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![Gustavo A. R. Silva](/assets/img/avatar_default.png)
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
550 lines
13 KiB
C
550 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Sensirion SPS30 particulate matter sensor driver
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*
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* Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
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*
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* I2C slave address: 0x69
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*/
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#include <asm/unaligned.h>
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#include <linux/crc8.h>
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#include <linux/delay.h>
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#include <linux/i2c.h>
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#include <linux/iio/buffer.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/sysfs.h>
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#include <linux/iio/trigger_consumer.h>
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#include <linux/iio/triggered_buffer.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#define SPS30_CRC8_POLYNOMIAL 0x31
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/* max number of bytes needed to store PM measurements or serial string */
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#define SPS30_MAX_READ_SIZE 48
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/* sensor measures reliably up to 3000 ug / m3 */
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#define SPS30_MAX_PM 3000
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/* minimum and maximum self cleaning periods in seconds */
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#define SPS30_AUTO_CLEANING_PERIOD_MIN 0
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#define SPS30_AUTO_CLEANING_PERIOD_MAX 604800
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/* SPS30 commands */
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#define SPS30_START_MEAS 0x0010
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#define SPS30_STOP_MEAS 0x0104
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#define SPS30_RESET 0xd304
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#define SPS30_READ_DATA_READY_FLAG 0x0202
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#define SPS30_READ_DATA 0x0300
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#define SPS30_READ_SERIAL 0xd033
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#define SPS30_START_FAN_CLEANING 0x5607
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#define SPS30_AUTO_CLEANING_PERIOD 0x8004
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/* not a sensor command per se, used only to distinguish write from read */
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#define SPS30_READ_AUTO_CLEANING_PERIOD 0x8005
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enum {
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PM1,
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PM2P5,
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PM4,
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PM10,
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};
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enum {
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RESET,
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MEASURING,
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};
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struct sps30_state {
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struct i2c_client *client;
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/*
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* Guards against concurrent access to sensor registers.
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* Must be held whenever sequence of commands is to be executed.
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*/
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struct mutex lock;
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int state;
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};
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DECLARE_CRC8_TABLE(sps30_crc8_table);
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static int sps30_write_then_read(struct sps30_state *state, u8 *txbuf,
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int txsize, u8 *rxbuf, int rxsize)
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{
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int ret;
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/*
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* Sensor does not support repeated start so instead of
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* sending two i2c messages in a row we just send one by one.
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*/
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ret = i2c_master_send(state->client, txbuf, txsize);
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if (ret != txsize)
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return ret < 0 ? ret : -EIO;
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if (!rxbuf)
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return 0;
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ret = i2c_master_recv(state->client, rxbuf, rxsize);
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if (ret != rxsize)
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return ret < 0 ? ret : -EIO;
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return 0;
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}
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static int sps30_do_cmd(struct sps30_state *state, u16 cmd, u8 *data, int size)
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{
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/*
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* Internally sensor stores measurements in a following manner:
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*
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* PM1: upper two bytes, crc8, lower two bytes, crc8
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* PM2P5: upper two bytes, crc8, lower two bytes, crc8
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* PM4: upper two bytes, crc8, lower two bytes, crc8
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* PM10: upper two bytes, crc8, lower two bytes, crc8
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*
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* What follows next are number concentration measurements and
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* typical particle size measurement which we omit.
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*/
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u8 buf[SPS30_MAX_READ_SIZE] = { cmd >> 8, cmd };
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int i, ret = 0;
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switch (cmd) {
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case SPS30_START_MEAS:
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buf[2] = 0x03;
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buf[3] = 0x00;
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buf[4] = crc8(sps30_crc8_table, &buf[2], 2, CRC8_INIT_VALUE);
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ret = sps30_write_then_read(state, buf, 5, NULL, 0);
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break;
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case SPS30_STOP_MEAS:
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case SPS30_RESET:
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case SPS30_START_FAN_CLEANING:
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ret = sps30_write_then_read(state, buf, 2, NULL, 0);
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break;
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case SPS30_READ_AUTO_CLEANING_PERIOD:
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buf[0] = SPS30_AUTO_CLEANING_PERIOD >> 8;
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buf[1] = (u8)(SPS30_AUTO_CLEANING_PERIOD & 0xff);
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fallthrough;
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case SPS30_READ_DATA_READY_FLAG:
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case SPS30_READ_DATA:
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case SPS30_READ_SERIAL:
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/* every two data bytes are checksummed */
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size += size / 2;
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ret = sps30_write_then_read(state, buf, 2, buf, size);
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break;
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case SPS30_AUTO_CLEANING_PERIOD:
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buf[2] = data[0];
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buf[3] = data[1];
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buf[4] = crc8(sps30_crc8_table, &buf[2], 2, CRC8_INIT_VALUE);
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buf[5] = data[2];
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buf[6] = data[3];
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buf[7] = crc8(sps30_crc8_table, &buf[5], 2, CRC8_INIT_VALUE);
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ret = sps30_write_then_read(state, buf, 8, NULL, 0);
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break;
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}
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if (ret)
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return ret;
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/* validate received data and strip off crc bytes */
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for (i = 0; i < size; i += 3) {
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u8 crc = crc8(sps30_crc8_table, &buf[i], 2, CRC8_INIT_VALUE);
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if (crc != buf[i + 2]) {
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dev_err(&state->client->dev,
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"data integrity check failed\n");
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return -EIO;
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}
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*data++ = buf[i];
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*data++ = buf[i + 1];
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}
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return 0;
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}
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static s32 sps30_float_to_int_clamped(const u8 *fp)
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{
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int val = get_unaligned_be32(fp);
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int mantissa = val & GENMASK(22, 0);
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/* this is fine since passed float is always non-negative */
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int exp = val >> 23;
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int fraction, shift;
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/* special case 0 */
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if (!exp && !mantissa)
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return 0;
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exp -= 127;
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if (exp < 0) {
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/* return values ranging from 1 to 99 */
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return ((((1 << 23) + mantissa) * 100) >> 23) >> (-exp);
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}
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/* return values ranging from 100 to 300000 */
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shift = 23 - exp;
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val = (1 << exp) + (mantissa >> shift);
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if (val >= SPS30_MAX_PM)
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return SPS30_MAX_PM * 100;
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fraction = mantissa & GENMASK(shift - 1, 0);
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return val * 100 + ((fraction * 100) >> shift);
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}
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static int sps30_do_meas(struct sps30_state *state, s32 *data, int size)
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{
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int i, ret, tries = 5;
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u8 tmp[16];
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if (state->state == RESET) {
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ret = sps30_do_cmd(state, SPS30_START_MEAS, NULL, 0);
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if (ret)
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return ret;
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state->state = MEASURING;
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}
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while (tries--) {
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ret = sps30_do_cmd(state, SPS30_READ_DATA_READY_FLAG, tmp, 2);
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if (ret)
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return -EIO;
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/* new measurements ready to be read */
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if (tmp[1] == 1)
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break;
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msleep_interruptible(300);
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}
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if (tries == -1)
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return -ETIMEDOUT;
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ret = sps30_do_cmd(state, SPS30_READ_DATA, tmp, sizeof(int) * size);
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if (ret)
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return ret;
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for (i = 0; i < size; i++)
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data[i] = sps30_float_to_int_clamped(&tmp[4 * i]);
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return 0;
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}
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static irqreturn_t sps30_trigger_handler(int irq, void *p)
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{
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struct iio_poll_func *pf = p;
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struct iio_dev *indio_dev = pf->indio_dev;
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struct sps30_state *state = iio_priv(indio_dev);
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int ret;
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struct {
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s32 data[4]; /* PM1, PM2P5, PM4, PM10 */
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s64 ts;
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} scan;
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mutex_lock(&state->lock);
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ret = sps30_do_meas(state, scan.data, ARRAY_SIZE(scan.data));
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mutex_unlock(&state->lock);
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if (ret)
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goto err;
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iio_push_to_buffers_with_timestamp(indio_dev, &scan,
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iio_get_time_ns(indio_dev));
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err:
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iio_trigger_notify_done(indio_dev->trig);
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return IRQ_HANDLED;
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}
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static int sps30_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct sps30_state *state = iio_priv(indio_dev);
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int data[4], ret = -EINVAL;
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switch (mask) {
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case IIO_CHAN_INFO_PROCESSED:
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switch (chan->type) {
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case IIO_MASSCONCENTRATION:
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mutex_lock(&state->lock);
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/* read up to the number of bytes actually needed */
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switch (chan->channel2) {
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case IIO_MOD_PM1:
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ret = sps30_do_meas(state, data, 1);
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break;
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case IIO_MOD_PM2P5:
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ret = sps30_do_meas(state, data, 2);
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break;
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case IIO_MOD_PM4:
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ret = sps30_do_meas(state, data, 3);
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break;
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case IIO_MOD_PM10:
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ret = sps30_do_meas(state, data, 4);
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break;
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}
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mutex_unlock(&state->lock);
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if (ret)
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return ret;
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*val = data[chan->address] / 100;
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*val2 = (data[chan->address] % 100) * 10000;
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return IIO_VAL_INT_PLUS_MICRO;
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default:
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return -EINVAL;
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}
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case IIO_CHAN_INFO_SCALE:
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switch (chan->type) {
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case IIO_MASSCONCENTRATION:
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switch (chan->channel2) {
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case IIO_MOD_PM1:
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case IIO_MOD_PM2P5:
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case IIO_MOD_PM4:
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case IIO_MOD_PM10:
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*val = 0;
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*val2 = 10000;
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return IIO_VAL_INT_PLUS_MICRO;
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default:
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return -EINVAL;
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}
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default:
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return -EINVAL;
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}
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}
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return -EINVAL;
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}
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static int sps30_do_cmd_reset(struct sps30_state *state)
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{
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int ret;
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ret = sps30_do_cmd(state, SPS30_RESET, NULL, 0);
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msleep(300);
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/*
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* Power-on-reset causes sensor to produce some glitch on i2c bus and
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* some controllers end up in error state. Recover simply by placing
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* some data on the bus, for example STOP_MEAS command, which
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* is NOP in this case.
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*/
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sps30_do_cmd(state, SPS30_STOP_MEAS, NULL, 0);
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state->state = RESET;
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return ret;
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}
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static ssize_t start_cleaning_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t len)
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{
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struct iio_dev *indio_dev = dev_to_iio_dev(dev);
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struct sps30_state *state = iio_priv(indio_dev);
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int val, ret;
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if (kstrtoint(buf, 0, &val) || val != 1)
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return -EINVAL;
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mutex_lock(&state->lock);
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ret = sps30_do_cmd(state, SPS30_START_FAN_CLEANING, NULL, 0);
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mutex_unlock(&state->lock);
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if (ret)
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return ret;
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return len;
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}
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static ssize_t cleaning_period_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct iio_dev *indio_dev = dev_to_iio_dev(dev);
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struct sps30_state *state = iio_priv(indio_dev);
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u8 tmp[4];
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int ret;
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mutex_lock(&state->lock);
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ret = sps30_do_cmd(state, SPS30_READ_AUTO_CLEANING_PERIOD, tmp, 4);
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mutex_unlock(&state->lock);
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if (ret)
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return ret;
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return sprintf(buf, "%d\n", get_unaligned_be32(tmp));
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}
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static ssize_t cleaning_period_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t len)
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{
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struct iio_dev *indio_dev = dev_to_iio_dev(dev);
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struct sps30_state *state = iio_priv(indio_dev);
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int val, ret;
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u8 tmp[4];
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if (kstrtoint(buf, 0, &val))
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return -EINVAL;
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if ((val < SPS30_AUTO_CLEANING_PERIOD_MIN) ||
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(val > SPS30_AUTO_CLEANING_PERIOD_MAX))
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return -EINVAL;
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put_unaligned_be32(val, tmp);
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mutex_lock(&state->lock);
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ret = sps30_do_cmd(state, SPS30_AUTO_CLEANING_PERIOD, tmp, 0);
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if (ret) {
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mutex_unlock(&state->lock);
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return ret;
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}
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msleep(20);
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/*
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* sensor requires reset in order to return up to date self cleaning
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* period
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*/
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ret = sps30_do_cmd_reset(state);
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if (ret)
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dev_warn(dev,
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"period changed but reads will return the old value\n");
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mutex_unlock(&state->lock);
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return len;
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}
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static ssize_t cleaning_period_available_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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return snprintf(buf, PAGE_SIZE, "[%d %d %d]\n",
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SPS30_AUTO_CLEANING_PERIOD_MIN, 1,
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SPS30_AUTO_CLEANING_PERIOD_MAX);
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}
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static IIO_DEVICE_ATTR_WO(start_cleaning, 0);
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static IIO_DEVICE_ATTR_RW(cleaning_period, 0);
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static IIO_DEVICE_ATTR_RO(cleaning_period_available, 0);
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static struct attribute *sps30_attrs[] = {
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&iio_dev_attr_start_cleaning.dev_attr.attr,
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&iio_dev_attr_cleaning_period.dev_attr.attr,
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&iio_dev_attr_cleaning_period_available.dev_attr.attr,
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NULL
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};
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static const struct attribute_group sps30_attr_group = {
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.attrs = sps30_attrs,
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};
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static const struct iio_info sps30_info = {
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.attrs = &sps30_attr_group,
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.read_raw = sps30_read_raw,
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};
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#define SPS30_CHAN(_index, _mod) { \
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.type = IIO_MASSCONCENTRATION, \
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.modified = 1, \
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.channel2 = IIO_MOD_ ## _mod, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
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.address = _mod, \
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.scan_index = _index, \
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.scan_type = { \
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.sign = 'u', \
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.realbits = 19, \
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.storagebits = 32, \
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.endianness = IIO_CPU, \
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}, \
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}
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static const struct iio_chan_spec sps30_channels[] = {
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SPS30_CHAN(0, PM1),
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SPS30_CHAN(1, PM2P5),
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SPS30_CHAN(2, PM4),
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SPS30_CHAN(3, PM10),
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IIO_CHAN_SOFT_TIMESTAMP(4),
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};
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static void sps30_stop_meas(void *data)
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{
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struct sps30_state *state = data;
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sps30_do_cmd(state, SPS30_STOP_MEAS, NULL, 0);
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}
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static const unsigned long sps30_scan_masks[] = { 0x0f, 0x00 };
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static int sps30_probe(struct i2c_client *client)
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{
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struct iio_dev *indio_dev;
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struct sps30_state *state;
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u8 buf[32];
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int ret;
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
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return -EOPNOTSUPP;
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indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*state));
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if (!indio_dev)
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return -ENOMEM;
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state = iio_priv(indio_dev);
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i2c_set_clientdata(client, indio_dev);
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state->client = client;
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state->state = RESET;
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indio_dev->info = &sps30_info;
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indio_dev->name = client->name;
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indio_dev->channels = sps30_channels;
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indio_dev->num_channels = ARRAY_SIZE(sps30_channels);
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->available_scan_masks = sps30_scan_masks;
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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");
|