vcnl4000.c

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/*
 * vcnl4000.c - Support for Vishay VCNL4000 combined ambient light and
 * proximity sensor
 *
 * Copyright 2012 Peter Meerwald <[email protected]>
 *
 * 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 VCNL4000 (7-bit I2C slave address 0x13)
 *
 * TODO:
 *   allow to adjust IR current
 *   proximity threshold and event handling
 */

#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 VCNL4000_DRV_NAME "vcnl4000"

#define VCNL4000_COMMAND    0x80 /* Command register */
#define VCNL4000_PROD_REV   0x81 /* Product ID and Revision ID */
#define VCNL4000_LED_CURRENT    0x83 /* IR LED current for proximity mode */
#define VCNL4000_AL_PARAM   0x84 /* Ambient light parameter register */
#define VCNL4000_AL_RESULT_HI   0x85 /* Ambient light result register, MSB */
#define VCNL4000_AL_RESULT_LO   0x86 /* Ambient light result register, LSB */
#define VCNL4000_PS_RESULT_HI   0x87 /* Proximity result register, MSB */
#define VCNL4000_PS_RESULT_LO   0x88 /* Proximity result register, LSB */
#define VCNL4000_PS_MEAS_FREQ   0x89 /* Proximity test signal frequency */
#define VCNL4000_PS_MOD_ADJ 0x8a /* Proximity modulator timing adjustment */

/* Bit masks for COMMAND register */
#define VCNL4000_AL_RDY     0x40 /* ALS data ready? */
#define VCNL4000_PS_RDY     0x20 /* proximity data ready? */
#define VCNL4000_AL_OD      0x10 /* start on-demand ALS measurement */
#define VCNL4000_PS_OD      0x08 /* start on-demand proximity measurement */

struct vcnl4000_data {
    struct i2c_client *client;
};

static const struct i2c_device_id vcnl4000_id[] = {
    { "vcnl4000", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, vcnl4000_id);

static int vcnl4000_measure(struct vcnl4000_data *data, u8 req_mask,
                u8 rdy_mask, u8 data_reg, int *val)
{
    int tries = 20;
    u16 buf;
    int ret;

    ret = i2c_smbus_write_byte_data(data->client, VCNL4000_COMMAND,
                    req_mask);
    if (ret < 0)
        return ret;

    /* wait for data to become ready */
    while (tries--) {
        ret = i2c_smbus_read_byte_data(data->client, VCNL4000_COMMAND);
        if (ret < 0)
            return ret;
        if (ret & rdy_mask)
            break;
        msleep(20); /* measurement takes up to 100 ms */
    }

    if (tries < 0) {
        dev_err(&data->client->dev,
            "vcnl4000_measure() failed, data not ready\n");
        return -EIO;
    }

    ret = i2c_smbus_read_i2c_block_data(data->client,
        data_reg, sizeof(buf), (u8 *) &buf);
    if (ret < 0)
        return ret;

    *val = be16_to_cpu(buf);

    return 0;
}

static const struct iio_chan_spec vcnl4000_channels[] = {
    {
        .type = IIO_LIGHT,
        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
            IIO_CHAN_INFO_SCALE_SEPARATE_BIT,
    }, {
        .type = IIO_PROXIMITY,
        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT,
    }
};

static int vcnl4000_read_raw(struct iio_dev *indio_dev,
                struct iio_chan_spec const *chan,
                int *val, int *val2, long mask)
{
    int ret = -EINVAL;
    struct vcnl4000_data *data = iio_priv(indio_dev);

    switch (mask) {
    case IIO_CHAN_INFO_RAW:
        switch (chan->type) {
        case IIO_LIGHT:
            ret = vcnl4000_measure(data,
                VCNL4000_AL_OD, VCNL4000_AL_RDY,
                VCNL4000_AL_RESULT_HI, val);
            if (ret < 0)
                return ret;
            ret = IIO_VAL_INT;
            break;
        case IIO_PROXIMITY:
            ret = vcnl4000_measure(data,
                VCNL4000_PS_OD, VCNL4000_PS_RDY,
                VCNL4000_PS_RESULT_HI, val);
            if (ret < 0)
                return ret;
            ret = IIO_VAL_INT;
            break;
        default:
            break;
        }
        break;
    case IIO_CHAN_INFO_SCALE:
        if (chan->type == IIO_LIGHT) {
            *val = 0;
            *val2 = 250000;
            ret = IIO_VAL_INT_PLUS_MICRO;
        }
        break;
    default:
        break;
    }

    return ret;
}

static const struct iio_info vcnl4000_info = {
    .read_raw = vcnl4000_read_raw,
    .driver_module = THIS_MODULE,
};

static int __devinit vcnl4000_probe(struct i2c_client *client,
                    const struct i2c_device_id *id)
{
    struct vcnl4000_data *data;
    struct iio_dev *indio_dev;
    int ret;

    indio_dev = iio_device_alloc(sizeof(*data));
    if (!indio_dev)
        return -ENOMEM;

    data = iio_priv(indio_dev);
    i2c_set_clientdata(client, indio_dev);
    data->client = client;

    ret = i2c_smbus_read_byte_data(data->client, VCNL4000_PROD_REV);
    if (ret < 0)
        goto error_free_dev;

    dev_info(&client->dev, "VCNL4000 Ambient light/proximity sensor, Prod %02x, Rev: %02x\n",
        ret >> 4, ret & 0xf);

    indio_dev->dev.parent = &client->dev;
    indio_dev->info = &vcnl4000_info;
    indio_dev->channels = vcnl4000_channels;
    indio_dev->num_channels = ARRAY_SIZE(vcnl4000_channels);
    indio_dev->name = VCNL4000_DRV_NAME;
    indio_dev->modes = INDIO_DIRECT_MODE;

    ret = iio_device_register(indio_dev);
    if (ret < 0)
        goto error_free_dev;

    return 0;

error_free_dev:
    iio_device_free(indio_dev);
    return ret;
}

static int __devexit vcnl4000_remove(struct i2c_client *client)
{
    struct iio_dev *indio_dev = i2c_get_clientdata(client);

    iio_device_unregister(indio_dev);
    iio_device_free(indio_dev);

    return 0;
}

static struct i2c_driver vcnl4000_driver = {
    .driver = {
        .name   = VCNL4000_DRV_NAME,
        .owner  = THIS_MODULE,
    },
    .probe  = vcnl4000_probe,
    .remove = __devexit_p(vcnl4000_remove),
    .id_table = vcnl4000_id,
};

module_i2c_driver(vcnl4000_driver);

MODULE_AUTHOR("Peter Meerwald <[email protected]>");
MODULE_DESCRIPTION("Vishay VCNL4000 proximity/ambient light sensor driver");
MODULE_LICENSE("GPL");