mc13783-adc.c

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/*
 * Driver for the ADC on Freescale Semiconductor MC13783 and MC13892 PMICs.
 *
 * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
 * Copyright (C) 2009 Sascha Hauer, Pengutronix
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <linux/mfd/mc13xxx.h>
#include <linux/platform_device.h>
#include <linux/hwmon-sysfs.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/hwmon.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/err.h>

#define DRIVER_NAME "mc13783-adc"

/* platform device id driver data */
#define MC13783_ADC_16CHANS 1
#define MC13783_ADC_BPDIV2  2

struct mc13783_adc_priv {
    struct mc13xxx *mc13xxx;
    struct device *hwmon_dev;
    char name[10];
};

static ssize_t mc13783_adc_show_name(struct device *dev, struct device_attribute
                  *devattr, char *buf)
{
    struct mc13783_adc_priv *priv = dev_get_drvdata(dev);

    return sprintf(buf, "%s\n", priv->name);
}

static int mc13783_adc_read(struct device *dev,
        struct device_attribute *devattr, unsigned int *val)
{
    struct mc13783_adc_priv *priv = dev_get_drvdata(dev);
    struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
    unsigned int channel = attr->index;
    unsigned int sample[4];
    int ret;

    ret = mc13xxx_adc_do_conversion(priv->mc13xxx,
            MC13XXX_ADC_MODE_MULT_CHAN,
            channel, 0, 0, sample);
    if (ret)
        return ret;

    channel &= 0x7;

    *val = (sample[channel % 4] >> (channel > 3 ? 14 : 2)) & 0x3ff;

    return 0;
}

static ssize_t mc13783_adc_read_bp(struct device *dev,
        struct device_attribute *devattr, char *buf)
{
    unsigned val;
    struct platform_device *pdev = to_platform_device(dev);
    kernel_ulong_t driver_data = platform_get_device_id(pdev)->driver_data;
    int ret = mc13783_adc_read(dev, devattr, &val);

    if (ret)
        return ret;

    if (driver_data & MC13783_ADC_BPDIV2)
        val = DIV_ROUND_CLOSEST(val * 9, 2);
    else
        /*
         * BP (channel 2) reports with offset 2.4V to the actual value
         * to fit the input range of the ADC.  unit = 2.25mV = 9/4 mV.
         */
        val = DIV_ROUND_CLOSEST(val * 9, 4) + 2400;

    return sprintf(buf, "%u\n", val);
}

static ssize_t mc13783_adc_read_gp(struct device *dev,
        struct device_attribute *devattr, char *buf)
{
    unsigned val;
    int ret = mc13783_adc_read(dev, devattr, &val);

    if (ret)
        return ret;

    /*
     * input range is [0, 2.3V], val has 10 bits, so each bit
     * is worth 9/4 mV.
     */
    val = DIV_ROUND_CLOSEST(val * 9, 4);

    return sprintf(buf, "%u\n", val);
}

static DEVICE_ATTR(name, S_IRUGO, mc13783_adc_show_name, NULL);
static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, mc13783_adc_read_bp, NULL, 2);
static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, mc13783_adc_read_gp, NULL, 5);
static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, mc13783_adc_read_gp, NULL, 6);
static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, mc13783_adc_read_gp, NULL, 7);
static SENSOR_DEVICE_ATTR(in8_input, S_IRUGO, mc13783_adc_read_gp, NULL, 8);
static SENSOR_DEVICE_ATTR(in9_input, S_IRUGO, mc13783_adc_read_gp, NULL, 9);
static SENSOR_DEVICE_ATTR(in10_input, S_IRUGO, mc13783_adc_read_gp, NULL, 10);
static SENSOR_DEVICE_ATTR(in11_input, S_IRUGO, mc13783_adc_read_gp, NULL, 11);
static SENSOR_DEVICE_ATTR(in12_input, S_IRUGO, mc13783_adc_read_gp, NULL, 12);
static SENSOR_DEVICE_ATTR(in13_input, S_IRUGO, mc13783_adc_read_gp, NULL, 13);
static SENSOR_DEVICE_ATTR(in14_input, S_IRUGO, mc13783_adc_read_gp, NULL, 14);
static SENSOR_DEVICE_ATTR(in15_input, S_IRUGO, mc13783_adc_read_gp, NULL, 15);

static struct attribute *mc13783_attr_base[] = {
    &dev_attr_name.attr,
    &sensor_dev_attr_in2_input.dev_attr.attr,
    &sensor_dev_attr_in5_input.dev_attr.attr,
    &sensor_dev_attr_in6_input.dev_attr.attr,
    &sensor_dev_attr_in7_input.dev_attr.attr,
    NULL
};

static const struct attribute_group mc13783_group_base = {
    .attrs = mc13783_attr_base,
};

/* these are only used if MC13783_ADC_16CHANS is provided in driver data */
static struct attribute *mc13783_attr_16chans[] = {
    &sensor_dev_attr_in8_input.dev_attr.attr,
    &sensor_dev_attr_in9_input.dev_attr.attr,
    &sensor_dev_attr_in10_input.dev_attr.attr,
    &sensor_dev_attr_in11_input.dev_attr.attr,
    NULL
};

static const struct attribute_group mc13783_group_16chans = {
    .attrs = mc13783_attr_16chans,
};

/* last four channels may be occupied by the touchscreen */
static struct attribute *mc13783_attr_ts[] = {
    &sensor_dev_attr_in12_input.dev_attr.attr,
    &sensor_dev_attr_in13_input.dev_attr.attr,
    &sensor_dev_attr_in14_input.dev_attr.attr,
    &sensor_dev_attr_in15_input.dev_attr.attr,
    NULL
};

static const struct attribute_group mc13783_group_ts = {
    .attrs = mc13783_attr_ts,
};

static int mc13783_adc_use_touchscreen(struct platform_device *pdev)
{
    struct mc13783_adc_priv *priv = platform_get_drvdata(pdev);
    unsigned flags = mc13xxx_get_flags(priv->mc13xxx);

    return flags & MC13XXX_USE_TOUCHSCREEN;
}

static int __init mc13783_adc_probe(struct platform_device *pdev)
{
    struct mc13783_adc_priv *priv;
    int ret;
    const struct platform_device_id *id = platform_get_device_id(pdev);
    char *dash;

    priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
    if (!priv)
        return -ENOMEM;

    priv->mc13xxx = dev_get_drvdata(pdev->dev.parent);
    snprintf(priv->name, ARRAY_SIZE(priv->name), "%s", id->name);
    dash = strchr(priv->name, '-');
    if (dash)
        *dash = '\0';

    platform_set_drvdata(pdev, priv);

    /* Register sysfs hooks */
    ret = sysfs_create_group(&pdev->dev.kobj, &mc13783_group_base);
    if (ret)
        return ret;

    if (id->driver_data & MC13783_ADC_16CHANS) {
        ret = sysfs_create_group(&pdev->dev.kobj,
                &mc13783_group_16chans);
        if (ret)
            goto out_err_create_16chans;
    }

    if (!mc13783_adc_use_touchscreen(pdev)) {
        ret = sysfs_create_group(&pdev->dev.kobj, &mc13783_group_ts);
        if (ret)
            goto out_err_create_ts;
    }

    priv->hwmon_dev = hwmon_device_register(&pdev->dev);
    if (IS_ERR(priv->hwmon_dev)) {
        ret = PTR_ERR(priv->hwmon_dev);
        dev_err(&pdev->dev,
                "hwmon_device_register failed with %d.\n", ret);
        goto out_err_register;
    }

    return 0;

out_err_register:

    if (!mc13783_adc_use_touchscreen(pdev))
        sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_ts);
out_err_create_ts:

    if (id->driver_data & MC13783_ADC_16CHANS)
        sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_16chans);
out_err_create_16chans:

    sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_base);
    return ret;
}

static int __devexit mc13783_adc_remove(struct platform_device *pdev)
{
    struct mc13783_adc_priv *priv = platform_get_drvdata(pdev);
    kernel_ulong_t driver_data = platform_get_device_id(pdev)->driver_data;

    hwmon_device_unregister(priv->hwmon_dev);

    if (!mc13783_adc_use_touchscreen(pdev))
        sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_ts);

    if (driver_data & MC13783_ADC_16CHANS)
        sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_16chans);

    sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_base);

    return 0;
}

static const struct platform_device_id mc13783_adc_idtable[] = {
    {
        .name = "mc13783-adc",
        .driver_data = MC13783_ADC_16CHANS,
    }, {
        .name = "mc13892-adc",
        .driver_data = MC13783_ADC_BPDIV2,
    }, {
        /* sentinel */
    }
};
MODULE_DEVICE_TABLE(platform, mc13783_adc_idtable);

static struct platform_driver mc13783_adc_driver = {
    .remove     = __devexit_p(mc13783_adc_remove),
    .driver     = {
        .owner  = THIS_MODULE,
        .name   = DRIVER_NAME,
    },
    .id_table   = mc13783_adc_idtable,
};

static int __init mc13783_adc_init(void)
{
    return platform_driver_probe(&mc13783_adc_driver, mc13783_adc_probe);
}

static void __exit mc13783_adc_exit(void)
{
    platform_driver_unregister(&mc13783_adc_driver);
}

module_init(mc13783_adc_init);
module_exit(mc13783_adc_exit);

MODULE_DESCRIPTION("MC13783 ADC driver");
MODULE_AUTHOR("Luotao Fu <[email protected]>");
MODULE_LICENSE("GPL");