blob: 2ea9a5c4d84629c14f92ee2698726b7ea18d3e78 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* Sensirion SPS30 particulate matter sensor driver
*
* Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
*
* I2C slave address: 0x69
*/
#include <asm/unaligned.h>
#include <linux/crc8.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/iio/buffer.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/kernel.h>
#include <linux/module.h>
#define SPS30_CRC8_POLYNOMIAL 0x31
/* max number of bytes needed to store PM measurements or serial string */
#define SPS30_MAX_READ_SIZE 48
/* sensor measures reliably up to 3000 ug / m3 */
#define SPS30_MAX_PM 3000
/* minimum and maximum self cleaning periods in seconds */
#define SPS30_AUTO_CLEANING_PERIOD_MIN 0
#define SPS30_AUTO_CLEANING_PERIOD_MAX 604800
/* SPS30 commands */
#define SPS30_START_MEAS 0x0010
#define SPS30_STOP_MEAS 0x0104
#define SPS30_RESET 0xd304
#define SPS30_READ_DATA_READY_FLAG 0x0202
#define SPS30_READ_DATA 0x0300
#define SPS30_READ_SERIAL 0xd033
#define SPS30_START_FAN_CLEANING 0x5607
#define SPS30_AUTO_CLEANING_PERIOD 0x8004
/* not a sensor command per se, used only to distinguish write from read */
#define SPS30_READ_AUTO_CLEANING_PERIOD 0x8005
enum {
PM1,
PM2P5,
PM4,
PM10,
};
enum {
RESET,
MEASURING,
};
struct sps30_state {
struct i2c_client *client;
/*
* Guards against concurrent access to sensor registers.
* Must be held whenever sequence of commands is to be executed.
*/
struct mutex lock;
int state;
};
DECLARE_CRC8_TABLE(sps30_crc8_table);
static int sps30_write_then_read(struct sps30_state *state, u8 *txbuf,
int txsize, u8 *rxbuf, int rxsize)
{
int ret;
/*
* Sensor does not support repeated start so instead of
* sending two i2c messages in a row we just send one by one.
*/
ret = i2c_master_send(state->client, txbuf, txsize);
if (ret != txsize)
return ret < 0 ? ret : -EIO;
if (!rxbuf)
return 0;
ret = i2c_master_recv(state->client, rxbuf, rxsize);
if (ret != rxsize)
return ret < 0 ? ret : -EIO;
return 0;
}
static int sps30_do_cmd(struct sps30_state *state, u16 cmd, u8 *data, int size)
{
/*
* Internally sensor stores measurements in a following manner:
*
* PM1: upper two bytes, crc8, lower two bytes, crc8
* PM2P5: upper two bytes, crc8, lower two bytes, crc8
* PM4: upper two bytes, crc8, lower two bytes, crc8
* PM10: upper two bytes, crc8, lower two bytes, crc8
*
* What follows next are number concentration measurements and
* typical particle size measurement which we omit.
*/
u8 buf[SPS30_MAX_READ_SIZE] = { cmd >> 8, cmd };
int i, ret = 0;
switch (cmd) {
case SPS30_START_MEAS:
buf[2] = 0x03;
buf[3] = 0x00;
buf[4] = crc8(sps30_crc8_table, &buf[2], 2, CRC8_INIT_VALUE);
ret = sps30_write_then_read(state, buf, 5, NULL, 0);
break;
case SPS30_STOP_MEAS:
case SPS30_RESET:
case SPS30_START_FAN_CLEANING:
ret = sps30_write_then_read(state, buf, 2, NULL, 0);
break;
case SPS30_READ_AUTO_CLEANING_PERIOD:
buf[0] = SPS30_AUTO_CLEANING_PERIOD >> 8;
buf[1] = (u8)(SPS30_AUTO_CLEANING_PERIOD & 0xff);
fallthrough;
case SPS30_READ_DATA_READY_FLAG:
case SPS30_READ_DATA:
case SPS30_READ_SERIAL:
/* every two data bytes are checksummed */
size += size / 2;
ret = sps30_write_then_read(state, buf, 2, buf, size);
break;
case SPS30_AUTO_CLEANING_PERIOD:
buf[2] = data[0];
buf[3] = data[1];
buf[4] = crc8(sps30_crc8_table, &buf[2], 2, CRC8_INIT_VALUE);
buf[5] = data[2];
buf[6] = data[3];
buf[7] = crc8(sps30_crc8_table, &buf[5], 2, CRC8_INIT_VALUE);
ret = sps30_write_then_read(state, buf, 8, NULL, 0);
break;
}
if (ret)
return ret;
/* validate received data and strip off crc bytes */
for (i = 0; i < size; i += 3) {
u8 crc = crc8(sps30_crc8_table, &buf[i], 2, CRC8_INIT_VALUE);
if (crc != buf[i + 2]) {
dev_err(&state->client->dev,
"data integrity check failed\n");
return -EIO;
}
*data++ = buf[i];
*data++ = buf[i + 1];
}
return 0;
}
static s32 sps30_float_to_int_clamped(const u8 *fp)
{
int val = get_unaligned_be32(fp);
int mantissa = val & GENMASK(22, 0);
/* this is fine since passed float is always non-negative */
int exp = val >> 23;
int fraction, shift;
/* special case 0 */
if (!exp && !mantissa)
return 0;
exp -= 127;
if (exp < 0) {
/* return values ranging from 1 to 99 */
return ((((1 << 23) + mantissa) * 100) >> 23) >> (-exp);
}
/* return values ranging from 100 to 300000 */
shift = 23 - exp;
val = (1 << exp) + (mantissa >> shift);
if (val >= SPS30_MAX_PM)
return SPS30_MAX_PM * 100;
fraction = mantissa & GENMASK(shift - 1, 0);
return val * 100 + ((fraction * 100) >> shift);
}
static int sps30_do_meas(struct sps30_state *state, s32 *data, int size)
{
int i, ret, tries = 5;
u8 tmp[16];
if (state->state == RESET) {
ret = sps30_do_cmd(state, SPS30_START_MEAS, NULL, 0);
if (ret)
return ret;
state->state = MEASURING;
}
while (tries--) {
ret = sps30_do_cmd(state, SPS30_READ_DATA_READY_FLAG, tmp, 2);
if (ret)
return -EIO;
/* new measurements ready to be read */
if (tmp[1] == 1)
break;
msleep_interruptible(300);
}
if (tries == -1)
return -ETIMEDOUT;
ret = sps30_do_cmd(state, SPS30_READ_DATA, tmp, sizeof(int) * size);
if (ret)
return ret;
for (i = 0; i < size; i++)
data[i] = sps30_float_to_int_clamped(&tmp[4 * i]);
return 0;
}
static irqreturn_t sps30_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct sps30_state *state = iio_priv(indio_dev);
int ret;
struct {
s32 data[4]; /* PM1, PM2P5, PM4, PM10 */
s64 ts;
} scan;
mutex_lock(&state->lock);
ret = sps30_do_meas(state, scan.data, ARRAY_SIZE(scan.data));
mutex_unlock(&state->lock);
if (ret)
goto err;
iio_push_to_buffers_with_timestamp(indio_dev, &scan,
iio_get_time_ns(indio_dev));
err:
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static int sps30_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct sps30_state *state = iio_priv(indio_dev);
int data[4], ret = -EINVAL;
switch (mask) {
case IIO_CHAN_INFO_PROCESSED:
switch (chan->type) {
case IIO_MASSCONCENTRATION:
mutex_lock(&state->lock);
/* read up to the number of bytes actually needed */
switch (chan->channel2) {
case IIO_MOD_PM1:
ret = sps30_do_meas(state, data, 1);
break;
case IIO_MOD_PM2P5:
ret = sps30_do_meas(state, data, 2);
break;
case IIO_MOD_PM4:
ret = sps30_do_meas(state, data, 3);
break;
case IIO_MOD_PM10:
ret = sps30_do_meas(state, data, 4);
break;
}
mutex_unlock(&state->lock);
if (ret)
return ret;
*val = data[chan->address] / 100;
*val2 = (data[chan->address] % 100) * 10000;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
case IIO_MASSCONCENTRATION:
switch (chan->channel2) {
case IIO_MOD_PM1:
case IIO_MOD_PM2P5:
case IIO_MOD_PM4:
case IIO_MOD_PM10:
*val = 0;
*val2 = 10000;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
default:
return -EINVAL;
}
}
return -EINVAL;
}
static int sps30_do_cmd_reset(struct sps30_state *state)
{
int ret;
ret = sps30_do_cmd(state, SPS30_RESET, NULL, 0);
msleep(300);
/*
* Power-on-reset causes sensor to produce some glitch on i2c bus and
* some controllers end up in error state. Recover simply by placing
* some data on the bus, for example STOP_MEAS command, which
* is NOP in this case.
*/
sps30_do_cmd(state, SPS30_STOP_MEAS, NULL, 0);
state->state = RESET;
return ret;
}
static ssize_t start_cleaning_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct sps30_state *state = iio_priv(indio_dev);
int val, ret;
if (kstrtoint(buf, 0, &val) || val != 1)
return -EINVAL;
mutex_lock(&state->lock);
ret = sps30_do_cmd(state, SPS30_START_FAN_CLEANING, NULL, 0);
mutex_unlock(&state->lock);
if (ret)
return ret;
return len;
}
static ssize_t cleaning_period_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct sps30_state *state = iio_priv(indio_dev);
u8 tmp[4];
int ret;
mutex_lock(&state->lock);
ret = sps30_do_cmd(state, SPS30_READ_AUTO_CLEANING_PERIOD, tmp, 4);
mutex_unlock(&state->lock);
if (ret)
return ret;
return sprintf(buf, "%d\n", get_unaligned_be32(tmp));
}
static ssize_t cleaning_period_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct sps30_state *state = iio_priv(indio_dev);
int val, ret;
u8 tmp[4];
if (kstrtoint(buf, 0, &val))
return -EINVAL;
if ((val < SPS30_AUTO_CLEANING_PERIOD_MIN) ||
(val > SPS30_AUTO_CLEANING_PERIOD_MAX))
return -EINVAL;
put_unaligned_be32(val, tmp);
mutex_lock(&state->lock);
ret = sps30_do_cmd(state, SPS30_AUTO_CLEANING_PERIOD, tmp, 0);
if (ret) {
mutex_unlock(&state->lock);
return ret;
}
msleep(20);
/*
* sensor requires reset in order to return up to date self cleaning
* period
*/
ret = sps30_do_cmd_reset(state);
if (ret)
dev_warn(dev,
"period changed but reads will return the old value\n");
mutex_unlock(&state->lock);
return len;
}
static ssize_t cleaning_period_available_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return snprintf(buf, PAGE_SIZE, "[%d %d %d]\n",
SPS30_AUTO_CLEANING_PERIOD_MIN, 1,
SPS30_AUTO_CLEANING_PERIOD_MAX);
}
static IIO_DEVICE_ATTR_WO(start_cleaning, 0);
static IIO_DEVICE_ATTR_RW(cleaning_period, 0);
static IIO_DEVICE_ATTR_RO(cleaning_period_available, 0);
static struct attribute *sps30_attrs[] = {
&iio_dev_attr_start_cleaning.dev_attr.attr,
&iio_dev_attr_cleaning_period.dev_attr.attr,
&iio_dev_attr_cleaning_period_available.dev_attr.attr,
NULL
};
static const struct attribute_group sps30_attr_group = {
.attrs = sps30_attrs,
};
static const struct iio_info sps30_info = {
.attrs = &sps30_attr_group,
.read_raw = sps30_read_raw,
};
#define SPS30_CHAN(_index, _mod) { \
.type = IIO_MASSCONCENTRATION, \
.modified = 1, \
.channel2 = IIO_MOD_ ## _mod, \
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.address = _mod, \
.scan_index = _index, \
.scan_type = { \
.sign = 'u', \
.realbits = 19, \
.storagebits = 32, \
.endianness = IIO_CPU, \
}, \
}
static const struct iio_chan_spec sps30_channels[] = {
SPS30_CHAN(0, PM1),
SPS30_CHAN(1, PM2P5),
SPS30_CHAN(2, PM4),
SPS30_CHAN(3, PM10),
IIO_CHAN_SOFT_TIMESTAMP(4),
};
static void sps30_stop_meas(void *data)
{
struct sps30_state *state = data;
sps30_do_cmd(state, SPS30_STOP_MEAS, NULL, 0);
}
static const unsigned long sps30_scan_masks[] = { 0x0f, 0x00 };
static int sps30_probe(struct i2c_client *client)
{
struct iio_dev *indio_dev;
struct sps30_state *state;
u8 buf[32];
int ret;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -EOPNOTSUPP;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*state));
if (!indio_dev)
return -ENOMEM;
state = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
state->client = client;
state->state = RESET;
indio_dev->info = &sps30_info;
indio_dev->name = client->name;
indio_dev->channels = sps30_channels;
indio_dev->num_channels = ARRAY_SIZE(sps30_channels);
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->available_scan_masks = sps30_scan_masks;
mutex_init(&state->lock);
crc8_populate_msb(sps30_crc8_table, SPS30_CRC8_POLYNOMIAL);
ret = sps30_do_cmd_reset(state);
if (ret) {
dev_err(&client->dev, "failed to reset device\n");
return ret;
}
ret = sps30_do_cmd(state, SPS30_READ_SERIAL, buf, sizeof(buf));
if (ret) {
dev_err(&client->dev, "failed to read serial number\n");
return ret;
}
/* returned serial number is already NUL terminated */
dev_info(&client->dev, "serial number: %s\n", buf);
ret = devm_add_action_or_reset(&client->dev, sps30_stop_meas, state);
if (ret)
return ret;
ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev, NULL,
sps30_trigger_handler, NULL);
if (ret)
return ret;
return devm_iio_device_register(&client->dev, indio_dev);
}
static const struct i2c_device_id sps30_id[] = {
{ "sps30" },
{ }
};
MODULE_DEVICE_TABLE(i2c, sps30_id);
static const struct of_device_id sps30_of_match[] = {
{ .compatible = "sensirion,sps30" },
{ }
};
MODULE_DEVICE_TABLE(of, sps30_of_match);
static struct i2c_driver sps30_driver = {
.driver = {
.name = "sps30",
.of_match_table = sps30_of_match,
},
.id_table = sps30_id,
.probe_new = sps30_probe,
};
module_i2c_driver(sps30_driver);
MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
MODULE_DESCRIPTION("Sensirion SPS30 particulate matter sensor driver");
MODULE_LICENSE("GPL v2");