linux-imx

/*

 * 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 */