diff options
Diffstat (limited to 'drivers/iio/chemical/sps30_i2c.c')
| -rw-r--r-- | drivers/iio/chemical/sps30_i2c.c | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/drivers/iio/chemical/sps30_i2c.c b/drivers/iio/chemical/sps30_i2c.c new file mode 100644 index 000000000000..d33560ed7184 --- /dev/null +++ b/drivers/iio/chemical/sps30_i2c.c @@ -0,0 +1,258 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Sensirion SPS30 particulate matter sensor i2c driver + * + * Copyright (c) 2020 Tomasz Duszynski <tomasz.duszynski@octakon.com> + * + * I2C slave address: 0x69 + */ +#include <asm/unaligned.h> +#include <linux/crc8.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/errno.h> +#include <linux/i2c.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/types.h> + +#include "sps30.h" + +#define SPS30_I2C_CRC8_POLYNOMIAL 0x31 +/* max number of bytes needed to store PM measurements or serial string */ +#define SPS30_I2C_MAX_BUF_SIZE 48 + +DECLARE_CRC8_TABLE(sps30_i2c_crc8_table); + +#define SPS30_I2C_START_MEAS 0x0010 +#define SPS30_I2C_STOP_MEAS 0x0104 +#define SPS30_I2C_READ_MEAS 0x0300 +#define SPS30_I2C_MEAS_READY 0x0202 +#define SPS30_I2C_RESET 0xd304 +#define SPS30_I2C_CLEAN_FAN 0x5607 +#define SPS30_I2C_PERIOD 0x8004 +#define SPS30_I2C_READ_SERIAL 0xd033 +#define SPS30_I2C_READ_VERSION 0xd100 + +static int sps30_i2c_xfer(struct sps30_state *state, unsigned char *txbuf, size_t txsize, + unsigned char *rxbuf, size_t rxsize) +{ + struct i2c_client *client = to_i2c_client(state->dev); + 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(client, txbuf, txsize); + if (ret < 0) + return ret; + if (ret != txsize) + return -EIO; + + if (!rxsize) + return 0; + + ret = i2c_master_recv(client, rxbuf, rxsize); + if (ret < 0) + return ret; + if (ret != rxsize) + return -EIO; + + return 0; +} + +static int sps30_i2c_command(struct sps30_state *state, u16 cmd, void *arg, size_t arg_size, + void *rsp, size_t rsp_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. + */ + unsigned char buf[SPS30_I2C_MAX_BUF_SIZE]; + unsigned char *tmp; + unsigned char crc; + size_t i; + int ret; + + put_unaligned_be16(cmd, buf); + i = 2; + + if (rsp) { + /* each two bytes are followed by a crc8 */ + rsp_size += rsp_size / 2; + } else { + tmp = arg; + + while (arg_size) { + buf[i] = *tmp++; + buf[i + 1] = *tmp++; + buf[i + 2] = crc8(sps30_i2c_crc8_table, buf + i, 2, CRC8_INIT_VALUE); + arg_size -= 2; + i += 3; + } + } + + ret = sps30_i2c_xfer(state, buf, i, buf, rsp_size); + if (ret) + return ret; + + /* validate received data and strip off crc bytes */ + tmp = rsp; + for (i = 0; i < rsp_size; i += 3) { + crc = crc8(sps30_i2c_crc8_table, buf + i, 2, CRC8_INIT_VALUE); + if (crc != buf[i + 2]) { + dev_err(state->dev, "data integrity check failed\n"); + return -EIO; + } + + *tmp++ = buf[i]; + *tmp++ = buf[i + 1]; + } + + return 0; +} + +static int sps30_i2c_start_meas(struct sps30_state *state) +{ + /* request BE IEEE754 formatted data */ + unsigned char buf[] = { 0x03, 0x00 }; + + return sps30_i2c_command(state, SPS30_I2C_START_MEAS, buf, sizeof(buf), NULL, 0); +} + +static int sps30_i2c_stop_meas(struct sps30_state *state) +{ + return sps30_i2c_command(state, SPS30_I2C_STOP_MEAS, NULL, 0, NULL, 0); +} + +static int sps30_i2c_reset(struct sps30_state *state) +{ + int ret; + + ret = sps30_i2c_command(state, SPS30_I2C_RESET, NULL, 0, NULL, 0); + msleep(500); + /* + * 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_i2c_stop_meas(state); + + return ret; +} + +static bool sps30_i2c_meas_ready(struct sps30_state *state) +{ + unsigned char buf[2]; + int ret; + + ret = sps30_i2c_command(state, SPS30_I2C_MEAS_READY, NULL, 0, buf, sizeof(buf)); + if (ret) + return false; + + return buf[1]; +} + +static int sps30_i2c_read_meas(struct sps30_state *state, __be32 *meas, size_t num) +{ + /* measurements are ready within a second */ + if (msleep_interruptible(1000)) + return -EINTR; + + if (!sps30_i2c_meas_ready(state)) + return -ETIMEDOUT; + + return sps30_i2c_command(state, SPS30_I2C_READ_MEAS, NULL, 0, meas, sizeof(num) * num); +} + +static int sps30_i2c_clean_fan(struct sps30_state *state) +{ + return sps30_i2c_command(state, SPS30_I2C_CLEAN_FAN, NULL, 0, NULL, 0); +} + +static int sps30_i2c_read_cleaning_period(struct sps30_state *state, __be32 *period) +{ + return sps30_i2c_command(state, SPS30_I2C_PERIOD, NULL, 0, period, sizeof(*period)); +} + +static int sps30_i2c_write_cleaning_period(struct sps30_state *state, __be32 period) +{ + return sps30_i2c_command(state, SPS30_I2C_PERIOD, &period, sizeof(period), NULL, 0); +} + +static int sps30_i2c_show_info(struct sps30_state *state) +{ + /* extra nul just in case */ + unsigned char buf[32 + 1] = { 0x00 }; + int ret; + + ret = sps30_i2c_command(state, SPS30_I2C_READ_SERIAL, NULL, 0, buf, sizeof(buf) - 1); + if (ret) + return ret; + + dev_info(state->dev, "serial number: %s\n", buf); + + ret = sps30_i2c_command(state, SPS30_I2C_READ_VERSION, NULL, 0, buf, 2); + if (ret) + return ret; + + dev_info(state->dev, "fw version: %u.%u\n", buf[0], buf[1]); + + return 0; +} + +static const struct sps30_ops sps30_i2c_ops = { + .start_meas = sps30_i2c_start_meas, + .stop_meas = sps30_i2c_stop_meas, + .read_meas = sps30_i2c_read_meas, + .reset = sps30_i2c_reset, + .clean_fan = sps30_i2c_clean_fan, + .read_cleaning_period = sps30_i2c_read_cleaning_period, + .write_cleaning_period = sps30_i2c_write_cleaning_period, + .show_info = sps30_i2c_show_info, +}; + +static int sps30_i2c_probe(struct i2c_client *client) +{ + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) + return -EOPNOTSUPP; + + crc8_populate_msb(sps30_i2c_crc8_table, SPS30_I2C_CRC8_POLYNOMIAL); + + return sps30_probe(&client->dev, client->name, NULL, &sps30_i2c_ops); +} + +static const struct i2c_device_id sps30_i2c_id[] = { + { "sps30" }, + { } +}; +MODULE_DEVICE_TABLE(i2c, sps30_i2c_id); + +static const struct of_device_id sps30_i2c_of_match[] = { + { .compatible = "sensirion,sps30" }, + { } +}; +MODULE_DEVICE_TABLE(of, sps30_i2c_of_match); + +static struct i2c_driver sps30_i2c_driver = { + .driver = { + .name = KBUILD_MODNAME, + .of_match_table = sps30_i2c_of_match, + }, + .id_table = sps30_i2c_id, + .probe_new = sps30_i2c_probe, +}; +module_i2c_driver(sps30_i2c_driver); + +MODULE_AUTHOR("Tomasz Duszynski <tomasz.duszynski@octakon.com>"); +MODULE_DESCRIPTION("Sensirion SPS30 particulate matter sensor i2c driver"); +MODULE_LICENSE("GPL v2"); |