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* [PATCH v2 0/3] add support for PMS7003 PM sensor
@ 2019-01-27 18:19 Tomasz Duszynski
  2019-01-27 18:19 ` [PATCH v2 1/3] iio: chemical: add support for Plantower PMS7003 sensor Tomasz Duszynski
                   ` (2 more replies)
  0 siblings, 3 replies; 12+ messages in thread
From: Tomasz Duszynski @ 2019-01-27 18:19 UTC (permalink / raw)
  To: linux-iio; +Cc: linux-kernel, devicetree, johan, robh, jic23, Tomasz Duszynski

This patch series adds support for Plantower PMS7003 PM matter sensor.

Unfortunately datasheet is not available for download from the Plantower
website so one needs to find it elsewhere, for instance here:

https://download.kamami.com/p564008-p564008-PMS7003%20series%20data%20manua_English_V2.5.pdf

v2:
 * check number of bytes returned from serdev_device_write()
   (due to changes in linux 5.0 serdev api)
 * add missing pins descriptions to the driver binding
 * keep commands in the lookup table
 * buffer data and process everything in one go instead of using state machine
 * keep pm offset in channel address to simplify reading measurements

Tomasz Duszynski (3):
  iio: chemical: add support for Plantower PMS7003 sensor
  dt-bindings: add Plantower to the vendor prefixes
  dt-bindings: iio: chemical: pms7003: add device tree support

 .../iio/chemical/plantower,pms7003.txt        |  19 +
 .../devicetree/bindings/vendor-prefixes.txt   |   1 +
 drivers/iio/chemical/Kconfig                  |  10 +
 drivers/iio/chemical/Makefile                 |   1 +
 drivers/iio/chemical/pms7003.c                | 343 ++++++++++++++++++
 5 files changed, 374 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
 create mode 100644 drivers/iio/chemical/pms7003.c

--
2.20.1


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH v2 1/3] iio: chemical: add support for Plantower PMS7003 sensor
  2019-01-27 18:19 [PATCH v2 0/3] add support for PMS7003 PM sensor Tomasz Duszynski
@ 2019-01-27 18:19 ` Tomasz Duszynski
  2019-01-27 18:53   ` Peter Meerwald-Stadler
  2019-01-27 18:19 ` [PATCH v2 2/3] dt-bindings: add Plantower to the vendor prefixes Tomasz Duszynski
  2019-01-27 18:19 ` [PATCH v2 3/3] dt-bindings: iio: chemical: pms7003: add device tree support Tomasz Duszynski
  2 siblings, 1 reply; 12+ messages in thread
From: Tomasz Duszynski @ 2019-01-27 18:19 UTC (permalink / raw)
  To: linux-iio; +Cc: linux-kernel, devicetree, johan, robh, jic23, Tomasz Duszynski

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
+
+#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;
+}
+
+
+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,
+			       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 */
+		if (size < 4)
+			return 0;
+
+		magic = get_unaligned_be16(buf);
+		if (magic != PMS7003_MAGIC)
+			return 2;
+
+		num = get_unaligned_be16(buf + 2);
+		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");
-- 
2.20.1


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH v2 2/3] dt-bindings: add Plantower to the vendor prefixes
  2019-01-27 18:19 [PATCH v2 0/3] add support for PMS7003 PM sensor Tomasz Duszynski
  2019-01-27 18:19 ` [PATCH v2 1/3] iio: chemical: add support for Plantower PMS7003 sensor Tomasz Duszynski
@ 2019-01-27 18:19 ` Tomasz Duszynski
  2019-01-27 18:19 ` [PATCH v2 3/3] dt-bindings: iio: chemical: pms7003: add device tree support Tomasz Duszynski
  2 siblings, 0 replies; 12+ messages in thread
From: Tomasz Duszynski @ 2019-01-27 18:19 UTC (permalink / raw)
  To: linux-iio; +Cc: linux-kernel, devicetree, johan, robh, jic23, Tomasz Duszynski

Add Plantower to the vendor prefixes.

Signed-off-by: Tomasz Duszynski <tduszyns@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
---
 Documentation/devicetree/bindings/vendor-prefixes.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt
index 3cfe0c8b8250..fa391a650f3a 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.txt
+++ b/Documentation/devicetree/bindings/vendor-prefixes.txt
@@ -300,6 +300,7 @@ phytec	PHYTEC Messtechnik GmbH
 picochip	Picochip Ltd
 pine64	Pine64
 pixcir  PIXCIR MICROELECTRONICS Co., Ltd
+plantower Plantower Co., Ltd
 plathome	Plat'Home Co., Ltd.
 plda	PLDA
 plx	Broadcom Corporation (formerly PLX Technology)
--
2.20.1


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH v2 3/3] dt-bindings: iio: chemical: pms7003: add device tree support
  2019-01-27 18:19 [PATCH v2 0/3] add support for PMS7003 PM sensor Tomasz Duszynski
  2019-01-27 18:19 ` [PATCH v2 1/3] iio: chemical: add support for Plantower PMS7003 sensor Tomasz Duszynski
  2019-01-27 18:19 ` [PATCH v2 2/3] dt-bindings: add Plantower to the vendor prefixes Tomasz Duszynski
@ 2019-01-27 18:19 ` Tomasz Duszynski
  2019-01-28  7:58   ` Johan Hovold
  2 siblings, 1 reply; 12+ messages in thread
From: Tomasz Duszynski @ 2019-01-27 18:19 UTC (permalink / raw)
  To: linux-iio; +Cc: linux-kernel, devicetree, johan, robh, jic23, Tomasz Duszynski

Add device tree support for Plantower PMS7003 particulate matter sensor.

Signed-off-by: Tomasz Duszynski <tduszyns@gmail.com>
---
 .../iio/chemical/plantower,pms7003.txt        | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt

diff --git a/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt b/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
new file mode 100644
index 000000000000..e4c7f2fb1e30
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
@@ -0,0 +1,19 @@
+* Plantower PMS7003 particulate matter sensor
+
+Required properties:
+- compatible: must be "plantower,pms7003"
+
+Optional properties:
+- vcc-supply: phandle to the regulator that provides power to the sensor
+- set-gpios: phandle to the GPIO connected to the SET line
+- reset-gpios: phandle to the GPIO connected to the RESET line
+
+Refer to serial/slave-device.txt for generic serial attached device bindings.
+
+Example:
+
+&uart0 {
+	pms7003 {
+		compatible = "plantower,pms7003";
+	};
+};
-- 
2.20.1


^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH v2 1/3] iio: chemical: add support for Plantower PMS7003 sensor
  2019-01-27 18:19 ` [PATCH v2 1/3] iio: chemical: add support for Plantower PMS7003 sensor Tomasz Duszynski
@ 2019-01-27 18:53   ` Peter Meerwald-Stadler
  2019-01-27 21:06     ` Tomasz Duszynski
  0 siblings, 1 reply; 12+ messages in thread
From: Peter Meerwald-Stadler @ 2019-01-27 18:53 UTC (permalink / raw)
  To: Tomasz Duszynski; +Cc: linux-iio, linux-kernel, johan, jic23

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

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH v2 1/3] iio: chemical: add support for Plantower PMS7003 sensor
  2019-01-27 18:53   ` Peter Meerwald-Stadler
@ 2019-01-27 21:06     ` Tomasz Duszynski
  0 siblings, 0 replies; 12+ messages in thread
From: Tomasz Duszynski @ 2019-01-27 21:06 UTC (permalink / raw)
  To: Peter Meerwald-Stadler
  Cc: Tomasz Duszynski, linux-iio, linux-kernel, johan, jic23

On Sun, Jan 27, 2019 at 07:53:58PM +0100, Peter Meerwald-Stadler wrote:
> On Sun, 27 Jan 2019, Tomasz Duszynski wrote:
>
> some minor comments below, looks good to me
>

Thanks for comments.

> > 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
>

Good catch, indeed no calls to prink() in the driver code.

> > +
> > +#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
>

Okay.

> > +
> > +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
>

From what I see serdev header file already has some documentation
regarding this. Perhaps there's no real value in repeating it here
again.

> > +			       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
>

Okay.

> > +		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 you do not have particularly strong opinion on this one I would like
to leave it as is. Otherwise I would likely need to replace other
numbers in this branch with sizeofs due to consistency.

> > +		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

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH v2 3/3] dt-bindings: iio: chemical: pms7003: add device tree support
  2019-01-27 18:19 ` [PATCH v2 3/3] dt-bindings: iio: chemical: pms7003: add device tree support Tomasz Duszynski
@ 2019-01-28  7:58   ` Johan Hovold
  2019-01-28 18:43     ` Tomasz Duszynski
  0 siblings, 1 reply; 12+ messages in thread
From: Johan Hovold @ 2019-01-28  7:58 UTC (permalink / raw)
  To: Tomasz Duszynski; +Cc: linux-iio, linux-kernel, devicetree, johan, robh, jic23

On Sun, Jan 27, 2019 at 07:19:16PM +0100, Tomasz Duszynski wrote:
> Add device tree support for Plantower PMS7003 particulate matter sensor.
> 
> Signed-off-by: Tomasz Duszynski <tduszyns@gmail.com>
> ---
>  .../iio/chemical/plantower,pms7003.txt        | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> 
> diff --git a/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt b/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> new file mode 100644
> index 000000000000..e4c7f2fb1e30
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> @@ -0,0 +1,19 @@
> +* Plantower PMS7003 particulate matter sensor
> +
> +Required properties:
> +- compatible: must be "plantower,pms7003"
> +
> +Optional properties:
> +- vcc-supply: phandle to the regulator that provides power to the sensor

Shouldn't this one be a required property?

> +- set-gpios: phandle to the GPIO connected to the SET line
> +- reset-gpios: phandle to the GPIO connected to the RESET line
> +
> +Refer to serial/slave-device.txt for generic serial attached device bindings.
> +
> +Example:
> +
> +&uart0 {
> +	pms7003 {

The node name should be generic and reflect the functionality rather
than model. Perhaps "pms" will do here.

> +		compatible = "plantower,pms7003";
> +	};
> +};

Johan

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH v2 3/3] dt-bindings: iio: chemical: pms7003: add device tree support
  2019-01-28  7:58   ` Johan Hovold
@ 2019-01-28 18:43     ` Tomasz Duszynski
  2019-01-30  9:12       ` Johan Hovold
  0 siblings, 1 reply; 12+ messages in thread
From: Tomasz Duszynski @ 2019-01-28 18:43 UTC (permalink / raw)
  To: Johan Hovold
  Cc: Tomasz Duszynski, linux-iio, linux-kernel, devicetree, robh, jic23

On Mon, Jan 28, 2019 at 08:58:19AM +0100, Johan Hovold wrote:
> On Sun, Jan 27, 2019 at 07:19:16PM +0100, Tomasz Duszynski wrote:
> > Add device tree support for Plantower PMS7003 particulate matter sensor.
> >
> > Signed-off-by: Tomasz Duszynski <tduszyns@gmail.com>
> > ---
> >  .../iio/chemical/plantower,pms7003.txt        | 19 +++++++++++++++++++
> >  1 file changed, 19 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> >
> > diff --git a/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt b/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> > new file mode 100644
> > index 000000000000..e4c7f2fb1e30
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> > @@ -0,0 +1,19 @@
> > +* Plantower PMS7003 particulate matter sensor
> > +
> > +Required properties:
> > +- compatible: must be "plantower,pms7003"
> > +
> > +Optional properties:
> > +- vcc-supply: phandle to the regulator that provides power to the sensor
>
> Shouldn't this one be a required property?
>

Driver does not use regulator framework hence to me this property fits
here better.

> > +- set-gpios: phandle to the GPIO connected to the SET line
> > +- reset-gpios: phandle to the GPIO connected to the RESET line
> > +
> > +Refer to serial/slave-device.txt for generic serial attached device bindings.
> > +
> > +Example:
> > +
> > +&uart0 {
> > +	pms7003 {
>
> The node name should be generic and reflect the functionality rather
> than model. Perhaps "pms" will do here.
>

Agree, ideally we should have a generic dt name for this kind of sensors
(something like air-pollution-sensor perhaps?). But unfortunately there isn't
anything available now so I guess compatible part name should be okay
(besides this is the type of naming commonly used in other iio bindings).

> > +		compatible = "plantower,pms7003";
> > +	};
> > +};
>
> Johan

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH v2 3/3] dt-bindings: iio: chemical: pms7003: add device tree support
  2019-01-28 18:43     ` Tomasz Duszynski
@ 2019-01-30  9:12       ` Johan Hovold
  2019-01-31 20:40         ` Tomasz Duszynski
  0 siblings, 1 reply; 12+ messages in thread
From: Johan Hovold @ 2019-01-30  9:12 UTC (permalink / raw)
  To: Tomasz Duszynski
  Cc: Johan Hovold, linux-iio, linux-kernel, devicetree, robh, jic23

On Mon, Jan 28, 2019 at 07:43:33PM +0100, Tomasz Duszynski wrote:
> On Mon, Jan 28, 2019 at 08:58:19AM +0100, Johan Hovold wrote:
> > On Sun, Jan 27, 2019 at 07:19:16PM +0100, Tomasz Duszynski wrote:
> > > Add device tree support for Plantower PMS7003 particulate matter sensor.
> > >
> > > Signed-off-by: Tomasz Duszynski <tduszyns@gmail.com>
> > > ---
> > >  .../iio/chemical/plantower,pms7003.txt        | 19 +++++++++++++++++++
> > >  1 file changed, 19 insertions(+)
> > >  create mode 100644 Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> > >
> > > diff --git a/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt b/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> > > new file mode 100644
> > > index 000000000000..e4c7f2fb1e30
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> > > @@ -0,0 +1,19 @@
> > > +* Plantower PMS7003 particulate matter sensor
> > > +
> > > +Required properties:
> > > +- compatible: must be "plantower,pms7003"
> > > +
> > > +Optional properties:
> > > +- vcc-supply: phandle to the regulator that provides power to the sensor
> >
> > Shouldn't this one be a required property?
> >
> 
> Driver does not use regulator framework hence to me this property fits
> here better.

The device tree describes hardware, not any particular driver.

That said, there is a bit of an on-going debate on whether mandatory
supplies (from a hardware perspective) should always be represented in
device tree or not.

	https://lore.kernel.org/lkml/20181123133126.GF2089@sirena.org.uk/T/#u
        https://lore.kernel.org/lkml/20180409102244.GB11532@sirena.org.uk/T/#u
	https://lore.kernel.org/lkml/20180425171123.xhyoay3nu463btoq@rob-hp-laptop/T/#u

> > > +- set-gpios: phandle to the GPIO connected to the SET line
> > > +- reset-gpios: phandle to the GPIO connected to the RESET line
> > > +
> > > +Refer to serial/slave-device.txt for generic serial attached device bindings.
> > > +
> > > +Example:
> > > +
> > > +&uart0 {
> > > +	pms7003 {
> >
> > The node name should be generic and reflect the functionality rather
> > than model. Perhaps "pms" will do here.
> 
> Agree, ideally we should have a generic dt name for this kind of sensors
> (something like air-pollution-sensor perhaps?). But unfortunately there isn't
> anything available now so I guess compatible part name should be okay
> (besides this is the type of naming commonly used in other iio bindings).

What's wrong with particulate matter sensor ("pms")?

Seems like a better fix than any particular model name to me at least.

> > > +		compatible = "plantower,pms7003";
> > > +	};
> > > +};

Johan

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH v2 3/3] dt-bindings: iio: chemical: pms7003: add device tree support
  2019-01-30  9:12       ` Johan Hovold
@ 2019-01-31 20:40         ` Tomasz Duszynski
  2019-02-01  9:12           ` Johan Hovold
  0 siblings, 1 reply; 12+ messages in thread
From: Tomasz Duszynski @ 2019-01-31 20:40 UTC (permalink / raw)
  To: Johan Hovold
  Cc: Tomasz Duszynski, linux-iio, linux-kernel, devicetree, robh, jic23

On Wed, Jan 30, 2019 at 10:12:54AM +0100, Johan Hovold wrote:
> On Mon, Jan 28, 2019 at 07:43:33PM +0100, Tomasz Duszynski wrote:
> > On Mon, Jan 28, 2019 at 08:58:19AM +0100, Johan Hovold wrote:
> > > On Sun, Jan 27, 2019 at 07:19:16PM +0100, Tomasz Duszynski wrote:
> > > > Add device tree support for Plantower PMS7003 particulate matter sensor.
> > > >
> > > > Signed-off-by: Tomasz Duszynski <tduszyns@gmail.com>
> > > > ---
> > > >  .../iio/chemical/plantower,pms7003.txt        | 19 +++++++++++++++++++
> > > >  1 file changed, 19 insertions(+)
> > > >  create mode 100644 Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt b/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> > > > new file mode 100644
> > > > index 000000000000..e4c7f2fb1e30
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> > > > @@ -0,0 +1,19 @@
> > > > +* Plantower PMS7003 particulate matter sensor
> > > > +
> > > > +Required properties:
> > > > +- compatible: must be "plantower,pms7003"
> > > > +
> > > > +Optional properties:
> > > > +- vcc-supply: phandle to the regulator that provides power to the sensor
> > >
> > > Shouldn't this one be a required property?
> > >
> >
> > Driver does not use regulator framework hence to me this property fits
> > here better.
>
> The device tree describes hardware, not any particular driver.
>
> That said, there is a bit of an on-going debate on whether mandatory
> supplies (from a hardware perspective) should always be represented in
> device tree or not.
>
> 	https://lore.kernel.org/lkml/20181123133126.GF2089@sirena.org.uk/T/#u
>         https://lore.kernel.org/lkml/20180409102244.GB11532@sirena.org.uk/T/#u
> 	https://lore.kernel.org/lkml/20180425171123.xhyoay3nu463btoq@rob-hp-laptop/T/#u
>

Even after going through this threads I am still unconvinced that
vcc-supply should be a requirement. Making this a mandatory property
would automatically imply using *_regulator_get() in a driver code
(on condition one is adding regulator support). In case there
isn't any physically connected we end up with a dummy one and a warning.

Is it how this should work?

> > > > +- set-gpios: phandle to the GPIO connected to the SET line
> > > > +- reset-gpios: phandle to the GPIO connected to the RESET line
> > > > +
> > > > +Refer to serial/slave-device.txt for generic serial attached device bindings.
> > > > +
> > > > +Example:
> > > > +
> > > > +&uart0 {
> > > > +	pms7003 {
> > >
> > > The node name should be generic and reflect the functionality rather
> > > than model. Perhaps "pms" will do here.
> >
> > Agree, ideally we should have a generic dt name for this kind of sensors
> > (something like air-pollution-sensor perhaps?). But unfortunately there isn't
> > anything available now so I guess compatible part name should be okay
> > (besides this is the type of naming commonly used in other iio bindings).
>
> What's wrong with particulate matter sensor ("pms")?
>
> Seems like a better fix than any particular model name to me at least.
>

Personally I would vote for a more descriptive node name, for example:
particulate-matter-sensor or air-pollution-sensor or other name
which clearly shows what device we are dealing with.

> > > > +		compatible = "plantower,pms7003";
> > > > +	};
> > > > +};
>
> Johan

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH v2 3/3] dt-bindings: iio: chemical: pms7003: add device tree support
  2019-01-31 20:40         ` Tomasz Duszynski
@ 2019-02-01  9:12           ` Johan Hovold
  2019-02-01 17:10             ` Tomasz Duszynski
  0 siblings, 1 reply; 12+ messages in thread
From: Johan Hovold @ 2019-02-01  9:12 UTC (permalink / raw)
  To: Tomasz Duszynski
  Cc: Johan Hovold, linux-iio, linux-kernel, devicetree, robh, jic23

On Thu, Jan 31, 2019 at 09:40:04PM +0100, Tomasz Duszynski wrote:
> On Wed, Jan 30, 2019 at 10:12:54AM +0100, Johan Hovold wrote:
> > On Mon, Jan 28, 2019 at 07:43:33PM +0100, Tomasz Duszynski wrote:
> > > On Mon, Jan 28, 2019 at 08:58:19AM +0100, Johan Hovold wrote:
> > > > On Sun, Jan 27, 2019 at 07:19:16PM +0100, Tomasz Duszynski wrote:
> > > > > Add device tree support for Plantower PMS7003 particulate matter sensor.
> > > > >
> > > > > Signed-off-by: Tomasz Duszynski <tduszyns@gmail.com>
> > > > > ---
> > > > >  .../iio/chemical/plantower,pms7003.txt        | 19 +++++++++++++++++++
> > > > >  1 file changed, 19 insertions(+)
> > > > >  create mode 100644 Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> > > > >
> > > > > diff --git a/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt b/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> > > > > new file mode 100644
> > > > > index 000000000000..e4c7f2fb1e30
> > > > > --- /dev/null
> > > > > +++ b/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> > > > > @@ -0,0 +1,19 @@
> > > > > +* Plantower PMS7003 particulate matter sensor
> > > > > +
> > > > > +Required properties:
> > > > > +- compatible: must be "plantower,pms7003"
> > > > > +
> > > > > +Optional properties:
> > > > > +- vcc-supply: phandle to the regulator that provides power to the sensor
> > > >
> > > > Shouldn't this one be a required property?
> > > >
> > >
> > > Driver does not use regulator framework hence to me this property fits
> > > here better.
> >
> > The device tree describes hardware, not any particular driver.
> >
> > That said, there is a bit of an on-going debate on whether mandatory
> > supplies (from a hardware perspective) should always be represented in
> > device tree or not.
> >
> > 	https://lore.kernel.org/lkml/20181123133126.GF2089@sirena.org.uk/T/#u
> >         https://lore.kernel.org/lkml/20180409102244.GB11532@sirena.org.uk/T/#u
> > 	https://lore.kernel.org/lkml/20180425171123.xhyoay3nu463btoq@rob-hp-laptop/T/#u
> >
> 
> Even after going through this threads I am still unconvinced that
> vcc-supply should be a requirement. Making this a mandatory property
> would automatically imply using *_regulator_get() in a driver code
> (on condition one is adding regulator support). In case there
> isn't any physically connected we end up with a dummy one and a warning.

How would the device work at all without a physical vcc supply?

> Is it how this should work?

As Mark mentioned in the threads above, you could add a fixed,
always-on regulator for cases where the device is always powered.

Boards failing to describe this supply would still work on Linux, but
would end up with a dummy regulator and a warning.

> > > > > +- set-gpios: phandle to the GPIO connected to the SET line
> > > > > +- reset-gpios: phandle to the GPIO connected to the RESET line
> > > > > +
> > > > > +Refer to serial/slave-device.txt for generic serial attached device bindings.
> > > > > +
> > > > > +Example:
> > > > > +
> > > > > +&uart0 {
> > > > > +	pms7003 {
> > > >
> > > > The node name should be generic and reflect the functionality rather
> > > > than model. Perhaps "pms" will do here.
> > >
> > > Agree, ideally we should have a generic dt name for this kind of sensors
> > > (something like air-pollution-sensor perhaps?). But unfortunately there isn't
> > > anything available now so I guess compatible part name should be okay
> > > (besides this is the type of naming commonly used in other iio bindings).
> >
> > What's wrong with particulate matter sensor ("pms")?
> >
> > Seems like a better fix than any particular model name to me at least.
> >
> 
> Personally I would vote for a more descriptive node name, for example:
> particulate-matter-sensor or air-pollution-sensor or other name
> which clearly shows what device we are dealing with.

Spelling it out seems preferable, yes. You know the domain better than
I do; I only suggest you come up with a generic node name.

Johan

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH v2 3/3] dt-bindings: iio: chemical: pms7003: add device tree support
  2019-02-01  9:12           ` Johan Hovold
@ 2019-02-01 17:10             ` Tomasz Duszynski
  0 siblings, 0 replies; 12+ messages in thread
From: Tomasz Duszynski @ 2019-02-01 17:10 UTC (permalink / raw)
  To: Johan Hovold
  Cc: Tomasz Duszynski, linux-iio, linux-kernel, devicetree, robh, jic23

On Fri, Feb 01, 2019 at 10:12:31AM +0100, Johan Hovold wrote:
> On Thu, Jan 31, 2019 at 09:40:04PM +0100, Tomasz Duszynski wrote:
> > On Wed, Jan 30, 2019 at 10:12:54AM +0100, Johan Hovold wrote:
> > > On Mon, Jan 28, 2019 at 07:43:33PM +0100, Tomasz Duszynski wrote:
> > > > On Mon, Jan 28, 2019 at 08:58:19AM +0100, Johan Hovold wrote:
> > > > > On Sun, Jan 27, 2019 at 07:19:16PM +0100, Tomasz Duszynski wrote:
> > > > > > Add device tree support for Plantower PMS7003 particulate matter sensor.
> > > > > >
> > > > > > Signed-off-by: Tomasz Duszynski <tduszyns@gmail.com>
> > > > > > ---
> > > > > >  .../iio/chemical/plantower,pms7003.txt        | 19 +++++++++++++++++++
> > > > > >  1 file changed, 19 insertions(+)
> > > > > >  create mode 100644 Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> > > > > >
> > > > > > diff --git a/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt b/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> > > > > > new file mode 100644
> > > > > > index 000000000000..e4c7f2fb1e30
> > > > > > --- /dev/null
> > > > > > +++ b/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt
> > > > > > @@ -0,0 +1,19 @@
> > > > > > +* Plantower PMS7003 particulate matter sensor
> > > > > > +
> > > > > > +Required properties:
> > > > > > +- compatible: must be "plantower,pms7003"
> > > > > > +
> > > > > > +Optional properties:
> > > > > > +- vcc-supply: phandle to the regulator that provides power to the sensor
> > > > >
> > > > > Shouldn't this one be a required property?
> > > > >
> > > >
> > > > Driver does not use regulator framework hence to me this property fits
> > > > here better.
> > >
> > > The device tree describes hardware, not any particular driver.
> > >
> > > That said, there is a bit of an on-going debate on whether mandatory
> > > supplies (from a hardware perspective) should always be represented in
> > > device tree or not.
> > >
> > > 	https://lore.kernel.org/lkml/20181123133126.GF2089@sirena.org.uk/T/#u
> > >         https://lore.kernel.org/lkml/20180409102244.GB11532@sirena.org.uk/T/#u
> > > 	https://lore.kernel.org/lkml/20180425171123.xhyoay3nu463btoq@rob-hp-laptop/T/#u
> > >
> >
> > Even after going through this threads I am still unconvinced that
> > vcc-supply should be a requirement. Making this a mandatory property
> > would automatically imply using *_regulator_get() in a driver code
> > (on condition one is adding regulator support). In case there
> > isn't any physically connected we end up with a dummy one and a warning.
>
> How would the device work at all without a physical vcc supply?
>

I meant the discrete IC regulator.

> > Is it how this should work?
>
> As Mark mentioned in the threads above, you could add a fixed,
> always-on regulator for cases where the device is always powered.
>
> Boards failing to describe this supply would still work on Linux, but
> would end up with a dummy regulator and a warning.
>

Fair enough.

> > > > > > +- set-gpios: phandle to the GPIO connected to the SET line
> > > > > > +- reset-gpios: phandle to the GPIO connected to the RESET line
> > > > > > +
> > > > > > +Refer to serial/slave-device.txt for generic serial attached device bindings.
> > > > > > +
> > > > > > +Example:
> > > > > > +
> > > > > > +&uart0 {
> > > > > > +	pms7003 {
> > > > >
> > > > > The node name should be generic and reflect the functionality rather
> > > > > than model. Perhaps "pms" will do here.
> > > >
> > > > Agree, ideally we should have a generic dt name for this kind of sensors
> > > > (something like air-pollution-sensor perhaps?). But unfortunately there isn't
> > > > anything available now so I guess compatible part name should be okay
> > > > (besides this is the type of naming commonly used in other iio bindings).
> > >
> > > What's wrong with particulate matter sensor ("pms")?
> > >
> > > Seems like a better fix than any particular model name to me at least.
> > >
> >
> > Personally I would vote for a more descriptive node name, for example:
> > particulate-matter-sensor or air-pollution-sensor or other name
> > which clearly shows what device we are dealing with.
>
> Spelling it out seems preferable, yes. You know the domain better than
> I do; I only suggest you come up with a generic node name.
>
> Johan

^ permalink raw reply	[flat|nested] 12+ messages in thread

end of thread, back to index

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-01-27 18:19 [PATCH v2 0/3] add support for PMS7003 PM sensor Tomasz Duszynski
2019-01-27 18:19 ` [PATCH v2 1/3] iio: chemical: add support for Plantower PMS7003 sensor Tomasz Duszynski
2019-01-27 18:53   ` Peter Meerwald-Stadler
2019-01-27 21:06     ` Tomasz Duszynski
2019-01-27 18:19 ` [PATCH v2 2/3] dt-bindings: add Plantower to the vendor prefixes Tomasz Duszynski
2019-01-27 18:19 ` [PATCH v2 3/3] dt-bindings: iio: chemical: pms7003: add device tree support Tomasz Duszynski
2019-01-28  7:58   ` Johan Hovold
2019-01-28 18:43     ` Tomasz Duszynski
2019-01-30  9:12       ` Johan Hovold
2019-01-31 20:40         ` Tomasz Duszynski
2019-02-01  9:12           ` Johan Hovold
2019-02-01 17:10             ` Tomasz Duszynski

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