// SPDX-License-Identifier: GPL-2.0-only
/*
* Vishay VEML6075 UVA and UVB light sensor
*
* Copyright 2023 Javier Carrasco <[email protected]>
*
* 7-bit I2C slave, address 0x10
*/
#include <linux/bitfield.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/regmap.h>
#include <linux/units.h>
#include <linux/iio/iio.h>
#define VEML6075_CMD_CONF 0x00 /* configuration register */
#define VEML6075_CMD_UVA 0x07 /* UVA channel */
#define VEML6075_CMD_UVB 0x09 /* UVB channel */
#define VEML6075_CMD_COMP1 0x0A /* visible light compensation */
#define VEML6075_CMD_COMP2 0x0B /* infrarred light compensation */
#define VEML6075_CMD_ID 0x0C /* device ID */
#define VEML6075_CONF_IT GENMASK(6, 4) /* intregration time */
#define VEML6075_CONF_HD BIT(3) /* dynamic setting */
#define VEML6075_CONF_TRIG BIT(2) /* trigger */
#define VEML6075_CONF_AF BIT(1) /* active force enable */
#define VEML6075_CONF_SD BIT(0) /* shutdown */
#define VEML6075_IT_50_MS 0x00
#define VEML6075_IT_100_MS 0x01
#define VEML6075_IT_200_MS 0x02
#define VEML6075_IT_400_MS 0x03
#define VEML6075_IT_800_MS 0x04
#define VEML6075_AF_DISABLE 0x00
#define VEML6075_AF_ENABLE 0x01
#define VEML6075_SD_DISABLE 0x00
#define VEML6075_SD_ENABLE 0x01
/* Open-air coefficients and responsivity */
#define VEML6075_A_COEF 2220
#define VEML6075_B_COEF 1330
#define VEML6075_C_COEF 2950
#define VEML6075_D_COEF 1740
#define VEML6075_UVA_RESP 1461
#define VEML6075_UVB_RESP 2591
static const int veml6075_it_ms[] = { 50, 100, 200, 400, 800 };
struct veml6075_data {
struct i2c_client *client;
struct regmap *regmap;
/*
* prevent integration time modification and triggering
* measurements while a measurement is underway.
*/
struct mutex lock;
};
/* channel number */
enum veml6075_chan {
CH_UVA,
CH_UVB,
};
static const struct iio_chan_spec veml6075_channels[] = {
{
.type = IIO_INTENSITY,
.channel = CH_UVA,
.modified = 1,
.channel2 = IIO_MOD_LIGHT_UVA,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME),
},
{
.type = IIO_INTENSITY,
.channel = CH_UVB,
.modified = 1,
.channel2 = IIO_MOD_LIGHT_UVB,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME),
},
{
.type = IIO_UVINDEX,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME),
.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME),
},
};
static int veml6075_request_measurement(struct veml6075_data *data)
{
int ret, conf, int_time;
ret = regmap_read(data->regmap, VEML6075_CMD_CONF, &conf);
if (ret < 0)
return ret;
/* disable shutdown and trigger measurement */
ret = regmap_write(data->regmap, VEML6075_CMD_CONF,
(conf | VEML6075_CONF_TRIG) & ~VEML6075_CONF_SD);
if (ret < 0)
return ret;
/*
* A measurement requires between 1.30 and 1.40 times the integration
* time for all possible configurations. Using a 1.50 factor simplifies
* operations and ensures reliability under all circumstances.
*/
int_time = veml6075_it_ms[FIELD_GET(VEML6075_CONF_IT, conf)];
msleep(int_time + (int_time / 2));
/* shutdown again, data registers are still accessible */
return regmap_update_bits(data->regmap, VEML6075_CMD_CONF,
VEML6075_CONF_SD, VEML6075_CONF_SD);
}
static int veml6075_uva_comp(int raw_uva, int comp1, int comp2)
{
int comp1a_c, comp2a_c, uva_comp;
comp1a_c = (comp1 * VEML6075_A_COEF) / 1000U;
comp2a_c = (comp2 * VEML6075_B_COEF) / 1000U;
uva_comp = raw_uva - comp1a_c - comp2a_c;
return clamp_val(uva_comp, 0, U16_MAX);
}
static int veml6075_uvb_comp(int raw_uvb, int comp1, int comp2)
{
int comp1b_c, comp2b_c, uvb_comp;
comp1b_c = (comp1 * VEML6075_C_COEF) / 1000U;
comp2b_c = (comp2 * VEML6075_D_COEF) / 1000U;
uvb_comp = raw_uvb - comp1b_c - comp2b_c;
return clamp_val(uvb_comp, 0, U16_MAX);
}
static int veml6075_read_comp(struct veml6075_data *data, int *c1, int *c2)
{
int ret;
ret = regmap_read(data->regmap, VEML6075_CMD_COMP1, c1);
if (ret < 0)
return ret;
return regmap_read(data->regmap, VEML6075_CMD_COMP2, c2);
}
static int veml6075_read_uv_direct(struct veml6075_data *data, int chan,
int *val)
{
int c1, c2, ret;
guard(mutex)(&data->lock);
ret = veml6075_request_measurement(data);
if (ret < 0)
return ret;
ret = veml6075_read_comp(data, &c1, &c2);
if (ret < 0)
return ret;
switch (chan) {
case CH_UVA:
ret = regmap_read(data->regmap, VEML6075_CMD_UVA, val);
if (ret < 0)
return ret;
*val = veml6075_uva_comp(*val, c1, c2);
return IIO_VAL_INT;
case CH_UVB:
ret = regmap_read(data->regmap, VEML6075_CMD_UVB, val);
if (ret < 0)
return ret;
*val = veml6075_uvb_comp(*val, c1, c2);
return IIO_VAL_INT;
default:
return -EINVAL;
}
}
static int veml6075_read_int_time_index(struct veml6075_data *data)
{
int ret, conf;
ret = regmap_read(data->regmap, VEML6075_CMD_CONF, &conf);
if (ret < 0)
return ret;
return FIELD_GET(VEML6075_CONF_IT, conf);
}
static int veml6075_read_int_time_ms(struct veml6075_data *data, int *val)
{
int int_index;
guard(mutex)(&data->lock);
int_index = veml6075_read_int_time_index(data);
if (int_index < 0)
return int_index;
*val = veml6075_it_ms[int_index];
return IIO_VAL_INT;
}
static int veml6075_get_uvi_micro(struct veml6075_data *data, int uva_comp,
int uvb_comp)
{
int uvia_micro = uva_comp * VEML6075_UVA_RESP;
int uvib_micro = uvb_comp * VEML6075_UVB_RESP;
int int_index;
int_index = veml6075_read_int_time_index(data);
if (int_index < 0)
return int_index;
switch (int_index) {
case VEML6075_IT_50_MS:
return uvia_micro + uvib_micro;
case VEML6075_IT_100_MS:
case VEML6075_IT_200_MS:
case VEML6075_IT_400_MS:
case VEML6075_IT_800_MS:
return (uvia_micro + uvib_micro) / (2 << int_index);
default:
return -EINVAL;
}
}
static int veml6075_read_uvi(struct veml6075_data *data, int *val, int *val2)
{
int ret, c1, c2, uva, uvb, uvi_micro;
guard(mutex)(&data->lock);
ret = veml6075_request_measurement(data);
if (ret < 0)
return ret;
ret = veml6075_read_comp(data, &c1, &c2);
if (ret < 0)
return ret;
ret = regmap_read(data->regmap, VEML6075_CMD_UVA, &uva);
if (ret < 0)
return ret;
ret = regmap_read(data->regmap, VEML6075_CMD_UVB, &uvb);
if (ret < 0)
return ret;
uvi_micro = veml6075_get_uvi_micro(data, veml6075_uva_comp(uva, c1, c2),
veml6075_uvb_comp(uvb, c1, c2));
if (uvi_micro < 0)
return uvi_micro;
*val = uvi_micro / MICRO;
*val2 = uvi_micro % MICRO;
return IIO_VAL_INT_PLUS_MICRO;
}
static int veml6075_read_responsivity(int chan, int *val, int *val2)
{
/* scale = 1 / resp */
switch (chan) {
case CH_UVA:
/* resp = 0.93 c/uW/cm2: scale = 1.75268817 */
*val = 1;
*val2 = 75268817;
return IIO_VAL_INT_PLUS_NANO;
case CH_UVB:
/* resp = 2.1 c/uW/cm2: scale = 0.476190476 */
*val = 0;
*val2 = 476190476;
return IIO_VAL_INT_PLUS_NANO;
default:
return -EINVAL;
}
}
static int veml6075_read_avail(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(veml6075_it_ms);
*vals = veml6075_it_ms;
*type = IIO_VAL_INT;
return IIO_AVAIL_LIST;
default:
return -EINVAL;
}
}
static int veml6075_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct veml6075_data *data = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_RAW:
return veml6075_read_uv_direct(data, chan->channel, val);
case IIO_CHAN_INFO_PROCESSED:
return veml6075_read_uvi(data, val, val2);
case IIO_CHAN_INFO_INT_TIME:
return veml6075_read_int_time_ms(data, val);
case IIO_CHAN_INFO_SCALE:
return veml6075_read_responsivity(chan->channel, val, val2);
default:
return -EINVAL;
}
}
static int veml6075_write_int_time_ms(struct veml6075_data *data, int val)
{
int i = ARRAY_SIZE(veml6075_it_ms);
guard(mutex)(&data->lock);
while (i-- > 0) {
if (val == veml6075_it_ms[i])
break;
}
if (i < 0)
return -EINVAL;
return regmap_update_bits(data->regmap, VEML6075_CMD_CONF,
VEML6075_CONF_IT,
FIELD_PREP(VEML6075_CONF_IT, i));
}
static int veml6075_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct veml6075_data *data = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_INT_TIME:
return veml6075_write_int_time_ms(data, val);
default:
return -EINVAL;
}
}
static const struct iio_info veml6075_info = {
.read_avail = veml6075_read_avail,
.read_raw = veml6075_read_raw,
.write_raw = veml6075_write_raw,
};
static bool veml6075_readable_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case VEML6075_CMD_CONF:
case VEML6075_CMD_UVA:
case VEML6075_CMD_UVB:
case VEML6075_CMD_COMP1:
case VEML6075_CMD_COMP2:
case VEML6075_CMD_ID:
return true;
default:
return false;
}
}
static bool veml6075_writable_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case VEML6075_CMD_CONF:
return true;
default:
return false;
}
}
static const struct regmap_config veml6075_regmap_config = {
.name = "veml6075",
.reg_bits = 8,
.val_bits = 16,
.max_register = VEML6075_CMD_ID,
.readable_reg = veml6075_readable_reg,
.writeable_reg = veml6075_writable_reg,
.val_format_endian = REGMAP_ENDIAN_LITTLE,
};
static int veml6075_probe(struct i2c_client *client)
{
struct veml6075_data *data;
struct iio_dev *indio_dev;
struct regmap *regmap;
int config, ret;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
regmap = devm_regmap_init_i2c(client, &veml6075_regmap_config);
if (IS_ERR(regmap))
return PTR_ERR(regmap);
data = iio_priv(indio_dev);
data->client = client;
data->regmap = regmap;
mutex_init(&data->lock);
indio_dev->name = "veml6075";
indio_dev->info = &veml6075_info;
indio_dev->channels = veml6075_channels;
indio_dev->num_channels = ARRAY_SIZE(veml6075_channels);
indio_dev->modes = INDIO_DIRECT_MODE;
ret = devm_regulator_get_enable(&client->dev, "vdd");
if (ret < 0)
return ret;
/* default: 100ms integration time, active force enable, shutdown */
config = FIELD_PREP(VEML6075_CONF_IT, VEML6075_IT_100_MS) |
FIELD_PREP(VEML6075_CONF_AF, VEML6075_AF_ENABLE) |
FIELD_PREP(VEML6075_CONF_SD, VEML6075_SD_ENABLE);
ret = regmap_write(data->regmap, VEML6075_CMD_CONF, config);
if (ret < 0)
return ret;
return devm_iio_device_register(&client->dev, indio_dev);
}
static const struct i2c_device_id veml6075_id[] = {
{ "veml6075" },
{ }
};
MODULE_DEVICE_TABLE(i2c, veml6075_id);
static const struct of_device_id veml6075_of_match[] = {
{ .compatible = "vishay,veml6075" },
{}
};
MODULE_DEVICE_TABLE(of, veml6075_of_match);
static struct i2c_driver veml6075_driver = {
.driver = {
.name = "veml6075",
.of_match_table = veml6075_of_match,
},
.probe = veml6075_probe,
.id_table = veml6075_id,
};
module_i2c_driver(veml6075_driver);
MODULE_AUTHOR("Javier Carrasco <[email protected]>");
MODULE_DESCRIPTION("Vishay VEML6075 UVA and UVB light sensor driver");
MODULE_LICENSE("GPL");
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