iio: Add Vishay VEML6070 UV A light sensor driver

ultraviolet (UV) light sensor with I2C interface with a peak
sensitivity at 355 nm

strangely, chip uses two addresses 0x38 and 0x39 for LSB and
MSB data, resp.

datasheet: http://www.vishay.com/docs/84277/veml6070.pdf

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

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index 5ee1d45..cbd7232 100644 (file)
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -331,4 +331,14 @@ config VCNL4000
         To compile this driver as a module, choose M here: the
         module will be called vcnl4000.
 
+config VEML6070
+       tristate "VEML6070 UV A light sensor"
+       depends on I2C
+       help
+        Say Y here if you want to build a driver for the Vishay VEML6070 UV A
+        light sensor.
+
+        To compile this driver as a module, choose M here: the
+        module will be called veml6070.
+
 endmenu

diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index 4aeee2b..8b246a6 100644 (file)
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -31,3 +31,4 @@ obj-$(CONFIG_TCS3472)         += tcs3472.o
 obj-$(CONFIG_TSL4531)          += tsl4531.o
 obj-$(CONFIG_US5182D)          += us5182d.o
 obj-$(CONFIG_VCNL4000)         += vcnl4000.o
+obj-$(CONFIG_VEML6070)         += veml6070.o

diff --git a/drivers/iio/light/veml6070.c b/drivers/iio/light/veml6070.c
new file mode 100644 (file)
index 0000000..bc1c4cb
--- /dev/null
+++ b/drivers/iio/light/veml6070.c
@@ -0,0 +1,218 @@
+/*
+ * veml6070.c - Support for Vishay VEML6070 UV A light sensor
+ *
+ * Copyright 2016 Peter Meerwald-Stadler <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 VEML6070 (7-bit I2C slave addresses 0x38 and 0x39)
+ *
+ * TODO: integration time, ACK signal
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define VEML6070_DRV_NAME "veml6070"
+
+#define VEML6070_ADDR_CONFIG_DATA_MSB 0x38 /* read: MSB data, write: config */
+#define VEML6070_ADDR_DATA_LSB 0x39 /* LSB data */
+
+#define VEML6070_COMMAND_ACK   BIT(5) /* raise interrupt when over threshold */
+#define VEML6070_COMMAND_IT    GENMASK(3, 2) /* bit mask integration time */
+#define VEML6070_COMMAND_RSRVD BIT(1) /* reserved, set to 1 */
+#define VEML6070_COMMAND_SD    BIT(0) /* shutdown mode when set */
+
+#define VEML6070_IT_10 0x04 /* integration time 1x */
+
+struct veml6070_data {
+       struct i2c_client *client1;
+       struct i2c_client *client2;
+       u8 config;
+       struct mutex lock;
+};
+
+static int veml6070_read(struct veml6070_data *data)
+{
+       int ret;
+       u8 msb, lsb;
+
+       mutex_lock(&data->lock);
+
+       /* disable shutdown */
+       ret = i2c_smbus_write_byte(data->client1,
+           data->config & ~VEML6070_COMMAND_SD);
+       if (ret < 0)
+               goto out;
+
+       msleep(125 + 10); /* measurement takes up to 125 ms for IT 1x */
+
+       ret = i2c_smbus_read_byte(data->client2); /* read MSB, address 0x39 */
+       if (ret < 0)
+               goto out;
+       msb = ret;
+
+       ret = i2c_smbus_read_byte(data->client1); /* read LSB, address 0x38 */
+       if (ret < 0)
+               goto out;
+       lsb = ret;
+
+       /* shutdown again */
+       ret = i2c_smbus_write_byte(data->client1, data->config);
+       if (ret < 0)
+               goto out;
+
+       ret = (msb << 8) | lsb;
+
+out:
+       mutex_unlock(&data->lock);
+       return ret;
+}
+
+static const struct iio_chan_spec veml6070_channels[] = {
+       {
+               .type = IIO_INTENSITY,
+               .modified = 1,
+               .channel2 = IIO_MOD_LIGHT_UV,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+       },
+       {
+               .type = IIO_UVINDEX,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+       }
+};
+
+static int veml6070_to_uv_index(unsigned val)
+{
+       /*
+        * conversion of raw UV intensity values to UV index depends on
+        * integration time (IT) and value of the resistor connected to
+        * the RSET pin (default: 270 KOhm)
+        */
+       unsigned uvi[11] = {
+               187, 373, 560, /* low */
+               746, 933, 1120, /* moderate */
+               1308, 1494, /* high */
+               1681, 1868, 2054}; /* very high */
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(uvi); i++)
+               if (val <= uvi[i])
+                       return i;
+
+       return 11; /* extreme */
+}
+
+static int veml6070_read_raw(struct iio_dev *indio_dev,
+                               struct iio_chan_spec const *chan,
+                               int *val, int *val2, long mask)
+{
+       struct veml6070_data *data = iio_priv(indio_dev);
+       int ret;
+
+       switch (mask) {
+       case IIO_CHAN_INFO_RAW:
+       case IIO_CHAN_INFO_PROCESSED:
+               ret = veml6070_read(data);
+               if (ret < 0)
+                       return ret;
+               if (mask == IIO_CHAN_INFO_PROCESSED)
+                       *val = veml6070_to_uv_index(ret);
+               else
+                       *val = ret;
+               return IIO_VAL_INT;
+       default:
+               return -EINVAL;
+       }
+}
+
+static const struct iio_info veml6070_info = {
+       .read_raw = veml6070_read_raw,
+       .driver_module = THIS_MODULE,
+};
+
+static int veml6070_probe(struct i2c_client *client,
+                         const struct i2c_device_id *id)
+{
+       struct veml6070_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->client1 = client;
+       mutex_init(&data->lock);
+
+       indio_dev->dev.parent = &client->dev;
+       indio_dev->info = &veml6070_info;
+       indio_dev->channels = veml6070_channels;
+       indio_dev->num_channels = ARRAY_SIZE(veml6070_channels);
+       indio_dev->name = VEML6070_DRV_NAME;
+       indio_dev->modes = INDIO_DIRECT_MODE;
+
+       data->client2 = i2c_new_dummy(client->adapter, VEML6070_ADDR_DATA_LSB);
+       if (!data->client2) {
+               dev_err(&client->dev, "i2c device for second chip address failed\n");
+               return -ENODEV;
+       }
+
+       data->config = VEML6070_IT_10 | VEML6070_COMMAND_RSRVD |
+               VEML6070_COMMAND_SD;
+       ret = i2c_smbus_write_byte(data->client1, data->config);
+       if (ret < 0)
+               goto fail;
+
+       ret = iio_device_register(indio_dev);
+       if (ret < 0)
+               goto fail;
+
+       return ret;
+
+fail:
+       i2c_unregister_device(data->client2);
+       return ret;
+}
+
+static int veml6070_remove(struct i2c_client *client)
+{
+       struct iio_dev *indio_dev = i2c_get_clientdata(client);
+       struct veml6070_data *data = iio_priv(indio_dev);
+
+       iio_device_unregister(indio_dev);
+       i2c_unregister_device(data->client2);
+
+       return 0;
+}
+
+static const struct i2c_device_id veml6070_id[] = {
+       { "veml6070", 0 },
+       { }
+};
+MODULE_DEVICE_TABLE(i2c, veml6070_id);
+
+static struct i2c_driver veml6070_driver = {
+       .driver = {
+               .name   = VEML6070_DRV_NAME,
+       },
+       .probe  = veml6070_probe,
+       .remove  = veml6070_remove,
+       .id_table = veml6070_id,
+};
+
+module_i2c_driver(veml6070_driver);
+
+MODULE_AUTHOR("Peter Meerwald-Stadler <pmeerw@pmeerw.net>");
+MODULE_DESCRIPTION("Vishay VEML6070 UV A light sensor driver");
+MODULE_LICENSE("GPL");