iio: add LM3533 ambient-light-sensor driver

Add sub-driver for the ambient-light-sensor interface on National
Semiconductor / TI LM3533 lighting power chips.

The sensor interface can be used to control the LEDs and backlights of
the chip through defining five light zones and three sets of
corresponding output-current values.

The driver provides raw and mean adc readings along with the current
light zone through sysfs. A threshold event can be generated on zone
changes. The ALS-control output values can be set per zone for the three
current output channels.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

5 files changed, 961 insertions, 0 deletions

diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
index 56eecef..cacc74d 100644
--- a/drivers/iio/Kconfig
+++ b/drivers/iio/Kconfig
@@ -50,5 +50,6 @@ config IIO_CONSUMERS_PER_TRIGGER
 
 source "drivers/iio/adc/Kconfig"
 source "drivers/iio/amplifiers/Kconfig"
+source "drivers/iio/light/Kconfig"
 
 endif # IIO
diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
index e425afd..060b674 100644
--- a/drivers/iio/Makefile
+++ b/drivers/iio/Makefile
@@ -11,3 +11,4 @@ obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
 
 obj-y += adc/
 obj-y += amplifiers/
+obj-y += light/
diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
new file mode 100644
index 0000000..db5618e
--- /dev/null
+++ b/drivers/iio/light/Kconfig
@@ -0,0 +1,22 @@
+#
+# Light sensors
+#
+menu "Light sensors"
+
+config SENSORS_LM3533
+	tristate "LM3533 ambient light sensor"
+	depends on MFD_LM3533
+	help
+	  If you say yes here you get support for the ambient light sensor
+	  interface on National Semiconductor / TI LM3533 Lighting Power
+	  chips.
+
+	  The sensor interface can be used to control the LEDs and backlights
+	  of the chip through defining five light zones and three sets of
+	  corresponding output-current values.
+
+	  The driver provides raw and mean adc readings along with the current
+	  light zone through sysfs. A threshold event can be generated on zone
+	  changes. The ALS-control output values can be set per zone for the
+	  three current output channels.
+endmenu
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
new file mode 100644
index 0000000..c1c23a0
--- /dev/null
+++ b/drivers/iio/light/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for IIO Light sensors
+#
+
+obj-$(CONFIG_SENSORS_LM3533)	+= lm3533-als.o
diff --git a/drivers/iio/light/lm3533-als.c b/drivers/iio/light/lm3533-als.c
new file mode 100644
index 0000000..c3e7bac
--- /dev/null
+++ b/drivers/iio/light/lm3533-als.c
@@ -0,0 +1,932 @@
+/*
+ * lm3533-als.c -- LM3533 Ambient Light Sensor driver
+ *
+ * Copyright (C) 2011-2012 Texas Instruments
+ *
+ * Author: Johan Hovold <jhovold@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under  the terms of the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/atomic.h>
+#include <linux/fs.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iio/events.h>
+#include <linux/iio/iio.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/mfd/core.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+#include <linux/mfd/lm3533.h>
+
+
+#define LM3533_ALS_RESISTOR_MIN			1
+#define LM3533_ALS_RESISTOR_MAX			127
+#define LM3533_ALS_CHANNEL_CURRENT_MAX		2
+#define LM3533_ALS_THRESH_MAX			3
+#define LM3533_ALS_ZONE_MAX			4
+
+#define LM3533_REG_ALS_RESISTOR_SELECT		0x30
+#define LM3533_REG_ALS_CONF			0x31
+#define LM3533_REG_ALS_ZONE_INFO		0x34
+#define LM3533_REG_ALS_READ_ADC_RAW		0x37
+#define LM3533_REG_ALS_READ_ADC_AVERAGE		0x38
+#define LM3533_REG_ALS_BOUNDARY_BASE		0x50
+#define LM3533_REG_ALS_TARGET_BASE		0x60
+
+#define LM3533_ALS_ENABLE_MASK			0x01
+#define LM3533_ALS_INPUT_MODE_MASK		0x02
+#define LM3533_ALS_INT_ENABLE_MASK		0x01
+
+#define LM3533_ALS_ZONE_SHIFT			2
+#define LM3533_ALS_ZONE_MASK			0x1c
+
+#define LM3533_ALS_FLAG_INT_ENABLED		1
+
+
+struct lm3533_als {
+	struct lm3533 *lm3533;
+	struct platform_device *pdev;
+
+	unsigned long flags;
+	int irq;
+
+	atomic_t zone;
+	struct mutex thresh_mutex;
+};
+
+
+static int lm3533_als_get_adc(struct iio_dev *indio_dev, bool average,
+								int *adc)
+{
+	struct lm3533_als *als = iio_priv(indio_dev);
+	u8 reg;
+	u8 val;
+	int ret;
+
+	if (average)
+		reg = LM3533_REG_ALS_READ_ADC_AVERAGE;
+	else
+		reg = LM3533_REG_ALS_READ_ADC_RAW;
+
+	ret = lm3533_read(als->lm3533, reg, &val);
+	if (ret) {
+		dev_err(&indio_dev->dev, "failed to read adc\n");
+		return ret;
+	}
+
+	*adc = val;
+
+	return 0;
+}
+
+static int _lm3533_als_get_zone(struct iio_dev *indio_dev, u8 *zone)
+{
+	struct lm3533_als *als = iio_priv(indio_dev);
+	u8 val;
+	int ret;
+
+	ret = lm3533_read(als->lm3533, LM3533_REG_ALS_ZONE_INFO, &val);
+	if (ret) {
+		dev_err(&indio_dev->dev, "failed to read zone\n");
+		return ret;
+	}
+
+	val = (val & LM3533_ALS_ZONE_MASK) >> LM3533_ALS_ZONE_SHIFT;
+	*zone = min_t(u8, val, LM3533_ALS_ZONE_MAX);
+
+	return 0;
+}
+
+static int lm3533_als_get_zone(struct iio_dev *indio_dev, u8 *zone)
+{
+	struct lm3533_als *als = iio_priv(indio_dev);
+	int ret;
+
+	if (test_bit(LM3533_ALS_FLAG_INT_ENABLED, &als->flags)) {
+		*zone = atomic_read(&als->zone);
+	} else {
+		ret = _lm3533_als_get_zone(indio_dev, zone);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * channel	output channel 0..2
+ * zone		zone 0..4
+ */
+static inline u8 lm3533_als_get_target_reg(unsigned channel, unsigned zone)
+{
+	return LM3533_REG_ALS_TARGET_BASE + 5 * channel + zone;
+}
+
+static int lm3533_als_get_target(struct iio_dev *indio_dev, unsigned channel,
+							unsigned zone, u8 *val)
+{
+	struct lm3533_als *als = iio_priv(indio_dev);
+	u8 reg;
+	int ret;
+
+	if (channel > LM3533_ALS_CHANNEL_CURRENT_MAX)
+		return -EINVAL;
+
+	if (zone > LM3533_ALS_ZONE_MAX)
+		return -EINVAL;
+
+	reg = lm3533_als_get_target_reg(channel, zone);
+	ret = lm3533_read(als->lm3533, reg, val);
+	if (ret)
+		dev_err(&indio_dev->dev, "failed to get target current\n");
+
+	return ret;
+}
+
+static int lm3533_als_set_target(struct iio_dev *indio_dev, unsigned channel,
+							unsigned zone, u8 val)
+{
+	struct lm3533_als *als = iio_priv(indio_dev);
+	u8 reg;
+	int ret;
+
+	if (channel > LM3533_ALS_CHANNEL_CURRENT_MAX)
+		return -EINVAL;
+
+	if (zone > LM3533_ALS_ZONE_MAX)
+		return -EINVAL;
+
+	reg = lm3533_als_get_target_reg(channel, zone);
+	ret = lm3533_write(als->lm3533, reg, val);
+	if (ret)
+		dev_err(&indio_dev->dev, "failed to set target current\n");
+
+	return ret;
+}
+
+static int lm3533_als_get_current(struct iio_dev *indio_dev, unsigned channel,
+								int *val)
+{
+	u8 zone;
+	u8 target;
+	int ret;
+
+	ret = lm3533_als_get_zone(indio_dev, &zone);
+	if (ret)
+		return ret;
+
+	ret = lm3533_als_get_target(indio_dev, channel, zone, &target);
+	if (ret)
+		return ret;
+
+	*val = target;
+
+	return 0;
+}
+
+static int lm3533_als_read_raw(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan,
+				int *val, int *val2, long mask)
+{
+	int ret;
+
+	switch (mask) {
+	case 0:
+		switch (chan->type) {
+		case IIO_LIGHT:
+			ret = lm3533_als_get_adc(indio_dev, false, val);
+			break;
+		case IIO_CURRENT:
+			ret = lm3533_als_get_current(indio_dev, chan->channel,
+									val);
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	case IIO_CHAN_INFO_AVERAGE_RAW:
+		ret = lm3533_als_get_adc(indio_dev, true, val);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (ret)
+		return ret;
+
+	return IIO_VAL_INT;
+}
+
+#define CHANNEL_CURRENT(_channel)					\
+	{								\
+		.type		= IIO_CURRENT,				\
+		.channel	= _channel,				\
+		.indexed	= true,					\
+		.output		= true,					\
+		.info_mask	= IIO_CHAN_INFO_RAW_SEPARATE_BIT,	\
+	}
+
+static const struct iio_chan_spec lm3533_als_channels[] = {
+	{
+		.type		= IIO_LIGHT,
+		.channel	= 0,
+		.indexed	= true,
+		.info_mask	= (IIO_CHAN_INFO_AVERAGE_RAW_SEPARATE_BIT |
+				   IIO_CHAN_INFO_RAW_SEPARATE_BIT),
+	},
+	CHANNEL_CURRENT(0),
+	CHANNEL_CURRENT(1),
+	CHANNEL_CURRENT(2),
+};
+
+static irqreturn_t lm3533_als_isr(int irq, void *dev_id)
+{
+
+	struct iio_dev *indio_dev = dev_id;
+	struct lm3533_als *als = iio_priv(indio_dev);
+	u8 zone;
+	int ret;
+
+	/* Clear interrupt by reading the ALS zone register. */
+	ret = _lm3533_als_get_zone(indio_dev, &zone);
+	if (ret)
+		goto out;
+
+	atomic_set(&als->zone, zone);
+
+	iio_push_event(indio_dev,
+		       IIO_UNMOD_EVENT_CODE(IIO_LIGHT,
+					    0,
+					    IIO_EV_TYPE_THRESH,
+					    IIO_EV_DIR_EITHER),
+		       iio_get_time_ns());
+out:
+	return IRQ_HANDLED;
+}
+
+static int lm3533_als_set_int_mode(struct iio_dev *indio_dev, int enable)
+{
+	struct lm3533_als *als = iio_priv(indio_dev);
+	u8 mask = LM3533_ALS_INT_ENABLE_MASK;
+	u8 val;
+	int ret;
+
+	if (enable)
+		val = mask;
+	else
+		val = 0;
+
+	ret = lm3533_update(als->lm3533, LM3533_REG_ALS_ZONE_INFO, val, mask);
+	if (ret) {
+		dev_err(&indio_dev->dev, "failed to set int mode %d\n",
+								enable);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int lm3533_als_get_int_mode(struct iio_dev *indio_dev, int *enable)
+{
+	struct lm3533_als *als = iio_priv(indio_dev);
+	u8 mask = LM3533_ALS_INT_ENABLE_MASK;
+	u8 val;
+	int ret;
+
+	ret = lm3533_read(als->lm3533, LM3533_REG_ALS_ZONE_INFO, &val);
+	if (ret) {
+		dev_err(&indio_dev->dev, "failed to get int mode\n");
+		return ret;
+	}
+
+	*enable = !!(val & mask);
+
+	return 0;
+}
+
+static inline u8 lm3533_als_get_threshold_reg(unsigned nr, bool raising)
+{
+	u8 offset = !raising;
+
+	return LM3533_REG_ALS_BOUNDARY_BASE + 2 * nr + offset;
+}
+
+static int lm3533_als_get_threshold(struct iio_dev *indio_dev, unsigned nr,
+							bool raising, u8 *val)
+{
+	struct lm3533_als *als = iio_priv(indio_dev);
+	u8 reg;
+	int ret;
+
+	if (nr > LM3533_ALS_THRESH_MAX)
+		return -EINVAL;
+
+	reg = lm3533_als_get_threshold_reg(nr, raising);
+	ret = lm3533_read(als->lm3533, reg, val);
+	if (ret)
+		dev_err(&indio_dev->dev, "failed to get threshold\n");
+
+	return ret;
+}
+
+static int lm3533_als_set_threshold(struct iio_dev *indio_dev, unsigned nr,
+							bool raising, u8 val)
+{
+	struct lm3533_als *als = iio_priv(indio_dev);
+	u8 val2;
+	u8 reg, reg2;
+	int ret;
+
+	if (nr > LM3533_ALS_THRESH_MAX)
+		return -EINVAL;
+
+	reg = lm3533_als_get_threshold_reg(nr, raising);
+	reg2 = lm3533_als_get_threshold_reg(nr, !raising);
+
+	mutex_lock(&als->thresh_mutex);
+	ret = lm3533_read(als->lm3533, reg2, &val2);
+	if (ret) {
+		dev_err(&indio_dev->dev, "failed to get threshold\n");
+		goto out;
+	}
+	/*
+	 * This device does not allow negative hysteresis (in fact, it uses
+	 * whichever value is smaller as the lower bound) so we need to make
+	 * sure that thresh_falling <= thresh_raising.
+	 */
+	if ((raising && (val < val2)) || (!raising && (val > val2))) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = lm3533_write(als->lm3533, reg, val);
+	if (ret) {
+		dev_err(&indio_dev->dev, "failed to set threshold\n");
+		goto out;
+	}
+out:
+	mutex_unlock(&als->thresh_mutex);
+
+	return ret;
+}
+
+static int lm3533_als_get_hysteresis(struct iio_dev *indio_dev, unsigned nr,
+								u8 *val)
+{
+	struct lm3533_als *als = iio_priv(indio_dev);
+	u8 falling;
+	u8 raising;
+	int ret;
+
+	if (nr > LM3533_ALS_THRESH_MAX)
+		return -EINVAL;
+
+	mutex_lock(&als->thresh_mutex);
+	ret = lm3533_als_get_threshold(indio_dev, nr, false, &falling);
+	if (ret)
+		goto out;
+	ret = lm3533_als_get_threshold(indio_dev, nr, true, &raising);
+	if (ret)
+		goto out;
+
+	*val = raising - falling;
+out:
+	mutex_unlock(&als->thresh_mutex);
+
+	return ret;
+}
+
+static int show_thresh_either_en(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct lm3533_als *als = iio_priv(indio_dev);
+	int enable;
+	int ret;
+
+	if (als->irq) {
+		ret = lm3533_als_get_int_mode(indio_dev, &enable);
+		if (ret)
+			return ret;
+	} else {
+		enable = 0;
+	}
+
+	return scnprintf(buf, PAGE_SIZE, "%u\n", enable);
+}
+
+static int store_thresh_either_en(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct lm3533_als *als = iio_priv(indio_dev);
+	unsigned long enable;
+	bool int_enabled;
+	u8 zone;
+	int ret;
+
+	if (!als->irq)
+		return -EBUSY;
+
+	if (kstrtoul(buf, 0, &enable))
+		return -EINVAL;
+
+	int_enabled = test_bit(LM3533_ALS_FLAG_INT_ENABLED, &als->flags);
+
+	if (enable && !int_enabled) {
+		ret = lm3533_als_get_zone(indio_dev, &zone);
+		if (ret)
+			return ret;
+
+		atomic_set(&als->zone, zone);
+
+		set_bit(LM3533_ALS_FLAG_INT_ENABLED, &als->flags);
+	}
+
+	ret = lm3533_als_set_int_mode(indio_dev, enable);
+	if (ret) {
+		if (!int_enabled)
+			clear_bit(LM3533_ALS_FLAG_INT_ENABLED, &als->flags);
+
+		return ret;
+	}
+
+	if (!enable)
+		clear_bit(LM3533_ALS_FLAG_INT_ENABLED, &als->flags);
+
+	return len;
+}
+
+static ssize_t show_zone(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	u8 zone;
+	int ret;
+
+	ret = lm3533_als_get_zone(indio_dev, &zone);
+	if (ret)
+		return ret;
+
+	return scnprintf(buf, PAGE_SIZE, "%u\n", zone);
+}
+
+enum lm3533_als_attribute_type {
+	LM3533_ATTR_TYPE_HYSTERESIS,
+	LM3533_ATTR_TYPE_TARGET,
+	LM3533_ATTR_TYPE_THRESH_FALLING,
+	LM3533_ATTR_TYPE_THRESH_RAISING,
+};
+
+struct lm3533_als_attribute {
+	struct device_attribute dev_attr;
+	enum lm3533_als_attribute_type type;
+	u8 val1;
+	u8 val2;
+};
+
+static inline struct lm3533_als_attribute *
+to_lm3533_als_attr(struct device_attribute *attr)
+{
+	return container_of(attr, struct lm3533_als_attribute, dev_attr);
+}
+
+static ssize_t show_als_attr(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct lm3533_als_attribute *als_attr = to_lm3533_als_attr(attr);
+	u8 val;
+	int ret;
+
+	switch (als_attr->type) {
+	case LM3533_ATTR_TYPE_HYSTERESIS:
+		ret = lm3533_als_get_hysteresis(indio_dev, als_attr->val1,
+									&val);
+		break;
+	case LM3533_ATTR_TYPE_TARGET:
+		ret = lm3533_als_get_target(indio_dev, als_attr->val1,
+							als_attr->val2, &val);
+		break;
+	case LM3533_ATTR_TYPE_THRESH_FALLING:
+		ret = lm3533_als_get_threshold(indio_dev, als_attr->val1,
+								false, &val);
+		break;
+	case LM3533_ATTR_TYPE_THRESH_RAISING:
+		ret = lm3533_als_get_threshold(indio_dev, als_attr->val1,
+								true, &val);
+		break;
+	default:
+		ret = -ENXIO;
+	}
+
+	if (ret)
+		return ret;
+
+	return scnprintf(buf, PAGE_SIZE, "%u\n", val);
+}
+
+static ssize_t store_als_attr(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct lm3533_als_attribute *als_attr = to_lm3533_als_attr(attr);
+	u8 val;
+	int ret;
+
+	if (kstrtou8(buf, 0, &val))
+		return -EINVAL;
+
+	switch (als_attr->type) {
+	case LM3533_ATTR_TYPE_TARGET:
+		ret = lm3533_als_set_target(indio_dev, als_attr->val1,
+							als_attr->val2, val);
+		break;
+	case LM3533_ATTR_TYPE_THRESH_FALLING:
+		ret = lm3533_als_set_threshold(indio_dev, als_attr->val1,
+								false, val);
+		break;
+	case LM3533_ATTR_TYPE_THRESH_RAISING:
+		ret = lm3533_als_set_threshold(indio_dev, als_attr->val1,
+								true, val);
+		break;
+	default:
+		ret = -ENXIO;
+	}
+
+	if (ret)
+		return ret;
+
+	return len;
+}
+
+#define ALS_ATTR(_name, _mode, _show, _store, _type, _val1, _val2)	\
+	{ .dev_attr	= __ATTR(_name, _mode, _show, _store),		\
+	  .type		= _type,					\
+	  .val1		= _val1,					\
+	  .val2		= _val2 }
+
+#define LM3533_ALS_ATTR(_name, _mode, _show, _store, _type, _val1, _val2) \
+	struct lm3533_als_attribute lm3533_als_attr_##_name =		  \
+		ALS_ATTR(_name, _mode, _show, _store, _type, _val1, _val2)
+
+#define ALS_TARGET_ATTR_RW(_channel, _zone)				\
+	LM3533_ALS_ATTR(out_current##_channel##_current##_zone##_raw,	\
+				S_IRUGO | S_IWUSR,			\
+				show_als_attr, store_als_attr,		\
+				LM3533_ATTR_TYPE_TARGET, _channel, _zone)
+/*
+ * ALS output current values (ALS mapper targets)
+ *
+ * out_current[0-2]_current[0-4]_raw		0-255
+ */
+static ALS_TARGET_ATTR_RW(0, 0);
+static ALS_TARGET_ATTR_RW(0, 1);
+static ALS_TARGET_ATTR_RW(0, 2);
+static ALS_TARGET_ATTR_RW(0, 3);
+static ALS_TARGET_ATTR_RW(0, 4);
+
+static ALS_TARGET_ATTR_RW(1, 0);
+static ALS_TARGET_ATTR_RW(1, 1);
+static ALS_TARGET_ATTR_RW(1, 2);
+static ALS_TARGET_ATTR_RW(1, 3);
+static ALS_TARGET_ATTR_RW(1, 4);
+
+static ALS_TARGET_ATTR_RW(2, 0);
+static ALS_TARGET_ATTR_RW(2, 1);
+static ALS_TARGET_ATTR_RW(2, 2);
+static ALS_TARGET_ATTR_RW(2, 3);
+static ALS_TARGET_ATTR_RW(2, 4);
+
+#define ALS_THRESH_FALLING_ATTR_RW(_nr)					\
+	LM3533_ALS_ATTR(in_illuminance0_thresh##_nr##_falling_value,	\
+			S_IRUGO | S_IWUSR,				\
+			show_als_attr, store_als_attr,		\
+			LM3533_ATTR_TYPE_THRESH_FALLING, _nr, 0)
+
+#define ALS_THRESH_RAISING_ATTR_RW(_nr)					\
+	LM3533_ALS_ATTR(in_illuminance0_thresh##_nr##_raising_value,	\
+			S_IRUGO | S_IWUSR,				\
+			show_als_attr, store_als_attr,			\
+			LM3533_ATTR_TYPE_THRESH_RAISING, _nr, 0)
+/*
+ * ALS Zone thresholds (boundaries)
+ *
+ * in_illuminance0_thresh[0-3]_falling_value	0-255
+ * in_illuminance0_thresh[0-3]_raising_value	0-255
+ */
+static ALS_THRESH_FALLING_ATTR_RW(0);
+static ALS_THRESH_FALLING_ATTR_RW(1);
+static ALS_THRESH_FALLING_ATTR_RW(2);
+static ALS_THRESH_FALLING_ATTR_RW(3);
+
+static ALS_THRESH_RAISING_ATTR_RW(0);
+static ALS_THRESH_RAISING_ATTR_RW(1);
+static ALS_THRESH_RAISING_ATTR_RW(2);
+static ALS_THRESH_RAISING_ATTR_RW(3);
+
+#define ALS_HYSTERESIS_ATTR_RO(_nr)					\
+	LM3533_ALS_ATTR(in_illuminance0_thresh##_nr##_hysteresis,	\
+			S_IRUGO, show_als_attr, NULL,			\
+			LM3533_ATTR_TYPE_HYSTERESIS, _nr, 0)
+/*
+ * ALS Zone threshold hysteresis
+ *
+ * threshY_hysteresis = threshY_raising - threshY_falling
+ *
+ * in_illuminance0_thresh[0-3]_hysteresis	0-255
+ * in_illuminance0_thresh[0-3]_hysteresis	0-255
+ */
+static ALS_HYSTERESIS_ATTR_RO(0);
+static ALS_HYSTERESIS_ATTR_RO(1);
+static ALS_HYSTERESIS_ATTR_RO(2);
+static ALS_HYSTERESIS_ATTR_RO(3);
+
+#define ILLUMINANCE_ATTR_RO(_name) \
+	DEVICE_ATTR(in_illuminance0_##_name, S_IRUGO, show_##_name, NULL)
+#define ILLUMINANCE_ATTR_RW(_name) \
+	DEVICE_ATTR(in_illuminance0_##_name, S_IRUGO | S_IWUSR , \
+						show_##_name, store_##_name)
+/*
+ * ALS Zone threshold-event enable
+ *
+ * in_illuminance0_thresh_either_en		0,1
+ */
+static ILLUMINANCE_ATTR_RW(thresh_either_en);
+
+/*
+ * ALS Current Zone
+ *
+ * in_illuminance0_zone		0-4
+ */
+static ILLUMINANCE_ATTR_RO(zone);
+
+static struct attribute *lm3533_als_event_attributes[] = {
+	&dev_attr_in_illuminance0_thresh_either_en.attr,
+	&lm3533_als_attr_in_illuminance0_thresh0_falling_value.dev_attr.attr,
+	&lm3533_als_attr_in_illuminance0_thresh0_hysteresis.dev_attr.attr,
+	&lm3533_als_attr_in_illuminance0_thresh0_raising_value.dev_attr.attr,
+	&lm3533_als_attr_in_illuminance0_thresh1_falling_value.dev_attr.attr,
+	&lm3533_als_attr_in_illuminance0_thresh1_hysteresis.dev_attr.attr,
+	&lm3533_als_attr_in_illuminance0_thresh1_raising_value.dev_attr.attr,
+	&lm3533_als_attr_in_illuminance0_thresh2_falling_value.dev_attr.attr,
+	&lm3533_als_attr_in_illuminance0_thresh2_hysteresis.dev_attr.attr,
+	&lm3533_als_attr_in_illuminance0_thresh2_raising_value.dev_attr.attr,
+	&lm3533_als_attr_in_illuminance0_thresh3_falling_value.dev_attr.attr,
+	&lm3533_als_attr_in_illuminance0_thresh3_hysteresis.dev_attr.attr,
+	&lm3533_als_attr_in_illuminance0_thresh3_raising_value.dev_attr.attr,
+	NULL
+};
+
+static struct attribute_group lm3533_als_event_attribute_group = {
+	.attrs = lm3533_als_event_attributes
+};
+
+static struct attribute *lm3533_als_attributes[] = {
+	&dev_attr_in_illuminance0_zone.attr,
+	&lm3533_als_attr_out_current0_current0_raw.dev_attr.attr,
+	&lm3533_als_attr_out_current0_current1_raw.dev_attr.attr,
+	&lm3533_als_attr_out_current0_current2_raw.dev_attr.attr,
+	&lm3533_als_attr_out_current0_current3_raw.dev_attr.attr,
+	&lm3533_als_attr_out_current0_current4_raw.dev_attr.attr,
+	&lm3533_als_attr_out_current1_current0_raw.dev_attr.attr,
+	&lm3533_als_attr_out_current1_current1_raw.dev_attr.attr,
+	&lm3533_als_attr_out_current1_current2_raw.dev_attr.attr,
+	&lm3533_als_attr_out_current1_current3_raw.dev_attr.attr,
+	&lm3533_als_attr_out_current1_current4_raw.dev_attr.attr,
+	&lm3533_als_attr_out_current2_current0_raw.dev_attr.attr,
+	&lm3533_als_attr_out_current2_current1_raw.dev_attr.attr,
+	&lm3533_als_attr_out_current2_current2_raw.dev_attr.attr,
+	&lm3533_als_attr_out_current2_current3_raw.dev_attr.attr,
+	&lm3533_als_attr_out_current2_current4_raw.dev_attr.attr,
+	NULL
+};
+
+static struct attribute_group lm3533_als_attribute_group = {
+	.attrs = lm3533_als_attributes
+};
+
+static int __devinit lm3533_als_set_input_mode(struct lm3533_als *als,
+								bool pwm_mode)
+{
+	u8 mask = LM3533_ALS_INPUT_MODE_MASK;
+	u8 val;
+	int ret;
+
+	if (pwm_mode)
+		val = mask;	/* pwm input */
+	else
+		val = 0;	/* analog input */
+
+	ret = lm3533_update(als->lm3533, LM3533_REG_ALS_CONF, val, mask);
+	if (ret) {
+		dev_err(&als->pdev->dev, "failed to set input mode %d\n",
+								pwm_mode);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int __devinit lm3533_als_set_resistor(struct lm3533_als *als, u8 val)
+{
+	int ret;
+
+	if (val < LM3533_ALS_RESISTOR_MIN || val > LM3533_ALS_RESISTOR_MAX)
+		return -EINVAL;
+
+	ret = lm3533_write(als->lm3533, LM3533_REG_ALS_RESISTOR_SELECT, val);
+	if (ret) {
+		dev_err(&als->pdev->dev, "failed to set resistor\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int __devinit lm3533_als_setup(struct lm3533_als *als,
+					struct lm3533_als_platform_data *pdata)
+{
+	int ret;
+
+	ret = lm3533_als_set_input_mode(als, pdata->pwm_mode);
+	if (ret)
+		return ret;
+
+	/* ALS input is always high impedance in PWM-mode. */
+	if (!pdata->pwm_mode) {
+		ret = lm3533_als_set_resistor(als, pdata->r_select);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int __devinit lm3533_als_setup_irq(struct lm3533_als *als, void *dev)
+{
+	u8 mask = LM3533_ALS_INT_ENABLE_MASK;
+	int ret;
+
+	/* Make sure interrupts are disabled. */
+	ret = lm3533_update(als->lm3533, LM3533_REG_ALS_ZONE_INFO, 0, mask);
+	if (ret) {
+		dev_err(&als->pdev->dev, "failed to disable interrupts\n");
+		return ret;
+	}
+
+	ret = request_threaded_irq(als->irq, NULL, lm3533_als_isr,
+					IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+					dev_name(&als->pdev->dev), dev);
+	if (ret) {
+		dev_err(&als->pdev->dev, "failed to request irq %d\n",
+								als->irq);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int __devinit lm3533_als_enable(struct lm3533_als *als)
+{
+	u8 mask = LM3533_ALS_ENABLE_MASK;
+	int ret;
+
+	ret = lm3533_update(als->lm3533, LM3533_REG_ALS_CONF, mask, mask);
+	if (ret)
+		dev_err(&als->pdev->dev, "failed to enable ALS\n");
+
+	return ret;
+}
+
+static int lm3533_als_disable(struct lm3533_als *als)
+{
+	u8 mask = LM3533_ALS_ENABLE_MASK;
+	int ret;
+
+	ret = lm3533_update(als->lm3533, LM3533_REG_ALS_CONF, 0, mask);
+	if (ret)
+		dev_err(&als->pdev->dev, "failed to disable ALS\n");
+
+	return ret;
+}
+
+static const struct iio_info lm3533_als_info = {
+	.attrs		= &lm3533_als_attribute_group,
+	.event_attrs	= &lm3533_als_event_attribute_group,
+	.driver_module	= THIS_MODULE,
+	.read_raw	= &lm3533_als_read_raw,
+};
+
+static int __devinit lm3533_als_probe(struct platform_device *pdev)
+{
+	struct lm3533 *lm3533;
+	struct lm3533_als_platform_data *pdata;
+	struct lm3533_als *als;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	lm3533 = dev_get_drvdata(pdev->dev.parent);
+	if (!lm3533)
+		return -EINVAL;
+
+	pdata = pdev->dev.platform_data;
+	if (!pdata) {
+		dev_err(&pdev->dev, "no platform data\n");
+		return -EINVAL;
+	}
+
+	indio_dev = iio_device_alloc(sizeof(*als));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	indio_dev->info = &lm3533_als_info;
+	indio_dev->channels = lm3533_als_channels;
+	indio_dev->num_channels = ARRAY_SIZE(lm3533_als_channels);
+	indio_dev->name = dev_name(&pdev->dev);
+	indio_dev->dev.parent = pdev->dev.parent;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	als = iio_priv(indio_dev);
+	als->lm3533 = lm3533;
+	als->pdev = pdev;
+	als->irq = lm3533->irq;
+	atomic_set(&als->zone, 0);
+	mutex_init(&als->thresh_mutex);
+
+	platform_set_drvdata(pdev, indio_dev);
+
+	if (als->irq) {
+		ret = lm3533_als_setup_irq(als, indio_dev);
+		if (ret)
+			goto err_free_dev;
+	}
+
+	ret = lm3533_als_setup(als, pdata);
+	if (ret)
+		goto err_free_irq;
+
+	ret = lm3533_als_enable(als);
+	if (ret)
+		goto err_free_irq;
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register ALS\n");
+		goto err_disable;
+	}
+
+	return 0;
+
+err_disable:
+	lm3533_als_disable(als);
+err_free_irq:
+	if (als->irq)
+		free_irq(als->irq, indio_dev);
+err_free_dev:
+	iio_device_free(indio_dev);
+
+	return ret;
+}
+
+static int __devexit lm3533_als_remove(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct lm3533_als *als = iio_priv(indio_dev);
+
+	lm3533_als_set_int_mode(indio_dev, false);
+	iio_device_unregister(indio_dev);
+	lm3533_als_disable(als);
+	if (als->irq)
+		free_irq(als->irq, indio_dev);
+	iio_device_free(indio_dev);
+
+	return 0;
+}
+
+static struct platform_driver lm3533_als_driver = {
+	.driver	= {
+		.name	= "lm3533-als",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= lm3533_als_probe,
+	.remove		= __devexit_p(lm3533_als_remove),
+};
+module_platform_driver(lm3533_als_driver);
+
+MODULE_AUTHOR("Johan Hovold <jhovold@gmail.com>");
+MODULE_DESCRIPTION("LM3533 Ambient Light Sensor driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:lm3533-als");