iio: light: Add support for Capella CM3323 color/light sensor

Minimal implementation providing raw light intensity and illuminance readings. For illuminance user can compute lux values using raw readings and scale.

This driver also supports CM3323E sensor chip.

Cc Kevin Tsai <[email protected]>

Signed-off-by Daniel Baluta <[email protected]>

---
 drivers/iio/light/Kconfig  |  10 ++
 drivers/iio/light/Makefile |   1 +
 drivers/iio/light/cm3323.c | 345 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 356 insertions(+)
 create mode 100644 drivers/iio/light/cm3323.c

drivers/iio/light/Kconfig +10 -0

index 5bea821..aeaf1c7 100644
@@ -48,6 +48,16 @@ config CM32181
 	 To compile this driver as a module, choose M here:
 	 the module will be called cm32181.
 
+config CM3323
+	depends on I2C
+	tristate "Capella CM3323 color/ambient light sensor"
+	help
+	 Say Y here if you want to build a driver for Capela CM3323
+	 color sensor. This driver also supports CM3323E sensor.
+
+	 To compile this driver as a module, choose M here: the module will
+	 be called cm3323.
+
 config CM36651
 	depends on I2C
 	tristate "CM36651 driver"

drivers/iio/light/Makefile +1 -0

index 47877a3..0815b38 100644
@@ -7,6 +7,7 @@ obj-$(CONFIG_ADJD_S311)		+= adjd_s311.o
 obj-$(CONFIG_AL3320A)		+= al3320a.o
 obj-$(CONFIG_APDS9300)		+= apds9300.o
 obj-$(CONFIG_CM32181)		+= cm32181.o
+obj-$(CONFIG_CM3323)		+= cm3323.o
 obj-$(CONFIG_CM36651)		+= cm36651.o
 obj-$(CONFIG_GP2AP020A00F)	+= gp2ap020a00f.o
 obj-$(CONFIG_HID_SENSOR_ALS)	+= hid-sensor-als.o

drivers/iio/light/cm3323.c new file +56 -0

new file mode 100644
index 0000000..5e9b32d
@@ -0,0 +1,345 @@
+/*
+ * CM3323/CM3323E - Capella Color/Ambient Light Sensor
+ *
+ * Copyright (c) 2015, Intel Corporation.
+ *
+ * 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.
+ *
+ * IIO driver for CM3323/CM3323E (7-bit I2C slave address 0x10)
+ *
+ * TODO: calibscale to correct the lens factor
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define CM3323_DRV_NAME "cm3323"
+
+#define CM3323_CMD_CONF		0x00
+#define CM3323_CMD_RED_DATA	0x08
+#define CM3323_CMD_GREEN_DATA	0x09
+#define CM3323_CMD_BLUE_DATA	0x0A
+#define CM3323_CMD_CLEAR_DATA	0x0B
+
+#define CM3323_CONF_SD_BIT	BIT(0) /* sensor disable */
+#define CM3323_CONF_AF_BIT	BIT(1) /* auto/manual force mode */
+#define CM3323_CONF_IT_MASK	(BIT(4) | BIT(5) | BIT(6))
+#define CM3323_CONF_IT_SHIFT	4
+
+#define CM3323_INT_TIME_AVAILABLE "0.04 0.08 0.16 0.32 0.64 1.28"
+#define CM3323_SCALE_AVAILABLE "0.18 0.09 0.045 0.0225 0.01125 0.005625"
+
+static const struct {
+	int val;
+	int val2;
+} cm3323_int_time[] = {
+	{0, 40000},  /* 40 ms */
+	{0, 80000},  /* 80 ms */
+	{0, 160000}, /* 160 ms */
+	{0, 320000}, /* 320 ms */
+	{0, 640000}, /* 640 ms */
+	{1, 280000}, /* 1280 ms */
+};
+
+/* scale depends on integration time */
+static int cm3323_uscale[] = {
+	180000, /* 40 ms */
+	 90000, /* 80 ms */
+	 45000, /* 160 ms */
+	 22500, /* 320 ms */
+	 11250, /* 640 ms */

drivers/iio/light/cm3323.c new file +251 -0

+	.type = IIO_INTENSITY, \
+	.modified = 1, \
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME), \
+	.channel2 = IIO_MOD_LIGHT_##_color, \
+	.address = _addr, \
+}
+
+/*
+ * CM3323's GREEN channel is used for reading illuminance
+ */
+#define CM3323_LIGHT_CHANNEL(_addr) {\
+	.type = IIO_LIGHT, \
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+			      BIT(IIO_CHAN_INFO_SCALE), \
+	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME), \
+	.address = _addr, \
+}
+
+static const struct iio_chan_spec cm3323_channels[] = {
+	CM3323_COLOR_CHANNEL(RED, CM3323_CMD_RED_DATA),
+	CM3323_COLOR_CHANNEL(GREEN, CM3323_CMD_GREEN_DATA),
+	CM3323_COLOR_CHANNEL(BLUE, CM3323_CMD_BLUE_DATA),
+	CM3323_COLOR_CHANNEL(CLEAR, CM3323_CMD_CLEAR_DATA),
+	CM3323_LIGHT_CHANNEL(CM3323_CMD_GREEN_DATA),
+};
+
+static IIO_CONST_ATTR(in_illuminance_scale_available, CM3323_SCALE_AVAILABLE);
+static IIO_CONST_ATTR_INT_TIME_AVAIL(CM3323_INT_TIME_AVAILABLE);
+
+static struct attribute *cm3323_attributes[] = {
+	&iio_const_attr_integration_time_available.dev_attr.attr,
+	&iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group cm3323_attribute_group = {
+	.attrs = cm3323_attributes,
+};
+
+static int cm3323_init(struct iio_dev *indio_dev)
+{
+	int ret;
+	struct cm3323_data *data = iio_priv(indio_dev);
+
+	ret = i2c_smbus_read_word_data(data->client, CM3323_CMD_CONF);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "Error reading reg_conf\n");
+		return ret;
+	}
+
+	/* enable sensor and set auto force mode */
+	ret &= ~(CM3323_CONF_SD_BIT | CM3323_CONF_AF_BIT);
+
+	ret = i2c_smbus_write_word_data(data->client, CM3323_CMD_CONF, ret);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "Error writing reg_conf\n");
+		return ret;
+	}
+
+	data->reg_conf = ret;
+
+	return 0;
+}
+
+static int cm3323_set_it_bits(struct cm3323_data *data, int val, int val2)
+{
+	int i, ret;
+	u16 reg_conf;
+
+	for (i = 0; i < ARRAY_SIZE(cm3323_int_time); i++) {
+		if (val == cm3323_int_time[i].val &&
+			val2 == cm3323_int_time[i].val2) {
+			reg_conf = data->reg_conf;
+			reg_conf |= i << CM3323_CONF_IT_SHIFT;
+
+			ret = i2c_smbus_write_word_data(data->client,
+				 CM3323_CMD_CONF, reg_conf);
+			if (ret < 0)
+				return ret;
+
+			data->reg_conf = reg_conf;
+			return 0;
+		}
+	}
+	return -EINVAL;
+}
+
+static int cm3323_set_scale(struct cm3323_data *data, int val, int val2)
+{
+	int i, ret;
+	u16 reg_conf;
+
+	if (val != 0)
+		return 0;
+
+	for (i = 0; i < ARRAY_SIZE(cm3323_uscale); i++) {
+		if (val2 == cm3323_uscale[i]) {
+			reg_conf = data->reg_conf;
+			reg_conf |= i << CM3323_CONF_IT_SHIFT;
+
+			ret = i2c_smbus_write_word_data(data->client,
+				 CM3323_CMD_CONF, reg_conf);
+			if (ret < 0)
+				return ret;
+
+			data->reg_conf = reg_conf;
+			return 0;
+		}
+	}
+	return -EINVAL;
+}
+
+static int cm3323_get_it_bits(struct cm3323_data *data)
+{
+	int bits;
+
+	bits = (data->reg_conf & CM3323_CONF_IT_MASK) >>
+		CM3323_CONF_IT_SHIFT;
+
+	if (bits >= ARRAY_SIZE(cm3323_int_time))
+		return -EINVAL;
+	return bits;
+}
+
+static int cm3323_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, int *val,
+			    int *val2, long mask)
+{
+	int i, ret;
+	struct cm3323_data *data = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		mutex_lock(&data->mutex);
+		ret = i2c_smbus_read_word_data(data->client, chan->address);
+		if (ret < 0) {
+			mutex_unlock(&data->mutex);
+			return ret;
+		}
+		*val = ret;
+		mutex_unlock(&data->mutex);
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_INT_TIME:
+		mutex_lock(&data->mutex);
+		i = cm3323_get_it_bits(data);
+		if (i < 0) {
+			mutex_unlock(&data->mutex);
+			return -EINVAL;
+		}
+
+		*val = cm3323_int_time[i].val;
+		*val2 = cm3323_int_time[i].val2;
+		mutex_unlock(&data->mutex);
+
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_SCALE:
+		if (chan->type != IIO_LIGHT)
+			return -EINVAL;
+
+		mutex_lock(&data->mutex);
+		i = cm3323_get_it_bits(data);
+		if (i < 0) {
+			mutex_unlock(&data->mutex);
+			return -EINVAL;
+		}
+		*val = 0;
+		*val2 = cm3323_uscale[i];
+		mutex_unlock(&data->mutex);
+
+		return IIO_VAL_INT_PLUS_MICRO;
+	}
+	return -EINVAL;
+}
+
+static int cm3323_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, int val,
+			    int val2, long mask)
+{
+	struct cm3323_data *data = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_INT_TIME:
+		mutex_lock(&data->mutex);
+		ret = cm3323_set_it_bits(data, val, val2);
+		mutex_unlock(&data->mutex);
+
+		return ret;
+	case IIO_CHAN_INFO_SCALE:
+		if (chan->type != IIO_LIGHT)
+			return -EINVAL;
+		mutex_lock(&data->mutex);
+		ret = cm3323_set_scale(data, val, val2);
+		mutex_unlock(&data->mutex);
+		return ret;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info cm3323_info = {
+	.driver_module	= THIS_MODULE,
+	.read_raw	= cm3323_read_raw,
+	.write_raw	= cm3323_write_raw,
+	.attrs		= &cm3323_attribute_group,
+};
+
+static int cm3323_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct cm3323_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;
+
+	mutex_init(&data->mutex);
+
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->info = &cm3323_info;
+	indio_dev->name = CM3323_DRV_NAME;
+	indio_dev->channels = cm3323_channels;
+	indio_dev->num_channels = ARRAY_SIZE(cm3323_channels);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = cm3323_init(indio_dev);
+	if (ret < 0) {
+		dev_err(&client->dev, "cm3323 chip init failed\n");
+		return ret;
+	}
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static int cm3323_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct cm3323_data *data  = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	/* disable sensor */
+	ret = i2c_smbus_write_word_data(client, CM3323_CMD_CONF,
+					CM3323_CONF_SD_BIT);

drivers/iio/light/cm3323.c new file +18 -0

+	{}
+};
+MODULE_DEVICE_TABLE(i2c, cm3323_id);
+
+static struct i2c_driver cm3323_driver = {
+	.driver = {
+		.name = CM3323_DRV_NAME,
+	},
+	.probe		= cm3323_probe,
+	.remove		= cm3323_remove,
+	.id_table	= cm3323_id,
+};
+
+module_i2c_driver(cm3323_driver);
+
+MODULE_AUTHOR("Daniel Baluta <[email protected]>");
+MODULE_DESCRIPTION("Capella CM3323 Color/Ambient Light Sensor driver");
+MODULE_LICENSE("GPL v2");

Minimal implementation providing raw light intensity and illuminance readings. For illuminance user can compute lux values using raw readings and scale.

This driver also supports CM3323E sensor chip.

Cc Kevin Tsai <[email protected]>

Signed-off-by Daniel Baluta <[email protected]>

---
 drivers/iio/light/Kconfig  |  10 ++
 drivers/iio/light/Makefile |   1 +
 drivers/iio/light/cm3323.c | 345 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 356 insertions(+)
 create mode 100644 drivers/iio/light/cm3323.c

drivers/iio/light/Kconfig +10 -0

index 5bea821..aeaf1c7 100644
@@ -48,6 +48,16 @@ config CM32181
 	 To compile this driver as a module, choose M here:
 	 the module will be called cm32181.
 
+config CM3323
+	depends on I2C
+	tristate "Capella CM3323 color/ambient light sensor"
+	help
+	 Say Y here if you want to build a driver for Capela CM3323
+	 color sensor. This driver also supports CM3323E sensor.
+
+	 To compile this driver as a module, choose M here: the module will
+	 be called cm3323.
+
 config CM36651
 	depends on I2C
 	tristate "CM36651 driver"

drivers/iio/light/Makefile +1 -0

index 47877a3..0815b38 100644
@@ -7,6 +7,7 @@ obj-$(CONFIG_ADJD_S311)		+= adjd_s311.o
 obj-$(CONFIG_AL3320A)		+= al3320a.o
 obj-$(CONFIG_APDS9300)		+= apds9300.o
 obj-$(CONFIG_CM32181)		+= cm32181.o
+obj-$(CONFIG_CM3323)		+= cm3323.o
 obj-$(CONFIG_CM36651)		+= cm36651.o
 obj-$(CONFIG_GP2AP020A00F)	+= gp2ap020a00f.o
 obj-$(CONFIG_HID_SENSOR_ALS)	+= hid-sensor-als.o

drivers/iio/light/cm3323.c new file +66 -0

new file mode 100644
index 0000000..5e9b32d
@@ -0,0 +1,345 @@
+/*
+ * CM3323/CM3323E - Capella Color/Ambient Light Sensor
+ *
+ * Copyright (c) 2015, Intel Corporation.
+ *
+ * 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.
+ *
+ * IIO driver for CM3323/CM3323E (7-bit I2C slave address 0x10)
+ *
+ * TODO: calibscale to correct the lens factor
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define CM3323_DRV_NAME "cm3323"
+
+#define CM3323_CMD_CONF		0x00
+#define CM3323_CMD_RED_DATA	0x08
+#define CM3323_CMD_GREEN_DATA	0x09
+#define CM3323_CMD_BLUE_DATA	0x0A
+#define CM3323_CMD_CLEAR_DATA	0x0B
+
+#define CM3323_CONF_SD_BIT	BIT(0) /* sensor disable */
+#define CM3323_CONF_AF_BIT	BIT(1) /* auto/manual force mode */
+#define CM3323_CONF_IT_MASK	(BIT(4) | BIT(5) | BIT(6))
+#define CM3323_CONF_IT_SHIFT	4
+
+#define CM3323_INT_TIME_AVAILABLE "0.04 0.08 0.16 0.32 0.64 1.28"
+#define CM3323_SCALE_AVAILABLE "0.18 0.09 0.045 0.0225 0.01125 0.005625"
+
+static const struct {
+	int val;
+	int val2;
+} cm3323_int_time[] = {
+	{0, 40000},  /* 40 ms */
+	{0, 80000},  /* 80 ms */
+	{0, 160000}, /* 160 ms */
+	{0, 320000}, /* 320 ms */
+	{0, 640000}, /* 640 ms */
+	{1, 280000}, /* 1280 ms */
+};
+
+/* scale depends on integration time */
+static int cm3323_uscale[] = {
+	180000, /* 40 ms */
+	 90000, /* 80 ms */
+	 45000, /* 160 ms */
+	 22500, /* 320 ms */
+	 11250, /* 640 ms */
+	 5625,  /* 1280 ms */
+};
+
+struct cm3323_data {
+	struct i2c_client *client;
+	u16 reg_conf;
+	struct mutex mutex;
+};
+
+#define CM3323_COLOR_CHANNEL(_color, _addr) {\

drivers/iio/light/cm3323.c new file +269 -0

+ */
+#define CM3323_LIGHT_CHANNEL(_addr) {\
+	.type = IIO_LIGHT, \
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+			      BIT(IIO_CHAN_INFO_SCALE), \
+	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME), \
+	.address = _addr, \
+}
+
+static const struct iio_chan_spec cm3323_channels[] = {
+	CM3323_COLOR_CHANNEL(RED, CM3323_CMD_RED_DATA),
+	CM3323_COLOR_CHANNEL(GREEN, CM3323_CMD_GREEN_DATA),
+	CM3323_COLOR_CHANNEL(BLUE, CM3323_CMD_BLUE_DATA),
+	CM3323_COLOR_CHANNEL(CLEAR, CM3323_CMD_CLEAR_DATA),
+	CM3323_LIGHT_CHANNEL(CM3323_CMD_GREEN_DATA),
+};
+
+static IIO_CONST_ATTR(in_illuminance_scale_available, CM3323_SCALE_AVAILABLE);
+static IIO_CONST_ATTR_INT_TIME_AVAIL(CM3323_INT_TIME_AVAILABLE);
+
+static struct attribute *cm3323_attributes[] = {
+	&iio_const_attr_integration_time_available.dev_attr.attr,
+	&iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group cm3323_attribute_group = {
+	.attrs = cm3323_attributes,
+};
+
+static int cm3323_init(struct iio_dev *indio_dev)
+{
+	int ret;
+	struct cm3323_data *data = iio_priv(indio_dev);
+
+	ret = i2c_smbus_read_word_data(data->client, CM3323_CMD_CONF);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "Error reading reg_conf\n");
+		return ret;
+	}
+
+	/* enable sensor and set auto force mode */
+	ret &= ~(CM3323_CONF_SD_BIT | CM3323_CONF_AF_BIT);
+
+	ret = i2c_smbus_write_word_data(data->client, CM3323_CMD_CONF, ret);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "Error writing reg_conf\n");
+		return ret;
+	}
+
+	data->reg_conf = ret;
+
+	return 0;
+}
+
+static int cm3323_set_it_bits(struct cm3323_data *data, int val, int val2)
+{
+	int i, ret;
+	u16 reg_conf;
+
+	for (i = 0; i < ARRAY_SIZE(cm3323_int_time); i++) {
+		if (val == cm3323_int_time[i].val &&
+			val2 == cm3323_int_time[i].val2) {
+			reg_conf = data->reg_conf;
+			reg_conf |= i << CM3323_CONF_IT_SHIFT;
+
+			ret = i2c_smbus_write_word_data(data->client,
+				 CM3323_CMD_CONF, reg_conf);
+			if (ret < 0)
+				return ret;
+
+			data->reg_conf = reg_conf;
+			return 0;
+		}
+	}
+	return -EINVAL;
+}
+
+static int cm3323_set_scale(struct cm3323_data *data, int val, int val2)
+{
+	int i, ret;
+	u16 reg_conf;
+
+	if (val != 0)
+		return 0;
+
+	for (i = 0; i < ARRAY_SIZE(cm3323_uscale); i++) {
+		if (val2 == cm3323_uscale[i]) {
+			reg_conf = data->reg_conf;
+			reg_conf |= i << CM3323_CONF_IT_SHIFT;
+
+			ret = i2c_smbus_write_word_data(data->client,
+				 CM3323_CMD_CONF, reg_conf);
+			if (ret < 0)
+				return ret;
+
+			data->reg_conf = reg_conf;
+			return 0;
+		}
+	}
+	return -EINVAL;
+}
+
+static int cm3323_get_it_bits(struct cm3323_data *data)
+{
+	int bits;
+
+	bits = (data->reg_conf & CM3323_CONF_IT_MASK) >>
+		CM3323_CONF_IT_SHIFT;
+
+	if (bits >= ARRAY_SIZE(cm3323_int_time))
+		return -EINVAL;
+	return bits;
+}
+
+static int cm3323_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, int *val,
+			    int *val2, long mask)
+{
+	int i, ret;
+	struct cm3323_data *data = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		mutex_lock(&data->mutex);
+		ret = i2c_smbus_read_word_data(data->client, chan->address);
+		if (ret < 0) {
+			mutex_unlock(&data->mutex);
+			return ret;
+		}
+		*val = ret;
+		mutex_unlock(&data->mutex);
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_INT_TIME:
+		mutex_lock(&data->mutex);
+		i = cm3323_get_it_bits(data);
+		if (i < 0) {
+			mutex_unlock(&data->mutex);
+			return -EINVAL;
+		}
+
+		*val = cm3323_int_time[i].val;
+		*val2 = cm3323_int_time[i].val2;
+		mutex_unlock(&data->mutex);
+
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_SCALE:
+		if (chan->type != IIO_LIGHT)
+			return -EINVAL;
+
+		mutex_lock(&data->mutex);
+		i = cm3323_get_it_bits(data);
+		if (i < 0) {
+			mutex_unlock(&data->mutex);
+			return -EINVAL;
+		}
+		*val = 0;
+		*val2 = cm3323_uscale[i];
+		mutex_unlock(&data->mutex);
+
+		return IIO_VAL_INT_PLUS_MICRO;
+	}
+	return -EINVAL;
+}
+
+static int cm3323_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, int val,
+			    int val2, long mask)
+{
+	struct cm3323_data *data = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_INT_TIME:
+		mutex_lock(&data->mutex);
+		ret = cm3323_set_it_bits(data, val, val2);
+		mutex_unlock(&data->mutex);
+
+		return ret;
+	case IIO_CHAN_INFO_SCALE:
+		if (chan->type != IIO_LIGHT)
+			return -EINVAL;
+		mutex_lock(&data->mutex);
+		ret = cm3323_set_scale(data, val, val2);
+		mutex_unlock(&data->mutex);
+		return ret;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info cm3323_info = {
+	.driver_module	= THIS_MODULE,
+	.read_raw	= cm3323_read_raw,
+	.write_raw	= cm3323_write_raw,
+	.attrs		= &cm3323_attribute_group,
+};
+
+static int cm3323_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct cm3323_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;
+
+	mutex_init(&data->mutex);
+
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->info = &cm3323_info;
+	indio_dev->name = CM3323_DRV_NAME;
+	indio_dev->channels = cm3323_channels;
+	indio_dev->num_channels = ARRAY_SIZE(cm3323_channels);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = cm3323_init(indio_dev);
+	if (ret < 0) {
+		dev_err(&client->dev, "cm3323 chip init failed\n");
+		return ret;
+	}
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static int cm3323_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct cm3323_data *data  = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	/* disable sensor */
+	ret = i2c_smbus_write_word_data(client, CM3323_CMD_CONF,
+					CM3323_CONF_SD_BIT);
+	if (ret < 0)
+		dev_err(&client->dev, "Error writing reg_conf\n");
+
+	mutex_unlock(&data->mutex);
+	return ret;
+}
+
+static const struct i2c_device_id cm3323_id[] = {
+	{"cm3323", 0},
+	{"cm3323e", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, cm3323_id);
+
+static struct i2c_driver cm3323_driver = {
+	.driver = {
+		.name = CM3323_DRV_NAME,
+	},
+	.probe		= cm3323_probe,
+	.remove		= cm3323_remove,
+	.id_table	= cm3323_id,
+};
+
+module_i2c_driver(cm3323_driver);
+
+MODULE_AUTHOR("Daniel Baluta <[email protected]>");
+MODULE_DESCRIPTION("Capella CM3323 Color/Ambient Light Sensor driver");
+MODULE_LICENSE("GPL v2");

Quoted 8 lines · Daniel Baluta

Minimal implementation providing raw light intensity and illuminance readings. For illuminance user can compute lux values using raw readings and scale.

This driver also supports CM3323E sensor chip.

Cc Kevin Tsai <[email protected]>

Signed-off-by Daniel Baluta <[email protected]>

Hi Daniel,

My only real question on this one is whether using the 'green' channel and pretending it is a measure of illuminance is a good idea or whether we are better leaving that decision to userspace...

I'm guessing the reason it is green rather than clear is that the clear is letting infrared through and we don't have an additional infrared sensor available to allow that component to be removed?

drivers/iio/light/cm3323.c line 76

Quoted 11 lines

drivers/iio/light/cm3323.c new file +11 -0

+#define CM3323_COLOR_CHANNEL(_color, _addr) {\
+     .type = IIO_INTENSITY, \
+     .modified = 1, \
+     .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+     .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME), \
+     .channel2 = IIO_MOD_LIGHT_##_color, \
+     .address = _addr, \
+}
+
+/*
+ * CM3323's GREEN channel is used for reading illuminance

That's impressively random and unlikely to be anywhere near correct pretty much all the time!

I'd personally prefer just not providing an illuminance channel and leaving it up to userspace to make the decision on whether the green channel is good enough...

Quoted 12 lines · Jonathan Cameron

Quoted 8 lines · Daniel Baluta

Minimal implementation providing raw light intensity and illuminance readings. For illuminance user can compute lux values using raw readings and scale.

This driver also supports CM3323E sensor chip.

Cc Kevin Tsai <[email protected]>

Signed-off-by Daniel Baluta <[email protected]>

Hi Daniel,

Quoted 7 lines

My only real question on this one is whether using the 'green' channel and pretending it is a measure of illuminance is a good idea or whether we are better leaving that decision to userspace...

I'm guessing the reason it is green rather than clear is that the clear is letting infrared through and we don't have an additional infrared sensor available to allow that component to be removed?

Hi Jonathan,

<snip>

Quoted 14 lines

drivers/iio/light/cm3323.c line 76

Quoted 11 lines

drivers/iio/light/cm3323.c new file +11 -0

+#define CM3323_COLOR_CHANNEL(_color, _addr) {\
+     .type = IIO_INTENSITY, \
+     .modified = 1, \
+     .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+     .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME), \
+     .channel2 = IIO_MOD_LIGHT_##_color, \
+     .address = _addr, \
+}
+
+/*
+ * CM3323's GREEN channel is used for reading illuminance

That's impressively random and unlikely to be anywhere near correct pretty much all the time!

Quoted 3 lines

I'd personally prefer just not providing an illuminance channel and leaving it up to userspace to make the decision on whether the green channel is good enough...

Datasheet says that the GREEN channel should be used for getting illuminance readings. I'm not sure if this is totally random.

I understand your worries, perhaps Kevin could 'enlighten' us here.

I would prefer to have the illuminance channel exported from IIO because there are already userspace applications/frameworks
written and tested for ALS that use IIO illuminance channel.
We want to use this driver without modifying user space.

Of course, one option for the moment would be to only export the INTENSITY channels as per your recommendation and to decide later what to do for the LIGHT channel.

Quoted 12 lines · Jonathan Cameron

Quoted 8 lines · Daniel Baluta

Minimal implementation providing raw light intensity and illuminance readings. For illuminance user can compute lux values using raw readings and scale.

This driver also supports CM3323E sensor chip.

Cc Kevin Tsai <[email protected]>

Signed-off-by Daniel Baluta <[email protected]>

Hi Daniel,

Quoted 7 lines

My only real question on this one is whether using the 'green' channel and pretending it is a measure of illuminance is a good idea or whether we are better leaving that decision to userspace...

I'm guessing the reason it is green rather than clear is that the clear is letting infrared through and we don't have an additional infrared sensor available to allow that component to be removed?

Hi Jonathan,

<snip>

Quoted 14 lines

drivers/iio/light/cm3323.c line 76

Quoted 11 lines

drivers/iio/light/cm3323.c new file +11 -0

+#define CM3323_COLOR_CHANNEL(_color, _addr) {\
+     .type = IIO_INTENSITY, \
+     .modified = 1, \
+     .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+     .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME), \
+     .channel2 = IIO_MOD_LIGHT_##_color, \
+     .address = _addr, \
+}
+
+/*
+ * CM3323's GREEN channel is used for reading illuminance

That's impressively random and unlikely to be anywhere near correct pretty much all the time!

Quoted 3 lines

I'd personally prefer just not providing an illuminance channel and leaving it up to userspace to make the decision on whether the green channel is good enough...

Datasheet says that the GREEN channel should be used for getting illuminance readings. I'm not sure if this is totally random.

I understand your worries, perhaps Kevin could 'enlighten' us here.

I would prefer to have the illuminance channel exported from IIO because there are already userspace applications/frameworks written and tested for ALS that use IIO illuminance channel.
We want to use this driver without modifying user space.

Of course, one option for the moment would be to only export the INTENSITY channels as per your recommendation and to decide later what to do for the LIGHT channel.

Hi Daniel,

Ambient light sensor is trying to match the brightness sensitivity of human visual system. Please see the following links:
http://en.wikipedia.org/wiki/Color_vision#mediaviewer/File:Eyesensitivity.svg
http://en.wikipedia.org/wiki/Color_vision

You can compare the spectrum with the datasheet. The green channel is matched with ALS spectrum.

Kevin Tsai
03/02/15

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Daniel Baluta
Sent: Monday, March 02, 2015 1:57 AM
To: Daniel Baluta
Cc: Jonathan Cameron; Kevin Tsai; Hartmut Knaack; Lars-Peter Clausen; Peter Meerwald; [email protected]; Linux Kernel Mailing List
Subject: Re: [PATCH] iio: light: Add support for Capella CM3323 color/light sensor

Quoted 47 lines · Daniel Baluta

Quoted 12 lines · Jonathan Cameron

Quoted 8 lines · Daniel Baluta

Minimal implementation providing raw light intensity and illuminance readings. For illuminance user can compute lux values using raw readings and scale.

This driver also supports CM3323E sensor chip.

Cc Kevin Tsai <[email protected]>

Signed-off-by Daniel Baluta <[email protected]>

Hi Daniel,

Quoted 7 lines

My only real question on this one is whether using the 'green' channel and pretending it is a measure of illuminance is a good idea or whether we are better leaving that decision to userspace...

I'm guessing the reason it is green rather than clear is that the clear is letting infrared through and we don't have an additional infrared sensor available to allow that component to be removed?

Hi Jonathan,

<snip>

Quoted 14 lines

drivers/iio/light/cm3323.c line 76

Quoted 11 lines

drivers/iio/light/cm3323.c new file +11 -0

+#define CM3323_COLOR_CHANNEL(_color, _addr) {\
+     .type = IIO_INTENSITY, \
+     .modified = 1, \
+     .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+     .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME), \
+     .channel2 = IIO_MOD_LIGHT_##_color, \
+     .address = _addr, \
+}
+
+/*
+ * CM3323's GREEN channel is used for reading illuminance

That's impressively random and unlikely to be anywhere near correct pretty much all the time!

Quoted 3 lines

I'd personally prefer just not providing an illuminance channel and leaving it up to userspace to make the decision on whether the green channel is good enough...

Datasheet says that the GREEN channel should be used for getting illuminance readings. I'm not sure if this is totally random.

I understand your worries, perhaps Kevin could 'enlighten' us here.

Quoted 8 lines

I would prefer to have the illuminance channel exported from IIO because there are already userspace applications/frameworks written and tested for ALS that use IIO illuminance channel.
We want to use this driver without modifying user space.

Of course, one option for the moment would be to only export the INTENSITY channels as per your recommendation and to decide later what to do for the LIGHT channel.

Hi Kevin,

Could you tell us how reliable is using the GREEN channel for getting illuminance readings?

If no objection, I will resend this driver exposing only INTENSITY channels for the moment.

thanks,
Daniel.

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Quoted 7 lines · Kevin Tsai

Hi Daniel,

Ambient light sensor is trying to match the brightness sensitivity of human visual system. Please see the following links:
http://en.wikipedia.org/wiki/Color_vision#mediaviewer/File:Eyesensitivity.svg
http://en.wikipedia.org/wiki/Color_vision

You can compare the spectrum with the datasheet. The green channel is matched with ALS spectrum.

It's close (ish) to the right measurement, but it isn't the right measurement. As such I'd argue we leave it up to userspace to make the jump and use Green if a true estimate if illuminance isn't available, but don't suggest it is available from the kernel.