// SPDX-License-Identifier: GPL-2.0-only
/*
* MAX44000 Ambient and Infrared Proximity Sensor
*
* Copyright (c) 2016, Intel Corporation.
*
* Data sheet: https://datasheets.maximintegrated.com/en/ds/MAX44000.pdf
*
* 7-bit I2C slave address 0x4a
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/regmap.h>
#include <linux/util_macros.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/acpi.h>
#define MAX44000_DRV_NAME "max44000"
/* Registers in datasheet order */
#define MAX44000_REG_STATUS 0x00
#define MAX44000_REG_CFG_MAIN 0x01
#define MAX44000_REG_CFG_RX 0x02
#define MAX44000_REG_CFG_TX 0x03
#define MAX44000_REG_ALS_DATA_HI 0x04
#define MAX44000_REG_ALS_DATA_LO 0x05
#define MAX44000_REG_PRX_DATA 0x16
#define MAX44000_REG_ALS_UPTHR_HI 0x06
#define MAX44000_REG_ALS_UPTHR_LO 0x07
#define MAX44000_REG_ALS_LOTHR_HI 0x08
#define MAX44000_REG_ALS_LOTHR_LO 0x09
#define MAX44000_REG_PST 0x0a
#define MAX44000_REG_PRX_IND 0x0b
#define MAX44000_REG_PRX_THR 0x0c
#define MAX44000_REG_TRIM_GAIN_GREEN 0x0f
#define MAX44000_REG_TRIM_GAIN_IR 0x10
/* REG_CFG bits */
#define MAX44000_CFG_ALSINTE 0x01
#define MAX44000_CFG_PRXINTE 0x02
#define MAX44000_CFG_MASK 0x1c
#define MAX44000_CFG_MODE_SHUTDOWN 0x00
#define MAX44000_CFG_MODE_ALS_GIR 0x04
#define MAX44000_CFG_MODE_ALS_G 0x08
#define MAX44000_CFG_MODE_ALS_IR 0x0c
#define MAX44000_CFG_MODE_ALS_PRX 0x10
#define MAX44000_CFG_MODE_PRX 0x14
#define MAX44000_CFG_TRIM 0x20
/*
* Upper 4 bits are not documented but start as 1 on powerup
* Setting them to 0 causes proximity to misbehave so set them to 1
*/
#define MAX44000_REG_CFG_RX_DEFAULT 0xf0
/* REG_RX bits */
#define MAX44000_CFG_RX_ALSTIM_MASK 0x0c
#define MAX44000_CFG_RX_ALSTIM_SHIFT 2
#define MAX44000_CFG_RX_ALSPGA_MASK 0x03
#define MAX44000_CFG_RX_ALSPGA_SHIFT 0
/* REG_TX bits */
#define MAX44000_LED_CURRENT_MASK 0xf
#define MAX44000_LED_CURRENT_MAX 11
#define MAX44000_LED_CURRENT_DEFAULT 6
#define MAX44000_ALSDATA_OVERFLOW 0x4000
struct max44000_data {
struct mutex lock;
struct regmap *regmap;
};
/* Default scale is set to the minimum of 0.03125 or 1 / (1 << 5) lux */
#define MAX44000_ALS_TO_LUX_DEFAULT_FRACTION_LOG2 5
/* Scale can be multiplied by up to 128x via ALSPGA for measurement gain */
static const int max44000_alspga_shift[] = {0, 2, 4, 7};
#define MAX44000_ALSPGA_MAX_SHIFT 7
/*
* Scale can be multiplied by up to 64x via ALSTIM because of lost resolution
*
* This scaling factor is hidden from userspace and instead accounted for when
* reading raw values from the device.
*
* This makes it possible to cleanly expose ALSPGA as IIO_CHAN_INFO_SCALE and
* ALSTIM as IIO_CHAN_INFO_INT_TIME without the values affecting each other.
*
* Handling this internally is also required for buffer support because the
* channel's scan_type can't be modified dynamically.
*/
#define MAX44000_ALSTIM_SHIFT(alstim) (2 * (alstim))
/* Available integration times with pretty manual alignment: */
static const int max44000_int_time_avail_ns_array[] = {
100000000,
25000000,
6250000,
1562500,
};
static const char max44000_int_time_avail_str[] =
"0.100 "
"0.025 "
"0.00625 "
"0.0015625";
/* Available scales (internal to ulux) with pretty manual alignment: */
static const int max44000_scale_avail_ulux_array[] = {
31250,
125000,
500000,
4000000,
};
static const char max44000_scale_avail_str[] =
"0.03125 "
"0.125 "
"0.5 "
"4";
#define MAX44000_SCAN_INDEX_ALS 0
#define MAX44000_SCAN_INDEX_PRX 1
static const struct iio_chan_spec max44000_channels[] = {
{
.type = IIO_LIGHT,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_INT_TIME),
.scan_index = MAX44000_SCAN_INDEX_ALS,
.scan_type = {
.sign = 'u',
.realbits = 14,
.storagebits = 16,
}
},
{
.type = IIO_PROXIMITY,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.scan_index = MAX44000_SCAN_INDEX_PRX,
.scan_type = {
.sign = 'u',
.realbits = 8,
.storagebits = 16,
}
},
IIO_CHAN_SOFT_TIMESTAMP(2),
{
.type = IIO_CURRENT,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
.extend_name = "led",
.output = 1,
.scan_index = -1,
},
};
static int max44000_read_alstim(struct max44000_data *data)
{
unsigned int val;
int ret;
ret = regmap_read(data->regmap, MAX44000_REG_CFG_RX, &val);
if (ret < 0)
return ret;
return (val & MAX44000_CFG_RX_ALSTIM_MASK) >> MAX44000_CFG_RX_ALSTIM_SHIFT;
}
static int max44000_write_alstim(struct max44000_data *data, int val)
{
return regmap_write_bits(data->regmap, MAX44000_REG_CFG_RX,
MAX44000_CFG_RX_ALSTIM_MASK,
val << MAX44000_CFG_RX_ALSTIM_SHIFT);
}
static int max44000_read_alspga(struct max44000_data *data)
{
unsigned int val;
int ret;
ret = regmap_read(data->regmap, MAX44000_REG_CFG_RX, &val);
if (ret < 0)
return ret;
return (val & MAX44000_CFG_RX_ALSPGA_MASK) >> MAX44000_CFG_RX_ALSPGA_SHIFT;
}
static int max44000_write_alspga(struct max44000_data *data, int val)
{
return regmap_write_bits(data->regmap, MAX44000_REG_CFG_RX,
MAX44000_CFG_RX_ALSPGA_MASK,
val << MAX44000_CFG_RX_ALSPGA_SHIFT);
}
static int max44000_read_alsval(struct max44000_data *data)
{
u16 regval;
__be16 val;
int alstim, ret;
ret = regmap_bulk_read(data->regmap, MAX44000_REG_ALS_DATA_HI,
&val, sizeof(val));
if (ret < 0)
return ret;
alstim = ret = max44000_read_alstim(data);
if (ret < 0)
return ret;
regval = be16_to_cpu(val);
/*
* Overflow is explained on datasheet page 17.
*
* It's a warning that either the G or IR channel has become saturated
* and that the value in the register is likely incorrect.
*
* The recommendation is to change the scale (ALSPGA).
* The driver just returns the max representable value.
*/
if (regval & MAX44000_ALSDATA_OVERFLOW)
return 0x3FFF;
return regval << MAX44000_ALSTIM_SHIFT(alstim);
}
static int max44000_write_led_current_raw(struct max44000_data *data, int val)
{
/* Maybe we should clamp the value instead? */
if (val < 0 || val > MAX44000_LED_CURRENT_MAX)
return -ERANGE;
if (val >= 8)
val += 4;
return regmap_write_bits(data->regmap, MAX44000_REG_CFG_TX,
MAX44000_LED_CURRENT_MASK, val);
}
static int max44000_read_led_current_raw(struct max44000_data *data)
{
unsigned int regval;
int ret;
ret = regmap_read(data->regmap, MAX44000_REG_CFG_TX, ®val);
if (ret < 0)
return ret;
regval &= MAX44000_LED_CURRENT_MASK;
if (regval >= 8)
regval -= 4;
return regval;
}
static int max44000_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct max44000_data *data = iio_priv(indio_dev);
int alstim, alspga;
unsigned int regval;
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
switch (chan->type) {
case IIO_LIGHT:
mutex_lock(&data->lock);
ret = max44000_read_alsval(data);
mutex_unlock(&data->lock);
if (ret < 0)
return ret;
*val = ret;
return IIO_VAL_INT;
case IIO_PROXIMITY:
mutex_lock(&data->lock);
ret = regmap_read(data->regmap, MAX44000_REG_PRX_DATA, ®val);
mutex_unlock(&data->lock);
if (ret < 0)
return ret;
*val = regval;
return IIO_VAL_INT;
case IIO_CURRENT:
mutex_lock(&data->lock);
ret = max44000_read_led_current_raw(data);
mutex_unlock(&data->lock);
if (ret < 0)
return ret;
*val = ret;
return IIO_VAL_INT;
default:
return -EINVAL;
}
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
case IIO_CURRENT:
/* Output register is in 10s of miliamps */
*val = 10;
return IIO_VAL_INT;
case IIO_LIGHT:
mutex_lock(&data->lock);
alspga = ret = max44000_read_alspga(data);
mutex_unlock(&data->lock);
if (ret < 0)
return ret;
/* Avoid negative shifts */
*val = (1 << MAX44000_ALSPGA_MAX_SHIFT);
*val2 = MAX44000_ALS_TO_LUX_DEFAULT_FRACTION_LOG2
+ MAX44000_ALSPGA_MAX_SHIFT
- max44000_alspga_shift[alspga];
return IIO_VAL_FRACTIONAL_LOG2;
default:
return -EINVAL;
}
case IIO_CHAN_INFO_INT_TIME:
mutex_lock(&data->lock);
alstim = ret = max44000_read_alstim(data);
mutex_unlock(&data->lock);
if (ret < 0)
return ret;
*val = 0;
*val2 = max44000_int_time_avail_ns_array[alstim];
return IIO_VAL_INT_PLUS_NANO;
default:
return -EINVAL;
}
}
static int max44000_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct max44000_data *data = iio_priv(indio_dev);
int ret;
if (mask == IIO_CHAN_INFO_RAW && chan->type == IIO_CURRENT) {
mutex_lock(&data->lock);
ret = max44000_write_led_current_raw(data, val);
mutex_unlock(&data->lock);
return ret;
} else if (mask == IIO_CHAN_INFO_INT_TIME && chan->type == IIO_LIGHT) {
s64 valns = val * NSEC_PER_SEC + val2;
int alstim = find_closest_descending(valns,
max44000_int_time_avail_ns_array,
ARRAY_SIZE(max44000_int_time_avail_ns_array));
mutex_lock(&data->lock);
ret = max44000_write_alstim(data, alstim);
mutex_unlock(&data->lock);
return ret;
} else if (mask == IIO_CHAN_INFO_SCALE && chan->type == IIO_LIGHT) {
s64 valus = val * USEC_PER_SEC + val2;
int alspga = find_closest(valus,
max44000_scale_avail_ulux_array,
ARRAY_SIZE(max44000_scale_avail_ulux_array));
mutex_lock(&data->lock);
ret = max44000_write_alspga(data, alspga);
mutex_unlock(&data->lock);
return ret;
}
return -EINVAL;
}
static int max44000_write_raw_get_fmt(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
long mask)
{
if (mask == IIO_CHAN_INFO_INT_TIME && chan->type == IIO_LIGHT)
return IIO_VAL_INT_PLUS_NANO;
else if (mask == IIO_CHAN_INFO_SCALE && chan->type == IIO_LIGHT)
return IIO_VAL_INT_PLUS_MICRO;
else
return IIO_VAL_INT;
}
static IIO_CONST_ATTR(illuminance_integration_time_available, max44000_int_time_avail_str);
static IIO_CONST_ATTR(illuminance_scale_available, max44000_scale_avail_str);
static struct attribute *max44000_attributes[] = {
&iio_const_attr_illuminance_integration_time_available.dev_attr.attr,
&iio_const_attr_illuminance_scale_available.dev_attr.attr,
NULL
};
static const struct attribute_group max44000_attribute_group = {
.attrs = max44000_attributes,
};
static const struct iio_info max44000_info = {
.read_raw = max44000_read_raw,
.write_raw = max44000_write_raw,
.write_raw_get_fmt = max44000_write_raw_get_fmt,
.attrs = &max44000_attribute_group,
};
static bool max44000_readable_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case MAX44000_REG_STATUS:
case MAX44000_REG_CFG_MAIN:
case MAX44000_REG_CFG_RX:
case MAX44000_REG_CFG_TX:
case MAX44000_REG_ALS_DATA_HI:
case MAX44000_REG_ALS_DATA_LO:
case MAX44000_REG_PRX_DATA:
case MAX44000_REG_ALS_UPTHR_HI:
case MAX44000_REG_ALS_UPTHR_LO:
case MAX44000_REG_ALS_LOTHR_HI:
case MAX44000_REG_ALS_LOTHR_LO:
case MAX44000_REG_PST:
case MAX44000_REG_PRX_IND:
case MAX44000_REG_PRX_THR:
case MAX44000_REG_TRIM_GAIN_GREEN:
case MAX44000_REG_TRIM_GAIN_IR:
return true;
default:
return false;
}
}
static bool max44000_writeable_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case MAX44000_REG_CFG_MAIN:
case MAX44000_REG_CFG_RX:
case MAX44000_REG_CFG_TX:
case MAX44000_REG_ALS_UPTHR_HI:
case MAX44000_REG_ALS_UPTHR_LO:
case MAX44000_REG_ALS_LOTHR_HI:
case MAX44000_REG_ALS_LOTHR_LO:
case MAX44000_REG_PST:
case MAX44000_REG_PRX_IND:
case MAX44000_REG_PRX_THR:
case MAX44000_REG_TRIM_GAIN_GREEN:
case MAX44000_REG_TRIM_GAIN_IR:
return true;
default:
return false;
}
}
static bool max44000_volatile_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case MAX44000_REG_STATUS:
case MAX44000_REG_ALS_DATA_HI:
case MAX44000_REG_ALS_DATA_LO:
case MAX44000_REG_PRX_DATA:
return true;
default:
return false;
}
}
static bool max44000_precious_reg(struct device *dev, unsigned int reg)
{
return reg == MAX44000_REG_STATUS;
}
static const struct regmap_config max44000_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.max_register = MAX44000_REG_PRX_DATA,
.readable_reg = max44000_readable_reg,
.writeable_reg = max44000_writeable_reg,
.volatile_reg = max44000_volatile_reg,
.precious_reg = max44000_precious_reg,
.use_single_read = true,
.use_single_write = true,
.cache_type = REGCACHE_RBTREE,
};
static irqreturn_t max44000_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct max44000_data *data = iio_priv(indio_dev);
u16 buf[8]; /* 2x u16 + padding + 8 bytes timestamp */
int index = 0;
unsigned int regval;
int ret;
mutex_lock(&data->lock);
if (test_bit(MAX44000_SCAN_INDEX_ALS, indio_dev->active_scan_mask)) {
ret = max44000_read_alsval(data);
if (ret < 0)
goto out_unlock;
buf[index++] = ret;
}
if (test_bit(MAX44000_SCAN_INDEX_PRX, indio_dev->active_scan_mask)) {
ret = regmap_read(data->regmap, MAX44000_REG_PRX_DATA, ®val);
if (ret < 0)
goto out_unlock;
buf[index] = regval;
}
mutex_unlock(&data->lock);
iio_push_to_buffers_with_timestamp(indio_dev, buf,
iio_get_time_ns(indio_dev));
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
out_unlock:
mutex_unlock(&data->lock);
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static int max44000_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct max44000_data *data;
struct iio_dev *indio_dev;
int ret, reg;
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, &max44000_regmap_config);
if (IS_ERR(data->regmap)) {
dev_err(&client->dev, "regmap_init failed!\n");
return PTR_ERR(data->regmap);
}
i2c_set_clientdata(client, indio_dev);
mutex_init(&data->lock);
indio_dev->dev.parent = &client->dev;
indio_dev->info = &max44000_info;
indio_dev->name = MAX44000_DRV_NAME;
indio_dev->channels = max44000_channels;
indio_dev->num_channels = ARRAY_SIZE(max44000_channels);
/*
* The device doesn't have a reset function so we just clear some
* important bits at probe time to ensure sane operation.
*
* Since we don't support interrupts/events the threshold values are
* not important. We also don't touch trim values.
*/
/* Reset ALS scaling bits */
ret = regmap_write(data->regmap, MAX44000_REG_CFG_RX,
MAX44000_REG_CFG_RX_DEFAULT);
if (ret < 0) {
dev_err(&client->dev, "failed to write default CFG_RX: %d\n",
ret);
return ret;
}
/*
* By default the LED pulse used for the proximity sensor is disabled.
* Set a middle value so that we get some sort of valid data by default.
*/
ret = max44000_write_led_current_raw(data, MAX44000_LED_CURRENT_DEFAULT);
if (ret < 0) {
dev_err(&client->dev, "failed to write init config: %d\n", ret);
return ret;
}
/* Reset CFG bits to ALS_PRX mode which allows easy reading of both values. */
reg = MAX44000_CFG_TRIM | MAX44000_CFG_MODE_ALS_PRX;
ret = regmap_write(data->regmap, MAX44000_REG_CFG_MAIN, reg);
if (ret < 0) {
dev_err(&client->dev, "failed to write init config: %d\n", ret);
return ret;
}
/* Read status at least once to clear any stale interrupt bits. */
ret = regmap_read(data->regmap, MAX44000_REG_STATUS, ®);
if (ret < 0) {
dev_err(&client->dev, "failed to read init status: %d\n", ret);
return ret;
}
ret = iio_triggered_buffer_setup(indio_dev, NULL, max44000_trigger_handler, NULL);
if (ret < 0) {
dev_err(&client->dev, "iio triggered buffer setup failed\n");
return ret;
}
return iio_device_register(indio_dev);
}
static int max44000_remove(struct i2c_client *client)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
return 0;
}
static const struct i2c_device_id max44000_id[] = {
{"max44000", 0},
{ }
};
MODULE_DEVICE_TABLE(i2c, max44000_id);
#ifdef CONFIG_ACPI
static const struct acpi_device_id max44000_acpi_match[] = {
{"MAX44000", 0},
{ }
};
MODULE_DEVICE_TABLE(acpi, max44000_acpi_match);
#endif
static struct i2c_driver max44000_driver = {
.driver = {
.name = MAX44000_DRV_NAME,
.acpi_match_table = ACPI_PTR(max44000_acpi_match),
},
.probe = max44000_probe,
.remove = max44000_remove,
.id_table = max44000_id,
};
module_i2c_driver(max44000_driver);
MODULE_AUTHOR("Crestez Dan Leonard <leonard.crestez@intel.com>");
MODULE_DESCRIPTION("MAX44000 Ambient and Infrared Proximity Sensor");
MODULE_LICENSE("GPL v2");