linux-kernel - Re: [PATCH v3 1/2] dt-bindings: leds: Add bindings for lm3697 driver

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Date:   Wed, 15 Aug 2018 18:56:33 +0200
From:   Jacek Anaszewski <jacek.anaszewski@...il.com>
To:     Dan Murphy <dmurphy@...com>, robh+dt@...nel.org, pavel@....cz
Cc:     devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-leds@...r.kernel.org
Subject: Re: [PATCH v3 1/2] dt-bindings: leds: Add bindings for lm3697 driver

Hi Dan,

Thank you for the update.

On 08/15/2018 06:17 PM, Dan Murphy wrote:
> Add the device tree bindings for the lm3697
> LED driver for backlighting and display.
> 
> Signed-off-by: Dan Murphy <dmurphy@...com>
> ---
> 
> v3 - Updated subject with prefered title - https://lore.kernel.org/patchwork/patch/972337/
> v2 - Fixed subject and patch commit message - https://lore.kernel.org/patchwork/patch/971326/
> 
>  .../devicetree/bindings/leds/leds-lm3697.txt  | 89 +++++++++++++++++++
>  1 file changed, 89 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/leds/leds-lm3697.txt
> 
> diff --git a/Documentation/devicetree/bindings/leds/leds-lm3697.txt b/Documentation/devicetree/bindings/leds/leds-lm3697.txt
> new file mode 100644
> index 000000000000..34403a48a0ce
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/leds-lm3697.txt
> @@ -0,0 +1,89 @@
> +* Texas Instruments - LM3697 Highly Efficient White LED Driver
> +
> +The LM3697 11-bit LED driver provides high-
> +performance backlight dimming for 1, 2, or 3 series
> +LED strings while delivering up to 90% efficiency.
> +
> +This device is suitable for Display and Keypad Lighting
> +
> +Required properties:
> +	- compatible:
> +		"ti,lm3967"
> +	- reg :  I2C slave address
> +	- #address-cells : 1
> +	- #size-cells : 0
> +
> +Optional properties:
> +	- enable-gpios : gpio pin to enable/disable the device.
> +	- vled-supply : LED supply
> +
> +Required child properties:
> +	- reg : 0 - LED is Controlled by bank A
> +		1 - LED is Controlled by bank B
> +	- led-sources - Indicates which HVLED string is associated to which
> +			control bank.  The HVLED string cannot be associated with
> +			two control banks.  This property is an array of 3 and
> +			all positions in the array must be populated.
> +			Additional information is contained
> +			in Documentation/devicetree/bindings/leds/common.txt
> +			0 - End of array if all 3 LEDs are not declared for a
> +			    single control bank.

This is needless complication. I propose to define led-sources as
an array of three boolean values, whose state signifies which LED
strings are controlled by the bank defined by the reg property in the
given child node. I.e. <HVLED1 HVLED2 HVLED3>.

I modified your examples below accordingly.

> +			1 - HVLED 1 string
> +			2 - HVLED 2 string
> +			3 - HVLED 3 string
> +
> +Optional child properties:
> +	- label : see Documentation/devicetree/bindings/leds/common.txt
> +	- linux,default-trigger :
> +	   see Documentation/devicetree/bindings/leds/common.txt
> +
> +Example:
> +
> +HVLED string 1 and 2 controlled by control bank A and HVLED string controlled by
> +control bank B.
> +
> +led-controller@36 {
> +	compatible = "ti,lm3967";
> +	reg = <0x36>;
> +	#address-cells = <1>;
> +	#size-cells = <0>;
> +
> +	enable-gpios = <&gpio1 28 GPIO_ACTIVE_HIGH>;
> +	vled-supply = <&vbatt>;
> +
> +	led@0 {
> +		reg = <0>;
> +		led-sources = <0x1 0x2 0x0>

		led-sources = <1 1 0>;
;
> +		label = "white:first_backlight_cluster";
> +		linux,default-trigger = "backlight";
> +	};
> +
> +	led@1 {
> +		reg = <1>;
> +		led-sources = <0x3 0x0 0x0>;

		led-sources = <0 0 1>;

> +		label = "white:second_backlight_cluster";
> +		linux,default-trigger = "backlight";
> +	};
> +}
> +
> +All HVLED strings controlled by control bank A
> +
> +led-controller@36 {
> +	compatible = "ti,lm3967";
> +	reg = <0x36>;
> +	#address-cells = <1>;
> +	#size-cells = <0>;
> +
> +	enable-gpios = <&gpio1 28 GPIO_ACTIVE_HIGH>;
> +	vled-supply = <&vbatt>;
> +
> +	led@0 {
> +		reg = <0>;
> +		led-sources = <0x1 0x2 0x3>;

		led-sources = <1 1 1>;

> +		label = "white:backlight_cluster";
> +		linux,default-trigger = "backlight";
> +	};
> +}
> +
> +For more product information please see the link below:
> +http://www.ti.com/lit/ds/symlink/lm3697.pdf
> 

-- 
Best regards,
Jacek Anaszewski