diff options
Diffstat (limited to 'drivers/iio/light/veml6070.c')
| -rw-r--r-- | drivers/iio/light/veml6070.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/drivers/iio/light/veml6070.c b/drivers/iio/light/veml6070.c new file mode 100644 index 000000000..f4bf3c5b5 --- /dev/null +++ b/drivers/iio/light/veml6070.c @@ -0,0 +1,217 @@ +/* + * 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, +}; + +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"); |