Date:	Wed, 10 Jul 2013 16:08:49 +0300
From:	Oleksandr Kravchenko <x0199363@...com>
To:	<linux-iio@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-doc@...r.kernel.org>
CC:	<grant.likely@...aro.org>, <rob.herring@...xeda.com>,
	<rob@...dley.net>, <jic23@....ac.uk>, <pmeerw@...erw.net>,
	<holler@...oftware.de>, <srinivas.pandruvada@...el.com>,
	<devicetree-discuss@...ts.ozlabs.org>,
	Oleksandr Kravchenko <o.v.kravchenko@...ballogic.com>
Subject: [PATCH] iio: add APDS9300 ambilent light sensor driver

From: Oleksandr Kravchenko <o.v.kravchenko@...ballogic.com>

This patch adds IIO driver for APDS9300 ambilent light sensor (ALS).
http://www.avagotech.com/docs/AV02-1077EN

The driver allows to read raw data from ADC registers or calculate
lux value. It also can handle threshold inrerrupt.

Signed-off-by: Oleksandr Kravchenko <o.v.kravchenko@...ballogic.com>
---
 .../devicetree/bindings/iio/light/apds9300.txt     |   22 +
 drivers/iio/light/Kconfig                          |   10 +
 drivers/iio/light/Makefile                         |    1 +
 drivers/iio/light/apds9300.c                       |  528 ++++++++++++++++++++
 4 files changed, 561 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/light/apds9300.txt
 create mode 100644 drivers/iio/light/apds9300.c

diff --git a/Documentation/devicetree/bindings/iio/light/apds9300.txt b/Documentation/devicetree/bindings/iio/light/apds9300.txt
new file mode 100644
index 0000000..d6f66c7
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/light/apds9300.txt
@@ -0,0 +1,22 @@
+* Avago APDS9300 ambient light sensor
+
+http://www.avagotech.com/docs/AV02-1077EN
+
+Required properties:
+
+  - compatible : should be "avago,apds9300"
+  - reg : the I2C address of the sensor
+
+Optional properties:
+
+  - interrupt-parent : should be the phandle for the interrupt controller
+  - interrupts : interrupt mapping for GPIO IRQ
+
+Example:
+
+apds9300@39 {
+	compatible = "avago,apds9300";
+	reg = <0x39>;
+	interrupt-parent = <&gpio2>;
+	interrupts = <29 8>;
+};
diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index 5ef1a39..08a6742 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -52,6 +52,16 @@ config VCNL4000
 	 To compile this driver as a module, choose M here: the
 	 module will be called vcnl4000.
 
+config APDS9300
+	tristate "APDS9300 ambient light sensor"
+	depends on I2C
+	help
+	 Say Y here if you want to build a driver for the Avago APDS9300
+	 ambient light sensor.
+
+	 To compile this driver as a module, choose M here: the
+	 module will be called apds9300.
+
 config HID_SENSOR_ALS
 	depends on HID_SENSOR_HUB
 	select IIO_BUFFER
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index 040d9c7..da58e12 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -6,4 +6,5 @@ obj-$(CONFIG_ADJD_S311)		+= adjd_s311.o
 obj-$(CONFIG_SENSORS_LM3533)	+= lm3533-als.o
 obj-$(CONFIG_SENSORS_TSL2563)	+= tsl2563.o
 obj-$(CONFIG_VCNL4000)		+= vcnl4000.o
+obj-$(CONFIG_APDS9300)		+= apds9300.o
 obj-$(CONFIG_HID_SENSOR_ALS)	+= hid-sensor-als.o
diff --git a/drivers/iio/light/apds9300.c b/drivers/iio/light/apds9300.c
new file mode 100644
index 0000000..2275ecc
--- /dev/null
+++ b/drivers/iio/light/apds9300.c
@@ -0,0 +1,528 @@
+/*
+ * apds9300.c - IIO driver for Avago APDS9300 ambient light sensor
+ *
+ * Copyright 2013 Oleksandr Kravchenko <o.v.kravchenko@...ballogic.com>
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License.  See the file COPYING in the main
+ * directory of this archive for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/pm.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/events.h>
+
+#define ALS_DRV_NAME "apds9300"
+#define ALS_IRQ_NAME "apds9300_event"
+
+/* Command register bits */
+#define ALS_CMD		BIT(7) /* Select command register. Must write as 1 */
+#define ALS_WORD	BIT(5) /* I2C write/read: if 1 word, if 0 byte */
+#define ALS_CLEAR	BIT(6) /* Interrupt clear. Clears pending interrupt */
+
+/* Register set */
+#define ALS_CONTROL		0x00 /* Control of basic functions */
+#define ALS_THRESHLOWLOW	0x02 /* Low byte of low interrupt threshold */
+#define ALS_THRESHHIGHLOW	0x04 /* Low byte of high interrupt threshold */
+#define ALS_INTERRUPT		0x06 /* Interrupt control */
+#define ALS_DATA0LOW		0x0c /* Low byte of ADC channel 0 */
+#define ALS_DATA1LOW		0x0e /* Low byte of ADC channel 1 */
+
+/* Power on/off value for ALS_CONTROL register */
+#define ALS_POWER_ON		0x03
+#define ALS_POWER_OFF		0x00
+
+/* Interrupts */
+#define ALS_INTR_ENABLE		0x10
+/* Interrupt Persist Function: Any value outside of threshold range */
+#define ALS_THRESH_INTR		0x01
+
+#define ALS_THRESH_MAX		0xffff /* Max threshold value */
+
+struct als_data {
+	struct i2c_client *client;
+	struct mutex mutex;
+	int power_state;
+	int thresh_low;
+	int thresh_hi;
+	int intr_en;
+};
+
+/* Lux calculation */
+
+/* Calculated values 1000 * (CH1/CH0)^1.4 for CH1/CH0 from 0 to 0.52 */
+static const u16 lux_ratio[] = {
+	0, 2, 4, 7, 11, 15, 19, 24, 29, 34, 40, 45, 51, 57, 64, 70, 77, 84, 91,
+	98, 105, 112, 120, 128, 136, 144, 152, 160, 168, 177, 185, 194, 203,
+	212, 221, 230, 239, 249, 258, 268, 277, 287, 297, 307, 317, 327, 337,
+	347, 358, 368, 379, 390, 400,
+};
+
+static unsigned long als_calculate_lux(u16 ch0, u16 ch1)
+{
+	unsigned long lux, tmp;
+	u64 tmp64;
+
+	/* avoid division by zero */
+	if (ch0 == 0)
+		return 0;
+
+	tmp = ch1 * 100 / ch0;
+	if (tmp <= 52) {
+		/*
+		 * Variable tmp64 need to avoid overflow of this part of lux
+		 * calculation formula.
+		 */
+		tmp64 = ch0 * lux_ratio[tmp] * 5930 / 1000;
+		lux = 3150 * ch0 - (unsigned long)tmp64;
+	}
+	else if (tmp <= 65)
+		lux = 2290 * ch0 - 2910 * ch1;
+	else if (tmp <= 80)
+		lux = 1570 * ch0 - 1800 * ch1;
+	else if (tmp <= 130)
+		lux = 338 * ch0 - 260 * ch1;
+	else
+		lux = 0;
+
+	return lux / 100000;
+}
+
+/* I2C I/O operations */
+
+static int als_set_power_state(struct als_data *data, int state)
+{
+	int ret;
+	u8 cmd;
+
+	cmd = state ? ALS_POWER_ON : ALS_POWER_OFF;
+	ret = i2c_smbus_write_byte_data(data->client,
+			ALS_CONTROL | ALS_CMD, cmd);
+	if (!ret)
+		data->power_state = state;
+	else
+		dev_err(&data->client->dev,
+				"failed to set power state %d\n", state);
+
+	return ret;
+}
+
+static int als_get_adc_val(struct als_data *data, int adc_number)
+{
+	int ret;
+	u8 flags = ALS_CMD | ALS_WORD;
+
+	if (!data->power_state)
+		return -EAGAIN;
+
+	/* Select ADC0 or ADC1 data register */
+	flags |= adc_number ? ALS_DATA1LOW : ALS_DATA0LOW;
+
+	ret = i2c_smbus_read_word_data(data->client, flags);
+	if (ret < 0)
+		dev_err(&data->client->dev,
+				"failed to read ADC%d value\n", adc_number);
+
+	return ret;
+}
+
+static int als_set_thresh_low(struct als_data *data, int value)
+{
+	int ret;
+
+	if (!data->power_state)
+		return -EAGAIN;
+
+	if (value > ALS_THRESH_MAX || value > data->thresh_hi)
+		return -EINVAL;
+
+	ret = i2c_smbus_write_word_data(data->client,
+			ALS_THRESHLOWLOW | ALS_CMD | ALS_WORD, value);
+	if (!ret)
+		data->thresh_low = value;
+	else
+		dev_err(&data->client->dev,
+				"failed to set thresh_low\n");
+
+	return ret;
+}
+
+static int als_set_thresh_hi(struct als_data *data, int value)
+{
+	int ret;
+
+	if (!data->power_state)
+		return -EAGAIN;
+
+	if (value > ALS_THRESH_MAX || value < data->thresh_low)
+		return -EINVAL;
+
+	ret = i2c_smbus_write_word_data(data->client,
+			ALS_THRESHHIGHLOW | ALS_CMD | ALS_WORD, value);
+	if (!ret)
+		data->thresh_hi = value;
+	else
+		dev_err(&data->client->dev,
+				"failed to set thresh_hi\n");
+
+	return ret;
+}
+
+static int als_set_intr_state(struct als_data *data, int state)
+{
+	int ret;
+	u8 cmd;
+
+	if (!data->power_state)
+		return -EAGAIN;
+
+	cmd = state ? ALS_INTR_ENABLE | ALS_THRESH_INTR : 0x00;
+	ret = i2c_smbus_write_byte_data(data->client,
+			ALS_INTERRUPT | ALS_CMD, cmd);
+	if (!ret)
+		data->intr_en = state;
+	else
+		dev_err(&data->client->dev,
+				"failed to set interrupt state %d\n", state);
+
+	return ret;
+}
+
+static void als_clear_intr(struct als_data *data)
+{
+	int ret;
+
+	ret = i2c_smbus_write_byte(data->client, ALS_CLEAR | ALS_CMD);
+	if (ret < 0)
+		dev_err(&data->client->dev,
+				"failed to clear interrupt\n");
+}
+
+static int als_chip_init(struct als_data *data)
+{
+	int ret;
+
+	/* Need to set power off to ensure that the chip is off */
+	ret = als_set_power_state(data, 0);
+	if (ret < 0)
+		goto err;
+	/*
+	 * Probe the chip. To do so we try to power up the device and then to
+	 * read back the 0x03 code
+	 */
+	ret = als_set_power_state(data, 1);
+	if (ret < 0)
+		goto err;
+	ret = i2c_smbus_read_byte_data(data->client, ALS_CONTROL | ALS_CMD);
+	if (ret != ALS_POWER_ON) {
+		ret = -ENODEV;
+		goto err;
+	}
+	/*
+	 * Disable interrupt to ensure thai it is doesn't enable
+	 * i.e. after device soft reset
+	 */
+	ret = als_set_intr_state(data, 0);
+	if (ret < 0)
+		goto err;
+
+	return 0;
+
+err:
+	dev_err(&data->client->dev, "failed to init the chip\n");
+	return ret;
+}
+
+/* Industrial I/O data and functions */
+
+static int als_read_raw(struct iio_dev *indio_dev,
+		struct iio_chan_spec const *chan, int *val, int *val2,
+		long mask)
+{
+	int ch0, ch1, ret = -EINVAL;
+	struct als_data *data = iio_priv(indio_dev);
+
+	mutex_lock(&data->mutex);
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+	case IIO_CHAN_INFO_PROCESSED:
+		switch (chan->type) {
+		case IIO_LIGHT:
+			ch0 = als_get_adc_val(data, 0);
+			if (ch0 < 0) {
+				ret = ch0;
+				break;
+			}
+			ch1 = als_get_adc_val(data, 1);
+			if (ch1 < 0) {
+				ret = ch1;
+				break;
+			}
+			*val = als_calculate_lux(ch0, ch1);
+			ret = IIO_VAL_INT;
+			break;
+		case IIO_INTENSITY:
+			ret = als_get_adc_val(data, chan->channel);
+			if (ret < 0)
+				break;
+			*val = ret;
+			ret = IIO_VAL_INT;
+			break;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int als_read_thresh(struct iio_dev *indio_dev, u64 event_code, int *val)
+{
+	struct als_data *data = iio_priv(indio_dev);
+
+	switch (IIO_EVENT_CODE_EXTRACT_DIR(event_code)) {
+	case IIO_EV_DIR_RISING:
+		*val = data->thresh_hi;
+		break;
+	case IIO_EV_DIR_FALLING:
+		*val = data->thresh_low;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int als_write_thresh(struct iio_dev *indio_dev, u64 event_code, int val)
+{
+	struct als_data *data = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	if (IIO_EVENT_CODE_EXTRACT_DIR(event_code) == IIO_EV_DIR_RISING)
+		ret = als_set_thresh_hi(data, val);
+	else
+		ret = als_set_thresh_low(data, val);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int als_read_interrupt_config(struct iio_dev *indio_dev,
+		u64 event_code)
+{
+	struct als_data *data = iio_priv(indio_dev);
+	return data->intr_en;
+}
+
+static int als_write_interrupt_config(struct iio_dev *indio_dev,
+		u64 event_code, int state)
+{
+	struct als_data *data = iio_priv(indio_dev);
+	int ret = 0;
+
+	mutex_lock(&data->mutex);
+	ret = als_set_intr_state(data, state);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static const struct iio_info als_info_no_irq = {
+	.driver_module	= THIS_MODULE,
+	.read_raw	= &als_read_raw,
+};
+
+static const struct iio_info als_info = {
+	.driver_module		= THIS_MODULE,
+	.read_raw		= als_read_raw,
+	.read_event_value	= &als_read_thresh,
+	.write_event_value	= &als_write_thresh,
+	.read_event_config	= &als_read_interrupt_config,
+	.write_event_config	= &als_write_interrupt_config,
+};
+
+static const struct iio_chan_spec als_channels[] = {
+	{
+		.type = IIO_LIGHT,
+		.channel = 0,
+		.indexed = true,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+	}, {
+		.type = IIO_INTENSITY,
+		.channel = 0,
+		.indexed = true,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.event_mask = (IIO_EV_BIT(IIO_EV_TYPE_THRESH,
+					  IIO_EV_DIR_RISING) |
+			       IIO_EV_BIT(IIO_EV_TYPE_THRESH,
+					  IIO_EV_DIR_FALLING)),
+	}, {
+		.type = IIO_INTENSITY,
+		.channel = 1,
+		.indexed = true,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+	},
+};
+
+static irqreturn_t als_interrupt_handler(int irq, void *private)
+{
+	struct iio_dev *dev_info = private;
+	struct als_data *data = iio_priv(dev_info);
+
+	iio_push_event(dev_info,
+			IIO_UNMOD_EVENT_CODE(IIO_INTENSITY, 0,
+				IIO_EV_TYPE_THRESH,
+				IIO_EV_DIR_FALLING),
+			iio_get_time_ns());
+
+	als_clear_intr(data);
+
+	return IRQ_HANDLED;
+}
+
+/* Probe/remove functions */
+
+static int als_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+	struct als_data *data;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = iio_device_alloc(sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+	data->client = client;
+
+	ret = als_chip_init(data);
+	if (ret < 0)
+		goto err;
+
+	mutex_init(&data->mutex);
+
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->channels = als_channels;
+	indio_dev->num_channels = ARRAY_SIZE(als_channels);
+	indio_dev->name = ALS_DRV_NAME;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	if (client->irq)
+		indio_dev->info = &als_info;
+	else
+		indio_dev->info = &als_info_no_irq;
+
+	if (client->irq) {
+		ret = devm_request_threaded_irq(&client->dev, client->irq,
+				NULL, als_interrupt_handler,
+				IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+				ALS_IRQ_NAME, indio_dev);
+		if (ret) {
+			dev_err(&client->dev, "irq request error %d\n", -ret);
+			goto err;
+		}
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret < 0)
+		goto err;
+
+	dev_info(&client->dev, "ambient light sensor\n");
+
+	return 0;
+
+err:
+	/* Ensure that power off in case of error */
+	als_set_power_state(data, 0);
+	iio_device_free(indio_dev);
+	return ret;
+}
+
+static int als_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct als_data *data = iio_priv(indio_dev);
+	int ret;
+
+	iio_device_unregister(indio_dev);
+
+	/* Ensure that power off and interrupts are disabled */
+	ret = als_set_intr_state(data, 0);
+	if (!ret)
+		ret = als_set_power_state(data, 0);
+
+	iio_device_free(indio_dev);
+
+	return ret;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int als_suspend(struct device *dev)
+{
+	struct als_data *data = i2c_get_clientdata(to_i2c_client(dev));
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = als_set_power_state(data, 0);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int als_resume(struct device *dev)
+{
+	struct als_data *data = i2c_get_clientdata(to_i2c_client(dev));
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = als_set_power_state(data, 1);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static SIMPLE_DEV_PM_OPS(als_pm_ops, als_suspend, als_resume);
+#define ALS_PM_OPS (&als_pm_ops)
+#else
+#define ALS_PM_OPS NULL
+#endif
+
+static struct i2c_device_id als_id[] = {
+	{ ALS_DRV_NAME, 0 },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(i2c, als_id);
+
+static struct i2c_driver als_driver = {
+	.driver = {
+		.name	= ALS_DRV_NAME,
+		.owner	= THIS_MODULE,
+		.pm	= ALS_PM_OPS,
+	},
+	.probe		= als_probe,
+	.remove		= als_remove,
+	.id_table	= als_id,
+};
+
+module_i2c_driver(als_driver);
+
+MODULE_AUTHOR("Kravchenko Oleksandr <o.v.kravchenko@...ballogic.com>");
+MODULE_AUTHOR("GlobalLogic inc.");
+MODULE_DESCRIPTION("APDS9300 ambient light photo sensor driver");
+MODULE_LICENSE("GPL");
-- 
1.7.9.5

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