LIMIT);
+		return ret;
+	}
+
+	exponent = OPT3001_REG_EXPONENT(opt->result);
+	mantissa = OPT3001_REG_MANTISSA(opt->result);
+
+	opt3001_to_iio_ret(opt, exponent, mantissa, val, val2);
+
+	return IIO_VAL_INT_PLUS_MICRO;
+}
+
+static int opt3001_get_int_time(struct opt3001 *opt, int *val, int *val2)
+{
+	*val = 0;
+	*val2 = opt->int_time;
+
+	return IIO_VAL_INT_PLUS_MICRO;
+}
+
+static int opt3001_set_int_time(struct opt3001 *opt, int time)
+{
+	int ret;
+	u16 reg;
+
+	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
+	if (ret < 0) {
+		dev_err(opt->dev, "failed to read register %02x\n",
+				OPT3001_CONFIGURATION);
+		return ret;
+	}
+
+	reg = ret;
+
+	switch (time) {
+	case 100000:
+		reg &= ~OPT3001_CONFIGURATION_CT;
+		opt->int_time = 100000;
+		break;
+	case 800000:
+		reg |= OPT3001_CONFIGURATION_CT;
+		opt->int_time = 800000;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
+			reg);
+}
+
+static int opt3001_read_raw(struct iio_dev *iio,
+		struct iio_chan_spec const *chan, int *val, int *val2,
+		long mask)
+{
+	struct opt3001 *opt = iio_priv(iio);
+	int ret;
+
+	if (opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
+		return -EBUSY;
+
+	if (chan->type != IIO_LIGHT)
+		return -EINVAL;
+
+	mutex_lock(&opt->lock);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_PROCESSED:
+		ret = opt3001_get_lux(opt, val, val2);
+		break;
+	case IIO_CHAN_INFO_INT_TIME:
+		ret = opt3001_get_int_time(opt, val, val2);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	mutex_unlock(&opt->lock);
+
+	return ret;
+}
+
+static int opt3001_write_raw(struct iio_dev *iio,
+		struct iio_chan_spec const *chan, int val, int val2,
+		long mask)
+{
+	struct opt3001 *opt = iio_priv(iio);
+	int ret;
+
+	if (opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
+		return -EBUSY;
+
+	if (chan->type != IIO_LIGHT)
+		return -EINVAL;
+
+	if (mask != IIO_CHAN_INFO_INT_TIME)
+		return -EINVAL;
+
+	if (val != 0)
+		return -EINVAL;
+
+	mutex_lock(&opt->lock);
+	ret = opt3001_set_int_time(opt, val2);
+	mutex_unlock(&opt->lock);
+
+	return ret;
+}
+
+static int opt3001_read_event_value(struct iio_dev *iio,
+		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 opt3001 *opt = iio_priv(iio);
+	int ret = IIO_VAL_INT_PLUS_MICRO;
+
+	mutex_lock(&opt->lock);
+
+	switch (dir) {
+	case IIO_EV_DIR_RISING:
+		opt3001_to_iio_ret(opt, opt->high_thresh_exp,
+				opt->high_thresh_mantissa, val, val2);
+		break;
+	case IIO_EV_DIR_FALLING:
+		opt3001_to_iio_ret(opt, opt->low_thresh_exp,
+				opt->low_thresh_mantissa, val, val2);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	mutex_unlock(&opt->lock);
+
+	return ret;
+}
+
+static int opt3001_write_event_value(struct iio_dev *iio,
+		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 opt3001 *opt = iio_priv(iio);
+	int ret;
+
+	u16 mantissa;
+	u16 value;
+	u16 reg;
+
+	u8 exponent;
+
+	if (val < 0)
+		return -EINVAL;
+
+	mutex_lock(&opt->lock);
+
+	ret = opt3001_find_scale(opt, val, val2, &exponent);
+	if (ret < 0) {
+		dev_err(opt->dev, "can't find scale for %d.%06u\n", val, val2);
+		goto err;
+	}
+
+	mantissa = (((val * 1000) + (val2 / 1000)) / 10) >> exponent;
+	value = (exponent << 12) | mantissa;
+
+	switch (dir) {
+	case IIO_EV_DIR_RISING:
+		reg = OPT3001_HIGH_LIMIT;
+		opt->high_thresh_mantissa = mantissa;
+		opt->high_thresh_exp = exponent;
+		break;
+	case IIO_EV_DIR_FALLING:
+		reg = OPT3001_LOW_LIMIT;
+		opt->low_thresh_mantissa = mantissa;
+		opt->low_thresh_exp = exponent;
+		break;
+	default:
+		ret = -EINVAL;
+		goto err;
+	}
+
+	ret = i2c_smbus_write_word_swapped(opt->client, reg, value);
+	if (ret < 0) {
+		dev_err(opt->dev, "failed to write register %02x\n", reg);
+		goto err;
+	}
+
+err:
+	mutex_unlock(&opt->lock);
+
+	return ret;
+}
+
+static int opt3001_read_event_config(struct iio_dev *iio,
+		const struct iio_chan_spec *chan, enum iio_event_type type,
+		enum iio_event_direction dir)
+{
+	struct opt3001 *opt = iio_priv(iio);
+
+	return opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS;
+}
+
+static int opt3001_write_event_config(struct iio_dev *iio,
+		const struct iio_chan_spec *chan, enum iio_event_type type,
+		enum iio_event_direction dir, int state)
+{
+	struct opt3001 *opt = iio_priv(iio);
+	int ret;
+	u16 mode;
+	u16 reg;
+
+	if (state && opt->mode == OPT3001_CONFIGURATION_M_CONTINUOUS)
+		return 0;
+
+	if (!state && opt->mode == OPT3001_CONFIGURATION_M_SHUTDOWN)
+		return 0;
+
+	mutex_lock(&opt->lock);
+
+	mode = state ? OPT3001_CONFIGURATION_M_CONTINUOUS
+		: OPT3001_CONFIGURATION_M_SHUTDOWN;
+
+	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
+	if (ret < 0) {
+		dev_err(opt->dev, "failed to read register %02x\n",
+				OPT3001_CONFIGURATION);
+		goto err;
+	}
+
+	reg = ret;
+	opt3001_set_mode(opt, &reg, mode);
+
+	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
+			reg);
+	if (ret < 0) {
+		dev_err(opt->dev, "failed to write register %02x\n",
+				OPT3001_CONFIGURATION);
+		goto err;
+	}
+
+err:
+	mutex_unlock(&opt->lock);
+
+	return ret;
+}
+
+static const struct iio_info opt3001_info = {
+	.driver_module = THIS_MODULE,
+	.attrs = &opt3001_attribute_group,
+	.read_raw = opt3001_read_raw,
+	.write_raw = opt3001_write_raw,
+	.read_event_value = opt3001_read_event_value,
+	.write_event_value = opt3001_write_event_value,
+	.read_event_config = opt3001_read_event_config,
+	.write_event_config = opt3001_write_event_config,
+};
+
+static int opt3001_read_id(struct opt3001 *opt)
+{
+	char manufacturer[2];
+	u16 device_id;
+	int ret;
+
+	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_MANUFACTURER_ID);
+	if (ret < 0) {
+		dev_err(opt->dev, "failed to read register %02x\n",
+				OPT3001_MANUFACTURER_ID);
+		return ret;
+	}
+
+	manufacturer[0] = ret >> 8;
+	manufacturer[1] = ret & 0xff;
+
+	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_DEVICE_ID);
+	if (ret < 0) {
+		dev_err(opt->dev, "failed to read register %02x\n",
+				OPT3001_DEVICE_ID);
+		return ret;
+	}
+
+	device_id = ret;
+
+	dev_info(opt->dev, "Found %c%c OPT%04x\n", manufacturer[0],
+			manufacturer[1], device_id);
+
+	return 0;
+}
+
+static int opt3001_configure(struct opt3001 *opt)
+{
+	int ret;
+	u16 reg;
+
+	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
+	if (ret < 0) {
+		dev_err(opt->dev, "failed to read register %02x\n",
+				OPT3001_CONFIGURATION);
+		return ret;
+	}
+
+	reg = ret;
+
+	/* Enable automatic full-scale setting mode */
+	reg &= ~OPT3001_CONFIGURATION_RN_MASK;
+	reg |= OPT3001_CONFIGURATION_RN_AUTO;
+
+	/* Reflect status of the device's integration time setting */
+	if (reg & OPT3001_CONFIGURATION_CT)
+		opt->int_time = 800000;
+	else
+		opt->int_time = 100000;
+
+	/* Ensure device is in shutdown initially */
+	opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SHUTDOWN);
+
+	/* Configure for latched window-style comparison operation */
+	reg |= OPT3001_CONFIGURATION_L;
+	reg &= ~OPT3001_CONFIGURATION_POL;
+	reg &= ~OPT3001_CONFIGURATION_ME;
+	reg &= ~OPT3001_CONFIGURATION_FC_MASK;
+
+	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
+			reg);
+	if (ret < 0) {
+		dev_err(opt->dev, "failed to write register %02x\n",
+				OPT3001_CONFIGURATION);
+		return ret;
+	}
+
+	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_LOW_LIMIT);
+	if (ret < 0) {
+		dev_err(opt->dev, "failed to read register %02x\n",
+				OPT3001_LOW_LIMIT);
+		return ret;
+	}
+
+	opt->low_thresh_mantissa = OPT3001_REG_MANTISSA(ret);
+	opt->low_thresh_exp = OPT3001_REG_EXPONENT(ret);
+
+	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_HIGH_LIMIT);
+	if (ret < 0) {
+		dev_err(opt->dev, "failed to read register %02x\n",
+				OPT3001_HIGH_LIMIT);
+		return ret;
+	}
+
+	opt->high_thresh_mantissa = OPT3001_REG_MANTISSA(ret);
+	opt->high_thresh_exp = OPT3001_REG_EXPONENT(ret);
+
+	return 0;
+}
+
+static irqreturn_t opt3001_irq(int irq, void *_iio)
+{
+	struct iio_dev *iio = _iio;
+	struct opt3001 *opt = iio_priv(iio);
+	int ret;
+
+	if (!opt->ok_to_ignore_lock)
+		mutex_lock(&opt->lock);
+
+	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
+	if (ret < 0) {
+		dev_err(opt->dev, "failed to read register %02x\n",
+				OPT3001_CONFIGURATION);
+		goto out;
+	}
+
+	if ((ret & OPT3001_CONFIGURATION_M_MASK) ==
+			OPT3001_CONFIGURATION_M_CONTINUOUS) {
+		if (ret & OPT3001_CONFIGURATION_FH)
+			iio_push_event(iio,
+					IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
+							IIO_EV_TYPE_THRESH,
+							IIO_EV_DIR_RISING),
+					iio_get_time_ns());
+		if (ret & OPT3001_CONFIGURATION_FL)
+			iio_push_event(iio,
+					IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
+							IIO_EV_TYPE_THRESH,
+							IIO_EV_DIR_FALLING),
+					iio_get_time_ns());
+	} else if (ret & OPT3001_CONFIGURATION_CRF) {
+		ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_RESULT);
+		if (ret < 0) {
+			dev_err(opt->dev, "failed to read register %02x\n",
+					OPT3001_RESULT);
+			goto out;
+		}
+		opt->result = ret;
+		opt->result_ready = true;
+		wake_up(&opt->result_ready_queue);
+	}
+
+out:
+	if (!opt->ok_to_ignore_lock)
+		mutex_unlock(&opt->lock);
+
+	return IRQ_HANDLED;
+}
+
+static int opt3001_probe(struct i2c_client *client,
+		const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+
+	struct iio_dev *iio;
+	struct opt3001 *opt;
+	int irq = client->irq;
+	int ret;
+
+	iio = devm_iio_device_alloc(dev, sizeof(*opt));
+	if (!iio)
+		return -ENOMEM;
+
+	opt = iio_priv(iio);
+	opt->client = client;
+	opt->dev = dev;
+
+	mutex_init(&opt->lock);
+	init_waitqueue_head(&opt->result_ready_queue);
+	i2c_set_clientdata(client, iio);
+
+	ret = opt3001_read_id(opt);
+	if (ret)
+		return ret;
+
+	ret = opt3001_configure(opt);
+	if (ret)
+		return ret;
+
+	iio->name = client->name;
+	iio->channels = opt3001_channels;
+	iio->num_channels = ARRAY_SIZE(opt3001_channels);
+	iio->dev.parent = dev;
+	iio->modes = INDIO_DIRECT_MODE;
+	iio->info = &opt3001_info;
+
+	ret = devm_iio_device_register(dev, iio);
+	if (ret) {
+		dev_err(dev, "failed to register IIO device\n");
+		return ret;
+	}
+
+	ret = request_threaded_irq(irq, NULL, opt3001_irq,
+			IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+			"opt3001", iio);
+	if (ret) {
+		dev_err(dev, "failed to request IRQ #%d\n", irq);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int opt3001_remove(struct i2c_client *client)
+{
+	struct iio_dev *iio = i2c_get_clientdata(client);
+	struct opt3001 *opt = iio_priv(iio);
+	int ret;
+	u16 reg;
+
+	free_irq(client->irq, iio);
+
+	ret = i2c_smbus_read_word_swapped(opt->client, OPT3001_CONFIGURATION);
+	if (ret < 0) {
+		dev_err(opt->dev, "failed to read register %02x\n",
+				OPT3001_CONFIGURATION);
+		return ret;
+	}
+
+	reg = ret;
+	opt3001_set_mode(opt, &reg, OPT3001_CONFIGURATION_M_SHUTDOWN);
+
+	ret = i2c_smbus_write_word_swapped(opt->client, OPT3001_CONFIGURATION,
+			reg);
+	if (ret < 0) {
+		dev_err(opt->dev, "failed to write register %02x\n",
+				OPT3001_CONFIGURATION);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct i2c_device_id opt3001_id[] = {
+	{ "opt3001", 0 },
+	{ } /* Terminating Entry */
+};
+MODULE_DEVICE_TABLE(i2c, opt3001_id);
+
+static const struct of_device_id opt3001_of_match[] = {
+	{ .compatible = "ti,opt3001" },
+	{ }
+};
+
+static struct i2c_driver opt3001_driver = {
+	.probe = opt3001_probe,
+	.remove = opt3001_remove,
+	.id_table = opt3001_id,
+
+	.driver = {
+		.name = "opt3001",
+		.of_match_table = of_match_ptr(opt3001_of_match),
+		.owner = THIS_MODULE,
+	},
+};
+
+module_i2c_driver(opt3001_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Andreas Dannenberg <dannenberg@ti.com>");
+MODULE_DESCRIPTION("Texas Instruments OPT3001 Light Sensor Driver");