lp8788_adc.c

Go to the documentation of this file.

/*
 * TI LP8788 MFD - ADC driver
 *
 * Copyright 2012 Texas Instruments
 *
 * Author: Milo(Woogyom) Kim <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/delay.h>
#include <linux/iio/iio.h>
#include <linux/iio/driver.h>
#include <linux/iio/machine.h>
#include <linux/mfd/lp8788.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

/* register address */
#define LP8788_ADC_CONF         0x60
#define LP8788_ADC_RAW          0x61
#define LP8788_ADC_DONE         0x63

#define ADC_CONV_START          1

struct lp8788_adc {
    struct lp8788 *lp;
    struct iio_map *map;
    struct mutex lock;
};

static const int lp8788_scale[LPADC_MAX] = {
    [LPADC_VBATT_5P5] = 1343101,
    [LPADC_VIN_CHG]   = 3052503,
    [LPADC_IBATT]     = 610500,
    [LPADC_IC_TEMP]   = 61050,
    [LPADC_VBATT_6P0] = 1465201,
    [LPADC_VBATT_5P0] = 1221001,
    [LPADC_ADC1]      = 610500,
    [LPADC_ADC2]      = 610500,
    [LPADC_VDD]       = 1025641,
    [LPADC_VCOIN]     = 757020,
    [LPADC_ADC3]      = 610500,
    [LPADC_ADC4]      = 610500,
};

static int lp8788_get_adc_result(struct lp8788_adc *adc, enum lp8788_adc_id id,
                int *val)
{
    unsigned int msb;
    unsigned int lsb;
    unsigned int result;
    u8 data;
    u8 rawdata[2];
    int size = ARRAY_SIZE(rawdata);
    int retry = 5;
    int ret;

    data = (id << 1) | ADC_CONV_START;
    ret = lp8788_write_byte(adc->lp, LP8788_ADC_CONF, data);
    if (ret)
        goto err_io;

    /* retry until adc conversion is done */
    data = 0;
    while (retry--) {
        usleep_range(100, 200);

        ret = lp8788_read_byte(adc->lp, LP8788_ADC_DONE, &data);
        if (ret)
            goto err_io;

        /* conversion done */
        if (data)
            break;
    }

    ret = lp8788_read_multi_bytes(adc->lp, LP8788_ADC_RAW, rawdata, size);
    if (ret)
        goto err_io;

    msb = (rawdata[0] << 4) & 0x00000ff0;
    lsb = (rawdata[1] >> 4) & 0x0000000f;
    result = msb | lsb;
    *val = result;

    return 0;

err_io:
    return ret;
}

static int lp8788_adc_read_raw(struct iio_dev *indio_dev,
            struct iio_chan_spec const *chan,
            int *val, int *val2, long mask)
{
    struct lp8788_adc *adc = iio_priv(indio_dev);
    enum lp8788_adc_id id = chan->channel;
    int ret;

    mutex_lock(&adc->lock);

    switch (mask) {
    case IIO_CHAN_INFO_RAW:
        ret = lp8788_get_adc_result(adc, id, val) ? -EIO : IIO_VAL_INT;
        break;
    case IIO_CHAN_INFO_SCALE:
        *val = lp8788_scale[id] / 1000000;
        *val2 = lp8788_scale[id] % 1000000;
        ret = IIO_VAL_INT_PLUS_MICRO;
        break;
    default:
        ret = -EINVAL;
        break;
    }

    mutex_unlock(&adc->lock);

    return ret;
}

static const struct iio_info lp8788_adc_info = {
    .read_raw = &lp8788_adc_read_raw,
    .driver_module = THIS_MODULE,
};

#define LP8788_CHAN(_id, _type) {               \
        .type = _type,                  \
        .indexed = 1,                   \
        .channel = LPADC_##_id,             \
        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |   \
            IIO_CHAN_INFO_SCALE_SEPARATE_BIT,   \
        .datasheet_name = #_id,             \
}

static const struct iio_chan_spec lp8788_adc_channels[] = {
    [LPADC_VBATT_5P5] = LP8788_CHAN(VBATT_5P5, IIO_VOLTAGE),
    [LPADC_VIN_CHG]   = LP8788_CHAN(VIN_CHG, IIO_VOLTAGE),
    [LPADC_IBATT]     = LP8788_CHAN(IBATT, IIO_CURRENT),
    [LPADC_IC_TEMP]   = LP8788_CHAN(IC_TEMP, IIO_TEMP),
    [LPADC_VBATT_6P0] = LP8788_CHAN(VBATT_6P0, IIO_VOLTAGE),
    [LPADC_VBATT_5P0] = LP8788_CHAN(VBATT_5P0, IIO_VOLTAGE),
    [LPADC_ADC1]      = LP8788_CHAN(ADC1, IIO_VOLTAGE),
    [LPADC_ADC2]      = LP8788_CHAN(ADC2, IIO_VOLTAGE),
    [LPADC_VDD]       = LP8788_CHAN(VDD, IIO_VOLTAGE),
    [LPADC_VCOIN]     = LP8788_CHAN(VCOIN, IIO_VOLTAGE),
    [LPADC_ADC3]      = LP8788_CHAN(ADC3, IIO_VOLTAGE),
    [LPADC_ADC4]      = LP8788_CHAN(ADC4, IIO_VOLTAGE),
};

/* default maps used by iio consumer (lp8788-charger driver) */
static struct iio_map lp8788_default_iio_maps[] = {
    {
        .consumer_dev_name = "lp8788-charger",
        .consumer_channel = "lp8788_vbatt_5p0",
        .adc_channel_label = "VBATT_5P0",
    },
    {
        .consumer_dev_name = "lp8788-charger",
        .consumer_channel = "lp8788_adc1",
        .adc_channel_label = "ADC1",
    },
    { }
};

static int lp8788_iio_map_register(struct iio_dev *indio_dev,
                struct lp8788_platform_data *pdata,
                struct lp8788_adc *adc)
{
    struct iio_map *map;
    int ret;

    map = (!pdata || !pdata->adc_pdata) ?
        lp8788_default_iio_maps : pdata->adc_pdata;

    ret = iio_map_array_register(indio_dev, map);
    if (ret) {
        dev_err(adc->lp->dev, "iio map err: %d\n", ret);
        return ret;
    }

    adc->map = map;
    return 0;
}

static inline void lp8788_iio_map_unregister(struct iio_dev *indio_dev,
                struct lp8788_adc *adc)
{
    iio_map_array_unregister(indio_dev, adc->map);
}

static int __devinit lp8788_adc_probe(struct platform_device *pdev)
{
    struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
    struct iio_dev *indio_dev;
    struct lp8788_adc *adc;
    int ret;

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

    adc = iio_priv(indio_dev);
    adc->lp = lp;
    platform_set_drvdata(pdev, indio_dev);

    ret = lp8788_iio_map_register(indio_dev, lp->pdata, adc);
    if (ret)
        goto err_iio_map;

    mutex_init(&adc->lock);

    indio_dev->dev.parent = lp->dev;
    indio_dev->name = pdev->name;
    indio_dev->modes = INDIO_DIRECT_MODE;
    indio_dev->info = &lp8788_adc_info;
    indio_dev->channels = lp8788_adc_channels;
    indio_dev->num_channels = ARRAY_SIZE(lp8788_adc_channels);

    ret = iio_device_register(indio_dev);
    if (ret) {
        dev_err(lp->dev, "iio dev register err: %d\n", ret);
        goto err_iio_device;
    }

    return 0;

err_iio_device:
    lp8788_iio_map_unregister(indio_dev, adc);
err_iio_map:
    iio_device_free(indio_dev);
    return ret;
}

static int __devexit lp8788_adc_remove(struct platform_device *pdev)
{
    struct iio_dev *indio_dev = platform_get_drvdata(pdev);
    struct lp8788_adc *adc = iio_priv(indio_dev);

    iio_device_unregister(indio_dev);
    lp8788_iio_map_unregister(indio_dev, adc);
    iio_device_free(indio_dev);

    return 0;
}

static struct platform_driver lp8788_adc_driver = {
    .probe = lp8788_adc_probe,
    .remove = __devexit_p(lp8788_adc_remove),
    .driver = {
        .name = LP8788_DEV_ADC,
        .owner = THIS_MODULE,
    },
};
module_platform_driver(lp8788_adc_driver);

MODULE_DESCRIPTION("Texas Instruments LP8788 ADC Driver");
MODULE_AUTHOR("Milo Kim");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:lp8788-adc");