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linux-next/drivers/iio/light/cm32181.c
Kevin Tsai 971672c0b3 iio: add Capella CM32181 ambient light sensor driver.
Add Capella Microsystem CM32181 Ambient Light Sensor IIO driver.
This driver will convert raw data to lux value under open-air
condition. Change the calibscale based on the cover material.

Signed-off-by: Kevin Tsai <ktsai@capellamicro.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2014-01-01 12:03:32 +00:00

380 lines
9.1 KiB
C

/*
* Copyright (C) 2013 Capella Microsystems Inc.
* Author: Kevin Tsai <ktsai@capellamicro.com>
*
* 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.
*/
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/regulator/consumer.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/events.h>
#include <linux/init.h>
/* Registers Address */
#define CM32181_REG_ADDR_CMD 0x00
#define CM32181_REG_ADDR_ALS 0x04
#define CM32181_REG_ADDR_STATUS 0x06
#define CM32181_REG_ADDR_ID 0x07
/* Number of Configurable Registers */
#define CM32181_CONF_REG_NUM 0x01
/* CMD register */
#define CM32181_CMD_ALS_ENABLE 0x00
#define CM32181_CMD_ALS_DISABLE 0x01
#define CM32181_CMD_ALS_INT_EN 0x02
#define CM32181_CMD_ALS_IT_SHIFT 6
#define CM32181_CMD_ALS_IT_MASK (0x0F << CM32181_CMD_ALS_IT_SHIFT)
#define CM32181_CMD_ALS_IT_DEFAULT (0x00 << CM32181_CMD_ALS_IT_SHIFT)
#define CM32181_CMD_ALS_SM_SHIFT 11
#define CM32181_CMD_ALS_SM_MASK (0x03 << CM32181_CMD_ALS_SM_SHIFT)
#define CM32181_CMD_ALS_SM_DEFAULT (0x01 << CM32181_CMD_ALS_SM_SHIFT)
#define CM32181_MLUX_PER_BIT 5 /* ALS_SM=01 IT=800ms */
#define CM32181_MLUX_PER_BIT_BASE_IT 800000 /* Based on IT=800ms */
#define CM32181_CALIBSCALE_DEFAULT 1000
#define CM32181_CALIBSCALE_RESOLUTION 1000
#define MLUX_PER_LUX 1000
static const u8 cm32181_reg[CM32181_CONF_REG_NUM] = {
CM32181_REG_ADDR_CMD,
};
static const int als_it_bits[] = {12, 8, 0, 1, 2, 3};
static const int als_it_value[] = {25000, 50000, 100000, 200000, 400000,
800000};
struct cm32181_chip {
struct i2c_client *client;
struct mutex lock;
u16 conf_regs[CM32181_CONF_REG_NUM];
int calibscale;
};
/**
* cm32181_reg_init() - Initialize CM32181 registers
* @cm32181: pointer of struct cm32181.
*
* Initialize CM32181 ambient light sensor register to default values.
*
* Return: 0 for success; otherwise for error code.
*/
static int cm32181_reg_init(struct cm32181_chip *cm32181)
{
struct i2c_client *client = cm32181->client;
int i;
s32 ret;
ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ID);
if (ret < 0)
return ret;
/* check device ID */
if ((ret & 0xFF) != 0x81)
return -ENODEV;
/* Default Values */
cm32181->conf_regs[CM32181_REG_ADDR_CMD] = CM32181_CMD_ALS_ENABLE |
CM32181_CMD_ALS_IT_DEFAULT | CM32181_CMD_ALS_SM_DEFAULT;
cm32181->calibscale = CM32181_CALIBSCALE_DEFAULT;
/* Initialize registers*/
for (i = 0; i < CM32181_CONF_REG_NUM; i++) {
ret = i2c_smbus_write_word_data(client, cm32181_reg[i],
cm32181->conf_regs[i]);
if (ret < 0)
return ret;
}
return 0;
}
/**
* cm32181_read_als_it() - Get sensor integration time (ms)
* @cm32181: pointer of struct cm32181
* @val: pointer of int to load the als_it value.
*
* Report the current integartion time by millisecond.
*
* Return: IIO_VAL_INT for success, otherwise -EINVAL.
*/
static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val)
{
u16 als_it;
int i;
als_it = cm32181->conf_regs[CM32181_REG_ADDR_CMD];
als_it &= CM32181_CMD_ALS_IT_MASK;
als_it >>= CM32181_CMD_ALS_IT_SHIFT;
for (i = 0; i < ARRAY_SIZE(als_it_bits); i++) {
if (als_it == als_it_bits[i]) {
*val = als_it_value[i];
return IIO_VAL_INT;
}
}
return -EINVAL;
}
/**
* cm32181_write_als_it() - Write sensor integration time
* @cm32181: pointer of struct cm32181.
* @val: integration time by millisecond.
*
* Convert integration time (ms) to sensor value.
*
* Return: i2c_smbus_write_word_data command return value.
*/
static int cm32181_write_als_it(struct cm32181_chip *cm32181, int val)
{
struct i2c_client *client = cm32181->client;
u16 als_it;
int ret, i, n;
n = ARRAY_SIZE(als_it_value);
for (i = 0; i < n; i++)
if (val <= als_it_value[i])
break;
if (i >= n)
i = n - 1;
als_it = als_it_bits[i];
als_it <<= CM32181_CMD_ALS_IT_SHIFT;
mutex_lock(&cm32181->lock);
cm32181->conf_regs[CM32181_REG_ADDR_CMD] &=
~CM32181_CMD_ALS_IT_MASK;
cm32181->conf_regs[CM32181_REG_ADDR_CMD] |=
als_it;
ret = i2c_smbus_write_word_data(client, CM32181_REG_ADDR_CMD,
cm32181->conf_regs[CM32181_REG_ADDR_CMD]);
mutex_unlock(&cm32181->lock);
return ret;
}
/**
* cm32181_get_lux() - report current lux value
* @cm32181: pointer of struct cm32181.
*
* Convert sensor raw data to lux. It depends on integration
* time and claibscale variable.
*
* Return: Positive value is lux, otherwise is error code.
*/
static int cm32181_get_lux(struct cm32181_chip *cm32181)
{
struct i2c_client *client = cm32181->client;
int ret;
int als_it;
unsigned long lux;
ret = cm32181_read_als_it(cm32181, &als_it);
if (ret < 0)
return -EINVAL;
lux = CM32181_MLUX_PER_BIT;
lux *= CM32181_MLUX_PER_BIT_BASE_IT;
lux /= als_it;
ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ALS);
if (ret < 0)
return ret;
lux *= ret;
lux *= cm32181->calibscale;
lux /= CM32181_CALIBSCALE_RESOLUTION;
lux /= MLUX_PER_LUX;
if (lux > 0xFFFF)
lux = 0xFFFF;
return lux;
}
static int cm32181_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct cm32181_chip *cm32181 = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_PROCESSED:
ret = cm32181_get_lux(cm32181);
if (ret < 0)
return ret;
*val = ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_CALIBSCALE:
*val = cm32181->calibscale;
return IIO_VAL_INT;
case IIO_CHAN_INFO_INT_TIME:
ret = cm32181_read_als_it(cm32181, val);
return ret;
}
return -EINVAL;
}
static int cm32181_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct cm32181_chip *cm32181 = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_CALIBSCALE:
cm32181->calibscale = val;
return val;
case IIO_CHAN_INFO_INT_TIME:
ret = cm32181_write_als_it(cm32181, val);
return ret;
}
return -EINVAL;
}
/**
* cm32181_get_it_available() - Get available ALS IT value
* @dev: pointer of struct device.
* @attr: pointer of struct device_attribute.
* @buf: pointer of return string buffer.
*
* Display the available integration time values by millisecond.
*
* Return: string length.
*/
static ssize_t cm32181_get_it_available(struct device *dev,
struct device_attribute *attr, char *buf)
{
int i, n, len;
n = ARRAY_SIZE(als_it_value);
for (i = 0, len = 0; i < n; i++)
len += sprintf(buf + len, "%d ", als_it_value[i]);
return len + sprintf(buf + len, "\n");
}
static const struct iio_chan_spec cm32181_channels[] = {
{
.type = IIO_LIGHT,
.info_mask_separate =
BIT(IIO_CHAN_INFO_PROCESSED) |
BIT(IIO_CHAN_INFO_CALIBSCALE) |
BIT(IIO_CHAN_INFO_INT_TIME),
}
};
static IIO_DEVICE_ATTR(in_illuminance_integration_time_available,
S_IRUGO, cm32181_get_it_available, NULL, 0);
static struct attribute *cm32181_attributes[] = {
&iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr,
NULL,
};
static const struct attribute_group cm32181_attribute_group = {
.attrs = cm32181_attributes
};
static const struct iio_info cm32181_info = {
.driver_module = THIS_MODULE,
.read_raw = &cm32181_read_raw,
.write_raw = &cm32181_write_raw,
.attrs = &cm32181_attribute_group,
};
static int cm32181_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct cm32181_chip *cm32181;
struct iio_dev *indio_dev;
int ret;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*cm32181));
if (!indio_dev) {
dev_err(&client->dev, "devm_iio_device_alloc failed\n");
return -ENOMEM;
}
cm32181 = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
cm32181->client = client;
mutex_init(&cm32181->lock);
indio_dev->dev.parent = &client->dev;
indio_dev->channels = cm32181_channels;
indio_dev->num_channels = ARRAY_SIZE(cm32181_channels);
indio_dev->info = &cm32181_info;
indio_dev->name = id->name;
indio_dev->modes = INDIO_DIRECT_MODE;
ret = cm32181_reg_init(cm32181);
if (ret) {
dev_err(&client->dev,
"%s: register init failed\n",
__func__);
return ret;
}
ret = iio_device_register(indio_dev);
if (ret) {
dev_err(&client->dev,
"%s: regist device failed\n",
__func__);
return ret;
}
return 0;
}
static int cm32181_remove(struct i2c_client *client)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
iio_device_unregister(indio_dev);
return 0;
}
static const struct i2c_device_id cm32181_id[] = {
{ "cm32181", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, cm32181_id);
static const struct of_device_id cm32181_of_match[] = {
{ .compatible = "capella,cm32181" },
{ }
};
static struct i2c_driver cm32181_driver = {
.driver = {
.name = "cm32181",
.of_match_table = of_match_ptr(cm32181_of_match),
.owner = THIS_MODULE,
},
.id_table = cm32181_id,
.probe = cm32181_probe,
.remove = cm32181_remove,
};
module_i2c_driver(cm32181_driver);
MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>");
MODULE_DESCRIPTION("CM32181 ambient light sensor driver");
MODULE_LICENSE("GPL");