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linux/drivers/iio/light/ltrf216a.c
Shreeya Patel 00799564ba iio: light: ltrf216a: Return floating point values 
For better precision of input light intesity, return floating point
values through sysfs instead of an integer value

Signed-off-by: Shreeya Patel <shreeya.patel@collabora.com>
Link: https://lore.kernel.org/r/20231107192005.285534-1-shreeya.patel@collabora.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2023-11-26 18:01:40 +00:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* LTRF216A Ambient Light Sensor
*
* Copyright (C) 2022 Collabora, Ltd.
* Author: Shreeya Patel <shreeya.patel@collabora.com>
*
* Copyright (C) 2021 Lite-On Technology Corp (Singapore)
* Author: Shi Zhigang <Zhigang.Shi@liteon.com>
*
* IIO driver for LTRF216A (7-bit I2C slave address 0x53).
*/
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/iopoll.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <linux/iio/iio.h>
#include <asm/unaligned.h>
#define LTRF216A_ALS_RESET_MASK BIT(4)
#define LTRF216A_ALS_DATA_STATUS BIT(3)
#define LTRF216A_ALS_ENABLE_MASK BIT(1)
#define LTRF216A_MAIN_CTRL 0x00
#define LTRF216A_ALS_MEAS_RES 0x04
#define LTRF216A_ALS_GAIN 0x05
#define LTRF216A_PART_ID 0x06
#define LTRF216A_MAIN_STATUS 0x07
#define LTRF216A_ALS_CLEAR_DATA_0 0x0a
#define LTRF216A_ALS_CLEAR_DATA_1 0x0b
#define LTRF216A_ALS_CLEAR_DATA_2 0x0c
#define LTRF216A_ALS_DATA_0 0x0d
#define LTRF216A_ALS_DATA_1 0x0e
#define LTRF216A_ALS_DATA_2 0x0f
#define LTRF216A_INT_CFG 0x19
#define LTRF216A_INT_PST 0x1a
#define LTRF216A_ALS_THRES_UP_0 0x21
#define LTRF216A_ALS_THRES_UP_1 0x22
#define LTRF216A_ALS_THRES_UP_2 0x23
#define LTRF216A_ALS_THRES_LOW_0 0x24
#define LTRF216A_ALS_THRES_LOW_1 0x25
#define LTRF216A_ALS_THRES_LOW_2 0x26
#define LTRF216A_ALS_READ_DATA_DELAY_US 20000
static const int ltrf216a_int_time_available[][2] = {
{ 0, 400000 },
{ 0, 200000 },
{ 0, 100000 },
{ 0, 50000 },
{ 0, 25000 },
};
static const int ltrf216a_int_time_reg[][2] = {
{ 400, 0x03 },
{ 200, 0x13 },
{ 100, 0x22 },
{ 50, 0x31 },
{ 25, 0x40 },
};
/*
* Window Factor is needed when the device is under Window glass
* with coated tinted ink. This is to compensate for the light loss
* due to the lower transmission rate of the window glass and helps
* in calculating lux.
*/
#define LTRF216A_WIN_FAC 1
struct ltrf216a_data {
struct regmap *regmap;
struct i2c_client *client;
u32 int_time;
u16 int_time_fac;
u8 als_gain_fac;
/*
* Protects regmap accesses and makes sure integration time
* remains constant during the measurement of lux.
*/
struct mutex lock;
};
static const struct iio_chan_spec ltrf216a_channels[] = {
{
.type = IIO_LIGHT,
.info_mask_separate =
BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_PROCESSED) |
BIT(IIO_CHAN_INFO_INT_TIME),
.info_mask_separate_available =
BIT(IIO_CHAN_INFO_INT_TIME),
},
};
static void ltrf216a_reset(struct iio_dev *indio_dev)
{
struct ltrf216a_data *data = iio_priv(indio_dev);
/* reset sensor, chip fails to respond to this, so ignore any errors */
regmap_write(data->regmap, LTRF216A_MAIN_CTRL, LTRF216A_ALS_RESET_MASK);
/* reset time */
usleep_range(1000, 2000);
}
static int ltrf216a_enable(struct iio_dev *indio_dev)
{
struct ltrf216a_data *data = iio_priv(indio_dev);
struct device *dev = &data->client->dev;
int ret;
/* enable sensor */
ret = regmap_set_bits(data->regmap,
LTRF216A_MAIN_CTRL, LTRF216A_ALS_ENABLE_MASK);
if (ret) {
dev_err(dev, "failed to enable sensor: %d\n", ret);
return ret;
}
/* sleep for one integration cycle after enabling the device */
msleep(ltrf216a_int_time_reg[0][0]);
return 0;
}
static int ltrf216a_disable(struct iio_dev *indio_dev)
{
struct ltrf216a_data *data = iio_priv(indio_dev);
struct device *dev = &data->client->dev;
int ret;
ret = regmap_write(data->regmap, LTRF216A_MAIN_CTRL, 0);
if (ret)
dev_err(dev, "failed to disable sensor: %d\n", ret);
return ret;
}
static void ltrf216a_cleanup(void *data)
{
struct iio_dev *indio_dev = data;
ltrf216a_disable(indio_dev);
}
static int ltrf216a_set_int_time(struct ltrf216a_data *data, int itime)
{
struct device *dev = &data->client->dev;
unsigned int i;
u8 reg_val;
int ret;
for (i = 0; i < ARRAY_SIZE(ltrf216a_int_time_available); i++) {
if (ltrf216a_int_time_available[i][1] == itime)
break;
}
if (i == ARRAY_SIZE(ltrf216a_int_time_available))
return -EINVAL;
reg_val = ltrf216a_int_time_reg[i][1];
ret = regmap_write(data->regmap, LTRF216A_ALS_MEAS_RES, reg_val);
if (ret) {
dev_err(dev, "failed to set integration time: %d\n", ret);
return ret;
}
data->int_time_fac = ltrf216a_int_time_reg[i][0];
data->int_time = itime;
return 0;
}
static int ltrf216a_get_int_time(struct ltrf216a_data *data,
int *val, int *val2)
{
*val = 0;
*val2 = data->int_time;
return IIO_VAL_INT_PLUS_MICRO;
}
static int ltrf216a_set_power_state(struct ltrf216a_data *data, bool on)
{
struct device *dev = &data->client->dev;
int ret = 0;
if (on) {
ret = pm_runtime_resume_and_get(dev);
if (ret) {
dev_err(dev, "failed to resume runtime PM: %d\n", ret);
return ret;
}
} else {
pm_runtime_mark_last_busy(dev);
pm_runtime_put_autosuspend(dev);
}
return ret;
}
static int ltrf216a_read_data(struct ltrf216a_data *data, u8 addr)
{
struct device *dev = &data->client->dev;
int ret, val;
u8 buf[3];
ret = regmap_read_poll_timeout(data->regmap, LTRF216A_MAIN_STATUS,
val, val & LTRF216A_ALS_DATA_STATUS,
LTRF216A_ALS_READ_DATA_DELAY_US,
LTRF216A_ALS_READ_DATA_DELAY_US * 50);
if (ret) {
dev_err(dev, "failed to wait for measurement data: %d\n", ret);
return ret;
}
ret = regmap_bulk_read(data->regmap, addr, buf, sizeof(buf));
if (ret) {
dev_err(dev, "failed to read measurement data: %d\n", ret);
return ret;
}
return get_unaligned_le24(&buf[0]);
}
static int ltrf216a_get_lux(struct ltrf216a_data *data)
{
int ret, greendata;
u64 lux;
ret = ltrf216a_set_power_state(data, true);
if (ret)
return ret;
greendata = ltrf216a_read_data(data, LTRF216A_ALS_DATA_0);
if (greendata < 0)
return greendata;
ltrf216a_set_power_state(data, false);
lux = greendata * 45 * LTRF216A_WIN_FAC;
return lux;
}
static int ltrf216a_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val,
int *val2, long mask)
{
struct ltrf216a_data *data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = ltrf216a_set_power_state(data, true);
if (ret)
return ret;
mutex_lock(&data->lock);
ret = ltrf216a_read_data(data, LTRF216A_ALS_DATA_0);
mutex_unlock(&data->lock);
ltrf216a_set_power_state(data, false);
if (ret < 0)
return ret;
*val = ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_PROCESSED:
mutex_lock(&data->lock);
ret = ltrf216a_get_lux(data);
mutex_unlock(&data->lock);
if (ret < 0)
return ret;
*val = ret;
*val2 = data->als_gain_fac * data->int_time_fac;
return IIO_VAL_FRACTIONAL;
case IIO_CHAN_INFO_INT_TIME:
mutex_lock(&data->lock);
ret = ltrf216a_get_int_time(data, val, val2);
mutex_unlock(&data->lock);
return ret;
default:
return -EINVAL;
}
}
static int ltrf216a_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int val,
int val2, long mask)
{
struct ltrf216a_data *data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_INT_TIME:
if (val != 0)
return -EINVAL;
mutex_lock(&data->lock);
ret = ltrf216a_set_int_time(data, val2);
mutex_unlock(&data->lock);
return ret;
default:
return -EINVAL;
}
}
static int ltrf216a_read_available(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
const int **vals, int *type, int *length,
long mask)
{
switch (mask) {
case IIO_CHAN_INFO_INT_TIME:
*length = ARRAY_SIZE(ltrf216a_int_time_available) * 2;
*vals = (const int *)ltrf216a_int_time_available;
*type = IIO_VAL_INT_PLUS_MICRO;
return IIO_AVAIL_LIST;
default:
return -EINVAL;
}
}
static const struct iio_info ltrf216a_info = {
.read_raw = ltrf216a_read_raw,
.write_raw = ltrf216a_write_raw,
.read_avail = ltrf216a_read_available,
};
static bool ltrf216a_readable_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case LTRF216A_MAIN_CTRL:
case LTRF216A_ALS_MEAS_RES:
case LTRF216A_ALS_GAIN:
case LTRF216A_PART_ID:
case LTRF216A_MAIN_STATUS:
case LTRF216A_ALS_CLEAR_DATA_0:
case LTRF216A_ALS_CLEAR_DATA_1:
case LTRF216A_ALS_CLEAR_DATA_2:
case LTRF216A_ALS_DATA_0:
case LTRF216A_ALS_DATA_1:
case LTRF216A_ALS_DATA_2:
case LTRF216A_INT_CFG:
case LTRF216A_INT_PST:
case LTRF216A_ALS_THRES_UP_0:
case LTRF216A_ALS_THRES_UP_1:
case LTRF216A_ALS_THRES_UP_2:
case LTRF216A_ALS_THRES_LOW_0:
case LTRF216A_ALS_THRES_LOW_1:
case LTRF216A_ALS_THRES_LOW_2:
return true;
default:
return false;
}
}
static bool ltrf216a_writable_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case LTRF216A_MAIN_CTRL:
case LTRF216A_ALS_MEAS_RES:
case LTRF216A_ALS_GAIN:
case LTRF216A_INT_CFG:
case LTRF216A_INT_PST:
case LTRF216A_ALS_THRES_UP_0:
case LTRF216A_ALS_THRES_UP_1:
case LTRF216A_ALS_THRES_UP_2:
case LTRF216A_ALS_THRES_LOW_0:
case LTRF216A_ALS_THRES_LOW_1:
case LTRF216A_ALS_THRES_LOW_2:
return true;
default:
return false;
}
}
static bool ltrf216a_volatile_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case LTRF216A_MAIN_STATUS:
case LTRF216A_ALS_CLEAR_DATA_0:
case LTRF216A_ALS_CLEAR_DATA_1:
case LTRF216A_ALS_CLEAR_DATA_2:
case LTRF216A_ALS_DATA_0:
case LTRF216A_ALS_DATA_1:
case LTRF216A_ALS_DATA_2:
return true;
default:
return false;
}
}
static bool ltrf216a_precious_reg(struct device *dev, unsigned int reg)
{
return reg == LTRF216A_MAIN_STATUS;
}
static const struct regmap_config ltrf216a_regmap_config = {
.name = "ltrf216a",
.reg_bits = 8,
.val_bits = 8,
.cache_type = REGCACHE_RBTREE,
.max_register = LTRF216A_ALS_THRES_LOW_2,
.readable_reg = ltrf216a_readable_reg,
.writeable_reg = ltrf216a_writable_reg,
.volatile_reg = ltrf216a_volatile_reg,
.precious_reg = ltrf216a_precious_reg,
.disable_locking = true,
};
static int ltrf216a_probe(struct i2c_client *client)
{
struct ltrf216a_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);
data->regmap = devm_regmap_init_i2c(client, &ltrf216a_regmap_config);
if (IS_ERR(data->regmap))
return dev_err_probe(&client->dev, PTR_ERR(data->regmap),
"regmap initialization failed\n");
i2c_set_clientdata(client, indio_dev);
data->client = client;
mutex_init(&data->lock);
indio_dev->info = &ltrf216a_info;
indio_dev->name = "ltrf216a";
indio_dev->channels = ltrf216a_channels;
indio_dev->num_channels = ARRAY_SIZE(ltrf216a_channels);
indio_dev->modes = INDIO_DIRECT_MODE;
ret = pm_runtime_set_active(&client->dev);
if (ret)
return ret;
/* reset sensor, chip fails to respond to this, so ignore any errors */
ltrf216a_reset(indio_dev);
ret = regmap_reinit_cache(data->regmap, &ltrf216a_regmap_config);
if (ret)
return dev_err_probe(&client->dev, ret,
"failed to reinit regmap cache\n");
ret = ltrf216a_enable(indio_dev);
if (ret)
return ret;
ret = devm_add_action_or_reset(&client->dev, ltrf216a_cleanup,
indio_dev);
if (ret)
return ret;
ret = devm_pm_runtime_enable(&client->dev);
if (ret)
return dev_err_probe(&client->dev, ret,
"failed to enable runtime PM\n");
pm_runtime_set_autosuspend_delay(&client->dev, 1000);
pm_runtime_use_autosuspend(&client->dev);
data->int_time = 100000;
data->int_time_fac = 100;
data->als_gain_fac = 3;
return devm_iio_device_register(&client->dev, indio_dev);
}
static int ltrf216a_runtime_suspend(struct device *dev)
{
struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
struct ltrf216a_data *data = iio_priv(indio_dev);
int ret;
ret = ltrf216a_disable(indio_dev);
if (ret)
return ret;
regcache_cache_only(data->regmap, true);
return 0;
}
static int ltrf216a_runtime_resume(struct device *dev)
{
struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
struct ltrf216a_data *data = iio_priv(indio_dev);
int ret;
regcache_cache_only(data->regmap, false);
regcache_mark_dirty(data->regmap);
ret = regcache_sync(data->regmap);
if (ret)
goto cache_only;
ret = ltrf216a_enable(indio_dev);
if (ret)
goto cache_only;
return 0;
cache_only:
regcache_cache_only(data->regmap, true);
return ret;
}
static DEFINE_RUNTIME_DEV_PM_OPS(ltrf216a_pm_ops, ltrf216a_runtime_suspend,
ltrf216a_runtime_resume, NULL);
static const struct i2c_device_id ltrf216a_id[] = {
{ "ltrf216a" },
{}
};
MODULE_DEVICE_TABLE(i2c, ltrf216a_id);
static const struct of_device_id ltrf216a_of_match[] = {
{ .compatible = "liteon,ltrf216a" },
{ .compatible = "ltr,ltrf216a" },
{}
};
MODULE_DEVICE_TABLE(of, ltrf216a_of_match);
static struct i2c_driver ltrf216a_driver = {
.driver = {
.name = "ltrf216a",
.pm = pm_ptr(&ltrf216a_pm_ops),
.of_match_table = ltrf216a_of_match,
},
.probe = ltrf216a_probe,
.id_table = ltrf216a_id,
};
module_i2c_driver(ltrf216a_driver);
MODULE_AUTHOR("Shreeya Patel <shreeya.patel@collabora.com>");
MODULE_AUTHOR("Shi Zhigang <Zhigang.Shi@liteon.com>");
MODULE_DESCRIPTION("LTRF216A ambient light sensor driver");
MODULE_LICENSE("GPL");
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