apds9802als.c

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/*
 * apds9802als.c - apds9802  ALS Driver
 *
 * Copyright (C) 2009 Intel Corp
 *
 *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * 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; version 2 of the License.
 *
 * 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/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>
#include <linux/pm_runtime.h>

#define ALS_MIN_RANGE_VAL 1
#define ALS_MAX_RANGE_VAL 2
#define POWER_STA_ENABLE 1
#define POWER_STA_DISABLE 0

#define DRIVER_NAME "apds9802als"

struct als_data {
    struct mutex mutex;
};

static ssize_t als_sensing_range_show(struct device *dev,
            struct device_attribute *attr,  char *buf)
{
    struct i2c_client *client = to_i2c_client(dev);
    int  val;

    val = i2c_smbus_read_byte_data(client, 0x81);
    if (val < 0)
        return val;
    if (val & 1)
        return sprintf(buf, "4095\n");
    else
        return sprintf(buf, "65535\n");
}

static int als_wait_for_data_ready(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    int ret;
    int retry = 10;

    do {
        msleep(30);
        ret = i2c_smbus_read_byte_data(client, 0x86);
    } while (!(ret & 0x80) && retry--);

    if (!retry) {
        dev_warn(dev, "timeout waiting for data ready\n");
        return -ETIMEDOUT;
    }

    return 0;
}

static ssize_t als_lux0_input_data_show(struct device *dev,
            struct device_attribute *attr, char *buf)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct als_data *data = i2c_get_clientdata(client);
    int ret_val;
    int temp;

    /* Protect against parallel reads */
    pm_runtime_get_sync(dev);
    mutex_lock(&data->mutex);

    /* clear EOC interrupt status */
    i2c_smbus_write_byte(client, 0x40);
    /* start measurement */
    temp = i2c_smbus_read_byte_data(client, 0x81);
    i2c_smbus_write_byte_data(client, 0x81, temp | 0x08);

    ret_val = als_wait_for_data_ready(dev);
    if (ret_val < 0)
        goto failed;

    temp = i2c_smbus_read_byte_data(client, 0x8C); /* LSB data */
    if (temp < 0) {
        ret_val = temp;
        goto failed;
    }
    ret_val = i2c_smbus_read_byte_data(client, 0x8D); /* MSB data */
    if (ret_val < 0)
        goto failed;

    mutex_unlock(&data->mutex);
    pm_runtime_put_sync(dev);

    temp = (ret_val << 8) | temp;
    return sprintf(buf, "%d\n", temp);
failed:
    mutex_unlock(&data->mutex);
    pm_runtime_put_sync(dev);
    return ret_val;
}

static ssize_t als_sensing_range_store(struct device *dev,
        struct device_attribute *attr, const  char *buf, size_t count)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct als_data *data = i2c_get_clientdata(client);
    int ret_val;
    unsigned long val;

    if (strict_strtoul(buf, 10, &val))
        return -EINVAL;

    if (val < 4096)
        val = 1;
    else if (val < 65536)
        val = 2;
    else
        return -ERANGE;

    pm_runtime_get_sync(dev);

    /* Make sure nobody else reads/modifies/writes 0x81 while we
       are active */
    mutex_lock(&data->mutex);

    ret_val = i2c_smbus_read_byte_data(client, 0x81);
    if (ret_val < 0)
        goto fail;

    /* Reset the bits before setting them */
    ret_val = ret_val & 0xFA;

    if (val == 1) /* Setting detection range up to 4k LUX */
        ret_val = (ret_val | 0x01);
    else /* Setting detection range up to 64k LUX*/
        ret_val = (ret_val | 0x00);

    ret_val = i2c_smbus_write_byte_data(client, 0x81, ret_val);

    if (ret_val >= 0) {
        /* All OK */
        mutex_unlock(&data->mutex);
        pm_runtime_put_sync(dev);
        return count;
    }
fail:
    mutex_unlock(&data->mutex);
    pm_runtime_put_sync(dev);
    return ret_val;
}

static int als_set_power_state(struct i2c_client *client, bool on_off)
{
    int ret_val;
    struct als_data *data = i2c_get_clientdata(client);

    mutex_lock(&data->mutex);
    ret_val = i2c_smbus_read_byte_data(client, 0x80);
    if (ret_val < 0)
        goto fail;
    if (on_off)
        ret_val = ret_val | 0x01;
    else
        ret_val = ret_val & 0xFE;
    ret_val = i2c_smbus_write_byte_data(client, 0x80, ret_val);
fail:
    mutex_unlock(&data->mutex);
    return ret_val;
}

static DEVICE_ATTR(lux0_sensor_range, S_IRUGO | S_IWUSR,
    als_sensing_range_show, als_sensing_range_store);
static DEVICE_ATTR(lux0_input, S_IRUGO, als_lux0_input_data_show, NULL);

static struct attribute *mid_att_als[] = {
    &dev_attr_lux0_sensor_range.attr,
    &dev_attr_lux0_input.attr,
    NULL
};

static struct attribute_group m_als_gr = {
    .name = "apds9802als",
    .attrs = mid_att_als
};

static int als_set_default_config(struct i2c_client *client)
{
    int ret_val;
    /* Write the command and then switch on */
    ret_val = i2c_smbus_write_byte_data(client, 0x80, 0x01);
    if (ret_val < 0) {
        dev_err(&client->dev, "failed default switch on write\n");
        return ret_val;
    }
    /* detection range: 1~64K Lux, maunal measurement */
    ret_val = i2c_smbus_write_byte_data(client, 0x81, 0x08);
    if (ret_val < 0)
        dev_err(&client->dev, "failed default LUX on write\n");

    /*  We always get 0 for the 1st measurement after system power on,
     *  so make sure it is finished before user asks for data.
     */
    als_wait_for_data_ready(&client->dev);

    return ret_val;
}

static int apds9802als_probe(struct i2c_client *client,
                 const struct i2c_device_id *id)
{
    int res;
    struct als_data *data;

    data = kzalloc(sizeof(struct als_data), GFP_KERNEL);
    if (data == NULL) {
        dev_err(&client->dev, "Memory allocation failed\n");
        return -ENOMEM;
    }
    i2c_set_clientdata(client, data);
    res = sysfs_create_group(&client->dev.kobj, &m_als_gr);
    if (res) {
        dev_err(&client->dev, "device create file failed\n");
        goto als_error1;
    }
    dev_info(&client->dev, "ALS chip found\n");
    als_set_default_config(client);
    mutex_init(&data->mutex);

    pm_runtime_set_active(&client->dev);
    pm_runtime_enable(&client->dev);

    return res;
als_error1:
    kfree(data);
    return res;
}

static int __devexit apds9802als_remove(struct i2c_client *client)
{
    struct als_data *data = i2c_get_clientdata(client);

    pm_runtime_get_sync(&client->dev);

    als_set_power_state(client, false);
    sysfs_remove_group(&client->dev.kobj, &m_als_gr);

    pm_runtime_disable(&client->dev);
    pm_runtime_set_suspended(&client->dev);
    pm_runtime_put_noidle(&client->dev);

    kfree(data);
    return 0;
}

#ifdef CONFIG_PM
static int apds9802als_suspend(struct i2c_client *client, pm_message_t mesg)
{
    als_set_power_state(client, false);
    return 0;
}

static int apds9802als_resume(struct i2c_client *client)
{
    als_set_default_config(client);
    return 0;
}

static int apds9802als_runtime_suspend(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);

    als_set_power_state(client, false);
    return 0;
}

static int apds9802als_runtime_resume(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);

    als_set_power_state(client, true);
    return 0;
}

static const struct dev_pm_ops apds9802als_pm_ops = {
    .runtime_suspend = apds9802als_runtime_suspend,
    .runtime_resume = apds9802als_runtime_resume,
};

#define APDS9802ALS_PM_OPS (&apds9802als_pm_ops)

#else   /* CONFIG_PM */
#define apds9802als_suspend NULL
#define apds9802als_resume NULL
#define APDS9802ALS_PM_OPS NULL
#endif  /* CONFIG_PM */

static struct i2c_device_id apds9802als_id[] = {
    { DRIVER_NAME, 0 },
    { }
};

MODULE_DEVICE_TABLE(i2c, apds9802als_id);

static struct i2c_driver apds9802als_driver = {
    .driver = {
        .name = DRIVER_NAME,
        .pm = APDS9802ALS_PM_OPS,
    },
    .probe = apds9802als_probe,
    .remove = __devexit_p(apds9802als_remove),
    .suspend = apds9802als_suspend,
    .resume = apds9802als_resume,
    .id_table = apds9802als_id,
};

module_i2c_driver(apds9802als_driver);

MODULE_AUTHOR("Anantha Narayanan <[email protected]");
MODULE_DESCRIPTION("Avago apds9802als ALS Driver");
MODULE_LICENSE("GPL v2");