[PATCH v2 0/2] New multiple GPIOs LED driver

[PATCH v2 0/2] New multiple GPIOs LED driver

[Hermes Zhang]

From: Hermes Zhang <chenhuiz@axis.com>

changes v2:
- use max_brightness(=2^gpio number) instead of LED_FULL
- alloc priv at once
- move driver code to new simple folder
- update commit message for dt-binding commit
- move dt-binding commit before driver code

Hermes Zhang (2):
  dt-binding: leds: Document leds-multi-gpio bindings
  leds: leds-multi-gpio: Add multiple GPIOs LED driver

 .../bindings/leds/leds-multi-gpio.yaml        |  50 ++++++
 drivers/leds/Kconfig                          |   3 +
 drivers/leds/Makefile                         |   3 +
 drivers/leds/simple/Kconfig                   |  23 +++
 drivers/leds/simple/Makefile                  |   3 +
 drivers/leds/simple/leds-multi-gpio.c         | 144 ++++++++++++++++++
 6 files changed, 226 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/leds-multi-gpio.yaml
 create mode 100644 drivers/leds/simple/Kconfig
 create mode 100644 drivers/leds/simple/Makefile
 create mode 100644 drivers/leds/simple/leds-multi-gpio.c

-- 
2.20.1

[PATCH v2 1/2] dt-binding: leds: Document leds-multi-gpio bindings

[Hermes Zhang]

From: Hermes Zhang <chenhuiz@axis.com>

This binding represents LED devices which are controller with
multiple GPIO lines in order to achieve more than two brightness
states.

Signed-off-by: Hermes Zhang <chenhuiz@axis.com>
---
 .../bindings/leds/leds-multi-gpio.yaml        | 50 +++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/leds-multi-gpio.yaml

diff --git a/Documentation/devicetree/bindings/leds/leds-multi-gpio.yaml b/Documentation/devicetree/bindings/leds/leds-multi-gpio.yaml
new file mode 100644
index 000000000000..1549f21e8d6e
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/leds-multi-gpio.yaml
@@ -0,0 +1,50 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/leds-multi-gpio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Multiple GPIOs LED driver
+
+maintainers:
+  - Hermes Zhang <chenhuiz@axis.com>
+
+description:
+  This will support some LED made of multiple GPIOs and the brightness of the
+  LED could map to different states of the GPIOs.
+
+properties:
+  compatible:
+    const: multi-gpio-led
+
+  led-gpios:
+    description: Array of one or more GPIOs pins used to control the LED.
+    minItems: 1
+    maxItems: 8  # Should be enough
+
+  led-states:
+    description: |
+      The array list the supported states here which will map to brightness
+      from 0 to maximum. Each item in the array will present all the GPIOs
+      value by bit.
+    $ref: /schemas/types.yaml#/definitions/uint8-array
+    minItems: 1
+    maxItems: 256 # Should be enough
+
+required:
+  - compatible
+  - led-gpios
+  - led-states
+
+additionalProperties: false
+
+examples:
+  - |
+    gpios-led {
+      compatible = "multi-gpio-led";
+
+      led-gpios = <&gpio0 23 0x1>,
+                  <&gpio0 24 0x1>;
+      led-states = /bits/ 8 <0x00 0x01 0x02 0x03>;
+    };
+...
-- 
2.20.1

[PATCH v2 2/2] leds: leds-multi-gpio: Add multiple GPIOs LED driver

[Hermes Zhang]

From: Hermes Zhang <chenhuiz@axis.com>

Introduce a new multiple GPIOs LED driver. This LED will made of
multiple GPIOs (up to 8) and will map different brightness to different
GPIOs states which defined in dts file.

Signed-off-by: Hermes Zhang <chenhuiz@axis.com>
---
 drivers/leds/Kconfig                  |   3 +
 drivers/leds/Makefile                 |   3 +
 drivers/leds/simple/Kconfig           |  23 ++++
 drivers/leds/simple/Makefile          |   3 +
 drivers/leds/simple/leds-multi-gpio.c | 144 ++++++++++++++++++++++++++
 5 files changed, 176 insertions(+)
 create mode 100644 drivers/leds/simple/Kconfig
 create mode 100644 drivers/leds/simple/Makefile
 create mode 100644 drivers/leds/simple/leds-multi-gpio.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index b6742b4231bf..f95217b2fcf1 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -937,4 +937,7 @@ source "drivers/leds/trigger/Kconfig"
 comment "LED Blink"
 source "drivers/leds/blink/Kconfig"
 
+comment "LED Simple"
+source "drivers/leds/simple/Kconfig"
+
 endif # NEW_LEDS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 2a698df9da57..26917d93fa03 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -111,3 +111,6 @@ obj-$(CONFIG_LEDS_TRIGGERS)		+= trigger/
 
 # LED Blink
 obj-$(CONFIG_LEDS_BLINK)                += blink/
+
+# LED Blink
+obj-$(CONFIG_LEDS_SIMPLE)		+= simple/
diff --git a/drivers/leds/simple/Kconfig b/drivers/leds/simple/Kconfig
new file mode 100644
index 000000000000..7aef82701f86
--- /dev/null
+++ b/drivers/leds/simple/Kconfig
@@ -0,0 +1,23 @@
+menuconfig LEDS_SIMPLE
+	bool "Simple LED support"
+	depends on LEDS_CLASS
+	help
+	  This option enables simple leds support for the leds class.
+	  If unsure, say Y.
+
+if LEDS_SIMPLE
+
+config LEDS_MULTI_GPIO
+	tristate "LED Support for multiple GPIOs LED"
+	depends on LEDS_CLASS
+	depends on GPIOLIB
+	depends on OF
+	help
+	  This option enables support for a multiple GPIOs LED. Such LED is made
+	  of multiple GPIOs and could change the brightness by setting different
+	  states of the GPIOs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called leds-multi-gpio.
+
+endif # LEDS_SIMPLE
diff --git a/drivers/leds/simple/Makefile b/drivers/leds/simple/Makefile
new file mode 100644
index 000000000000..2ba655fdc175
--- /dev/null
+++ b/drivers/leds/simple/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_LEDS_MULTI_GPIO)	+= leds-multi-gpio.o
diff --git a/drivers/leds/simple/leds-multi-gpio.c b/drivers/leds/simple/leds-multi-gpio.c
new file mode 100644
index 000000000000..14fdaa5a2aac
--- /dev/null
+++ b/drivers/leds/simple/leds-multi-gpio.c
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 Axis Communications AB
+ */
+
+#include <linux/leds.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+
+#define MAX_GPIO_NUM  8
+
+struct multi_gpio_led_priv {
+	struct led_classdev cdev;
+
+	struct gpio_descs *gpios;
+
+	u16 nr_states;
+
+	u8 states[0];
+};
+
+
+static void multi_gpio_led_set(struct led_classdev *led_cdev,
+	enum led_brightness value)
+{
+	struct multi_gpio_led_priv *priv;
+	int idx;
+
+	DECLARE_BITMAP(values, MAX_GPIO_NUM);
+
+	priv = container_of(led_cdev, struct multi_gpio_led_priv, cdev);
+
+	idx = value > led_cdev->max_brightness ? led_cdev->max_brightness : value;
+
+	values[0] = priv->states[idx];
+
+	gpiod_set_array_value(priv->gpios->ndescs, priv->gpios->desc,
+	    priv->gpios->info, values);
+}
+
+static int multi_gpio_led_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	struct multi_gpio_led_priv *priv = NULL;
+	int ret;
+	const char *state = NULL;
+	struct led_init_data init_data = {};
+	struct gpio_descs *gpios;
+	u16 nr_states;
+
+	gpios = devm_gpiod_get_array(dev, "led", GPIOD_OUT_LOW);
+	if (IS_ERR(gpios))
+		return PTR_ERR(gpios);
+
+	if (gpios->ndescs >= MAX_GPIO_NUM) {
+		dev_err(dev, "Too many GPIOs\n");
+		return -EINVAL;
+	}
+
+	ret = of_property_count_u8_elems(node, "led-states");
+	if (ret < 0)
+		return ret;
+
+	if (ret != 1 << gpios->ndescs) {
+		dev_err(dev, "led-states number should equal to 2^led-gpios\n");
+		return -EINVAL;
+	}
+
+	nr_states = ret;
+
+	priv = devm_kzalloc(dev, sizeof(struct multi_gpio_led_priv)
+			+ sizeof(u8) * nr_states , GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	ret = of_property_read_u8_array(node, "led-states", priv->states, nr_states);
+	if (ret)
+		return ret;
+
+	priv->gpios = gpios;
+	priv->nr_states = nr_states;
+
+	priv->cdev.max_brightness = nr_states;
+	priv->cdev.default_trigger = of_get_property(node, "linux,default-trigger", NULL);
+	priv->cdev.brightness_set = multi_gpio_led_set;
+
+	init_data.fwnode = of_fwnode_handle(node);
+
+	ret = devm_led_classdev_register_ext(dev, &priv->cdev, &init_data);
+	if (ret < 0)
+		return ret;
+
+	of_property_read_string(node, "default-state", &state);
+	if (!strcmp(state, "on"))
+		multi_gpio_led_set(&priv->cdev, priv->cdev.max_brightness);
+	else
+		multi_gpio_led_set(&priv->cdev, 0);
+
+	platform_set_drvdata(pdev, priv);
+
+	return 0;
+}
+
+static void multi_gpio_led_shutdown(struct platform_device *pdev)
+{
+	struct multi_gpio_led_priv *priv = platform_get_drvdata(pdev);
+
+	multi_gpio_led_set(&priv->cdev, 0);
+}
+
+static int multi_gpio_led_remove(struct platform_device *pdev)
+{
+	multi_gpio_led_shutdown(pdev);
+
+	return 0;
+}
+
+static const struct of_device_id of_multi_gpio_led_match[] = {
+	{ .compatible = "multi-gpio-led", },
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, of_multi_gpio_led_match);
+
+static struct platform_driver multi_gpio_led_driver = {
+	.probe		= multi_gpio_led_probe,
+	.remove		= multi_gpio_led_remove,
+	.shutdown	= multi_gpio_led_shutdown,
+	.driver		= {
+		.name	= "multi-gpio-led",
+		.of_match_table = of_multi_gpio_led_match,
+	},
+};
+
+module_platform_driver(multi_gpio_led_driver);
+
+MODULE_AUTHOR("Hermes Zhang <chenhui.zhang@axis.com>");
+MODULE_DESCRIPTION("Multiple GPIOs LED driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:leds-multi-gpio");
-- 
2.20.1

Re: [PATCH v2 2/2] leds: leds-multi-gpio: Add multiple GPIOs LED driver

[Alexander Dahl]

[-- Attachment #1: Type: text/plain, Size: 7708 bytes --]

Hello Hermes,

great to see your improved series. See below for my remarks.

On Fri, Mar 26, 2021 at 01:28:01PM +0800, Hermes Zhang wrote:
> From: Hermes Zhang <chenhuiz@axis.com>
> 
> Introduce a new multiple GPIOs LED driver. This LED will made of
> multiple GPIOs (up to 8) and will map different brightness to different
> GPIOs states which defined in dts file.
> 
> Signed-off-by: Hermes Zhang <chenhuiz@axis.com>
> ---
>  drivers/leds/Kconfig                  |   3 +
>  drivers/leds/Makefile                 |   3 +
>  drivers/leds/simple/Kconfig           |  23 ++++
>  drivers/leds/simple/Makefile          |   3 +
>  drivers/leds/simple/leds-multi-gpio.c | 144 ++++++++++++++++++++++++++
>  5 files changed, 176 insertions(+)
>  create mode 100644 drivers/leds/simple/Kconfig
>  create mode 100644 drivers/leds/simple/Makefile
>  create mode 100644 drivers/leds/simple/leds-multi-gpio.c
> 
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index b6742b4231bf..f95217b2fcf1 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -937,4 +937,7 @@ source "drivers/leds/trigger/Kconfig"
>  comment "LED Blink"
>  source "drivers/leds/blink/Kconfig"
>  
> +comment "LED Simple"
> +source "drivers/leds/simple/Kconfig"
> +
>  endif # NEW_LEDS
> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> index 2a698df9da57..26917d93fa03 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -111,3 +111,6 @@ obj-$(CONFIG_LEDS_TRIGGERS)		+= trigger/
>  
>  # LED Blink
>  obj-$(CONFIG_LEDS_BLINK)                += blink/
> +
> +# LED Blink
> +obj-$(CONFIG_LEDS_SIMPLE)		+= simple/

That comment should read "LED Simple", right?

> diff --git a/drivers/leds/simple/Kconfig b/drivers/leds/simple/Kconfig
> new file mode 100644
> index 000000000000..7aef82701f86
> --- /dev/null
> +++ b/drivers/leds/simple/Kconfig
> @@ -0,0 +1,23 @@
> +menuconfig LEDS_SIMPLE
> +	bool "Simple LED support"
> +	depends on LEDS_CLASS
> +	help
> +	  This option enables simple leds support for the leds class.
> +	  If unsure, say Y.
> +
> +if LEDS_SIMPLE
> +
> +config LEDS_MULTI_GPIO
> +	tristate "LED Support for multiple GPIOs LED"
> +	depends on LEDS_CLASS
> +	depends on GPIOLIB
> +	depends on OF
> +	help
> +	  This option enables support for a multiple GPIOs LED. Such LED is made
> +	  of multiple GPIOs and could change the brightness by setting different
> +	  states of the GPIOs.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called leds-multi-gpio.
> +
> +endif # LEDS_SIMPLE

I'm wondering why this is part of this driver? I suppose there's no
such folder yet, although Pavel suggested. Would it make sense to put
that Kconfig menu entry and folder creation to a separate commit?

> diff --git a/drivers/leds/simple/Makefile b/drivers/leds/simple/Makefile
> new file mode 100644
> index 000000000000..2ba655fdc175
> --- /dev/null
> +++ b/drivers/leds/simple/Makefile
> @@ -0,0 +1,3 @@
> +# SPDX-License-Identifier: GPL-2.0
> +
> +obj-$(CONFIG_LEDS_MULTI_GPIO)	+= leds-multi-gpio.o
> diff --git a/drivers/leds/simple/leds-multi-gpio.c b/drivers/leds/simple/leds-multi-gpio.c
> new file mode 100644
> index 000000000000..14fdaa5a2aac
> --- /dev/null
> +++ b/drivers/leds/simple/leds-multi-gpio.c
> @@ -0,0 +1,144 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2021 Axis Communications AB
> + */
> +
> +#include <linux/leds.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +
> +
> +#define MAX_GPIO_NUM  8
> +
> +struct multi_gpio_led_priv {
> +	struct led_classdev cdev;
> +
> +	struct gpio_descs *gpios;
> +
> +	u16 nr_states;
> +
> +	u8 states[0];
> +};
> +
> +
> +static void multi_gpio_led_set(struct led_classdev *led_cdev,
> +	enum led_brightness value)
> +{
> +	struct multi_gpio_led_priv *priv;
> +	int idx;
> +
> +	DECLARE_BITMAP(values, MAX_GPIO_NUM);
> +
> +	priv = container_of(led_cdev, struct multi_gpio_led_priv, cdev);
> +
> +	idx = value > led_cdev->max_brightness ? led_cdev->max_brightness : value;
> +
> +	values[0] = priv->states[idx];
> +
> +	gpiod_set_array_value(priv->gpios->ndescs, priv->gpios->desc,
> +	    priv->gpios->info, values);
> +}
> +
> +static int multi_gpio_led_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *node = dev->of_node;
> +	struct multi_gpio_led_priv *priv = NULL;
> +	int ret;
> +	const char *state = NULL;
> +	struct led_init_data init_data = {};
> +	struct gpio_descs *gpios;
> +	u16 nr_states;
> +
> +	gpios = devm_gpiod_get_array(dev, "led", GPIOD_OUT_LOW);
> +	if (IS_ERR(gpios))
> +		return PTR_ERR(gpios);
> +
> +	if (gpios->ndescs >= MAX_GPIO_NUM) {
> +		dev_err(dev, "Too many GPIOs\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = of_property_count_u8_elems(node, "led-states");
> +	if (ret < 0)
> +		return ret;
> +
> +	if (ret != 1 << gpios->ndescs) {
> +		dev_err(dev, "led-states number should equal to 2^led-gpios\n");
> +		return -EINVAL;
> +	}
> +
> +	nr_states = ret;
> +
> +	priv = devm_kzalloc(dev, sizeof(struct multi_gpio_led_priv)
> +			+ sizeof(u8) * nr_states , GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	ret = of_property_read_u8_array(node, "led-states", priv->states, nr_states);
> +	if (ret)
> +		return ret;
> +
> +	priv->gpios = gpios;
> +	priv->nr_states = nr_states;
> +
> +	priv->cdev.max_brightness = nr_states;
> +	priv->cdev.default_trigger = of_get_property(node, "linux,default-trigger", NULL);
> +	priv->cdev.brightness_set = multi_gpio_led_set;
> +
> +	init_data.fwnode = of_fwnode_handle(node);
> +
> +	ret = devm_led_classdev_register_ext(dev, &priv->cdev, &init_data);
> +	if (ret < 0)
> +		return ret;
> +
> +	of_property_read_string(node, "default-state", &state);
> +	if (!strcmp(state, "on"))
> +		multi_gpio_led_set(&priv->cdev, priv->cdev.max_brightness);
> +	else
> +		multi_gpio_led_set(&priv->cdev, 0);
> +
> +	platform_set_drvdata(pdev, priv);
> +
> +	return 0;
> +}
> +
> +static void multi_gpio_led_shutdown(struct platform_device *pdev)
> +{
> +	struct multi_gpio_led_priv *priv = platform_get_drvdata(pdev);
> +
> +	multi_gpio_led_set(&priv->cdev, 0);
> +}
> +
> +static int multi_gpio_led_remove(struct platform_device *pdev)
> +{
> +	multi_gpio_led_shutdown(pdev);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id of_multi_gpio_led_match[] = {
> +	{ .compatible = "multi-gpio-led", },
> +	{},
> +};
> +
> +MODULE_DEVICE_TABLE(of, of_multi_gpio_led_match);
> +
> +static struct platform_driver multi_gpio_led_driver = {
> +	.probe		= multi_gpio_led_probe,
> +	.remove		= multi_gpio_led_remove,
> +	.shutdown	= multi_gpio_led_shutdown,
> +	.driver		= {
> +		.name	= "multi-gpio-led",
> +		.of_match_table = of_multi_gpio_led_match,
> +	},
> +};
> +
> +module_platform_driver(multi_gpio_led_driver);
> +
> +MODULE_AUTHOR("Hermes Zhang <chenhui.zhang@axis.com>");
> +MODULE_DESCRIPTION("Multiple GPIOs LED driver");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:leds-multi-gpio");

I did not review thouroughly, but in my mail the indentation looks
wrong. Did checkpatch complain?

Greets
Alex

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Re: [PATCH v2 2/2] leds: leds-multi-gpio: Add multiple GPIOs LED driver

[Hermes Zhang]

On 3/26/21 1:56 PM, Alexander Dahl wrote:
>> +
>> +module_platform_driver(multi_gpio_led_driver);
>> +
>> +MODULE_AUTHOR("Hermes Zhang <chenhui.zhang@axis.com>");
>> +MODULE_DESCRIPTION("Multiple GPIOs LED driver");
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_ALIAS("platform:leds-multi-gpio");
> I did not review thouroughly, but in my mail the indentation looks
> wrong. Did checkpatch complain?

Sorry, I forgot to check the style before commit, but seems one problem
about extra space:

$ chkernel
ERROR: space prohibited before that ',' (ctx:WxW)
#164: FILE: drivers/leds/simple/leds-multi-gpio.c:76:
+            + sizeof(u8) * nr_states , GFP_KERNEL);
                                                   ^

I will fix it in next commit.


Best Regards,

Hermes

Re: [PATCH v2 2/2] leds: leds-multi-gpio: Add multiple GPIOs LED driver

[Pavel Machek]

[-- Attachment #1: Type: text/plain, Size: 1191 bytes --]

Hi!

> Introduce a new multiple GPIOs LED driver. This LED will made of
> multiple GPIOs (up to 8) and will map different brightness to different
> GPIOs states which defined in dts file.
> 
> Signed-off-by: Hermes Zhang <chenhuiz@axis.com>


> index 000000000000..7aef82701f86
> --- /dev/null
> +++ b/drivers/leds/simple/Kconfig
> @@ -0,0 +1,23 @@
> +menuconfig LEDS_SIMPLE
> +	bool "Simple LED support"
> +	depends on LEDS_CLASS
> +	help
> +	  This option enables simple leds support for the leds class.
> +	  If unsure, say Y.

No need for new config symbol.

> +	if (ret != 1 << gpios->ndescs) {

I'd do (ret != (1 << gpios->ndescs))

> +	priv = devm_kzalloc(dev, sizeof(struct multi_gpio_led_priv)
> +			+ sizeof(u8) * nr_states , GFP_KERNEL);

Sizeof(u8) is always 1, no need for space before , . 

> +	of_property_read_string(node, "default-state", &state);
> +	if (!strcmp(state, "on"))
> +		multi_gpio_led_set(&priv->cdev, priv->cdev.max_brightness);
> +	else
> +		multi_gpio_led_set(&priv->cdev, 0);

No need for default-state handling, unless you are using it.

Best regards,
									Pavel

-- 
http://www.livejournal.com/~pavelmachek

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Re: [PATCH v2 1/2] dt-binding: leds: Document leds-multi-gpio bindings

[Rob Herring]

On Fri, Mar 26, 2021 at 01:28:00PM +0800, Hermes Zhang wrote:
> From: Hermes Zhang <chenhuiz@axis.com>
> 
> This binding represents LED devices which are controller with
> multiple GPIO lines in order to achieve more than two brightness
> states.
> 
> Signed-off-by: Hermes Zhang <chenhuiz@axis.com>
> ---
>  .../bindings/leds/leds-multi-gpio.yaml        | 50 +++++++++++++++++++
>  1 file changed, 50 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/leds/leds-multi-gpio.yaml
> 
> diff --git a/Documentation/devicetree/bindings/leds/leds-multi-gpio.yaml b/Documentation/devicetree/bindings/leds/leds-multi-gpio.yaml
> new file mode 100644
> index 000000000000..1549f21e8d6e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/leds-multi-gpio.yaml
> @@ -0,0 +1,50 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/leds/leds-multi-gpio.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Multiple GPIOs LED driver
> +
> +maintainers:
> +  - Hermes Zhang <chenhuiz@axis.com>
> +
> +description:
> +  This will support some LED made of multiple GPIOs and the brightness of the
> +  LED could map to different states of the GPIOs.
> +
> +properties:
> +  compatible:
> +    const: multi-gpio-led
> +
> +  led-gpios:
> +    description: Array of one or more GPIOs pins used to control the LED.
> +    minItems: 1
> +    maxItems: 8  # Should be enough
> +
> +  led-states:
> +    description: |
> +      The array list the supported states here which will map to brightness
> +      from 0 to maximum. Each item in the array will present all the GPIOs
> +      value by bit.
> +    $ref: /schemas/types.yaml#/definitions/uint8-array
> +    minItems: 1
> +    maxItems: 256 # Should be enough

Isn't this the same as the standard 'brightness-levels' from backlight 
binding? The index is the level and the value is the h/w specific 
setting.

> +
> +required:
> +  - compatible
> +  - led-gpios
> +  - led-states
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    gpios-led {
> +      compatible = "multi-gpio-led";
> +
> +      led-gpios = <&gpio0 23 0x1>,
> +                  <&gpio0 24 0x1>;
> +      led-states = /bits/ 8 <0x00 0x01 0x02 0x03>;
> +    };
> +...
> -- 
> 2.20.1
> 

Re: [PATCH v2 2/2] leds: leds-multi-gpio: Add multiple GPIOs LED driver

[Hermes Zhang]

On 3/26/21 9:49 PM, Pavel Machek wrote:
>> +	of_property_read_string(node, "default-state", &state);
>> +	if (!strcmp(state, "on"))
>> +		multi_gpio_led_set(&priv->cdev, priv->cdev.max_brightness);
>> +	else
>> +		multi_gpio_led_set(&priv->cdev, 0);
> No need for default-state handling, unless you are using it.
>
We will use it, to make the LED default on or off.


Best Regards,

Hermes

Re: [PATCH v2 1/2] dt-binding: leds: Document leds-multi-gpio bindings

[Hermes Zhang]

On 3/28/21 2:12 AM, Rob Herring wrote:
>> +
>> +  led-gpios:
>> +    description: Array of one or more GPIOs pins used to control the LED.
>> +    minItems: 1
>> +    maxItems: 8  # Should be enough
>> +
>> +  led-states:
>> +    description: |
>> +      The array list the supported states here which will map to brightness
>> +      from 0 to maximum. Each item in the array will present all the GPIOs
>> +      value by bit.
>> +    $ref: /schemas/types.yaml#/definitions/uint8-array
>> +    minItems: 1
>> +    maxItems: 256 # Should be enough
> Isn't this the same as the standard 'brightness-levels' from backlight 
> binding? The index is the level and the value is the h/w specific 
> setting.

Yes, it seems same.


Best Regards,

Hermes