[PATCH v5 1/3] dt-bindings: vendor-prefixes: add aosong

[PATCH v5 1/3] dt-bindings: vendor-prefixes: add aosong

[Anshul Dalal]

Aosong Electronic Co., LTD. is a supplier for MEMS sensors such as AHT20
temperature and humidity sensor under the brand name Asair

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Anshul Dalal <anshulusr@gmail.com>
---

Changes for v5,4,3:
- no updates

Changes for v2:
- Changed vendor prefix from asair to aosong

Previous versions:
v4: https://lore.kernel.org/lkml/20231125100139.193584-2-anshulusr@gmail.com/
v3: https://lore.kernel.org/lkml/20231121095800.2180870-1-anshulusr@gmail.com/
v2: https://lore.kernel.org/lkml/20231115125810.1394854-1-anshulusr@gmail.com/
v1: https://lore.kernel.org/lkml/20231107173100.62715-1-anshulusr@gmail.com/
---
 Documentation/devicetree/bindings/vendor-prefixes.yaml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/vendor-prefixes.yaml b/Documentation/devicetree/bindings/vendor-prefixes.yaml
index 573578db9509..48d4ff635562 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.yaml
+++ b/Documentation/devicetree/bindings/vendor-prefixes.yaml
@@ -117,6 +117,8 @@ patternProperties:
     description: Andes Technology Corporation
   "^anvo,.*":
     description: Anvo-Systems Dresden GmbH
+  "^aosong,.*":
+    description: Guangzhou Aosong Electronic Co., Ltd.
   "^apm,.*":
     description: Applied Micro Circuits Corporation (APM)
   "^apple,.*":
-- 
2.43.0

[PATCH v5 2/3] dt-bindings: iio: chemical: add aosong,ags02ma

[Anshul Dalal]

Add bindings for Aosong AGS02MA TVOC sensor.

The sensor communicates over i2c with the default address 0x1a.
TVOC values can be read in the units of ppb and ug/m^3 at register 0x00.

Datasheet: https://asairsensors.com/wp-content/uploads/2021/09/AGS02MA.pdf
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Anshul Dalal <anshulusr@gmail.com>
---

Changes for v5:
- Made vdd-supply a required property

Changes for v4:
- Changed node name from 'light-sensor' to 'voc-sensor'

Changes for v3:
- Fixed commit message
- Removed "asair,ags02ma" compatible

Changes for v2:
- Removed device from trivial-devices
- Added standalone binding with vdd-supply property

Previous versions:
v4: https://lore.kernel.org/lkml/20231125100139.193584-2-anshulusr@gmail.com/
v3: https://lore.kernel.org/lkml/20231121095800.2180870-2-anshulusr@gmail.com/
v2: https://lore.kernel.org/lkml/20231115125810.1394854-2-anshulusr@gmail.com/
v1: https://lore.kernel.org/lkml/20231107173100.62715-2-anshulusr@gmail.com/
---
 .../bindings/iio/chemical/aosong,ags02ma.yaml | 47 +++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/chemical/aosong,ags02ma.yaml

diff --git a/Documentation/devicetree/bindings/iio/chemical/aosong,ags02ma.yaml b/Documentation/devicetree/bindings/iio/chemical/aosong,ags02ma.yaml
new file mode 100644
index 000000000000..35e7b094e878
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/chemical/aosong,ags02ma.yaml
@@ -0,0 +1,47 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/chemical/aosong,ags02ma.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Aosong AGS02MA VOC Sensor
+
+description: |
+  AGS02MA is an TVOC (Total Volatile Organic Compounds) i2c sensor with default
+  address of 0x1a.
+
+  Datasheet:
+    https://asairsensors.com/wp-content/uploads/2021/09/AGS02MA.pdf
+
+maintainers:
+  - Anshul Dalal <anshulusr@gmail.com>
+
+properties:
+  compatible:
+    enum:
+      - aosong,ags02ma
+
+  reg:
+    maxItems: 1
+
+  vdd-supply: true
+
+required:
+  - compatible
+  - reg
+  - vdd-supply
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        voc-sensor@1a {
+            compatible = "aosong,ags02ma";
+            reg = <0x1a>;
+            vdd-supply = <&vdd_regulator>;
+        };
+    };
-- 
2.43.0

[PATCH v5 3/3] iio: chemical: add support for Aosong AGS02MA

[Anshul Dalal]

A simple driver for the TVOC (Total Volatile Organic Compounds)
sensor from Aosong: AGS02MA

Steps in reading the VOC sensor value over i2c:
  1. Read 5 bytes from the register `AGS02MA_TVOC_READ_REG` [0x00]
  2. The first 4 bytes are taken as the big endian sensor data with final
     byte being the CRC
  3. The CRC is verified and the value is returned over an
     `IIO_CHAN_INFO_RAW` channel as percents

Tested on Raspberry Pi Zero 2W

Datasheet: https://asairsensors.com/wp-content/uploads/2021/09/AGS02MA.pdf
Signed-off-by: Anshul Dalal <anshulusr@gmail.com>
---

Changes for v5:
- Removed AGS02MA_DEVICE_NAME define
- Saperated return value from data in
  `ags02ma_register_read`
- Added IIO_CHAN_INFO_SCALE for ppb to percent conversion
- Changed `ags02ma_channels` (iio_chan_spec[1]) to
  `ags02ma_channel` (iio_chan_spec) since only driver only
  uses a single channel
- Use `dev_err_probe` instead of `dev_err`
- removed unnecessary `i2c_set_clientdata(..)`
- Removed `of_match_ptr(..)`

Changes for v4:
- Fixed warning: unused variable 'ags02ma_of_table'
- Fixed warning: unsigned 'ret' is never less than zero in
  `ags02ma_register_read`

Changes for v3:
- Added of_device_id

Changes for v2:
- Fixed Kconfig not selecting CRC8 (used to be `select crc8`)
- Changed instances of asair to aosong
- Report raw readings in percents instead of ppb
- Added myself as maintainer for the device binding

Previous versions:
v4: https://lore.kernel.org/lkml/20231125100139.193584-3-anshulusr@gmail.com/
v3: https://lore.kernel.org/lkml/20231121095800.2180870-3-anshulusr@gmail.com/
v2: https://lore.kernel.org/lkml/20231115125810.1394854-3-anshulusr@gmail.com/
v1: https://lore.kernel.org/lkml/20231107173100.62715-3-anshulusr@gmail.com/
---
 MAINTAINERS                    |   7 ++
 drivers/iio/chemical/Kconfig   |  11 +++
 drivers/iio/chemical/Makefile  |   1 +
 drivers/iio/chemical/ags02ma.c | 164 +++++++++++++++++++++++++++++++++
 4 files changed, 183 insertions(+)
 create mode 100644 drivers/iio/chemical/ags02ma.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 81d5fc0bba68..ba3c950aca1b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3028,6 +3028,13 @@ S:	Supported
 W:	http://www.akm.com/
 F:	drivers/iio/magnetometer/ak8974.c
 
+AOSONG AGS02MA TVOC SENSOR DRIVER
+M:	Anshul Dalal <anshulusr@gmail.com>
+L:	linux-iio@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/iio/chemical/aosong,ags02ma.yaml
+F:	drivers/iio/chemical/ags02ma.c
+
 ASC7621 HARDWARE MONITOR DRIVER
 M:	George Joseph <george.joseph@fairview5.com>
 L:	linux-hwmon@vger.kernel.org
diff --git a/drivers/iio/chemical/Kconfig b/drivers/iio/chemical/Kconfig
index c30657e10ee1..02649ab81b3c 100644
--- a/drivers/iio/chemical/Kconfig
+++ b/drivers/iio/chemical/Kconfig
@@ -5,6 +5,17 @@
 
 menu "Chemical Sensors"
 
+config AOSONG_AGS02MA
+	tristate "Aosong AGS02MA TVOC sensor driver"
+	depends on I2C
+	select CRC8
+	help
+	  Say Y here to build support for Aosong AGS02MA TVOC (Total Volatile
+	  Organic Compounds) sensor.
+
+	  To compile this driver as module, choose M here: the module will be
+	  called ags02ma.
+
 config ATLAS_PH_SENSOR
 	tristate "Atlas Scientific OEM SM sensors"
 	depends on I2C
diff --git a/drivers/iio/chemical/Makefile b/drivers/iio/chemical/Makefile
index a11e777a7a00..2f3dee8bb779 100644
--- a/drivers/iio/chemical/Makefile
+++ b/drivers/iio/chemical/Makefile
@@ -4,6 +4,7 @@
 #
 
 # When adding new entries keep the list in alphabetical order
+obj-$(CONFIG_AOSONG_AGS02MA)	+= ags02ma.o
 obj-$(CONFIG_ATLAS_PH_SENSOR)	+= atlas-sensor.o
 obj-$(CONFIG_ATLAS_EZO_SENSOR)	+= atlas-ezo-sensor.o
 obj-$(CONFIG_BME680) += bme680_core.o
diff --git a/drivers/iio/chemical/ags02ma.c b/drivers/iio/chemical/ags02ma.c
new file mode 100644
index 000000000000..b2fe056083b3
--- /dev/null
+++ b/drivers/iio/chemical/ags02ma.c
@@ -0,0 +1,164 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2023 Anshul Dalal <anshulusr@gmail.com>
+ *
+ * Driver for Aosong AGS02MA
+ *
+ * Datasheet:
+ *   https://asairsensors.com/wp-content/uploads/2021/09/AGS02MA.pdf
+ * Product Page:
+ *   http://www.aosong.com/m/en/products-33.html
+ */
+
+#include <linux/crc8.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+
+#include <linux/iio/iio.h>
+
+#define AGS02MA_TVOC_READ_REG		   0x00
+#define AGS02MA_VERSION_REG		   0x11
+
+#define AGS02MA_VERSION_PROCESSING_DELAY   30
+#define AGS02MA_TVOC_READ_PROCESSING_DELAY 1500
+
+#define AGS02MA_CRC8_INIT		   0xff
+#define AGS02MA_CRC8_POLYNOMIAL		   0x31
+
+DECLARE_CRC8_TABLE(ags02ma_crc8_table);
+
+struct ags02ma_data {
+	struct i2c_client *client;
+};
+
+struct ags02ma_reading {
+	__be32 data;
+	u8 crc;
+} __packed;
+
+static int ags02ma_register_read(struct i2c_client *client, u8 reg, u16 delay,
+				 u32 *val)
+{
+	int ret;
+	u8 crc;
+	struct ags02ma_reading read_buffer;
+
+	ret = i2c_master_send(client, &reg, sizeof(reg));
+	if (ret < 0) {
+		dev_err(&client->dev,
+			"Failed to send data to register 0x%x: %d", reg, ret);
+		return ret;
+	}
+
+	/* Processing Delay, Check Table 7.7 in the datasheet */
+	msleep_interruptible(delay);
+
+	ret = i2c_master_recv(client, (u8 *)&read_buffer, sizeof(read_buffer));
+	if (ret < 0) {
+		dev_err(&client->dev,
+			"Failed to receive from register 0x%x: %d", reg, ret);
+		return ret;
+	}
+
+	crc = crc8(ags02ma_crc8_table, (u8 *)&read_buffer.data,
+		   sizeof(read_buffer.data), AGS02MA_CRC8_INIT);
+	if (crc != read_buffer.crc) {
+		dev_err(&client->dev, "CRC error\n");
+		return -EIO;
+	}
+
+	*val = be32_to_cpu(read_buffer.data);
+	return 0;
+}
+
+static int ags02ma_read_raw(struct iio_dev *iio_device,
+			    struct iio_chan_spec const *chan, int *val,
+			    int *val2, long mask)
+{
+	int ret;
+	struct ags02ma_data *data = iio_priv(iio_device);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = ags02ma_register_read(data->client, AGS02MA_TVOC_READ_REG,
+					    AGS02MA_TVOC_READ_PROCESSING_DELAY,
+					    val);
+		if (ret < 0)
+			return ret;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		/* The sensor reads data as ppb */
+		*val = 0;
+		*val2 = 100;
+		return IIO_VAL_INT_PLUS_NANO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info ags02ma_info = {
+	.read_raw = ags02ma_read_raw,
+};
+
+static const struct iio_chan_spec ags02ma_channel = {
+	.type = IIO_CONCENTRATION,
+	.channel2 = IIO_MOD_VOC,
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE)
+};
+
+static int ags02ma_probe(struct i2c_client *client)
+{
+	int ret;
+	struct ags02ma_data *data;
+	struct iio_dev *indio_dev;
+	u32 version;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	crc8_populate_msb(ags02ma_crc8_table, AGS02MA_CRC8_POLYNOMIAL);
+
+	ret = ags02ma_register_read(client, AGS02MA_VERSION_REG,
+				    AGS02MA_VERSION_PROCESSING_DELAY, &version);
+	if (ret < 0)
+		return dev_err_probe(&client->dev, ret,
+			      "Failed to read device version\n");
+	dev_dbg(&client->dev, "Aosong AGS02MA, Version: 0x%x", version);
+
+	data = iio_priv(indio_dev);
+	data->client = client;
+	indio_dev->info = &ags02ma_info;
+	indio_dev->channels = &ags02ma_channel;
+	indio_dev->num_channels = 1;
+	indio_dev->name = "ags02ma";
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id ags02ma_id_table[] = {
+	{ "ags02ma" },
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(i2c, ags02ma_id_table);
+
+static const struct of_device_id ags02ma_of_table[] = {
+	{ .compatible = "aosong,ags02ma" },
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ags02ma_of_table);
+
+static struct i2c_driver ags02ma_driver = {
+	.driver = {
+		.name = "ags02ma",
+		.of_match_table = ags02ma_of_table,
+	},
+	.id_table = ags02ma_id_table,
+	.probe = ags02ma_probe,
+};
+module_i2c_driver(ags02ma_driver);
+
+MODULE_AUTHOR("Anshul Dalal <anshulusr@gmail.com>");
+MODULE_DESCRIPTION("Aosong AGS02MA TVOC Driver");
+MODULE_LICENSE("GPL");
-- 
2.43.0

Re: [PATCH v5 3/3] iio: chemical: add support for Aosong AGS02MA

[Jonathan Cameron]

On Fri, 15 Dec 2023 21:53:11 +0530
Anshul Dalal <anshulusr@gmail.com> wrote:

> A simple driver for the TVOC (Total Volatile Organic Compounds)
> sensor from Aosong: AGS02MA
> 
> Steps in reading the VOC sensor value over i2c:
>   1. Read 5 bytes from the register `AGS02MA_TVOC_READ_REG` [0x00]
>   2. The first 4 bytes are taken as the big endian sensor data with final
>      byte being the CRC
>   3. The CRC is verified and the value is returned over an
>      `IIO_CHAN_INFO_RAW` channel as percents
> 
> Tested on Raspberry Pi Zero 2W
> 
> Datasheet: https://asairsensors.com/wp-content/uploads/2021/09/AGS02MA.pdf
> Signed-off-by: Anshul Dalal <anshulusr@gmail.com>

Hi Anshul, Just one trivial thing. I'll fix up whilst applying.

Applied to the togreg branch of iio.git. Will be initially pushed out as testing
for 0-day to see if it can find anything we missed.

Thanks,

Jonathan

> +
> +static const struct iio_info ags02ma_info = {
> +	.read_raw = ags02ma_read_raw,
> +};
> +
> +static const struct iio_chan_spec ags02ma_channel = {
> +	.type = IIO_CONCENTRATION,
> +	.channel2 = IIO_MOD_VOC,
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE)

Comma after this line. I'll fix up if there isn't much else.
The reason for this is that it is very plausible we'll add more to this
channel description in the future and the absence of the comma would make that
messier.


> +};