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/*
* 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");
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