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- // 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");
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