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// 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 = 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");
MODULE_IMPORT_NS(IIO_SPS30);