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linux/drivers/iio/light/ltrf216a.c
Shreeya Patel f5ffeca508 iio: light: ltrf216a: Add raw attribute 
Add IIO_CHAN_INFO_RAW to the mask to be able to read raw values
from the light sensor.

The userspace code for brightness control in steam deck uses the
in_illuminance_input value through sysfs and multiplies it
with a constant stored in BIOS at factory calibration time.

The downstream driver for LTRF216A that we have been using
has incorrect formula for LUX calculation which we corrected
in the upstreamed driver.

Now to be able to use the upstreamed driver, we need to add some
magic in userspace so that the brightness control works like before
even with the updated LUX formula.

Hence, we need the raw data to calculate a constant that can be
added in userspace code.

Downstream driver LUX formula :-
(greendata*8*LTRF216A_WIN_FAC) / (data->als_gain_fac*data->int_time_fac*10)

Upstreamed driver LUX formula :-
(greendata*45*LTRF216A_WIN_FAC) / (data->als_gain_fac*data->int_time_fac)

greendata is the ALS_DATA which we would like to get through sysfs using
the raw attribute.

Signed-off-by: Shreeya Patel <shreeya.patel@collabora.com>
Link: https://lore.kernel.org/r/20220812100424.529425-1-shreeya.patel@collabora.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2022-08-30 18:35:38 +01:00

551 lines
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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, div;
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 * 100;
div = data->als_gain_fac * data->int_time_fac * 100;
return div_u64(lux, div);
}
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;
return IIO_VAL_INT;
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_new = 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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