From 62129a0849d27cc94ced832bcf9dcde283dcbe08 Mon Sep 17 00:00:00 2001 From: Tomasz Duszynski Date: Tue, 15 Jan 2019 20:00:06 +0100 Subject: [PATCH] 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 Signed-off-by: Jonathan Cameron --- Documentation/ABI/testing/sysfs-bus-iio-sps30 | 20 +++ drivers/iio/chemical/sps30.c | 143 +++++++++++++++--- 2 files changed, 145 insertions(+), 18 deletions(-) --- a/Documentation/ABI/testing/sysfs-bus-iio-sps30 +++ b/Documentation/ABI/testing/sysfs-bus-iio-sps30 @@ -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. --- a/drivers/iio/chemical/sps30.c +++ b/drivers/iio/chemical/sps30.c @@ -5,9 +5,6 @@ * Copyright (c) Tomasz Duszynski * * I2C slave address: 0x69 - * - * TODO: - * - support for reading/setting auto cleaning interval */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt @@ -21,6 +18,7 @@ #include #include #include +#include #include #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_sta 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_sta 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_st 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 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(stru 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 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 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 /* 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;