/*
* AL3320A - Dyna Image Ambient Light Sensor
*
* Copyright (c) 2014, Intel Corporation.
*
* This file is subject to the terms and conditions of version 2 of
* the GNU General Public License. See the file COPYING in the main
* directory of this archive for more details.
*
* IIO driver for AL3320A (7-bit I2C slave address 0x1C).
*
* TODO: interrupt support, thresholds
*
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#define AL3320A_DRV_NAME "al3320a"
#define AL3320A_REG_CONFIG 0x00
#define AL3320A_REG_STATUS 0x01
#define AL3320A_REG_INT 0x02
#define AL3320A_REG_WAIT 0x06
#define AL3320A_REG_CONFIG_RANGE 0x07
#define AL3320A_REG_PERSIST 0x08
#define AL3320A_REG_MEAN_TIME 0x09
#define AL3320A_REG_ADUMMY 0x0A
#define AL3320A_REG_DATA_LOW 0x22
#define AL3320A_REG_LOW_THRESH_LOW 0x30
#define AL3320A_REG_LOW_THRESH_HIGH 0x31
#define AL3320A_REG_HIGH_THRESH_LOW 0x32
#define AL3320A_REG_HIGH_THRESH_HIGH 0x33
#define AL3320A_CONFIG_DISABLE 0x00
#define AL3320A_CONFIG_ENABLE 0x01
#define AL3320A_GAIN_SHIFT 1
#define AL3320A_GAIN_MASK (BIT(2) | BIT(1))
/* chip params default values */
#define AL3320A_DEFAULT_MEAN_TIME 4
#define AL3320A_DEFAULT_WAIT_TIME 0 /* no waiting */
#define AL3320A_SCALE_AVAILABLE "0.512 0.128 0.032 0.01"
enum al3320a_range {
AL3320A_RANGE_1, /* 33.28 Klx */
AL3320A_RANGE_2, /* 8.32 Klx */
AL3320A_RANGE_3, /* 2.08 Klx */
AL3320A_RANGE_4 /* 0.65 Klx */
};
static const int al3320a_scales[][2] = {
{0, 512000}, {0, 128000}, {0, 32000}, {0, 10000}
};
struct al3320a_data {
struct i2c_client *client;
};
static const struct iio_chan_spec al3320a_channels[] = {
{
.type = IIO_LIGHT,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
}
};
static IIO_CONST_ATTR(in_illuminance_scale_available, AL3320A_SCALE_AVAILABLE);
static struct attribute *al3320a_attributes[] = {
&iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
NULL,
};
static const struct attribute_group al3320a_attribute_group = {
.attrs = al3320a_attributes,
};
static int al3320a_init(struct al3320a_data *data)
{
int ret;
/* power on */
ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG,
AL3320A_CONFIG_ENABLE);
if (ret < 0)
return ret;
ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG_RANGE,
AL3320A_RANGE_3 << AL3320A_GAIN_SHIFT);
if (ret < 0)
return ret;
ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_MEAN_TIME,
AL3320A_DEFAULT_MEAN_TIME);
if (ret < 0)
return ret;
ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_WAIT,
AL3320A_DEFAULT_WAIT_TIME);
if (ret < 0)
return ret;
return 0;
}
static int al3320a_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val,
int *val2, long mask)
{
struct al3320a_data *data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
/*
* ALS ADC value is stored in two adjacent registers:
* - low byte of output is stored at AL3320A_REG_DATA_LOW
* - high byte of output is stored at AL3320A_REG_DATA_LOW + 1
*/
ret = i2c_smbus_read_word_data(data->client,
AL3320A_REG_DATA_LOW);
if (ret < 0)
return ret;
*val = ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
ret = i2c_smbus_read_byte_data(data->client,
AL3320A_REG_CONFIG_RANGE);
if (ret < 0)
return ret;
ret = (ret & AL3320A_GAIN_MASK) >> AL3320A_GAIN_SHIFT;
*val = al3320a_scales[ret][0];
*val2 = al3320a_scales[ret][1];
return IIO_VAL_INT_PLUS_MICRO;
}
return -EINVAL;
}
static int al3320a_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int val,
int val2, long mask)
{
struct al3320a_data *data = iio_priv(indio_dev);
int i;
switch (mask) {
case IIO_CHAN_INFO_SCALE:
for (i = 0; i < ARRAY_SIZE(al3320a_scales); i++) {
if (val == al3320a_scales[i][0] &&
val2 == al3320a_scales[i][1])
return i2c_smbus_write_byte_data(data->client,
AL3320A_REG_CONFIG_RANGE,
i << AL3320A_GAIN_SHIFT);
}
break;
}
return -EINVAL;
}
static const struct iio_info al3320a_info = {
.read_raw = al3320a_read_raw,
.write_raw = al3320a_write_raw,
.attrs = &al3320a_attribute_group,
};
static int al3320a_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct al3320a_data *data;
struct iio_dev *indio_dev;
int ret;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
data->client = client;
indio_dev->dev.parent = &client->dev;
indio_dev->info = &al3320a_info;
indio_dev->name = AL3320A_DRV_NAME;
indio_dev->channels = al3320a_channels;
indio_dev->num_channels = ARRAY_SIZE(al3320a_channels);
indio_dev->modes = INDIO_DIRECT_MODE;
ret = al3320a_init(data);
if (ret < 0) {
dev_err(&client->dev, "al3320a chip init failed\n");
return ret;
}
return devm_iio_device_register(&client->dev, indio_dev);
}
static int al3320a_remove(struct i2c_client *client)
{
return i2c_smbus_write_byte_data(client, AL3320A_REG_CONFIG,
AL3320A_CONFIG_DISABLE);
}
static const struct i2c_device_id al3320a_id[] = {
{"al3320a", 0},
{}
};
MODULE_DEVICE_TABLE(i2c, al3320a_id);
static struct i2c_driver al3320a_driver = {
.driver = {
.name = AL3320A_DRV_NAME,
},
.probe = al3320a_probe,
.remove = al3320a_remove,
.id_table = al3320a_id,
};
module_i2c_driver(al3320a_driver);
MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
MODULE_DESCRIPTION("AL3320A Ambient Light Sensor driver");
MODULE_LICENSE("GPL v2");
