iio: add APDS9300 ambilent light sensor driver

This patch adds IIO driver for APDS9300 ambient 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 interrupt.

Signed-off-by: Oleksandr Kravchenko <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>

Documentation/devicetree/bindings/iio/light/apds9300.txt

···
+* 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>;
+};

drivers/iio/light/Kconfig

···
 	 This driver can also be built as a module.  If so, the module
 	 will be called adjd_s311.
 
+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

drivers/iio/light/Makefile

···
 
 # When adding new entries keep the list in alphabetical order
 obj-$(CONFIG_ADJD_S311)		+= adjd_s311.o
+obj-$(CONFIG_APDS9300)		+= apds9300.o
 obj-$(CONFIG_HID_SENSOR_ALS)	+= hid-sensor-als.o
 obj-$(CONFIG_SENSORS_LM3533)	+= lm3533-als.o
 obj-$(CONFIG_SENSORS_TSL2563)	+= tsl2563.o

drivers/iio/light/apds9300.c

···
+/*
+ * apds9300.c - IIO driver for Avago APDS9300 ambient light sensor
+ *
+ * Copyright 2013 Oleksandr Kravchenko <[e-mail]>
+ *
+ * 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/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/events.h>
+
+#define APDS9300_DRV_NAME "apds9300"
+#define APDS9300_IRQ_NAME "apds9300_event"
+
+/* Command register bits */
+#define APDS9300_CMD	BIT(7) /* Select command register. Must write as 1 */
+#define APDS9300_WORD	BIT(5) /* I2C write/read: if 1 word, if 0 byte */
+#define APDS9300_CLEAR	BIT(6) /* Interrupt clear. Clears pending interrupt */
+
+/* Register set */
+#define APDS9300_CONTROL	0x00 /* Control of basic functions */
+#define APDS9300_THRESHLOWLOW	0x02 /* Low byte of low interrupt threshold */
+#define APDS9300_THRESHHIGHLOW	0x04 /* Low byte of high interrupt threshold */
+#define APDS9300_INTERRUPT	0x06 /* Interrupt control */
+#define APDS9300_DATA0LOW	0x0c /* Low byte of ADC channel 0 */
+#define APDS9300_DATA1LOW	0x0e /* Low byte of ADC channel 1 */
+
+/* Power on/off value for APDS9300_CONTROL register */
+#define APDS9300_POWER_ON	0x03
+#define APDS9300_POWER_OFF	0x00
+
+/* Interrupts */
+#define APDS9300_INTR_ENABLE	0x10
+/* Interrupt Persist Function: Any value outside of threshold range */
+#define APDS9300_THRESH_INTR	0x01
+
+#define APDS9300_THRESH_MAX	0xffff /* Max threshold value */
+
+struct apds9300_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 apds9300_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 apds9300_calculate_lux(u16 ch0, u16 ch1)
+{
+	unsigned long lux, tmp;
+
+	/* avoid division by zero */
+	if (ch0 == 0)
+		return 0;
+
+	tmp = DIV_ROUND_UP(ch1 * 100, ch0);
+	if (tmp <= 52) {
+		lux = 3150 * ch0 - (unsigned long)DIV_ROUND_UP_ULL(ch0
+				* apds9300_lux_ratio[tmp] * 5930ull, 1000);
+	} 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;
+}
+
+static int apds9300_get_adc_val(struct apds9300_data *data, int adc_number)
+{
+	int ret;
+	u8 flags = APDS9300_CMD | APDS9300_WORD;
+
+	if (!data->power_state)
+		return -EBUSY;
+
+	/* Select ADC0 or ADC1 data register */
+	flags |= adc_number ? APDS9300_DATA1LOW : APDS9300_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 apds9300_set_thresh_low(struct apds9300_data *data, int value)
+{
+	int ret;
+
+	if (!data->power_state)
+		return -EBUSY;
+
+	if (value > APDS9300_THRESH_MAX)
+		return -EINVAL;
+
+	ret = i2c_smbus_write_word_data(data->client, APDS9300_THRESHLOWLOW
+			| APDS9300_CMD | APDS9300_WORD, value);
+	if (ret) {
+		dev_err(&data->client->dev, "failed to set thresh_low\n");
+		return ret;
+	}
+	data->thresh_low = value;
+
+	return 0;
+}
+
+static int apds9300_set_thresh_hi(struct apds9300_data *data, int value)
+{
+	int ret;
+
+	if (!data->power_state)
+		return -EBUSY;
+
+	if (value > APDS9300_THRESH_MAX)
+		return -EINVAL;
+
+	ret = i2c_smbus_write_word_data(data->client, APDS9300_THRESHHIGHLOW
+			| APDS9300_CMD | APDS9300_WORD, value);
+	if (ret) {
+		dev_err(&data->client->dev, "failed to set thresh_hi\n");
+		return ret;
+	}
+	data->thresh_hi = value;
+
+	return 0;
+}
+
+static int apds9300_set_intr_state(struct apds9300_data *data, int state)
+{
+	int ret;
+	u8 cmd;
+
+	if (!data->power_state)
+		return -EBUSY;
+
+	cmd = state ? APDS9300_INTR_ENABLE | APDS9300_THRESH_INTR : 0x00;
+	ret = i2c_smbus_write_byte_data(data->client,
+			APDS9300_INTERRUPT | APDS9300_CMD, cmd);
+	if (ret) {
+		dev_err(&data->client->dev,
+			"failed to set interrupt state %d\n", state);
+		return ret;
+	}
+	data->intr_en = state;
+
+	return 0;
+}
+
+static int apds9300_set_power_state(struct apds9300_data *data, int state)
+{
+	int ret;
+	u8 cmd;
+
+	cmd = state ? APDS9300_POWER_ON : APDS9300_POWER_OFF;
+	ret = i2c_smbus_write_byte_data(data->client,
+			APDS9300_CONTROL | APDS9300_CMD, cmd);
+	if (ret) {
+		dev_err(&data->client->dev,
+			"failed to set power state %d\n", state);
+		return ret;
+	}
+	data->power_state = state;
+
+	return 0;
+}
+
+static void apds9300_clear_intr(struct apds9300_data *data)
+{
+	int ret;
+
+	ret = i2c_smbus_write_byte(data->client, APDS9300_CLEAR | APDS9300_CMD);
+	if (ret < 0)
+		dev_err(&data->client->dev, "failed to clear interrupt\n");
+}
+
+static int apds9300_chip_init(struct apds9300_data *data)
+{
+	int ret;
+
+	/* Need to set power off to ensure that the chip is off */
+	ret = apds9300_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 = apds9300_set_power_state(data, 1);
+	if (ret < 0)
+		goto err;
+	ret = i2c_smbus_read_byte_data(data->client,
+			APDS9300_CONTROL | APDS9300_CMD);
+	if (ret != APDS9300_POWER_ON) {
+		ret = -ENODEV;
+		goto err;
+	}
+	/*
+	 * Disable interrupt to ensure thai it is doesn't enable
+	 * i.e. after device soft reset
+	 */
+	ret = apds9300_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;
+}
+
+static int apds9300_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 apds9300_data *data = iio_priv(indio_dev);
+
+	mutex_lock(&data->mutex);
+	switch (chan->type) {
+	case IIO_LIGHT:
+		ch0 = apds9300_get_adc_val(data, 0);
+		if (ch0 < 0) {
+			ret = ch0;
+			break;
+		}
+		ch1 = apds9300_get_adc_val(data, 1);
+		if (ch1 < 0) {
+			ret = ch1;
+			break;
+		}
+		*val = apds9300_calculate_lux(ch0, ch1);
+		ret = IIO_VAL_INT;
+		break;
+	case IIO_INTENSITY:
+		ret = apds9300_get_adc_val(data, chan->channel);
+		if (ret < 0)
+			break;
+		*val = ret;
+		ret = IIO_VAL_INT;
+		break;
+	default:
+		break;
+	}
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int apds9300_read_thresh(struct iio_dev *indio_dev, u64 event_code,
+		int *val)
+{
+	struct apds9300_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 apds9300_write_thresh(struct iio_dev *indio_dev, u64 event_code,
+		int val)
+{
+	struct apds9300_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 = apds9300_set_thresh_hi(data, val);
+	else
+		ret = apds9300_set_thresh_low(data, val);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int apds9300_read_interrupt_config(struct iio_dev *indio_dev,
+		u64 event_code)
+{
+	struct apds9300_data *data = iio_priv(indio_dev);
+
+	return data->intr_en;
+}
+
+static int apds9300_write_interrupt_config(struct iio_dev *indio_dev,
+		u64 event_code, int state)
+{
+	struct apds9300_data *data = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = apds9300_set_intr_state(data, state);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static const struct iio_info apds9300_info_no_irq = {
+	.driver_module	= THIS_MODULE,
+	.read_raw	= apds9300_read_raw,
+};
+
+static const struct iio_info apds9300_info = {
+	.driver_module		= THIS_MODULE,
+	.read_raw		= apds9300_read_raw,
+	.read_event_value	= apds9300_read_thresh,
+	.write_event_value	= apds9300_write_thresh,
+	.read_event_config	= apds9300_read_interrupt_config,
+	.write_event_config	= apds9300_write_interrupt_config,
+};
+
+static const struct iio_chan_spec apds9300_channels[] = {
+	{
+		.type = IIO_LIGHT,
+		.channel = 0,
+		.indexed = true,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+	}, {
+		.type = IIO_INTENSITY,
+		.channel = 0,
+		.channel2 = IIO_MOD_LIGHT_BOTH,
+		.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,
+		.channel2 = IIO_MOD_LIGHT_IR,
+		.indexed = true,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+	},
+};
+
+static irqreturn_t apds9300_interrupt_handler(int irq, void *private)
+{
+	struct iio_dev *dev_info = private;
+	struct apds9300_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_EITHER),
+		       iio_get_time_ns());
+
+	apds9300_clear_intr(data);
+
+	return IRQ_HANDLED;
+}
+
+static int apds9300_probe(struct i2c_client *client,
+		const struct i2c_device_id *id)
+{
+	struct apds9300_data *data;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+	data->client = client;
+
+	ret = apds9300_chip_init(data);
+	if (ret < 0)
+		goto err;
+
+	mutex_init(&data->mutex);
+
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->channels = apds9300_channels;
+	indio_dev->num_channels = ARRAY_SIZE(apds9300_channels);
+	indio_dev->name = APDS9300_DRV_NAME;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	if (client->irq)
+		indio_dev->info = &apds9300_info;
+	else
+		indio_dev->info = &apds9300_info_no_irq;
+
+	if (client->irq) {
+		ret = devm_request_threaded_irq(&client->dev, client->irq,
+				NULL, apds9300_interrupt_handler,
+				IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+				APDS9300_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;
+
+	return 0;
+
+err:
+	/* Ensure that power off in case of error */
+	apds9300_set_power_state(data, 0);
+	return ret;
+}
+
+static int apds9300_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct apds9300_data *data = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+
+	/* Ensure that power off and interrupts are disabled */
+	apds9300_set_intr_state(data, 0);
+	apds9300_set_power_state(data, 0);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int apds9300_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct apds9300_data *data = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = apds9300_set_power_state(data, 0);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int apds9300_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct apds9300_data *data = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = apds9300_set_power_state(data, 1);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static SIMPLE_DEV_PM_OPS(apds9300_pm_ops, apds9300_suspend, apds9300_resume);
+#define APDS9300_PM_OPS (&apds9300_pm_ops)
+#else
+#define APDS9300_PM_OPS NULL
+#endif
+
+static struct i2c_device_id apds9300_id[] = {
+	{ APDS9300_DRV_NAME, 0 },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(i2c, apds9300_id);
+
+static struct i2c_driver apds9300_driver = {
+	.driver = {
+		.name	= APDS9300_DRV_NAME,
+		.owner	= THIS_MODULE,
+		.pm	= APDS9300_PM_OPS,
+	},
+	.probe		= apds9300_probe,
+	.remove		= apds9300_remove,
+	.id_table	= apds9300_id,
+};
+
+module_i2c_driver(apds9300_driver);
+
+MODULE_AUTHOR("Kravchenko Oleksandr <[e-mail]>");
+MODULE_AUTHOR("GlobalLogic inc.");
+MODULE_DESCRIPTION("APDS9300 ambient light photo sensor driver");
+MODULE_LICENSE("GPL");