[PATCH v3 0/7] iio: light: AL3010 introduction

[PATCH v3 0/7] iio: light: AL3010 introduction

[David Heidelberg]

These patches implement support for simple iio light sensor AL3010 and
also improves and align formating of AL3320a which is origin of al3010
driver.

AL3010 is used in many devices, mostly tegra2/3 based.
This effort is aimed for reducing number of out-of-tree patches for
tegra tablets and phones.

This sensor is tested on Nexus 7 (2012, grouper/tilapia).

David Heidelberg (7):
  dt-bindings: iio: light: add support for Dyna-Image AL3320A
  dt-bindings: iio: light: add support for Dyna-Image AL3010
  iio: light: al3320a slightly improve code formatting
  iio: light: add Dyna-Image AL3010 driver
  iio: light: al3010 implement suspend support
  iio: light: al3320a implement suspend support
  iio: light: al3320a allow module autoload and polish

 .../devicetree/bindings/iio/light/al3010.yaml |  45 ++++
 .../bindings/iio/light/al3320a.yaml           |  45 ++++
 .../devicetree/bindings/vendor-prefixes.yaml  |   2 +
 drivers/iio/light/Kconfig                     |  10 +
 drivers/iio/light/Makefile                    |   1 +
 drivers/iio/light/al3010.c                    | 237 ++++++++++++++++++
 drivers/iio/light/al3320a.c                   |  63 +++--
 7 files changed, 389 insertions(+), 14 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/iio/light/al3010.yaml
 create mode 100644 Documentation/devicetree/bindings/iio/light/al3320a.yaml
 create mode 100644 drivers/iio/light/al3010.c

-- 
2.25.0

[PATCH v3 1/7] dt-bindings: iio: light: add support for Dyna-Image AL3320A

[David Heidelberg]

This commit add dt-bindings support to al3320a driver and vendor-prefix
dynaimage.
Partly based on unmerged commit:
"iio: Add Dyna-Image AP3223 ambient light and proximity driver"


Signed-off-by: David Heidelberg <david@ixit.cz>
---
 .../bindings/iio/light/al3320a.yaml           | 45 +++++++++++++++++++
 .../devicetree/bindings/vendor-prefixes.yaml  |  2 +
 2 files changed, 47 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/light/al3320a.yaml

diff --git a/Documentation/devicetree/bindings/iio/light/al3320a.yaml b/Documentation/devicetree/bindings/iio/light/al3320a.yaml
new file mode 100644
index 000000000000..08e7ee4bdf55
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/light/al3320a.yaml
@@ -0,0 +1,45 @@
+# SPDX-License-Identifier: (GPL-2.0-only)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/light/al3320a.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Dyna-Image AL3320A sensor
+
+maintainers:
+  - David Heidelberg <david@ixit.cz>
+
+properties:
+  compatible:
+    const: dynaimage,al3320a
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  vdd-supply:
+    description: Regulator that provides power to the sensor
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - vdd-supply
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        al3320a@1c {
+            compatible = "dynaimage,al3320a";
+            reg = <0x1c>;
+            vdd-supply = <&vdd_reg>;
+            interrupts = <0 99 4>;
+        };
+    };
diff --git a/Documentation/devicetree/bindings/vendor-prefixes.yaml b/Documentation/devicetree/bindings/vendor-prefixes.yaml
index 9cd52d9e1f7f..8d2ebf3d0aa1 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.yaml
+++ b/Documentation/devicetree/bindings/vendor-prefixes.yaml
@@ -267,6 +267,8 @@ patternProperties:
     description: Dragino Technology Co., Limited
   "^dserve,.*":
     description: dServe Technology B.V.
+  "^dynaimage,.*":
+    description: Dyna-Image
   "^ea,.*":
     description: Embedded Artists AB
   "^ebs-systart,.*":
-- 
2.25.0

[PATCH v3 1/7] dt-bindings: iio: light: add support for Dyna-Image AL3320A

[David Heidelberg]

Subject: [PATCH v3 2/7] dt-bindings: iio: light: add support for Dyna-Image
 AL3010
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The Dyna-Image AL3010 is a 16-bit digital ambient light sensor which
provides a multiple gain function with linear response over a dynamic
range 1216/4863/19452/77806.

Signed-off-by: David Heidelberg <david@ixit.cz>
---
 .../devicetree/bindings/iio/light/al3010.yaml | 45 +++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/light/al3010.yaml

diff --git a/Documentation/devicetree/bindings/iio/light/al3010.yaml b/Documentation/devicetree/bindings/iio/light/al3010.yaml
new file mode 100644
index 000000000000..e7e0281476bd
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/light/al3010.yaml
@@ -0,0 +1,45 @@
+# SPDX-License-Identifier: (GPL-2.0-only)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/light/al3010.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Dyna-Image AL3010 sensor
+
+maintainers:
+  - David Heidelberg <david@ixit.cz>
+
+properties:
+  compatible:
+    const: dynaimage,al3010
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  vdd-supply:
+    description: Regulator that provides power to the sensor
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - vdd-supply
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        al3010@1c {
+            compatible = "dynaimage,al3010";
+            reg = <0x1c>;
+            vdd-supply = <&vdd_reg>;
+            interrupts = <0 99 4>;
+        };
+    };
-- 
2.25.0

Re: [PATCH v3 1/7] dt-bindings: iio: light: add support for Dyna-Image AL3320A

[Dmitry Osipenko]

01.02.2020 21:00, David Heidelberg пишет:
> Subject: [PATCH v3 2/7] dt-bindings: iio: light: add support for Dyna-Image
>  AL3010
> MIME-Version: 1.0
> Content-Type: text/plain; charset=UTF-8
> Content-Transfer-Encoding: 8bit

Looks like something went wrong, ^ this shouldn't be in the patch's body.

> The Dyna-Image AL3010 is a 16-bit digital ambient light sensor which
> provides a multiple gain function with linear response over a dynamic
> range 1216/4863/19452/77806.
> 
> Signed-off-by: David Heidelberg <david@ixit.cz>
> ---

You should put individual changelog for each patch under the ---, or
just add a cover-letter with global changelog.

>  .../devicetree/bindings/iio/light/al3010.yaml | 45 +++++++++++++++++++
>  1 file changed, 45 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/light/al3010.yaml
...

[PATCH v3 1/7] dt-bindings: iio: light: add support for Dyna-Image AL3320A

[David Heidelberg]

Subject: [PATCH v3 3/7] iio: light: al3320a slightly improve code formatting

Modified to be in part with al3010 driver.

Signed-off-by: David Heidelberg <david@ixit.cz>
---
 drivers/iio/light/al3320a.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/light/al3320a.c b/drivers/iio/light/al3320a.c
index a21aa99e74e4..613830b7df6e 100644
--- a/drivers/iio/light/al3320a.c
+++ b/drivers/iio/light/al3320a.c
@@ -38,6 +38,11 @@
 
 #define AL3320A_GAIN_SHIFT		1
 #define AL3320A_GAIN_MASK		(BIT(2) | BIT(1))
+#define AL3320A_GAIN_READ(g) \
+	(((g) & AL3320A_GAIN_MASK) >> AL3320A_GAIN_SHIFT)
+#define AL3320A_GAIN_WRITE(g) \
+	(((g) << AL3320A_GAIN_SHIFT) & AL3320A_GAIN_MASK)
+
 
 /* chip params default values */
 #define AL3320A_DEFAULT_MEAN_TIME	4
@@ -90,7 +95,7 @@ static int al3320a_init(struct al3320a_data *data)
 		return ret;
 
 	ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG_RANGE,
-					AL3320A_RANGE_3 << AL3320A_GAIN_SHIFT);
+					AL3320A_GAIN_WRITE(AL3320A_RANGE_3));
 	if (ret < 0)
 		return ret;
 
@@ -133,7 +138,7 @@ static int al3320a_read_raw(struct iio_dev *indio_dev,
 		if (ret < 0)
 			return ret;
 
-		ret = (ret & AL3320A_GAIN_MASK) >> AL3320A_GAIN_SHIFT;
+		ret = AL3320A_GAIN_READ(ret);
 		*val = al3320a_scales[ret][0];
 		*val2 = al3320a_scales[ret][1];
 
@@ -152,11 +157,13 @@ static int al3320a_write_raw(struct iio_dev *indio_dev,
 	switch (mask) {
 	case IIO_CHAN_INFO_SCALE:
 		for (i = 0; i < ARRAY_SIZE(al3320a_scales); i++) {
-			if (val == al3320a_scales[i][0] &&
-			    val2 == al3320a_scales[i][1])
-				return i2c_smbus_write_byte_data(data->client,
-					AL3320A_REG_CONFIG_RANGE,
-					i << AL3320A_GAIN_SHIFT);
+			if (val != al3320a_scales[i][0] ||
+			    val2 != al3320a_scales[i][1])
+				continue;
+
+			return i2c_smbus_write_byte_data(data->client,
+						AL3320A_REG_CONFIG_RANGE,
+						AL3320A_GAIN_WRITE(i));
 		}
 		break;
 	}
-- 
2.25.0

[PATCH v3 4/7] iio: light: add Dyna-Image AL3010 driver

[David Heidelberg]

Based on:
- 3320A in-kernel driver
- https://www.spinics.net/lists/linux-iio/msg25145.html
- https://lore.kernel.org/patchwork/patch/684179/

I decided to keep it aside of AL3320A due to different approach and much
simpler design of 3010.

Tested on Nexus 7 2012 (grouper/tilapia).

Tested-by: David Heidelberg <david@ixit.cz>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: David Heidelberg <david@ixit.cz>
---
 drivers/iio/light/Kconfig  |  10 ++
 drivers/iio/light/Makefile |   1 +
 drivers/iio/light/al3010.c | 217 +++++++++++++++++++++++++++++++++++++
 3 files changed, 228 insertions(+)
 create mode 100644 drivers/iio/light/al3010.c

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index 9968f982fbc7..43d9b830279d 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -43,6 +43,16 @@ config ADUX1020
 	 To compile this driver as a module, choose M here: the
 	 module will be called adux1020.
 
+config AL3010
+	tristate "AL3010 ambient light sensor"
+	depends on I2C
+	help
+	  Say Y here if you want to build a driver for the Dyna Image AL3010
+	  ambient light sensor.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called al3010.
+
 config AL3320A
 	tristate "AL3320A ambient light sensor"
 	depends on I2C
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index c98d1cefb861..88bb93550fcc 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -7,6 +7,7 @@
 obj-$(CONFIG_ACPI_ALS)		+= acpi-als.o
 obj-$(CONFIG_ADJD_S311)		+= adjd_s311.o
 obj-$(CONFIG_ADUX1020)		+= adux1020.o
+obj-$(CONFIG_AL3010)		+= al3010.o
 obj-$(CONFIG_AL3320A)		+= al3320a.o
 obj-$(CONFIG_APDS9300)		+= apds9300.o
 obj-$(CONFIG_APDS9960)		+= apds9960.o
diff --git a/drivers/iio/light/al3010.c b/drivers/iio/light/al3010.c
new file mode 100644
index 000000000000..4b951c087c83
--- /dev/null
+++ b/drivers/iio/light/al3010.c
@@ -0,0 +1,217 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AL3010 - Dyna Image Ambient Light Sensor
+ *
+ * Copyright (c) 2014, Intel Corporation.
+ * Copyright (c) 2016, Dyna-Image Corp.
+ *
+ * IIO driver for AL3010 (7-bit I2C slave address 0x1C).
+ *
+ * TODO: interrupt support, thresholds
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define AL3010_DRV_NAME "al3010"
+
+#define AL3010_REG_SYSTEM		0x00
+#define AL3010_REG_DATA_LOW		0x0c
+#define AL3010_REG_CONFIG		0x10
+
+#define AL3010_CONFIG_DISABLE		0x00
+#define AL3010_CONFIG_ENABLE		0x01
+
+#define AL3010_GAIN_SHIFT		4
+#define AL3010_GAIN_MASK		(BIT(6) | BIT(5) | BIT(4))
+
+#define AL3010_GAIN_READ(g) \
+	(((g) & AL3010_GAIN_MASK) >> AL3010_GAIN_SHIFT)
+
+#define AL3010_GAIN_WRITE(g) \
+	(((g) << AL3010_GAIN_SHIFT) & AL3010_GAIN_MASK)
+
+#define AL3010_SCALE_AVAILABLE "1.1872 0.2968 0.0742 0.018"
+
+enum al3xxxx_range {
+	AL3XXX_RANGE_1, /* 77806 lx */
+	AL3XXX_RANGE_2, /* 19542 lx */
+	AL3XXX_RANGE_3, /*  4863 lx */
+	AL3XXX_RANGE_4  /*  1216 lx */
+};
+
+static const int al3010_scales[][2] = {
+	{0, 1187200}, {0, 296800}, {0, 74200}, {0, 18600}
+};
+
+struct al3010_data {
+	struct i2c_client *client;
+};
+
+static const struct iio_chan_spec al3010_channels[] = {
+	{
+		.type	= IIO_LIGHT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_SCALE),
+	}
+};
+
+static IIO_CONST_ATTR(in_illuminance_scale_available, AL3010_SCALE_AVAILABLE);
+
+static struct attribute *al3010_attributes[] = {
+	&iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group al3010_attribute_group = {
+	.attrs = al3010_attributes,
+};
+
+static int al3010_init(struct al3010_data *data)
+{
+	int ret;
+
+	/* power on */
+	ret = i2c_smbus_write_byte_data(data->client, AL3010_REG_SYSTEM,
+					AL3010_CONFIG_ENABLE);
+	if (ret < 0)
+		return ret;
+
+	ret = i2c_smbus_write_byte_data(data->client, AL3010_REG_CONFIG,
+					AL3010_GAIN_WRITE(AL3XXX_RANGE_3));
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int al3010_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan, int *val,
+			   int *val2, long mask)
+{
+	struct al3010_data *data = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		/*
+		 * ALS ADC value is stored in two adjacent registers:
+		 * - low byte of output is stored at AL3010_REG_DATA_LOW
+		 * - high byte of output is stored at AL3010_REG_DATA_LOW + 1
+		 */
+		ret = i2c_smbus_read_word_data(data->client,
+					       AL3010_REG_DATA_LOW);
+		if (ret < 0)
+			return ret;
+		*val = ret;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		ret = i2c_smbus_read_byte_data(data->client,
+					       AL3010_REG_CONFIG);
+		if (ret < 0)
+			return ret;
+
+		ret = AL3010_GAIN_READ(ret);
+		*val = al3010_scales[ret][0];
+		*val2 = al3010_scales[ret][1];
+
+		return IIO_VAL_INT_PLUS_MICRO;
+	}
+	return -EINVAL;
+}
+
+static int al3010_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, int val,
+			    int val2, long mask)
+{
+	struct al3010_data *data = iio_priv(indio_dev);
+	int i;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		for (i = 0; i < ARRAY_SIZE(al3010_scales); i++) {
+			if (val != al3010_scales[i][0] ||
+			    val2 != al3010_scales[i][1])
+				continue;
+
+			return i2c_smbus_write_byte_data(data->client,
+						AL3010_REG_CONFIG,
+						AL3010_GAIN_WRITE(i));
+		}
+		break;
+	}
+	return -EINVAL;
+}
+
+static const struct iio_info al3010_info = {
+	.read_raw	= al3010_read_raw,
+	.write_raw	= al3010_write_raw,
+	.attrs		= &al3010_attribute_group,
+};
+
+static int al3010_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct al3010_data *data;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+	data->client = client;
+
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->info = &al3010_info;
+	indio_dev->name = AL3010_DRV_NAME;
+	indio_dev->channels = al3010_channels;
+	indio_dev->num_channels = ARRAY_SIZE(al3010_channels);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = al3010_init(data);
+	if (ret < 0) {
+		dev_err(&client->dev, "al3010 chip init failed\n");
+		return ret;
+	}
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static int al3010_remove(struct i2c_client *client)
+{
+	return i2c_smbus_write_byte_data(client, AL3010_REG_SYSTEM,
+					 AL3010_CONFIG_DISABLE);
+}
+
+static const struct i2c_device_id al3010_id[] = {
+	{"al3010", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, al3010_id);
+
+static const struct of_device_id al3010_of_match[] = {
+	{ .compatible = "dynaimage,al3010", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, al3010_of_match);
+
+static struct i2c_driver al3010_driver = {
+	.driver = {
+		.name = AL3010_DRV_NAME,
+		.of_match_table = al3010_of_match,
+	},
+	.probe		= al3010_probe,
+	.remove		= al3010_remove,
+	.id_table	= al3010_id,
+};
+module_i2c_driver(al3010_driver);
+
+MODULE_AUTHOR("Daniel Baluta <daniel.baluta@nxp.com>");
+MODULE_DESCRIPTION("AL3010 Ambient Light Sensor driver");
+MODULE_LICENSE("GPL v2");
-- 
2.25.0

Re: [PATCH v3 4/7] iio: light: add Dyna-Image AL3010 driver

[Jonathan Cameron]

On Sat,  1 Feb 2020 19:00:21 +0100
David Heidelberg <david@ixit.cz> wrote:

> Based on:
> - 3320A in-kernel driver
> - https://www.spinics.net/lists/linux-iio/msg25145.html
> - https://lore.kernel.org/patchwork/patch/684179/
> 
> I decided to keep it aside of AL3320A due to different approach and much
> simpler design of 3010.
> 
> Tested on Nexus 7 2012 (grouper/tilapia).
> 
> Tested-by: David Heidelberg <david@ixit.cz>
> Tested-by: Dmitry Osipenko <digetx@gmail.com>
> Signed-off-by: David Heidelberg <david@ixit.cz>
Hi,

A few minor bits inline.

Thanks,

Jonathan

> ---
>  drivers/iio/light/Kconfig  |  10 ++
>  drivers/iio/light/Makefile |   1 +
>  drivers/iio/light/al3010.c | 217 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 228 insertions(+)
>  create mode 100644 drivers/iio/light/al3010.c
> 
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> index 9968f982fbc7..43d9b830279d 100644
> --- a/drivers/iio/light/Kconfig
> +++ b/drivers/iio/light/Kconfig
> @@ -43,6 +43,16 @@ config ADUX1020
>  	 To compile this driver as a module, choose M here: the
>  	 module will be called adux1020.
>  
> +config AL3010
> +	tristate "AL3010 ambient light sensor"
> +	depends on I2C
> +	help
> +	  Say Y here if you want to build a driver for the Dyna Image AL3010
> +	  ambient light sensor.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called al3010.
> +
>  config AL3320A
>  	tristate "AL3320A ambient light sensor"
>  	depends on I2C
> diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
> index c98d1cefb861..88bb93550fcc 100644
> --- a/drivers/iio/light/Makefile
> +++ b/drivers/iio/light/Makefile
> @@ -7,6 +7,7 @@
>  obj-$(CONFIG_ACPI_ALS)		+= acpi-als.o
>  obj-$(CONFIG_ADJD_S311)		+= adjd_s311.o
>  obj-$(CONFIG_ADUX1020)		+= adux1020.o
> +obj-$(CONFIG_AL3010)		+= al3010.o
>  obj-$(CONFIG_AL3320A)		+= al3320a.o
>  obj-$(CONFIG_APDS9300)		+= apds9300.o
>  obj-$(CONFIG_APDS9960)		+= apds9960.o
> diff --git a/drivers/iio/light/al3010.c b/drivers/iio/light/al3010.c
> new file mode 100644
> index 000000000000..4b951c087c83
> --- /dev/null
> +++ b/drivers/iio/light/al3010.c
> @@ -0,0 +1,217 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * AL3010 - Dyna Image Ambient Light Sensor
> + *
> + * Copyright (c) 2014, Intel Corporation.
> + * Copyright (c) 2016, Dyna-Image Corp.
> + *
> + * IIO driver for AL3010 (7-bit I2C slave address 0x1C).
> + *
> + * TODO: interrupt support, thresholds
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> +#define AL3010_DRV_NAME "al3010"
> +
> +#define AL3010_REG_SYSTEM		0x00
> +#define AL3010_REG_DATA_LOW		0x0c
> +#define AL3010_REG_CONFIG		0x10
> +
> +#define AL3010_CONFIG_DISABLE		0x00
> +#define AL3010_CONFIG_ENABLE		0x01
> +
> +#define AL3010_GAIN_SHIFT		4
> +#define AL3010_GAIN_MASK		(BIT(6) | BIT(5) | BIT(4))

GENMASK

> +
> +#define AL3010_GAIN_READ(g) \
> +	(((g) & AL3010_GAIN_MASK) >> AL3010_GAIN_SHIFT)
> +
> +#define AL3010_GAIN_WRITE(g) \
> +	(((g) << AL3010_GAIN_SHIFT) & AL3010_GAIN_MASK)
> +
> +#define AL3010_SCALE_AVAILABLE "1.1872 0.2968 0.0742 0.018"
> +
> +enum al3xxxx_range {
> +	AL3XXX_RANGE_1, /* 77806 lx */
> +	AL3XXX_RANGE_2, /* 19542 lx */
> +	AL3XXX_RANGE_3, /*  4863 lx */
> +	AL3XXX_RANGE_4  /*  1216 lx */
> +};
> +
> +static const int al3010_scales[][2] = {
> +	{0, 1187200}, {0, 296800}, {0, 74200}, {0, 18600}
> +};
> +
> +struct al3010_data {
> +	struct i2c_client *client;
> +};
> +
> +static const struct iio_chan_spec al3010_channels[] = {
> +	{
> +		.type	= IIO_LIGHT,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +				      BIT(IIO_CHAN_INFO_SCALE),
> +	}
> +};
> +
> +static IIO_CONST_ATTR(in_illuminance_scale_available, AL3010_SCALE_AVAILABLE);
> +
> +static struct attribute *al3010_attributes[] = {
> +	&iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group al3010_attribute_group = {
> +	.attrs = al3010_attributes,
> +};
> +
> +static int al3010_init(struct al3010_data *data)
> +{
> +	int ret;
> +
> +	/* power on */
Comment is fairly obvious given the code so I wouldn't bother having it.
Comments that don't add significant benefit just add stuff that can become
wrong in the future ;)

> +	ret = i2c_smbus_write_byte_data(data->client, AL3010_REG_SYSTEM,
> +					AL3010_CONFIG_ENABLE);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = i2c_smbus_write_byte_data(data->client, AL3010_REG_CONFIG,
> +					AL3010_GAIN_WRITE(AL3XXX_RANGE_3));
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int al3010_read_raw(struct iio_dev *indio_dev,
> +			   struct iio_chan_spec const *chan, int *val,
> +			   int *val2, long mask)
> +{
> +	struct al3010_data *data = iio_priv(indio_dev);
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		/*
> +		 * ALS ADC value is stored in two adjacent registers:
> +		 * - low byte of output is stored at AL3010_REG_DATA_LOW
> +		 * - high byte of output is stored at AL3010_REG_DATA_LOW + 1
> +		 */
> +		ret = i2c_smbus_read_word_data(data->client,
> +					       AL3010_REG_DATA_LOW);
> +		if (ret < 0)
> +			return ret;
> +		*val = ret;
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_SCALE:
> +		ret = i2c_smbus_read_byte_data(data->client,
> +					       AL3010_REG_CONFIG);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = AL3010_GAIN_READ(ret);
> +		*val = al3010_scales[ret][0];
> +		*val2 = al3010_scales[ret][1];
> +
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	}
> +	return -EINVAL;
> +}
> +
> +static int al3010_write_raw(struct iio_dev *indio_dev,
> +			    struct iio_chan_spec const *chan, int val,
> +			    int val2, long mask)
> +{
> +	struct al3010_data *data = iio_priv(indio_dev);
> +	int i;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_SCALE:
> +		for (i = 0; i < ARRAY_SIZE(al3010_scales); i++) {
> +			if (val != al3010_scales[i][0] ||
> +			    val2 != al3010_scales[i][1])
> +				continue;
> +
> +			return i2c_smbus_write_byte_data(data->client,
> +						AL3010_REG_CONFIG,
> +						AL3010_GAIN_WRITE(i));
> +		}
> +		break;
> +	}
> +	return -EINVAL;
> +}
> +
> +static const struct iio_info al3010_info = {
> +	.read_raw	= al3010_read_raw,
> +	.write_raw	= al3010_write_raw,
> +	.attrs		= &al3010_attribute_group,
> +};
> +
> +static int al3010_probe(struct i2c_client *client,
> +			const struct i2c_device_id *id)
> +{
> +	struct al3010_data *data;
> +	struct iio_dev *indio_dev;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	data = iio_priv(indio_dev);
> +	i2c_set_clientdata(client, indio_dev);
> +	data->client = client;
> +
> +	indio_dev->dev.parent = &client->dev;
> +	indio_dev->info = &al3010_info;
> +	indio_dev->name = AL3010_DRV_NAME;
> +	indio_dev->channels = al3010_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(al3010_channels);
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	ret = al3010_init(data);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "al3010 chip init failed\n");
> +		return ret;
> +	}
> +	return devm_iio_device_register(&client->dev, indio_dev);
> +}
> +
> +static int al3010_remove(struct i2c_client *client)
> +{
> +	return i2c_smbus_write_byte_data(client, AL3010_REG_SYSTEM,
> +					 AL3010_CONFIG_DISABLE);
There is a race here.  Until the call to iio_device_unregister
is called, the userspace interfaces (and in kernel) interfaces
are exposed.  When using managed (devm_) interfaces that occurs
after remove. 

So 2 options to avoid this:
1) Don't use devm_ version of iio_device_register then you can
explicitly unregister before turning off the device.
2) Use devm_add_action_or_reset to automatically disable the device
and allow you to get rid of the remove function entirely.
 

> +}
> +
> +static const struct i2c_device_id al3010_id[] = {
> +	{"al3010", 0},

No need to set the data field if not using it.
	{ "als3010" }
is fine.

> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, al3010_id);
> +
> +static const struct of_device_id al3010_of_match[] = {
> +	{ .compatible = "dynaimage,al3010", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, al3010_of_match);
> +
> +static struct i2c_driver al3010_driver = {
> +	.driver = {
> +		.name = AL3010_DRV_NAME,
> +		.of_match_table = al3010_of_match,
> +	},
> +	.probe		= al3010_probe,
> +	.remove		= al3010_remove,
> +	.id_table	= al3010_id,
> +};
> +module_i2c_driver(al3010_driver);
> +
> +MODULE_AUTHOR("Daniel Baluta <daniel.baluta@nxp.com>");
> +MODULE_DESCRIPTION("AL3010 Ambient Light Sensor driver");
> +MODULE_LICENSE("GPL v2");

Re: [PATCH v3 4/7] iio: light: add Dyna-Image AL3010 driver

[Michał Mirosław]

On Sat, Feb 01, 2020 at 07:00:21PM +0100, David Heidelberg wrote:
> Based on:
> - 3320A in-kernel driver
> - https://www.spinics.net/lists/linux-iio/msg25145.html
> - https://lore.kernel.org/patchwork/patch/684179/

Haha! This is such a simple device, that there is not many ways you can
write a driver quickly. Just look at [1]. ;-)

[1] https://rere.qmqm.pl/git/?p=linux;a=commit;h=f40bf1646c9166f9b8daeb7cf55703be3c5f78b3

[...]
> --- /dev/nulla
> +++ b/drivers/iio/light/al3010.c
[...]
> +#define AL3010_GAIN_SHIFT		4
> +#define AL3010_GAIN_MASK		(BIT(6) | BIT(5) | BIT(4))
> +
> +#define AL3010_GAIN_READ(g) \
> +	(((g) & AL3010_GAIN_MASK) >> AL3010_GAIN_SHIFT)
> +
> +#define AL3010_GAIN_WRITE(g) \
> +	(((g) << AL3010_GAIN_SHIFT) & AL3010_GAIN_MASK)

There are FIELD_GET and FIELD_PREP macros available from
<linux/bitfield.h> that make accessing the registers a lot easier
to code and read.

> +#define AL3010_SCALE_AVAILABLE "1.1872 0.2968 0.0742 0.018"

I have used (albeit with a bug) more precise numbers. This doesn't
matter much, though, since I would expect noise to be much higher
than 0.1% for the measurement.

> +
> +enum al3xxxx_range {
> +	AL3XXX_RANGE_1, /* 77806 lx */
> +	AL3XXX_RANGE_2, /* 19542 lx */
> +	AL3XXX_RANGE_3, /*  4863 lx */
> +	AL3XXX_RANGE_4  /*  1216 lx */
> +};

The enums don't look very useful.

[...]

Tested-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>

Best Regards,
Michał Mirosław

[PATCH v3 5/7] iio: light: al3010 implement suspend support

[David Heidelberg]

AL3010 is fairly simple chip, so for suspend is enough to disable and
later enable it again.

Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: David Heidelberg <david@ixit.cz>
---
 drivers/iio/light/al3010.c | 30 +++++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/light/al3010.c b/drivers/iio/light/al3010.c
index 4b951c087c83..202f25b595c8 100644
--- a/drivers/iio/light/al3010.c
+++ b/drivers/iio/light/al3010.c
@@ -8,6 +8,9 @@
  * IIO driver for AL3010 (7-bit I2C slave address 0x1C).
  *
  * TODO: interrupt support, thresholds
+ * When the driver will get support for interrupt handling, then interrupt
+ * will need to be disabled before turning sensor OFF in order to avoid
+ * potential races with the interrupt handling.
  */
 
 #include <linux/i2c.h>
@@ -71,13 +74,18 @@ static const struct attribute_group al3010_attribute_group = {
 	.attrs = al3010_attributes,
 };
 
+static int al3010_set_pwr(struct i2c_client *client, bool pwr)
+{
+	u8 val = pwr ? AL3010_CONFIG_ENABLE : AL3010_CONFIG_DISABLE;
+	return i2c_smbus_write_byte_data(client, AL3010_REG_SYSTEM, val);
+}
+
 static int al3010_init(struct al3010_data *data)
 {
 	int ret;
 
-	/* power on */
-	ret = i2c_smbus_write_byte_data(data->client, AL3010_REG_SYSTEM,
-					AL3010_CONFIG_ENABLE);
+	ret = al3010_set_pwr(data->client, true);
+
 	if (ret < 0)
 		return ret;
 
@@ -185,10 +193,21 @@ static int al3010_probe(struct i2c_client *client,
 
 static int al3010_remove(struct i2c_client *client)
 {
-	return i2c_smbus_write_byte_data(client, AL3010_REG_SYSTEM,
-					 AL3010_CONFIG_DISABLE);
+	return al3010_set_pwr(client, false);
 }
 
+static int __maybe_unused al3010_suspend(struct device *dev)
+{
+	return al3010_set_pwr(to_i2c_client(dev), false);
+}
+
+static int __maybe_unused al3010_resume(struct device *dev)
+{
+	return al3010_set_pwr(to_i2c_client(dev), true);
+}
+
+SIMPLE_DEV_PM_OPS(al3010_pm_ops, al3010_suspend, al3010_resume);
+
 static const struct i2c_device_id al3010_id[] = {
 	{"al3010", 0},
 	{}
@@ -205,6 +224,7 @@ static struct i2c_driver al3010_driver = {
 	.driver = {
 		.name = AL3010_DRV_NAME,
 		.of_match_table = al3010_of_match,
+		.pm = &al3010_pm_ops,
 	},
 	.probe		= al3010_probe,
 	.remove		= al3010_remove,
-- 
2.25.0

[PATCH v3 6/7] iio: light: al3320a implement suspend support

[David Heidelberg]

AL3320a is fairly simple chip, so for suspend is enough to disable and
later enable it again.

Signed-off-by: David Heidelberg <david@ixit.cz>
---
 drivers/iio/light/al3320a.c | 31 ++++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/light/al3320a.c b/drivers/iio/light/al3320a.c
index 613830b7df6e..d99f9d139b5f 100644
--- a/drivers/iio/light/al3320a.c
+++ b/drivers/iio/light/al3320a.c
@@ -7,6 +7,9 @@
  * IIO driver for AL3320A (7-bit I2C slave address 0x1C).
  *
  * TODO: interrupt support, thresholds
+ * When the driver will get support for interrupt handling, then interrupt
+ * will need to be disabled before turning sensor OFF in order to avoid
+ * potential races with the interrupt handling.
  */
 
 #include <linux/module.h>
@@ -84,13 +87,19 @@ static const struct attribute_group al3320a_attribute_group = {
 	.attrs = al3320a_attributes,
 };
 
+static int al3320a_set_pwr(struct i2c_client *client, bool pwr)
+{
+	u8 val = pwr ? AL3320A_CONFIG_ENABLE : AL3320A_CONFIG_DISABLE;
+	return i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG, val);
+}
+
+
 static int al3320a_init(struct al3320a_data *data)
 {
 	int ret;
 
-	/* power on */
-	ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG,
-					AL3320A_CONFIG_ENABLE);
+	ret = al3320a_set_pwr(data->client, true);
+
 	if (ret < 0)
 		return ret;
 
@@ -208,10 +217,21 @@ static int al3320a_probe(struct i2c_client *client,
 
 static int al3320a_remove(struct i2c_client *client)
 {
-	return i2c_smbus_write_byte_data(client, AL3320A_REG_CONFIG,
-					 AL3320A_CONFIG_DISABLE);
+	return al3320a_set_pwr(client, false);
+}
+
+static int __maybe_unused al3320a_suspend(struct device *dev)
+{
+	return al3320a_set_pwr(to_i2c_client(dev), false);
+}
+
+static int __maybe_unused al3320a_resume(struct device *dev)
+{
+	return al3320a_set_pwr(to_i2c_client(dev), true);
 }
 
+SIMPLE_DEV_PM_OPS(al3320a_pm_ops, al3320a_suspend, al3320a_resume);
+
 static const struct i2c_device_id al3320a_id[] = {
 	{"al3320a", 0},
 	{}
@@ -221,6 +241,7 @@ MODULE_DEVICE_TABLE(i2c, al3320a_id);
 static struct i2c_driver al3320a_driver = {
 	.driver = {
 		.name = AL3320A_DRV_NAME,
+		.pm = &al3320a_pm_ops,
 	},
 	.probe		= al3320a_probe,
 	.remove		= al3320a_remove,
-- 
2.25.0

Re: [PATCH v3 6/7] iio: light: al3320a implement suspend support

[Jonathan Cameron]

On Sat,  1 Feb 2020 19:00:23 +0100
David Heidelberg <david@ixit.cz> wrote:

> AL3320a is fairly simple chip, so for suspend is enough to disable and
> later enable it again.
> 
> Signed-off-by: David Heidelberg <david@ixit.cz>
> ---
>  drivers/iio/light/al3320a.c | 31 ++++++++++++++++++++++++++-----
>  1 file changed, 26 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/iio/light/al3320a.c b/drivers/iio/light/al3320a.c
> index 613830b7df6e..d99f9d139b5f 100644
> --- a/drivers/iio/light/al3320a.c
> +++ b/drivers/iio/light/al3320a.c
> @@ -7,6 +7,9 @@
>   * IIO driver for AL3320A (7-bit I2C slave address 0x1C).
>   *
>   * TODO: interrupt support, thresholds
> + * When the driver will get support for interrupt handling, then interrupt
> + * will need to be disabled before turning sensor OFF in order to avoid
> + * potential races with the interrupt handling.
>   */
>  
>  #include <linux/module.h>
> @@ -84,13 +87,19 @@ static const struct attribute_group al3320a_attribute_group = {
>  	.attrs = al3320a_attributes,
>  };
>  
> +static int al3320a_set_pwr(struct i2c_client *client, bool pwr)
> +{
> +	u8 val = pwr ? AL3320A_CONFIG_ENABLE : AL3320A_CONFIG_DISABLE;
> +	return i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG, val);
> +}
> +

One blank line is almost always enough.

> +
>  static int al3320a_init(struct al3320a_data *data)
>  {
>  	int ret;
>  
> -	/* power on */
> -	ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG,
> -					AL3320A_CONFIG_ENABLE);
> +	ret = al3320a_set_pwr(data->client, true);
> +
>  	if (ret < 0)
>  		return ret;
>  
> @@ -208,10 +217,21 @@ static int al3320a_probe(struct i2c_client *client,
>  
>  static int al3320a_remove(struct i2c_client *client)
>  {
> -	return i2c_smbus_write_byte_data(client, AL3320A_REG_CONFIG,
> -					 AL3320A_CONFIG_DISABLE);
> +	return al3320a_set_pwr(client, false);
> +}
> +
> +static int __maybe_unused al3320a_suspend(struct device *dev)
> +{
> +	return al3320a_set_pwr(to_i2c_client(dev), false);
> +}
> +
> +static int __maybe_unused al3320a_resume(struct device *dev)
> +{
> +	return al3320a_set_pwr(to_i2c_client(dev), true);
>  }
>  
> +SIMPLE_DEV_PM_OPS(al3320a_pm_ops, al3320a_suspend, al3320a_resume);
> +
>  static const struct i2c_device_id al3320a_id[] = {
>  	{"al3320a", 0},
>  	{}
> @@ -221,6 +241,7 @@ MODULE_DEVICE_TABLE(i2c, al3320a_id);
>  static struct i2c_driver al3320a_driver = {
>  	.driver = {
>  		.name = AL3320A_DRV_NAME,
> +		.pm = &al3320a_pm_ops,
>  	},
>  	.probe		= al3320a_probe,
>  	.remove		= al3320a_remove,

[PATCH v3 7/7] iio: light: al3320a allow module autoload and polish

[David Heidelberg]

- allow autoloading when build as module and defined inside DT
- drop init.h and alphabetically sort includes

Signed-off-by: David Heidelberg <david@ixit.cz>
---
 drivers/iio/light/al3320a.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/light/al3320a.c b/drivers/iio/light/al3320a.c
index d99f9d139b5f..d66c85b27907 100644
--- a/drivers/iio/light/al3320a.c
+++ b/drivers/iio/light/al3320a.c
@@ -12,9 +12,9 @@
  * potential races with the interrupt handling.
  */
 
-#include <linux/module.h>
-#include <linux/init.h>
 #include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
@@ -238,9 +238,16 @@ static const struct i2c_device_id al3320a_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, al3320a_id);
 
+static const struct of_device_id al3320a_of_match[] = {
+	{ .compatible = "dynaimage,al3320a", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, al3320a_of_match);
+
 static struct i2c_driver al3320a_driver = {
 	.driver = {
 		.name = AL3320A_DRV_NAME,
+		.of_match_table = al3320a_of_match,
 		.pm = &al3320a_pm_ops,
 	},
 	.probe		= al3320a_probe,
-- 
2.25.0