[PATCH v3 0/2] Add Turris Omnia LEDs driver

[PATCH v3 0/2] Add Turris Omnia LEDs driver

[Marek Behún]

Hi,

so I am sending version 3, this time using the multicolor framework.
These patches should apply on top of Pavel's tree after he applies Dan's
patches adding the multicolor LED framework.

Since all the LEDs are only RGB (there is no other possibility for
different channels nor different order of channels), this driver
registers all LEDs via the multicolor framework. In the device-tree only
the address of the LED needs to be specified, any child nodes describing
the red, green and blue channels are ignored.

Marek

changes since v2:
- using multicolor LED framework now, major rewrite
- added support for global brightness (Omnia has a button which can
  switch between 8 levels of intensity of all the LEDs at once, but
  in reality any value between 0% and 100% can be set, and we want to
  access this setting via software)

Marek Behún (2):
  dt-bindings: leds: add cznic,turris-omnia-leds binding
  leds: initial support for Turris Omnia LEDs

 .../leds/cznic,turris-omnia-leds.yaml         |  82 +++++
 drivers/leds/Kconfig                          |  11 +
 drivers/leds/Makefile                         |   1 +
 drivers/leds/leds-turris-omnia.c              | 296 ++++++++++++++++++
 4 files changed, 390 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml
 create mode 100644 drivers/leds/leds-turris-omnia.c

-- 
2.26.2

[PATCH v3 1/2] dt-bindings: leds: add cznic,turris-omnia-leds binding

[Marek Behún]

Add device-tree bindings documentation for Turris Omnia RGB LEDs.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
---
 .../leds/cznic,turris-omnia-leds.yaml         | 82 +++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml

diff --git a/Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml b/Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml
new file mode 100644
index 000000000000..9817ea3ac69b
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml
@@ -0,0 +1,82 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/cznic,turris-omnia-leds.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: CZ.NIC's Turris Omnia LEDs driver
+
+maintainers:
+  - Marek Behún <marek.behun@nic.cz>
+
+description:
+  This module adds support for the RGB LEDs found on the fron panel of the
+  Turris Omnia router. There are 12 RGB LEDs, they are controlled by device's
+  microcontroller with which the system communicates via I2C. Each LED is
+  described as a subnode of this I2C device.
+
+properties:
+  compatible:
+    const: cznic,turris-omnia-leds
+
+  reg:
+    description: I2C slave address of the microcontroller.
+    maxItems: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+patternProperties:
+  "^multi-led[0-9a-f]$":
+    type: object
+    allOf:
+      - $ref: leds-class-multicolor.yaml#
+    description:
+      This node represents one of the RGB LED devices on Turris Omnia.
+
+    properties:
+      reg:
+        minimum: 0
+        maximum: 11
+        description:
+          This property identifies one of the LEDs on the front panel of the
+          Turris Omnia router.
+
+    required:
+      - reg
+
+examples:
+  - |
+
+    #include <dt-bindings/leds/common.h>
+
+    i2c0 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        led-controller@2b {
+            compatible = "cznic,turris-omnia-leds";
+            reg = <0x2b>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            multi-led@0 {
+                reg = <0>;
+                color = <LED_COLOR_ID_MULTI>;
+                function = LED_FUNCTION_POWER;
+                linux,default-trigger = "heartbeat";
+            };
+
+            multi-led@a {
+                reg = <0xa>;
+                color = <LED_COLOR_ID_MULTI>;
+                function = LED_FUNCTION_INDICATOR;
+                function-enumerator = <1>;
+            };
+        };
+    };
+
+...
-- 
2.26.2

[PATCH v3 2/2] leds: initial support for Turris Omnia LEDs

[Marek Behún]

This adds basic support for LEDs on the front side of CZ.NIC's Turris
Omnia router.

There are 12 RGB LEDs. The controller supports HW triggering mode for
the LEDs, but this driver does not support it yet, and sets all the LEDs
defined in device-tree into SW mode upon probe.

This driver uses the multi color LED framework.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
---
 drivers/leds/Kconfig             |  11 ++
 drivers/leds/Makefile            |   1 +
 drivers/leds/leds-turris-omnia.c | 296 +++++++++++++++++++++++++++++++
 3 files changed, 308 insertions(+)
 create mode 100644 drivers/leds/leds-turris-omnia.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 04e0cb39f92e..0f960ecdd950 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -176,6 +176,17 @@ config LEDS_EL15203000
 	  To compile this driver as a module, choose M here: the module
 	  will be called leds-el15203000.
 
+config LEDS_TURRIS_OMNIA
+	tristate "LED support for CZ.NIC's Turris Omnia"
+	depends on LEDS_CLASS_MULTI_COLOR
+	depends on I2C
+	depends on MACH_ARMADA_38X || COMPILE_TEST
+	depends on OF
+	help
+	  This option enables basic support for the LEDs found on the front
+	  side of CZ.NIC's Turris Omnia router. There are 12 RGB LEDs on the
+	  front panel.
+
 config LEDS_LM3530
 	tristate "LCD Backlight driver for LM3530"
 	depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 68c05faec99e..0dcea0322fd3 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -88,6 +88,7 @@ obj-$(CONFIG_LEDS_TCA6507)		+= leds-tca6507.o
 obj-$(CONFIG_LEDS_TI_LMU_COMMON)	+= leds-ti-lmu-common.o
 obj-$(CONFIG_LEDS_TLC591XX)		+= leds-tlc591xx.o
 obj-$(CONFIG_LEDS_TPS6105X)		+= leds-tps6105x.o
+obj-$(CONFIG_LEDS_TURRIS_OMNIA)		+= leds-turris-omnia.o
 obj-$(CONFIG_LEDS_WM831X_STATUS)	+= leds-wm831x-status.o
 obj-$(CONFIG_LEDS_WM8350)		+= leds-wm8350.o
 obj-$(CONFIG_LEDS_WRAP)			+= leds-wrap.o
diff --git a/drivers/leds/leds-turris-omnia.c b/drivers/leds/leds-turris-omnia.c
new file mode 100644
index 000000000000..0aa79abf0ed4
--- /dev/null
+++ b/drivers/leds/leds-turris-omnia.c
@@ -0,0 +1,296 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CZ.NIC's Turris Omnia LEDs driver
+ *
+ * 2020 by Marek Behun <marek.behun@nic.cz>
+ */
+
+#include <linux/i2c.h>
+#include <linux/led-class-multicolor.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include "leds.h"
+
+#define OMNIA_BOARD_LEDS		12
+
+#define CMD_LED_MODE			3
+#define CMD_LED_MODE_LED(l)		((l) & 0x0f)
+#define CMD_LED_MODE_USER		0x10
+
+#define CMD_LED_STATE			4
+#define CMD_LED_STATE_LED(l)		((l) & 0x0f)
+#define CMD_LED_STATE_ON		0x10
+
+#define CMD_LED_COLOR			5
+#define CMD_LED_SET_BRIGHTNESS		7
+#define CMD_LED_GET_BRIGHTNESS		8
+
+#define OMNIA_CMD			0
+
+#define OMNIA_CMD_LED_COLOR_LED		1
+#define OMNIA_CMD_LED_COLOR_R		2
+#define OMNIA_CMD_LED_COLOR_G		3
+#define OMNIA_CMD_LED_COLOR_B		4
+#define OMNIA_CMD_LED_COLOR_LEN		5
+
+struct omnia_led {
+	struct led_classdev_mc mc_cdev;
+	struct mc_subled subled_info[3];
+	int reg;
+};
+
+#define to_omnia_led(l)		container_of(l, struct omnia_led, mc_cdev)
+
+struct omnia_leds {
+	struct i2c_client *client;
+	struct mutex lock;
+	int nleds;
+	struct omnia_led leds[0];
+};
+
+static int omnia_led_brightness_set_blocking(struct led_classdev *cdev,
+					     enum led_brightness brightness)
+{
+	struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
+	struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
+	struct omnia_led *led = to_omnia_led(mc_cdev);
+	u8 buf[OMNIA_CMD_LED_COLOR_LEN], state;
+	int ret;
+
+	led_mc_calc_color_components(&led->mc_cdev, brightness);
+
+	mutex_lock(&leds->lock);
+
+	buf[OMNIA_CMD] = CMD_LED_COLOR;
+	buf[OMNIA_CMD_LED_COLOR_LED] = led->reg;
+	buf[OMNIA_CMD_LED_COLOR_R] = mc_cdev->subled_info[0].brightness;
+	buf[OMNIA_CMD_LED_COLOR_G] = mc_cdev->subled_info[1].brightness;
+	buf[OMNIA_CMD_LED_COLOR_B] = mc_cdev->subled_info[2].brightness;
+
+	state = CMD_LED_STATE_LED(led->reg);
+	if (buf[OMNIA_CMD_LED_COLOR_R] || buf[OMNIA_CMD_LED_COLOR_G] || buf[OMNIA_CMD_LED_COLOR_B])
+		state |= CMD_LED_STATE_ON;
+
+	ret = i2c_smbus_write_byte_data(leds->client, CMD_LED_STATE, state);
+	if (ret >= 0 && (state & CMD_LED_STATE_ON))
+		ret = i2c_master_send(leds->client, buf, 5);
+
+	mutex_unlock(&leds->lock);
+
+	return ret;
+}
+
+static int omnia_led_register(struct omnia_leds *leds, struct device_node *np)
+{
+	struct i2c_client *client = leds->client;
+	struct led_init_data init_data = {};
+	struct device *dev = &client->dev;
+	struct led_classdev *cdev;
+	struct omnia_led *led;
+	int ret, color;
+
+	led = &leds->leds[leds->nleds];
+
+	ret = of_property_read_u32(np, "reg", &led->reg);
+	if (ret || led->reg >= OMNIA_BOARD_LEDS) {
+		dev_warn(dev,
+			 "Node %pOF: must contain 'reg' property with values between 0 and %i\n",
+			 np, OMNIA_BOARD_LEDS - 1);
+		return 0;
+	}
+
+	ret = of_property_read_u32(np, "color", &color);
+	if (ret || color != LED_COLOR_ID_MULTI) {
+		dev_warn(dev,
+			 "Node %pOF: must contain 'color' property with value LED_COLOR_ID_MULTI\n",
+			 np);
+		return 0;
+	}
+
+	led->subled_info[0].color_index = LED_COLOR_ID_RED;
+	led->subled_info[0].channel = 0;
+	led->subled_info[1].color_index = LED_COLOR_ID_GREEN;
+	led->subled_info[1].channel = 1;
+	led->subled_info[2].color_index = LED_COLOR_ID_BLUE;
+	led->subled_info[2].channel = 2;
+
+	led->mc_cdev.subled_info = led->subled_info;
+	led->mc_cdev.num_colors = 3;
+
+	init_data.fwnode = &np->fwnode;
+
+	cdev = &led->mc_cdev.led_cdev;
+	cdev->max_brightness = 255;
+	cdev->brightness_set_blocking = omnia_led_brightness_set_blocking;
+
+	of_property_read_string(np, "linux,default-trigger", &cdev->default_trigger);
+
+	/* put the LED into software mode */
+	ret = i2c_smbus_write_byte_data(client, CMD_LED_MODE,
+					CMD_LED_MODE_LED(led->reg) |
+					CMD_LED_MODE_USER);
+	if (ret < 0) {
+		dev_err(dev, "Cannot set LED %pOF to software mode: %i\n", np, ret);
+		return ret;
+	}
+
+	/* disable the LED */
+	ret = i2c_smbus_write_byte_data(client, CMD_LED_STATE, CMD_LED_STATE_LED(led->reg));
+	if (ret < 0) {
+		dev_err(dev, "Cannot set LED %pOF brightness: %i\n", np, ret);
+		return ret;
+	}
+
+	ret = devm_led_classdev_multicolor_register_ext(dev, &led->mc_cdev, &init_data);
+	if (ret < 0) {
+		dev_err(dev, "Cannot register LED %pOF: %i\n", np, ret);
+		return ret;
+	}
+
+	++leds->nleds;
+
+	return 0;
+}
+
+/*
+ * On the front panel of the Turris Omnia router there is also a button which can be used to control
+ * the intensity of all the LEDs at once, so that if they are too bright, user can dim them.
+ * The microcontroller cycles between 8 levels of this global brightness (from 100% to 0%), but this
+ * setting can have any integer value between 0 and 100.
+ * It is usable to be able to change this value from software, so that it does not start at 100%
+ * after every power on and annoy the user.
+ * We expose this setting via a sysfs attribute file called "brightness". This file lives in the
+ * device directory of the LED controller, not an individual LED, so it should not confuse users.
+ */
+static ssize_t brightness_show(struct device *dev, struct device_attribute *a, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct omnia_leds *leds = i2c_get_clientdata(client);
+	int ret;
+
+	mutex_lock(&leds->lock);
+	ret = i2c_smbus_read_byte_data(client, CMD_LED_GET_BRIGHTNESS);
+	mutex_unlock(&leds->lock);
+
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%d\n", ret);
+}
+
+static ssize_t brightness_store(struct device *dev, struct device_attribute *a, const char *buf,
+				size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct omnia_leds *leds = i2c_get_clientdata(client);
+	unsigned int brightness;
+	int ret;
+
+	if (sscanf(buf, "%u", &brightness) != 1)
+		return -EINVAL;
+
+	if (brightness > 100)
+		return -EINVAL;
+
+	mutex_lock(&leds->lock);
+	ret = i2c_smbus_write_byte_data(client, CMD_LED_SET_BRIGHTNESS, (u8) brightness);
+	mutex_unlock(&leds->lock);
+
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+static DEVICE_ATTR_RW(brightness);
+
+static struct attribute *omnia_led_controller_attrs[] = {
+	&dev_attr_brightness.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(omnia_led_controller);
+
+static int omnia_leds_probe(struct i2c_client *client,
+			    const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct device_node *np = dev->of_node, *child;
+	struct omnia_leds *leds;
+	int ret, count;
+
+	count = of_get_available_child_count(np);
+	if (!count) {
+		dev_err(dev, "LEDs are not defined in device tree!\n");
+		return -ENODEV;
+	} else if (count > OMNIA_BOARD_LEDS) {
+		dev_err(dev, "Too many LEDs defined in device tree!\n");
+		return -EINVAL;
+	}
+
+	leds = devm_kzalloc(dev, sizeof(*leds) + count * sizeof(leds->leds[0]),
+			    GFP_KERNEL);
+	if (!leds)
+		return -ENOMEM;
+
+	leds->client = client;
+	i2c_set_clientdata(client, leds);
+
+	mutex_init(&leds->lock);
+
+	for_each_available_child_of_node(np, child) {
+		ret = omnia_led_register(leds, child);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (devm_device_add_groups(dev, omnia_led_controller_groups))
+		dev_warn(dev, "Could not add attribute group!\n");
+
+	return 0;
+}
+
+static int omnia_leds_remove(struct i2c_client *client)
+{
+	u8 buf[OMNIA_CMD_LED_COLOR_LEN];
+
+	/* put all LEDs into default (HW triggered) mode */
+	i2c_smbus_write_byte_data(client, CMD_LED_MODE,
+				  CMD_LED_MODE_LED(OMNIA_BOARD_LEDS));
+
+	/* set all LEDs color to [255, 255, 255] */
+	buf[OMNIA_CMD] = CMD_LED_COLOR;
+	buf[OMNIA_CMD_LED_COLOR_LED] = OMNIA_BOARD_LEDS;
+	buf[OMNIA_CMD_LED_COLOR_R] = 255;
+	buf[OMNIA_CMD_LED_COLOR_G] = 255;
+	buf[OMNIA_CMD_LED_COLOR_B] = 255;
+
+	i2c_master_send(client, buf, 5);
+
+	return 0;
+}
+
+static const struct of_device_id of_omnia_leds_match[] = {
+	{ .compatible = "cznic,turris-omnia-leds", },
+	{},
+};
+
+static const struct i2c_device_id omnia_id[] = {
+	{ "omnia", 0 },
+	{ }
+};
+
+static struct i2c_driver omnia_leds_driver = {
+	.probe		= omnia_leds_probe,
+	.remove		= omnia_leds_remove,
+	.id_table	= omnia_id,
+	.driver		= {
+		.name	= "leds-turris-omnia",
+		.of_match_table = of_omnia_leds_match,
+	},
+};
+
+module_i2c_driver(omnia_leds_driver);
+
+MODULE_AUTHOR("Marek Behun <marek.behun@nic.cz>");
+MODULE_DESCRIPTION("CZ.NIC's Turris Omnia LEDs");
+MODULE_LICENSE("GPL v2");
-- 
2.26.2

Re: [PATCH v3 1/2] dt-bindings: leds: add cznic,turris-omnia-leds binding

[Jacek Anaszewski]

Hi Marek,

Thank you for the patch. One note below.

On 7/12/20 11:06 PM, Marek Behún wrote:
> Add device-tree bindings documentation for Turris Omnia RGB LEDs.
> 
> Signed-off-by: Marek Behún <marek.behun@nic.cz>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: devicetree@vger.kernel.org
> ---
>   .../leds/cznic,turris-omnia-leds.yaml         | 82 +++++++++++++++++++
>   1 file changed, 82 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml
> 
> diff --git a/Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml b/Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml
> new file mode 100644
> index 000000000000..9817ea3ac69b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml
> @@ -0,0 +1,82 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/leds/cznic,turris-omnia-leds.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: CZ.NIC's Turris Omnia LEDs driver
> +
> +maintainers:
> +  - Marek Behún <marek.behun@nic.cz>
> +
> +description:
> +  This module adds support for the RGB LEDs found on the fron panel of the
> +  Turris Omnia router. There are 12 RGB LEDs, they are controlled by device's
> +  microcontroller with which the system communicates via I2C. Each LED is
> +  described as a subnode of this I2C device.
> +
> +properties:
> +  compatible:
> +    const: cznic,turris-omnia-leds
> +
> +  reg:
> +    description: I2C slave address of the microcontroller.
> +    maxItems: 1
> +
> +  "#address-cells":
> +    const: 1
> +
> +  "#size-cells":
> +    const: 0
> +
> +patternProperties:
> +  "^multi-led[0-9a-f]$":
> +    type: object
> +    allOf:
> +      - $ref: leds-class-multicolor.yaml#
> +    description:
> +      This node represents one of the RGB LED devices on Turris Omnia.
> +
> +    properties:
> +      reg:
> +        minimum: 0
> +        maximum: 11
> +        description:
> +          This property identifies one of the LEDs on the front panel of the
> +          Turris Omnia router.
> +
> +    required:
> +      - reg
> +
> +examples:
> +  - |
> +
> +    #include <dt-bindings/leds/common.h>
> +
> +    i2c0 {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        led-controller@2b {
> +            compatible = "cznic,turris-omnia-leds";
> +            reg = <0x2b>;
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +
> +            multi-led@0 {
> +                reg = <0>;
> +                color = <LED_COLOR_ID_MULTI>;
> +                function = LED_FUNCTION_POWER;

Please provide child nodes for each color LED. Let's stick
to the bindings closely and not make any deviations from
the beginning.

> +                linux,default-trigger = "heartbeat";
> +            };
> +
> +            multi-led@a {
> +                reg = <0xa>;
> +                color = <LED_COLOR_ID_MULTI>;
> +                function = LED_FUNCTION_INDICATOR;
> +                function-enumerator = <1>;
> +            };
> +        };
> +    };
> +
> +...
> 

-- 
Best regards,
Jacek Anaszewski

Re: [PATCH v3 1/2] dt-bindings: leds: add cznic,turris-omnia-leds binding

[Marek Behun]

On Sun, 12 Jul 2020 23:27:07 +0200
Jacek Anaszewski <jacek.anaszewski@gmail.com> wrote:

> > +            multi-led@0 {
> > +                reg = <0>;
> > +                color = <LED_COLOR_ID_MULTI>;
> > +                function = LED_FUNCTION_POWER;  
> 
> Please provide child nodes for each color LED. Let's stick
> to the bindings closely and not make any deviations from
> the beginning.

Why? It would make sense if there were devices using this controller
having other configuration, but on Omnia, all LEDs are RGB.

Also, if I do this, should I also make the driver check in the probe
function whether the per-channel child nodes are correct? Eg. if they
are always three: one for red, one for green and one for blue? Or
should the driver ignore this and only the device tree binding specify
it?

Because the way the driver is written now, it only registers
multi-color RGB LEDs.

Marek

Re: [PATCH v3 1/2] dt-bindings: leds: add cznic,turris-omnia-leds binding

[Jacek Anaszewski]

On 7/12/20 11:40 PM, Marek Behun wrote:
> On Sun, 12 Jul 2020 23:27:07 +0200
> Jacek Anaszewski <jacek.anaszewski@gmail.com> wrote:
> 
>>> +            multi-led@0 {
>>> +                reg = <0>;
>>> +                color = <LED_COLOR_ID_MULTI>;
>>> +                function = LED_FUNCTION_POWER;
>>
>> Please provide child nodes for each color LED. Let's stick
>> to the bindings closely and not make any deviations from
>> the beginning.
> 
> Why? It would make sense if there were devices using this controller
> having other configuration, but on Omnia, all LEDs are RGB.
> 
> Also, if I do this, should I also make the driver check in the probe
> function whether the per-channel child nodes are correct? Eg. if they
> are always three: one for red, one for green and one for blue? Or
> should the driver ignore this and only the device tree binding specify
> it?
> 
> Because the way the driver is written now, it only registers
> multi-color RGB LEDs.

This is not RGB framework, but multicolor framework. It is not justified
to pretend that RGB is default. Unless you would state that clearly in
the comment in DT, but that should be agreed upon with Rob.

-- 
Best regards,
Jacek Anaszewski

Re: [PATCH v3 1/2] dt-bindings: leds: add cznic,turris-omnia-leds binding

[Rob Herring]

On Mon, Jul 13, 2020 at 12:11:51AM +0200, Jacek Anaszewski wrote:
> On 7/12/20 11:40 PM, Marek Behun wrote:
> > On Sun, 12 Jul 2020 23:27:07 +0200
> > Jacek Anaszewski <jacek.anaszewski@gmail.com> wrote:
> > 
> > > > +            multi-led@0 {
> > > > +                reg = <0>;
> > > > +                color = <LED_COLOR_ID_MULTI>;
> > > > +                function = LED_FUNCTION_POWER;
> > > 
> > > Please provide child nodes for each color LED. Let's stick
> > > to the bindings closely and not make any deviations from
> > > the beginning.
> > 
> > Why? It would make sense if there were devices using this controller
> > having other configuration, but on Omnia, all LEDs are RGB.
> > 
> > Also, if I do this, should I also make the driver check in the probe
> > function whether the per-channel child nodes are correct? Eg. if they
> > are always three: one for red, one for green and one for blue? Or
> > should the driver ignore this and only the device tree binding specify
> > it?
> > 
> > Because the way the driver is written now, it only registers
> > multi-color RGB LEDs.
> 
> This is not RGB framework, but multicolor framework. It is not justified
> to pretend that RGB is default. Unless you would state that clearly in
> the comment in DT, but that should be agreed upon with Rob.

If the LEDs are fixed in h/w and never vary for this controller, then 
they don't need to be in DT. However, is it really possible that a 
channel only supports 1 color of LED? I don't think so.

Rob

Re: [PATCH v3 1/2] dt-bindings: leds: add cznic,turris-omnia-leds binding

[Jacek Anaszewski]

On 7/13/20 5:06 PM, Rob Herring wrote:
> On Mon, Jul 13, 2020 at 12:11:51AM +0200, Jacek Anaszewski wrote:
>> On 7/12/20 11:40 PM, Marek Behun wrote:
>>> On Sun, 12 Jul 2020 23:27:07 +0200
>>> Jacek Anaszewski <jacek.anaszewski@gmail.com> wrote:
>>>
>>>>> +            multi-led@0 {
>>>>> +                reg = <0>;
>>>>> +                color = <LED_COLOR_ID_MULTI>;
>>>>> +                function = LED_FUNCTION_POWER;
>>>>
>>>> Please provide child nodes for each color LED. Let's stick
>>>> to the bindings closely and not make any deviations from
>>>> the beginning.
>>>
>>> Why? It would make sense if there were devices using this controller
>>> having other configuration, but on Omnia, all LEDs are RGB.
>>>
>>> Also, if I do this, should I also make the driver check in the probe
>>> function whether the per-channel child nodes are correct? Eg. if they
>>> are always three: one for red, one for green and one for blue? Or
>>> should the driver ignore this and only the device tree binding specify
>>> it?
>>>
>>> Because the way the driver is written now, it only registers
>>> multi-color RGB LEDs.
>>
>> This is not RGB framework, but multicolor framework. It is not justified
>> to pretend that RGB is default. Unless you would state that clearly in
>> the comment in DT, but that should be agreed upon with Rob.
> 
> If the LEDs are fixed in h/w and never vary for this controller, then
> they don't need to be in DT. However, is it really possible that a
> channel only supports 1 color of LED? I don't think so.

Theoretically we could allow for registering two LEDs as LED multi
color device and the other one as monochrome LED class device
but I admit that this would be a bit convoluted and entail unnecessary
complexity in the driver.

So I'm OK with no child nodes for these bindings, but let's add some
comment justifying that.

-- 
Best regards,
Jacek Anaszewski