diff options
Diffstat (limited to 'drivers/iio/chemical/sps30.c')
| -rw-r--r-- | drivers/iio/chemical/sps30.c | 548 |
1 files changed, 548 insertions, 0 deletions
diff --git a/drivers/iio/chemical/sps30.c b/drivers/iio/chemical/sps30.c new file mode 100644 index 000000000000..edbb956e81e8 --- /dev/null +++ b/drivers/iio/chemical/sps30.c @@ -0,0 +1,548 @@ +// 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; + /* fall through */ + 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; + s32 data[4 + 2]; /* PM1, PM2P5, PM4, PM10, timestamp */ + + mutex_lock(&state->lock); + ret = sps30_do_meas(state, data, 4); + mutex_unlock(&state->lock); + if (ret) + goto err; + + iio_push_to_buffers_with_timestamp(indio_dev, data, + 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->dev.parent = &client->dev; + 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"); |