iio: light: Add support for Capella CM3323 color sensor

Minimal implementation providing raw light intensity
and integration time attribute.

Userspace applications can use GREEN channel for raw
illuminance readings following this table:

Integration Time | G Sensitivity
================================
40 ms            | 0.18
80 ms            | 0.09
160 ms           | 0.045
320 ms           | 0.0225
640 ms           | 0.01125
1280 ms          | 0.005625

Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

3 files changed, 297 insertions, 0 deletions

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index ae68c64bdad3..cd937d9293ff 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -59,6 +59,16 @@ config CM3232
          To compile this driver as a module, choose M here:
          the module will be called cm3232.
 
+config CM3323
+        depends on I2C
+        tristate "Capella CM3323 color light sensor"
+        help
+         Say Y here if you want to build a driver for Capela CM3323
+         color 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"
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index b12a5160d9e0..ad7c30fe443b 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_AL3320A)		+= al3320a.o
 obj-$(CONFIG_APDS9300)          += apds9300.o
 obj-$(CONFIG_CM32181)           += cm32181.o
 obj-$(CONFIG_CM3232)            += cm3232.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
diff --git a/drivers/iio/light/cm3323.c b/drivers/iio/light/cm3323.c
new file mode 100644
index 000000000000..869033e48a1f
--- /dev/null
+++ b/drivers/iio/light/cm3323.c
@@ -0,0 +1,286 @@
+/*
+ * CM3323 - Capella Color 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 (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"
+
+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 */
+};
+
+struct cm3323_data {
+        struct i2c_client *client;
+        u16 reg_conf;
+        struct mutex mutex;
+};
+
+#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, \
+}
+
+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),
+};
+
+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,
+        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 void cm3323_disable(struct iio_dev *indio_dev)
+{
+        int ret;
+        struct cm3323_data *data = iio_priv(indio_dev);
+
+        ret = i2c_smbus_write_word_data(data->client, CM3323_CMD_CONF,
+                                        CM3323_CONF_SD_BIT);
+        if (ret < 0)
+                dev_err(&data->client->dev, "Error writing reg_conf\n");
+}
+
+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_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;
+        default:
+                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;
+        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;
+        }
+        ret = iio_device_register(indio_dev);
+        if (ret < 0) {
+                dev_err(&client->dev, "failed to register iio dev\n");
+                goto err_init;
+        }
+        return 0;
+err_init:
+        cm3323_disable(indio_dev);
+        return ret;
+}
+
+static int cm3323_remove(struct i2c_client *client)
+{
+        struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+        iio_device_unregister(indio_dev);
+        cm3323_disable(indio_dev);
+
+        return 0;
+}
+
+static const struct i2c_device_id cm3323_id[] = {
+        {"cm3323", 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 <daniel.baluta@intel.com>");
+MODULE_DESCRIPTION("Capella CM3323 Color Light Sensor driver");
+MODULE_LICENSE("GPL v2");