iio: Add tsl4531 ambient light sensor driver

driver for the TSL4531 family of 16-bit I2C ambient light
sensors; information is here:
http://www.ams.com/eng/Products/Light-Sensors/Ambient-Light-Sensor-ALS/TSL45315

the chip offers simple lux output

v3 (thanks Lars-Peter Clausen):
* add mutex to when updating integration time
* fix chip ID checking
* code cleanups
v2:
* rename to tsl4351
* use INT_TIME

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

3 files changed, 269 insertions, 0 deletions

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index bf9fa0d7aff9..488fff7cd80d 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -65,6 +65,16 @@ config SENSORS_TSL2563
          This driver can also be built as a module.  If so, the module
          will be called tsl2563.
 
+config TSL4531
+        tristate "TAOS TSL4531 ambient light sensors"
+        depends on I2C
+        help
+         Say Y here if you want to build a driver for the TAOS TSL4531 family
+         of ambient light sensors with direct lux output.
+
+         To compile this driver as a module, choose M here: the
+         module will be called tsl4531.
+
 config VCNL4000
         tristate "VCNL4000 combined ALS and proximity sensor"
         depends on I2C
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index 354ee9ab2379..cd6f3cfe6259 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -8,4 +8,5 @@ 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
+obj-$(CONFIG_TSL4531)           += tsl4531.o
 obj-$(CONFIG_VCNL4000)          += vcnl4000.o
diff --git a/drivers/iio/light/tsl4531.c b/drivers/iio/light/tsl4531.c
new file mode 100644
index 000000000000..a15006efa137
--- /dev/null
+++ b/drivers/iio/light/tsl4531.c
@@ -0,0 +1,258 @@
+/*
+ * tsl4531.c - Support for TAOS TSL4531 ambient light sensor
+ *
+ * Copyright 2013 Peter Meerwald <pmeerw@pmeerw.net>
+ *
+ * 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 the TSL4531x family
+ *   TSL45311/TSL45313: 7-bit I2C slave address 0x39
+ *   TSL45315/TSL45317: 7-bit I2C slave address 0x29
+ *
+ * TODO: single cycle measurement
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define TSL4531_DRV_NAME "tsl4531"
+
+#define TCS3472_COMMAND BIT(7)
+
+#define TSL4531_CONTROL (TCS3472_COMMAND | 0x00)
+#define TSL4531_CONFIG (TCS3472_COMMAND | 0x01)
+#define TSL4531_DATA (TCS3472_COMMAND | 0x04)
+#define TSL4531_ID (TCS3472_COMMAND | 0x0a)
+
+/* operating modes in control register */
+#define TSL4531_MODE_POWERDOWN 0x00
+#define TSL4531_MODE_SINGLE_ADC 0x02
+#define TSL4531_MODE_NORMAL 0x03
+
+/* integration time control in config register */
+#define TSL4531_TCNTRL_400MS 0x00
+#define TSL4531_TCNTRL_200MS 0x01
+#define TSL4531_TCNTRL_100MS 0x02
+
+/* part number in id register */
+#define TSL45311_ID 0x8
+#define TSL45313_ID 0x9
+#define TSL45315_ID 0xa
+#define TSL45317_ID 0xb
+#define TSL4531_ID_SHIFT 4
+
+struct tsl4531_data {
+        struct i2c_client *client;
+        struct mutex lock;
+        int int_time;
+};
+
+static IIO_CONST_ATTR_INT_TIME_AVAIL("0.1 0.2 0.4");
+
+static struct attribute *tsl4531_attributes[] = {
+        &iio_const_attr_integration_time_available.dev_attr.attr,
+        NULL
+};
+
+static const struct attribute_group tsl4531_attribute_group = {
+        .attrs = tsl4531_attributes,
+};
+
+static const struct iio_chan_spec tsl4531_channels[] = {
+        {
+                .type = IIO_LIGHT,
+                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+                        BIT(IIO_CHAN_INFO_SCALE) |
+                        BIT(IIO_CHAN_INFO_INT_TIME)
+        }
+};
+
+static int tsl4531_read_raw(struct iio_dev *indio_dev,
+                                struct iio_chan_spec const *chan,
+                                int *val, int *val2, long mask)
+{
+        struct tsl4531_data *data = iio_priv(indio_dev);
+        int ret;
+
+        switch (mask) {
+        case IIO_CHAN_INFO_RAW:
+                ret = i2c_smbus_read_word_data(data->client,
+                        TSL4531_DATA);
+                if (ret < 0)
+                        return ret;
+                *val = ret;
+                return IIO_VAL_INT;
+        case IIO_CHAN_INFO_SCALE:
+                /* 0.. 1x, 1 .. 2x, 2 .. 4x */
+                *val = 1 << data->int_time;
+                return IIO_VAL_INT;
+        case IIO_CHAN_INFO_INT_TIME:
+                if (data->int_time == 0)
+                        *val2 = 400000;
+                else if (data->int_time == 1)
+                        *val2 = 200000;
+                else if (data->int_time == 2)
+                        *val2 = 100000;
+                else
+                        return -EINVAL;
+                *val = 0;
+                return IIO_VAL_INT_PLUS_MICRO;
+        default:
+                return -EINVAL;
+        }
+}
+
+static int tsl4531_write_raw(struct iio_dev *indio_dev,
+                             struct iio_chan_spec const *chan,
+                             int val, int val2, long mask)
+{
+        struct tsl4531_data *data = iio_priv(indio_dev);
+        int int_time, ret;
+
+        switch (mask) {
+        case IIO_CHAN_INFO_INT_TIME:
+                if (val != 0)
+                        return -EINVAL;
+                if (val2 == 400000)
+                        int_time = 0;
+                else if (val2 == 200000)
+                        int_time = 1;
+                else if (val2 == 100000)
+                        int_time = 2;
+                else
+                        return -EINVAL;
+                mutex_lock(&data->lock);
+                ret = i2c_smbus_write_byte_data(data->client,
+                        TSL4531_CONFIG, int_time);
+                if (ret >= 0)
+                        data->int_time = int_time;
+                mutex_unlock(&data->lock);
+                return ret;
+        default:
+                return -EINVAL;
+        }
+}
+
+static const struct iio_info tsl4531_info = {
+        .read_raw = tsl4531_read_raw,
+        .write_raw = tsl4531_write_raw,
+        .attrs = &tsl4531_attribute_group,
+        .driver_module = THIS_MODULE,
+};
+
+static int tsl4531_check_id(struct i2c_client *client)
+{
+        int ret = i2c_smbus_read_byte_data(client, TSL4531_ID);
+        if (ret < 0)
+                return ret;
+
+        switch (ret >> TSL4531_ID_SHIFT) {
+        case TSL45311_ID:
+        case TSL45313_ID:
+        case TSL45315_ID:
+        case TSL45317_ID:
+                return 1;
+        default:
+                return 0;
+        }
+}
+
+static int tsl4531_probe(struct i2c_client *client,
+                          const struct i2c_device_id *id)
+{
+        struct tsl4531_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->lock);
+
+        if (!tsl4531_check_id(client)) {
+                dev_err(&client->dev, "no TSL4531 sensor\n");
+                return -ENODEV;
+        }
+
+        ret = i2c_smbus_write_byte_data(data->client, TSL4531_CONTROL,
+                TSL4531_MODE_NORMAL);
+        if (ret < 0)
+                return ret;
+
+        ret = i2c_smbus_write_byte_data(data->client, TSL4531_CONFIG,
+                TSL4531_TCNTRL_400MS);
+        if (ret < 0)
+                return ret;
+
+        indio_dev->dev.parent = &client->dev;
+        indio_dev->info = &tsl4531_info;
+        indio_dev->channels = tsl4531_channels;
+        indio_dev->num_channels = ARRAY_SIZE(tsl4531_channels);
+        indio_dev->name = TSL4531_DRV_NAME;
+        indio_dev->modes = INDIO_DIRECT_MODE;
+
+        return iio_device_register(indio_dev);
+}
+
+static int tsl4531_powerdown(struct i2c_client *client)
+{
+        return i2c_smbus_write_byte_data(client, TSL4531_CONTROL,
+                TSL4531_MODE_POWERDOWN);
+}
+
+static int tsl4531_remove(struct i2c_client *client)
+{
+        iio_device_unregister(i2c_get_clientdata(client));
+        tsl4531_powerdown(client);
+
+        return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int tsl4531_suspend(struct device *dev)
+{
+        return tsl4531_powerdown(to_i2c_client(dev));
+}
+
+static int tsl4531_resume(struct device *dev)
+{
+        return i2c_smbus_write_byte_data(to_i2c_client(dev), TSL4531_CONTROL,
+                TSL4531_MODE_NORMAL);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(tsl4531_pm_ops, tsl4531_suspend, tsl4531_resume);
+
+static const struct i2c_device_id tsl4531_id[] = {
+        { "tsl4531", 0 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, tsl4531_id);
+
+static struct i2c_driver tsl4531_driver = {
+        .driver = {
+                .name   = TSL4531_DRV_NAME,
+                .pm     = &tsl4531_pm_ops,
+                .owner  = THIS_MODULE,
+        },
+        .probe  = tsl4531_probe,
+        .remove = tsl4531_remove,
+        .id_table = tsl4531_id,
+};
+
+module_i2c_driver(tsl4531_driver);
+
+MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
+MODULE_DESCRIPTION("TAOS TSL4531 ambient light sensors driver");
+MODULE_LICENSE("GPL");