380 lines
8.3 KiB
C
380 lines
8.3 KiB
C
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// 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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#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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#include "sps30.h"
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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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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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static s32 sps30_float_to_int_clamped(__be32 *fp)
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{
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int val = be32_to_cpup(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;
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if (state->state == RESET) {
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ret = state->ops->start_meas(state);
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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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ret = state->ops->read_meas(state, (__be32 *)data, 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((__be32 *)&data[i]);
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return 0;
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}
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static int sps30_do_reset(struct sps30_state *state)
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{
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int ret;
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ret = state->ops->reset(state);
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if (ret)
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return ret;
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state->state = RESET;
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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 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 = state->ops->clean_fan(state);
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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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__be32 val;
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int ret;
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mutex_lock(&state->lock);
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ret = state->ops->read_cleaning_period(state, &val);
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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 sysfs_emit(buf, "%d\n", be32_to_cpu(val));
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}
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static ssize_t cleaning_period_store(struct device *dev, 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))
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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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mutex_lock(&state->lock);
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ret = state->ops->write_cleaning_period(state, cpu_to_be32(val));
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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_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 sysfs_emit(buf, "[%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_devm_stop_meas(void *data)
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{
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struct sps30_state *state = data;
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if (state->state == MEASURING)
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state->ops->stop_meas(state);
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}
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static const unsigned long sps30_scan_masks[] = { 0x0f, 0x00 };
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int sps30_probe(struct device *dev, const char *name, void *priv, const struct sps30_ops *ops)
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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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int ret;
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indio_dev = devm_iio_device_alloc(dev, sizeof(*state));
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if (!indio_dev)
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return -ENOMEM;
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dev_set_drvdata(dev, indio_dev);
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state = iio_priv(indio_dev);
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state->dev = dev;
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state->priv = priv;
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state->ops = ops;
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mutex_init(&state->lock);
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indio_dev->info = &sps30_info;
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indio_dev->name = 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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ret = sps30_do_reset(state);
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if (ret) {
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dev_err(dev, "failed to reset device\n");
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return ret;
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}
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ret = state->ops->show_info(state);
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if (ret) {
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dev_err(dev, "failed to read device info\n");
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return ret;
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}
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ret = devm_add_action_or_reset(dev, sps30_devm_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(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(dev, indio_dev);
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}
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EXPORT_SYMBOL_GPL(sps30_probe);
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MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
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MODULE_DESCRIPTION("Sensirion SPS30 particulate matter sensor driver");
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MODULE_LICENSE("GPL v2");
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