isl29003.c

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/*
 *  isl29003.c - Linux kernel module for
 *  Intersil ISL29003 ambient light sensor
 *
 *  See file:Documentation/misc-devices/isl29003
 *
 *  Copyright (c) 2009 Daniel Mack <[email protected]>
 *
 *  Based on code written by
 *      Rodolfo Giometti <[email protected]>
 *      Eurotech S.p.A. <[email protected]>
 *
 *  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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
#include <linux/delay.h>

#define ISL29003_DRV_NAME   "isl29003"
#define DRIVER_VERSION      "1.0"

#define ISL29003_REG_COMMAND        0x00
#define ISL29003_ADC_ENABLED        (1 << 7)
#define ISL29003_ADC_PD         (1 << 6)
#define ISL29003_TIMING_INT     (1 << 5)
#define ISL29003_MODE_SHIFT     (2)
#define ISL29003_MODE_MASK      (0x3 << ISL29003_MODE_SHIFT)
#define ISL29003_RES_SHIFT      (0)
#define ISL29003_RES_MASK       (0x3 << ISL29003_RES_SHIFT)

#define ISL29003_REG_CONTROL        0x01
#define ISL29003_INT_FLG        (1 << 5)
#define ISL29003_RANGE_SHIFT        (2)
#define ISL29003_RANGE_MASK     (0x3 << ISL29003_RANGE_SHIFT)
#define ISL29003_INT_PERSISTS_SHIFT (0)
#define ISL29003_INT_PERSISTS_MASK  (0xf << ISL29003_INT_PERSISTS_SHIFT)

#define ISL29003_REG_IRQ_THRESH_HI  0x02
#define ISL29003_REG_IRQ_THRESH_LO  0x03
#define ISL29003_REG_LSB_SENSOR     0x04
#define ISL29003_REG_MSB_SENSOR     0x05
#define ISL29003_REG_LSB_TIMER      0x06
#define ISL29003_REG_MSB_TIMER      0x07

#define ISL29003_NUM_CACHABLE_REGS  4

struct isl29003_data {
    struct i2c_client *client;
    struct mutex lock;
    u8 reg_cache[ISL29003_NUM_CACHABLE_REGS];
    u8 power_state_before_suspend;
};

static int gain_range[] = {
    1000, 4000, 16000, 64000
};

/*
 * register access helpers
 */

static int __isl29003_read_reg(struct i2c_client *client,
                   u32 reg, u8 mask, u8 shift)
{
    struct isl29003_data *data = i2c_get_clientdata(client);
    return (data->reg_cache[reg] & mask) >> shift;
}

static int __isl29003_write_reg(struct i2c_client *client,
                u32 reg, u8 mask, u8 shift, u8 val)
{
    struct isl29003_data *data = i2c_get_clientdata(client);
    int ret = 0;
    u8 tmp;

    if (reg >= ISL29003_NUM_CACHABLE_REGS)
        return -EINVAL;

    mutex_lock(&data->lock);

    tmp = data->reg_cache[reg];
    tmp &= ~mask;
    tmp |= val << shift;

    ret = i2c_smbus_write_byte_data(client, reg, tmp);
    if (!ret)
        data->reg_cache[reg] = tmp;

    mutex_unlock(&data->lock);
    return ret;
}

/*
 * internally used functions
 */

/* range */
static int isl29003_get_range(struct i2c_client *client)
{
    return __isl29003_read_reg(client, ISL29003_REG_CONTROL,
        ISL29003_RANGE_MASK, ISL29003_RANGE_SHIFT);
}

static int isl29003_set_range(struct i2c_client *client, int range)
{
    return __isl29003_write_reg(client, ISL29003_REG_CONTROL,
        ISL29003_RANGE_MASK, ISL29003_RANGE_SHIFT, range);
}

/* resolution */
static int isl29003_get_resolution(struct i2c_client *client)
{
    return __isl29003_read_reg(client, ISL29003_REG_COMMAND,
        ISL29003_RES_MASK, ISL29003_RES_SHIFT);
}

static int isl29003_set_resolution(struct i2c_client *client, int res)
{
    return __isl29003_write_reg(client, ISL29003_REG_COMMAND,
        ISL29003_RES_MASK, ISL29003_RES_SHIFT, res);
}

/* mode */
static int isl29003_get_mode(struct i2c_client *client)
{
    return __isl29003_read_reg(client, ISL29003_REG_COMMAND,
        ISL29003_RES_MASK, ISL29003_RES_SHIFT);
}

static int isl29003_set_mode(struct i2c_client *client, int mode)
{
    return __isl29003_write_reg(client, ISL29003_REG_COMMAND,
        ISL29003_RES_MASK, ISL29003_RES_SHIFT, mode);
}

/* power_state */
static int isl29003_set_power_state(struct i2c_client *client, int state)
{
    return __isl29003_write_reg(client, ISL29003_REG_COMMAND,
                ISL29003_ADC_ENABLED | ISL29003_ADC_PD, 0,
                state ? ISL29003_ADC_ENABLED : ISL29003_ADC_PD);
}

static int isl29003_get_power_state(struct i2c_client *client)
{
    struct isl29003_data *data = i2c_get_clientdata(client);
    u8 cmdreg = data->reg_cache[ISL29003_REG_COMMAND];
    return ~cmdreg & ISL29003_ADC_PD;
}

static int isl29003_get_adc_value(struct i2c_client *client)
{
    struct isl29003_data *data = i2c_get_clientdata(client);
    int lsb, msb, range, bitdepth;

    mutex_lock(&data->lock);
    lsb = i2c_smbus_read_byte_data(client, ISL29003_REG_LSB_SENSOR);

    if (lsb < 0) {
        mutex_unlock(&data->lock);
        return lsb;
    }

    msb = i2c_smbus_read_byte_data(client, ISL29003_REG_MSB_SENSOR);
    mutex_unlock(&data->lock);

    if (msb < 0)
        return msb;

    range = isl29003_get_range(client);
    bitdepth = (4 - isl29003_get_resolution(client)) * 4;
    return (((msb << 8) | lsb) * gain_range[range]) >> bitdepth;
}

/*
 * sysfs layer
 */

/* range */
static ssize_t isl29003_show_range(struct device *dev,
                   struct device_attribute *attr, char *buf)
{
    struct i2c_client *client = to_i2c_client(dev);
    return sprintf(buf, "%i\n", isl29003_get_range(client));
}

static ssize_t isl29003_store_range(struct device *dev,
                    struct device_attribute *attr,
                    const char *buf, size_t count)
{
    struct i2c_client *client = to_i2c_client(dev);
    unsigned long val;
    int ret;

    if ((strict_strtoul(buf, 10, &val) < 0) || (val > 3))
        return -EINVAL;

    ret = isl29003_set_range(client, val);
    if (ret < 0)
        return ret;

    return count;
}

static DEVICE_ATTR(range, S_IWUSR | S_IRUGO,
           isl29003_show_range, isl29003_store_range);


/* resolution */
static ssize_t isl29003_show_resolution(struct device *dev,
                    struct device_attribute *attr,
                    char *buf)
{
    struct i2c_client *client = to_i2c_client(dev);
    return sprintf(buf, "%d\n", isl29003_get_resolution(client));
}

static ssize_t isl29003_store_resolution(struct device *dev,
                     struct device_attribute *attr,
                     const char *buf, size_t count)
{
    struct i2c_client *client = to_i2c_client(dev);
    unsigned long val;
    int ret;

    if ((strict_strtoul(buf, 10, &val) < 0) || (val > 3))
        return -EINVAL;

    ret = isl29003_set_resolution(client, val);
    if (ret < 0)
        return ret;

    return count;
}

static DEVICE_ATTR(resolution, S_IWUSR | S_IRUGO,
           isl29003_show_resolution, isl29003_store_resolution);

/* mode */
static ssize_t isl29003_show_mode(struct device *dev,
                  struct device_attribute *attr, char *buf)
{
    struct i2c_client *client = to_i2c_client(dev);
    return sprintf(buf, "%d\n", isl29003_get_mode(client));
}

static ssize_t isl29003_store_mode(struct device *dev,
        struct device_attribute *attr, const char *buf, size_t count)
{
    struct i2c_client *client = to_i2c_client(dev);
    unsigned long val;
    int ret;

    if ((strict_strtoul(buf, 10, &val) < 0) || (val > 2))
        return -EINVAL;

    ret = isl29003_set_mode(client, val);
    if (ret < 0)
        return ret;

    return count;
}

static DEVICE_ATTR(mode, S_IWUSR | S_IRUGO,
           isl29003_show_mode, isl29003_store_mode);


/* power state */
static ssize_t isl29003_show_power_state(struct device *dev,
                     struct device_attribute *attr,
                     char *buf)
{
    struct i2c_client *client = to_i2c_client(dev);
    return sprintf(buf, "%d\n", isl29003_get_power_state(client));
}

static ssize_t isl29003_store_power_state(struct device *dev,
                      struct device_attribute *attr,
                      const char *buf, size_t count)
{
    struct i2c_client *client = to_i2c_client(dev);
    unsigned long val;
    int ret;

    if ((strict_strtoul(buf, 10, &val) < 0) || (val > 1))
        return -EINVAL;

    ret = isl29003_set_power_state(client, val);
    return ret ? ret : count;
}

static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
           isl29003_show_power_state, isl29003_store_power_state);


/* lux */
static ssize_t isl29003_show_lux(struct device *dev,
                 struct device_attribute *attr, char *buf)
{
    struct i2c_client *client = to_i2c_client(dev);

    /* No LUX data if not operational */
    if (!isl29003_get_power_state(client))
        return -EBUSY;

    return sprintf(buf, "%d\n", isl29003_get_adc_value(client));
}

static DEVICE_ATTR(lux, S_IRUGO, isl29003_show_lux, NULL);

static struct attribute *isl29003_attributes[] = {
    &dev_attr_range.attr,
    &dev_attr_resolution.attr,
    &dev_attr_mode.attr,
    &dev_attr_power_state.attr,
    &dev_attr_lux.attr,
    NULL
};

static const struct attribute_group isl29003_attr_group = {
    .attrs = isl29003_attributes,
};

static int isl29003_init_client(struct i2c_client *client)
{
    struct isl29003_data *data = i2c_get_clientdata(client);
    int i;

    /* read all the registers once to fill the cache.
     * if one of the reads fails, we consider the init failed */
    for (i = 0; i < ARRAY_SIZE(data->reg_cache); i++) {
        int v = i2c_smbus_read_byte_data(client, i);
        if (v < 0)
            return -ENODEV;

        data->reg_cache[i] = v;
    }

    /* set defaults */
    isl29003_set_range(client, 0);
    isl29003_set_resolution(client, 0);
    isl29003_set_mode(client, 0);
    isl29003_set_power_state(client, 0);

    return 0;
}

/*
 * I2C layer
 */

static int __devinit isl29003_probe(struct i2c_client *client,
                    const struct i2c_device_id *id)
{
    struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
    struct isl29003_data *data;
    int err = 0;

    if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
        return -EIO;

    data = kzalloc(sizeof(struct isl29003_data), GFP_KERNEL);
    if (!data)
        return -ENOMEM;

    data->client = client;
    i2c_set_clientdata(client, data);
    mutex_init(&data->lock);

    /* initialize the ISL29003 chip */
    err = isl29003_init_client(client);
    if (err)
        goto exit_kfree;

    /* register sysfs hooks */
    err = sysfs_create_group(&client->dev.kobj, &isl29003_attr_group);
    if (err)
        goto exit_kfree;

    dev_info(&client->dev, "driver version %s enabled\n", DRIVER_VERSION);
    return 0;

exit_kfree:
    kfree(data);
    return err;
}

static int __devexit isl29003_remove(struct i2c_client *client)
{
    sysfs_remove_group(&client->dev.kobj, &isl29003_attr_group);
    isl29003_set_power_state(client, 0);
    kfree(i2c_get_clientdata(client));
    return 0;
}

#ifdef CONFIG_PM
static int isl29003_suspend(struct i2c_client *client, pm_message_t mesg)
{
    struct isl29003_data *data = i2c_get_clientdata(client);

    data->power_state_before_suspend = isl29003_get_power_state(client);
    return isl29003_set_power_state(client, 0);
}

static int isl29003_resume(struct i2c_client *client)
{
    int i;
    struct isl29003_data *data = i2c_get_clientdata(client);

    /* restore registers from cache */
    for (i = 0; i < ARRAY_SIZE(data->reg_cache); i++)
        if (i2c_smbus_write_byte_data(client, i, data->reg_cache[i]))
            return -EIO;

    return isl29003_set_power_state(client,
        data->power_state_before_suspend);
}

#else
#define isl29003_suspend    NULL
#define isl29003_resume     NULL
#endif /* CONFIG_PM */

static const struct i2c_device_id isl29003_id[] = {
    { "isl29003", 0 },
    {}
};
MODULE_DEVICE_TABLE(i2c, isl29003_id);

static struct i2c_driver isl29003_driver = {
    .driver = {
        .name   = ISL29003_DRV_NAME,
        .owner  = THIS_MODULE,
    },
    .suspend = isl29003_suspend,
    .resume = isl29003_resume,
    .probe  = isl29003_probe,
    .remove = __devexit_p(isl29003_remove),
    .id_table = isl29003_id,
};

module_i2c_driver(isl29003_driver);

MODULE_AUTHOR("Daniel Mack <[email protected]>");
MODULE_DESCRIPTION("ISL29003 ambient light sensor driver");
MODULE_LICENSE("GPL v2");
MODULE_VERSION(DRIVER_VERSION);