/*
 * vcnl4000.c - Support for Vishay VCNL4000 combined ambient light and
 * proximity sensor
 *
 * Copyright 2012 Peter Meerwald <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 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;
        __be16 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_separate = BIT(IIO_CHAN_INFO_RAW) |
                        BIT(IIO_CHAN_INFO_SCALE),
        }, {
                .type = IIO_PROXIMITY,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
        }
};

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 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 = 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->client = client;

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

        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;

        return devm_iio_device_register(&client->dev, indio_dev);
}

static struct i2c_driver vcnl4000_driver = {
        .driver = {
                .name   = VCNL4000_DRV_NAME,
        },
        .probe  = vcnl4000_probe,
        .id_table = vcnl4000_id,
};

module_i2c_driver(vcnl4000_driver);

MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_DESCRIPTION("Vishay VCNL4000 proximity/ambient light sensor driver");
MODULE_LICENSE("GPL");