iio: chemical: sps30: allow changing self cleaning period (62129a08) · Commits · 戴 / test

Documentation/ABI/testing/sysfs-bus-iio-sps30

+20 −0

Original line number	Diff line number	Diff line
		@@ -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.

drivers/iio/chemical/sps30.c

+125 −18

Original line number	Diff line number	Diff line
		@@ -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;

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