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550 lines
13 KiB
550 lines
13 KiB
// 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 <[email protected]> |
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* |
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* I2C slave address: 0x69 |
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*/ |
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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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|
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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); |
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crc8_populate_msb(sps30_crc8_table, SPS30_CRC8_POLYNOMIAL); |
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ret = sps30_do_cmd_reset(state); |
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if (ret) { |
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dev_err(&client->dev, "failed to reset device\n"); |
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return ret; |
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} |
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ret = sps30_do_cmd(state, SPS30_READ_SERIAL, buf, sizeof(buf)); |
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if (ret) { |
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dev_err(&client->dev, "failed to read serial number\n"); |
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return ret; |
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} |
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/* returned serial number is already NUL terminated */ |
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dev_info(&client->dev, "serial number: %s\n", buf); |
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ret = devm_add_action_or_reset(&client->dev, sps30_stop_meas, state); |
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if (ret) |
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return ret; |
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ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev, NULL, |
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sps30_trigger_handler, NULL); |
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if (ret) |
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return ret; |
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return devm_iio_device_register(&client->dev, indio_dev); |
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} |
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static const struct i2c_device_id sps30_id[] = { |
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{ "sps30" }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(i2c, sps30_id); |
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static const struct of_device_id sps30_of_match[] = { |
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{ .compatible = "sensirion,sps30" }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(of, sps30_of_match); |
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static struct i2c_driver sps30_driver = { |
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.driver = { |
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.name = "sps30", |
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.of_match_table = sps30_of_match, |
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}, |
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.id_table = sps30_id, |
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.probe_new = sps30_probe, |
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}; |
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module_i2c_driver(sps30_driver); |
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MODULE_AUTHOR("Tomasz Duszynski <[email protected]>"); |
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MODULE_DESCRIPTION("Sensirion SPS30 particulate matter sensor driver"); |
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MODULE_LICENSE("GPL v2");
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