s3c-hwmon.c

Go to the documentation of this file.

/* linux/drivers/hwmon/s3c-hwmon.c
 *
 * Copyright (C) 2005, 2008, 2009 Simtec Electronics
 *  http://armlinux.simtec.co.uk/
 *  Ben Dooks <[email protected]>
 *
 * S3C24XX/S3C64XX ADC hwmon support
 *
 * 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.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>

#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>

#include <plat/adc.h>
#include <linux/platform_data/hwmon-s3c.h>

struct s3c_hwmon_attr {
    struct sensor_device_attribute  in;
    struct sensor_device_attribute  label;
    char                in_name[12];
    char                label_name[12];
};

struct s3c_hwmon {
    struct mutex        lock;
    struct s3c_adc_client   *client;
    struct device       *hwmon_dev;

    struct s3c_hwmon_attr   attrs[8];
};

static int s3c_hwmon_read_ch(struct device *dev,
                 struct s3c_hwmon *hwmon, int channel)
{
    int ret;

    ret = mutex_lock_interruptible(&hwmon->lock);
    if (ret < 0)
        return ret;

    dev_dbg(dev, "reading channel %d\n", channel);

    ret = s3c_adc_read(hwmon->client, channel);
    mutex_unlock(&hwmon->lock);

    return ret;
}

#ifdef CONFIG_SENSORS_S3C_RAW

static ssize_t s3c_hwmon_show_raw(struct device *dev,
                  struct device_attribute *attr, char *buf)
{
    struct s3c_hwmon *adc = platform_get_drvdata(to_platform_device(dev));
    struct sensor_device_attribute *sa = to_sensor_dev_attr(attr);
    int ret;

    ret = s3c_hwmon_read_ch(dev, adc, sa->index);

    return  (ret < 0) ? ret : snprintf(buf, PAGE_SIZE, "%d\n", ret);
}

#define DEF_ADC_ATTR(x) \
    static SENSOR_DEVICE_ATTR(adc##x##_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, x)

DEF_ADC_ATTR(0);
DEF_ADC_ATTR(1);
DEF_ADC_ATTR(2);
DEF_ADC_ATTR(3);
DEF_ADC_ATTR(4);
DEF_ADC_ATTR(5);
DEF_ADC_ATTR(6);
DEF_ADC_ATTR(7);

static struct attribute *s3c_hwmon_attrs[9] = {
    &sensor_dev_attr_adc0_raw.dev_attr.attr,
    &sensor_dev_attr_adc1_raw.dev_attr.attr,
    &sensor_dev_attr_adc2_raw.dev_attr.attr,
    &sensor_dev_attr_adc3_raw.dev_attr.attr,
    &sensor_dev_attr_adc4_raw.dev_attr.attr,
    &sensor_dev_attr_adc5_raw.dev_attr.attr,
    &sensor_dev_attr_adc6_raw.dev_attr.attr,
    &sensor_dev_attr_adc7_raw.dev_attr.attr,
    NULL,
};

static struct attribute_group s3c_hwmon_attrgroup = {
    .attrs  = s3c_hwmon_attrs,
};

static inline int s3c_hwmon_add_raw(struct device *dev)
{
    return sysfs_create_group(&dev->kobj, &s3c_hwmon_attrgroup);
}

static inline void s3c_hwmon_remove_raw(struct device *dev)
{
    sysfs_remove_group(&dev->kobj, &s3c_hwmon_attrgroup);
}

#else

static inline int s3c_hwmon_add_raw(struct device *dev) { return 0; }
static inline void s3c_hwmon_remove_raw(struct device *dev) { }

#endif /* CONFIG_SENSORS_S3C_RAW */

static ssize_t s3c_hwmon_ch_show(struct device *dev,
                 struct device_attribute *attr,
                 char *buf)
{
    struct sensor_device_attribute *sen_attr = to_sensor_dev_attr(attr);
    struct s3c_hwmon *hwmon = platform_get_drvdata(to_platform_device(dev));
    struct s3c_hwmon_pdata *pdata = dev->platform_data;
    struct s3c_hwmon_chcfg *cfg;
    int ret;

    cfg = pdata->in[sen_attr->index];

    ret = s3c_hwmon_read_ch(dev, hwmon, sen_attr->index);
    if (ret < 0)
        return ret;

    ret *= cfg->mult;
    ret = DIV_ROUND_CLOSEST(ret, cfg->div);

    return snprintf(buf, PAGE_SIZE, "%d\n", ret);
}

static ssize_t s3c_hwmon_label_show(struct device *dev,
                    struct device_attribute *attr,
                    char *buf)
{
    struct sensor_device_attribute *sen_attr = to_sensor_dev_attr(attr);
    struct s3c_hwmon_pdata *pdata = dev->platform_data;
    struct s3c_hwmon_chcfg *cfg;

    cfg = pdata->in[sen_attr->index];

    return snprintf(buf, PAGE_SIZE, "%s\n", cfg->name);
}

static int s3c_hwmon_create_attr(struct device *dev,
                 struct s3c_hwmon_chcfg *cfg,
                 struct s3c_hwmon_attr *attrs,
                 int channel)
{
    struct sensor_device_attribute *attr;
    int ret;

    snprintf(attrs->in_name, sizeof(attrs->in_name), "in%d_input", channel);

    attr = &attrs->in;
    attr->index = channel;
    sysfs_attr_init(&attr->dev_attr.attr);
    attr->dev_attr.attr.name  = attrs->in_name;
    attr->dev_attr.attr.mode  = S_IRUGO;
    attr->dev_attr.show = s3c_hwmon_ch_show;

    ret =  device_create_file(dev, &attr->dev_attr);
    if (ret < 0) {
        dev_err(dev, "failed to create input attribute\n");
        return ret;
    }

    /* if this has a name, add a label */
    if (cfg->name) {
        snprintf(attrs->label_name, sizeof(attrs->label_name),
             "in%d_label", channel);

        attr = &attrs->label;
        attr->index = channel;
        sysfs_attr_init(&attr->dev_attr.attr);
        attr->dev_attr.attr.name  = attrs->label_name;
        attr->dev_attr.attr.mode  = S_IRUGO;
        attr->dev_attr.show = s3c_hwmon_label_show;

        ret = device_create_file(dev, &attr->dev_attr);
        if (ret < 0) {
            device_remove_file(dev, &attrs->in.dev_attr);
            dev_err(dev, "failed to create label attribute\n");
        }
    }

    return ret;
}

static void s3c_hwmon_remove_attr(struct device *dev,
                  struct s3c_hwmon_attr *attrs)
{
    device_remove_file(dev, &attrs->in.dev_attr);
    device_remove_file(dev, &attrs->label.dev_attr);
}

static int __devinit s3c_hwmon_probe(struct platform_device *dev)
{
    struct s3c_hwmon_pdata *pdata = dev->dev.platform_data;
    struct s3c_hwmon *hwmon;
    int ret = 0;
    int i;

    if (!pdata) {
        dev_err(&dev->dev, "no platform data supplied\n");
        return -EINVAL;
    }

    hwmon = devm_kzalloc(&dev->dev, sizeof(struct s3c_hwmon), GFP_KERNEL);
    if (hwmon == NULL) {
        dev_err(&dev->dev, "no memory\n");
        return -ENOMEM;
    }

    platform_set_drvdata(dev, hwmon);

    mutex_init(&hwmon->lock);

    /* Register with the core ADC driver. */

    hwmon->client = s3c_adc_register(dev, NULL, NULL, 0);
    if (IS_ERR(hwmon->client)) {
        dev_err(&dev->dev, "cannot register adc\n");
        return PTR_ERR(hwmon->client);
    }

    /* add attributes for our adc devices. */

    ret = s3c_hwmon_add_raw(&dev->dev);
    if (ret)
        goto err_registered;

    /* register with the hwmon core */

    hwmon->hwmon_dev = hwmon_device_register(&dev->dev);
    if (IS_ERR(hwmon->hwmon_dev)) {
        dev_err(&dev->dev, "error registering with hwmon\n");
        ret = PTR_ERR(hwmon->hwmon_dev);
        goto err_raw_attribute;
    }

    for (i = 0; i < ARRAY_SIZE(pdata->in); i++) {
        struct s3c_hwmon_chcfg *cfg = pdata->in[i];

        if (!cfg)
            continue;

        if (cfg->mult >= 0x10000)
            dev_warn(&dev->dev,
                 "channel %d multiplier too large\n",
                 i);

        if (cfg->div == 0) {
            dev_err(&dev->dev, "channel %d divider zero\n", i);
            continue;
        }

        ret = s3c_hwmon_create_attr(&dev->dev, pdata->in[i],
                        &hwmon->attrs[i], i);
        if (ret) {
            dev_err(&dev->dev,
                    "error creating channel %d\n", i);

            for (i--; i >= 0; i--)
                s3c_hwmon_remove_attr(&dev->dev,
                                  &hwmon->attrs[i]);

            goto err_hwmon_register;
        }
    }

    return 0;

 err_hwmon_register:
    hwmon_device_unregister(hwmon->hwmon_dev);

 err_raw_attribute:
    s3c_hwmon_remove_raw(&dev->dev);

 err_registered:
    s3c_adc_release(hwmon->client);

    return ret;
}

static int __devexit s3c_hwmon_remove(struct platform_device *dev)
{
    struct s3c_hwmon *hwmon = platform_get_drvdata(dev);
    int i;

    s3c_hwmon_remove_raw(&dev->dev);

    for (i = 0; i < ARRAY_SIZE(hwmon->attrs); i++)
        s3c_hwmon_remove_attr(&dev->dev, &hwmon->attrs[i]);

    hwmon_device_unregister(hwmon->hwmon_dev);
    s3c_adc_release(hwmon->client);

    return 0;
}

static struct platform_driver s3c_hwmon_driver = {
    .driver = {
        .name       = "s3c-hwmon",
        .owner      = THIS_MODULE,
    },
    .probe      = s3c_hwmon_probe,
    .remove     = __devexit_p(s3c_hwmon_remove),
};

module_platform_driver(s3c_hwmon_driver);

MODULE_AUTHOR("Ben Dooks <[email protected]>");
MODULE_DESCRIPTION("S3C ADC HWMon driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:s3c-hwmon");