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iio: chemical: sps30: allow changing self cleaning period 

Sensor can periodically trigger self cleaning. Period can be changed by
writing a new value to a dedicated attribute. Upon attribute read
current period gets returned.

Signed-off-by: Tomasz Duszynski <tduszyns@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
hifive-unleashed-5.1
Tomasz Duszynski 2019-01-15 20:00:06 +01:00 committed by Jonathan Cameron
parent 8b1352a008
commit 62129a0849
2 changed files with 145 additions and 18 deletions
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20
Documentation/ABI/testing/sysfs-bus-iio-sps30
View File

@ -6,3 +6,23 @@ Description:
Writing 1 starts sensor self cleaning. Internal fan accelerates
to its maximum speed and keeps spinning for about 10 seconds in
order to blow out accumulated dust.
What: /sys/bus/iio/devices/iio:deviceX/cleaning_period
Date: January 2019
KernelVersion: 5.1
Contact: linux-iio@vger.kernel.org
Description:
Sensor is capable of triggering self cleaning periodically.
Period can be changed by writing a new value here. Upon reading
the current one is returned. Units are seconds.
Writing 0 disables periodical self cleaning entirely.
What: /sys/bus/iio/devices/iio:deviceX/cleaning_period_available
Date: January 2019
KernelVersion: 5.1
Contact: linux-iio@vger.kernel.org
Description:
The range of available values in seconds represented as the
minimum value, the step and the maximum value, all enclosed in
square brackets.

143
drivers/iio/chemical/sps30.c
View File

@ -5,9 +5,6 @@
* Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
*
* I2C slave address: 0x69
*
* TODO:
* - support for reading/setting auto cleaning interval
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@ -21,6 +18,7 @@
#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
@ -28,6 +26,9 @@
#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
@ -37,6 +38,9 @@
#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,
@ -45,6 +49,11 @@ enum {
PM10,
};
enum {
RESET,
MEASURING,
};
struct sps30_state {
struct i2c_client *client;
/*
@ -52,6 +61,7 @@ struct sps30_state {
* Must be held whenever sequence of commands is to be executed.
*/
struct mutex lock;
int state;
};
DECLARE_CRC8_TABLE(sps30_crc8_table);
@ -107,6 +117,9 @@ static int sps30_do_cmd(struct sps30_state *state, u16 cmd, u8 *data, int size)
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;
case SPS30_READ_DATA_READY_FLAG:
case SPS30_READ_DATA:
case SPS30_READ_SERIAL:
@ -114,6 +127,15 @@ static int sps30_do_cmd(struct sps30_state *state, u16 cmd, u8 *data, int size)
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)
@ -170,6 +192,14 @@ 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)
@ -276,6 +306,24 @@ static int sps30_read_raw(struct iio_dev *indio_dev,
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)
@ -296,10 +344,82 @@ static ssize_t start_cleaning_store(struct device *dev,
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
};
@ -362,6 +482,7 @@ static int sps30_probe(struct i2c_client *client)
state = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
state->client = client;
state->state = RESET;
indio_dev->dev.parent = &client->dev;
indio_dev->info = &sps30_info;
indio_dev->name = client->name;
@ -373,19 +494,11 @@ static int sps30_probe(struct i2c_client *client)
mutex_init(&state->lock);
crc8_populate_msb(sps30_crc8_table, SPS30_CRC8_POLYNOMIAL);
ret = sps30_do_cmd(state, SPS30_RESET, NULL, 0);
ret = sps30_do_cmd_reset(state);
if (ret) {
dev_err(&client->dev, "failed to reset device\n");
return ret;
}
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);
ret = sps30_do_cmd(state, SPS30_READ_SERIAL, buf, sizeof(buf));
if (ret) {
@ -395,12 +508,6 @@ static int sps30_probe(struct i2c_client *client)
/* returned serial number is already NUL terminated */
dev_info(&client->dev, "serial number: %s\n", buf);
ret = sps30_do_cmd(state, SPS30_START_MEAS, NULL, 0);
if (ret) {
dev_err(&client->dev, "failed to start measurement\n");
return ret;
}
ret = devm_add_action_or_reset(&client->dev, sps30_stop_meas, state);
if (ret)
return ret;