Re: [PATCH v2 1/3] iio: chemical: add support for Plantower PMS7003 sensor

Peter Meerwald-Stadler
2019-01-27T18:54:02Z

On Sun, 27 Jan 2019, Tomasz Duszynski wrote:

some minor comments below, looks good to me

> Add support for Plantower PMS7003 particulate matter sensor.
>
> Signed-off-by: Tomasz Duszynski <tduszyns@gmail.com>
> ---
> drivers/iio/chemical/Kconfig | 10 +
> drivers/iio/chemical/Makefile | 1 +
> drivers/iio/chemical/pms7003.c | 343 +++++++++++++++++++++++++++++++++
> 3 files changed, 354 insertions(+)
> create mode 100644 drivers/iio/chemical/pms7003.c
>
> diff --git a/drivers/iio/chemical/Kconfig b/drivers/iio/chemical/Kconfig
> index 57832b4360e9..d5d146e9e372 100644
> --- a/drivers/iio/chemical/Kconfig
> +++ b/drivers/iio/chemical/Kconfig
> @@ -61,6 +61,16 @@ config IAQCORE
> iAQ-Core Continuous/Pulsed VOC (Volatile Organic Compounds)
> sensors
>
> +config PMS7003
> + tristate "Plantower PMS7003 particulate matter sensor"
> + depends on SERIAL_DEV_BUS
> + help
> + Say Y here to build support for the Plantower PMS7003 particulate
> + matter sensor.
> +
> + To compile this driver as a module, choose M here: the module will
> + be called pms7003.
> +
> config SPS30
> tristate "SPS30 particulate matter sensor"
> depends on I2C
> diff --git a/drivers/iio/chemical/Makefile b/drivers/iio/chemical/Makefile
> index 65bf0f89c0e4..f5d1365acb49 100644
> --- a/drivers/iio/chemical/Makefile
> +++ b/drivers/iio/chemical/Makefile
> @@ -9,6 +9,7 @@ obj-$(CONFIG_BME680_I2C) += bme680_i2c.o
> obj-$(CONFIG_BME680_SPI) += bme680_spi.o
> obj-$(CONFIG_CCS811) += ccs811.o
> obj-$(CONFIG_IAQCORE) += ams-iaq-core.o
> +obj-$(CONFIG_PMS7003) += pms7003.o
> obj-$(CONFIG_SENSIRION_SGP30) += sgp30.o
> obj-$(CONFIG_SPS30) += sps30.o
> obj-$(CONFIG_VZ89X) += vz89x.o
> diff --git a/drivers/iio/chemical/pms7003.c b/drivers/iio/chemical/pms7003.c
> new file mode 100644
> index 000000000000..b1ac4aeea989
> --- /dev/null
> +++ b/drivers/iio/chemical/pms7003.c
> @@ -0,0 +1,343 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Plantower PMS7003 particulate matter sensor driver
> + *
> + * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
> + */
> +
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

pr_fmt() is not used

> +
> +#include <asm/unaligned.h>
> +#include <linux/completion.h>
> +#include <linux/device.h>
> +#include <linux/errno.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/triggered_buffer.h>
> +#include <linux/jiffies.h>
> +#include <linux/kernel.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/serdev.h>
> +
> +#define PMS7003_DRIVER_NAME "pms7003"
> +
> +#define PMS7003_MAGIC 0x424d
> +/* last 2 data bytes hold frame checksum */
> +#define PMS7003_MAX_DATA_LENGTH 28
> +#define PMS7003_CHECKSUM_LENGTH 2
> +#define PMS7003_PM10_OFFSET 10
> +#define PMS7003_PM2P5_OFFSET 8
> +#define PMS7003_PM1_OFFSET 6
> +
> +#define PMS7003_TIMEOUT msecs_to_jiffies(6000)
> +#define PMS7003_CMD_LENGTH 7
> +#define PMS7003_PM_MAX 1000
> +#define PMS7003_PM_MIN 0
> +
> +enum {
> + PM1,
> + PM2P5,
> + PM10,
> +};
> +
> +enum pms7003_cmd {
> + CMD_WAKEUP,
> + CMD_ENTER_PASSIVE_MODE,
> + CMD_READ_PASSIVE,
> + CMD_SLEEP,
> +};
> +
> +/*
> + * commands have following format:
> + *
> + * +------+------+-----+------+-----+-----------+-----------+
> + * | 0x42 | 0x4d | cmd | 0x00 | arg | cksum msb | cksum lsb |
> + * +------+------+-----+------+-----+-----------+-----------+
> + */
> +static const u8 pms7003_cmd_tbl[][PMS7003_CMD_LENGTH] = {
> + [CMD_WAKEUP] = { 0x42, 0x4d, 0xe4, 0x00, 0x01, 0x01, 0x74 },
> + [CMD_ENTER_PASSIVE_MODE] = { 0x42, 0x4d, 0xe1, 0x00, 0x00, 0x01, 0x70 },
> + [CMD_READ_PASSIVE] = { 0x42, 0x4d, 0xe2, 0x00, 0x00, 0x01, 0x71 },
> + [CMD_SLEEP] = { 0x42, 0x4d, 0xe4, 0x00, 0x00, 0x01, 0x73 },
> +};
> +
> +struct pms7003_frame {
> + u8 data[PMS7003_MAX_DATA_LENGTH];
> + u16 expected_length;
> + u16 length;
> +};
> +
> +struct pms7003_state {
> + struct serdev_device *serdev;
> + struct pms7003_frame frame;
> + struct completion frame_ready;
> + struct mutex lock; /* must be held whenever state gets touched */
> +};
> +
> +static int pms7003_do_cmd(struct pms7003_state *state, enum pms7003_cmd cmd)
> +{
> + int ret;
> +
> + ret = serdev_device_write(state->serdev, pms7003_cmd_tbl[cmd],
> + PMS7003_CMD_LENGTH, PMS7003_TIMEOUT);
> + if (ret < PMS7003_CMD_LENGTH)
> + return ret < 0 ? ret : -EIO;
> +
> + ret = wait_for_completion_interruptible_timeout(&state->frame_ready,
> + PMS7003_TIMEOUT);
> + if (!ret)
> + ret = -ETIMEDOUT;
> +
> + return ret < 0 ? ret : 0;
> +}
> +
> +static u16 pms7003_get_pm(const u8 *data)
> +{
> + return clamp_val(get_unaligned_be16(data),
> + PMS7003_PM_MIN, PMS7003_PM_MAX);
> +}
> +
> +static irqreturn_t pms7003_trigger_handler(int irq, void *p)
> +{
> + struct iio_poll_func *pf = p;
> + struct iio_dev *indio_dev = pf->indio_dev;
> + struct pms7003_state *state = iio_priv(indio_dev);
> + struct pms7003_frame *frame = &state->frame;
> + u16 data[3 + 1 + 4]; /* PM1, PM2P5, PM10, padding, timestamp */
> + int ret;
> +
> + mutex_lock(&state->lock);
> + ret = pms7003_do_cmd(state, CMD_READ_PASSIVE);
> + if (ret) {
> + mutex_unlock(&state->lock);
> + goto err;
> + }
> +
> + data[PM1] = pms7003_get_pm(frame->data + PMS7003_PM1_OFFSET);
> + data[PM2P5] = pms7003_get_pm(frame->data + PMS7003_PM2P5_OFFSET);
> + data[PM10] = pms7003_get_pm(frame->data + PMS7003_PM10_OFFSET);
> + mutex_unlock(&state->lock);
> +
> + iio_push_to_buffers_with_timestamp(indio_dev, data,
> + iio_get_time_ns(indio_dev));
> +err:
> + iio_trigger_notify_done(indio_dev->trig);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int pms7003_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long mask)
> +{
> + struct pms7003_state *state = iio_priv(indio_dev);
> + struct pms7003_frame *frame = &state->frame;
> + int ret;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_PROCESSED:
> + switch (chan->type) {
> + case IIO_MASSCONCENTRATION:
> + mutex_lock(&state->lock);
> + ret = pms7003_do_cmd(state, CMD_READ_PASSIVE);
> + if (ret) {
> + mutex_unlock(&state->lock);
> + return ret;
> + }
> +
> + *val = pms7003_get_pm(frame->data + chan->address);
> + mutex_unlock(&state->lock);
> +
> + return IIO_VAL_INT;
> + default:
> + return -EINVAL;
> + }
> + }
> +
> + return -EINVAL;
> +}
> +

remove dup newline

> +
> +static const struct iio_info pms7003_info = {
> + .read_raw = pms7003_read_raw,
> +};
> +
> +#define PMS7003_CHAN(_index, _mod, _addr) { \
> + .type = IIO_MASSCONCENTRATION, \
> + .modified = 1, \
> + .channel2 = IIO_MOD_ ## _mod, \
> + .address = _addr, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
> + .scan_index = _index, \
> + .scan_type = { \
> + .sign = 'u', \
> + .realbits = 10, \
> + .storagebits = 16, \
> + .endianness = IIO_CPU, \
> + }, \
> +}
> +
> +static const struct iio_chan_spec pms7003_channels[] = {
> + PMS7003_CHAN(0, PM1, PMS7003_PM1_OFFSET),
> + PMS7003_CHAN(1, PM2P5, PMS7003_PM2P5_OFFSET),
> + PMS7003_CHAN(2, PM10, PMS7003_PM10_OFFSET),
> + IIO_CHAN_SOFT_TIMESTAMP(3),
> +};
> +
> +static u16 pms7003_calc_checksum(struct pms7003_frame *frame)
> +{
> + u16 checksum = (PMS7003_MAGIC >> 8) + (u8)PMS7003_MAGIC +
> + (frame->length >> 8) + (u8)frame->length;
> + int i;
> +
> + for (i = 0; i < frame->length - PMS7003_CHECKSUM_LENGTH; i++)
> + checksum += frame->data[i];
> +
> + return checksum;
> +}
> +
> +static bool pms7003_frame_is_okay(struct pms7003_frame *frame)
> +{
> + int offset = frame->length - PMS7003_CHECKSUM_LENGTH;
> + u16 checksum = get_unaligned_be16(frame->data + offset);
> +
> + return checksum == pms7003_calc_checksum(frame);
> +}
> +
> +static int pms7003_receive_buf(struct serdev_device *serdev,

maybe add a comment what the return value of this function is

> + const unsigned char *buf, size_t size)
> +{
> + struct iio_dev *indio_dev = serdev_device_get_drvdata(serdev);
> + struct pms7003_state *state = iio_priv(indio_dev);
> + struct pms7003_frame *frame = &state->frame;
> + int num;
> +
> + if (!frame->expected_length) {
> + u16 magic;
> +
> + /* wait for SOF and data length */

remove extra space after SOF

> + if (size < 4)
> + return 0;
> +
> + magic = get_unaligned_be16(buf);
> + if (magic != PMS7003_MAGIC)
> + return 2;
> +
> + num = get_unaligned_be16(buf + 2);

2 is sizeof(MAGIC)

> + if (num <= PMS7003_MAX_DATA_LENGTH) {
> + frame->expected_length = num;
> + frame->length = 0;
> + }
> +
> + return 4;
> + }
> +
> + num = min(size, (size_t)(frame->expected_length - frame->length));
> + memcpy(frame->data + frame->length, buf, num);
> + frame->length += num;
> +
> + if (frame->length == frame->expected_length) {
> + if (pms7003_frame_is_okay(frame))
> + complete(&state->frame_ready);
> +
> + frame->expected_length = 0;
> + }
> +
> + return num;
> +}
> +
> +static const struct serdev_device_ops pms7003_serdev_ops = {
> + .receive_buf = pms7003_receive_buf,
> + .write_wakeup = serdev_device_write_wakeup,
> +};
> +
> +static void pms7003_stop(void *data)
> +{
> + struct pms7003_state *state = data;
> +
> + pms7003_do_cmd(state, CMD_SLEEP);
> +}
> +
> +static const unsigned long pms7003_scan_masks[] = { 0x07, 0x00 };
> +
> +static int pms7003_probe(struct serdev_device *serdev)
> +{
> + struct pms7003_state *state;
> + struct iio_dev *indio_dev;
> + int ret;
> +
> + indio_dev = devm_iio_device_alloc(&serdev->dev, sizeof(*state));
> + if (!indio_dev)
> + return -ENOMEM;
> +
> + state = iio_priv(indio_dev);
> + serdev_device_set_drvdata(serdev, indio_dev);
> + state->serdev = serdev;
> + indio_dev->dev.parent = &serdev->dev;
> + indio_dev->info = &pms7003_info;
> + indio_dev->name = PMS7003_DRIVER_NAME;
> + indio_dev->channels = pms7003_channels,
> + indio_dev->num_channels = ARRAY_SIZE(pms7003_channels);
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->available_scan_masks = pms7003_scan_masks;
> +
> + mutex_init(&state->lock);
> + init_completion(&state->frame_ready);
> +
> + serdev_device_set_client_ops(serdev, &pms7003_serdev_ops);
> + ret = devm_serdev_device_open(&serdev->dev, serdev);
> + if (ret)
> + return ret;
> +
> + serdev_device_set_baudrate(serdev, 9600);
> + serdev_device_set_flow_control(serdev, false);
> +
> + ret = serdev_device_set_parity(serdev, SERDEV_PARITY_NONE);
> + if (ret)
> + return ret;
> +
> + ret = pms7003_do_cmd(state, CMD_WAKEUP);
> + if (ret) {
> + dev_err(&serdev->dev, "failed to wakeup sensor\n");
> + return ret;
> + }
> +
> + ret = pms7003_do_cmd(state, CMD_ENTER_PASSIVE_MODE);
> + if (ret) {
> + dev_err(&serdev->dev, "failed to enter passive mode\n");
> + return ret;
> + }
> +
> + ret = devm_add_action_or_reset(&serdev->dev, pms7003_stop, state);
> + if (ret)
> + return ret;
> +
> + ret = devm_iio_triggered_buffer_setup(&serdev->dev, indio_dev, NULL,
> + pms7003_trigger_handler, NULL);
> + if (ret)
> + return ret;
> +
> + return devm_iio_device_register(&serdev->dev, indio_dev);
> +}
> +
> +static const struct of_device_id pms7003_of_match[] = {
> + { .compatible = "plantower,pms7003" },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, pms7003_of_match);
> +
> +static struct serdev_device_driver pms7003_driver = {
> + .driver = {
> + .name = PMS7003_DRIVER_NAME,
> + .of_match_table = pms7003_of_match,
> + },
> + .probe = pms7003_probe,
> +};
> +module_serdev_device_driver(pms7003_driver);
> +
> +MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
> +MODULE_DESCRIPTION("Plantower PMS7003 particulate matter sensor driver");
> +MODULE_LICENSE("GPL v2");
>

--

Peter Meerwald-Stadler
Mobile: +43 664 24 44 418