[PATCH v5 0/2] Make AUX gpio pin optional for ktd2692

[PATCH v5 0/2] Make AUX gpio pin optional for ktd2692

[Markuss Broks]

Some appliances of ktd2692 don't have the AUX pin connected to
a GPIO. Specifically, Samsung Galaxy J5 (2015), which uses ktd2692
for driving the front flash LED, has the pin not connected anywhere on
schematics. Make specifying the AUX pin optional, since it is additional
functionality and only affects amount of current going through the LED.

Also convert the txt device-tree bindings to yaml and pick up maintenance
over the yaml binding and the driver itself.

v2:
- fix the dt_binding_check
v3:
- set the aux_gpio to NULL to avoid passing ERR_PTR as a gpio
v4:
- maintainership -> maintenance (description)
- remove the if (led->aux_gpio)
- use devm_gpiod_get_optional for aux gpio
v5:
- use ret to pass a correct error return code (Christophe)

Markuss Broks (2):
  dt-bindings: leds: convert ktd2692 bindings to yaml
  leds: ktd2692: Make aux-gpios optional

 .../bindings/leds/kinetic,ktd2692.yaml        | 87 +++++++++++++++++++
 .../devicetree/bindings/leds/leds-ktd2692.txt | 50 -----------
 MAINTAINERS                                   |  6 ++
 drivers/leds/flash/leds-ktd2692.c             | 18 ++--
 4 files changed, 103 insertions(+), 58 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/leds/kinetic,ktd2692.yaml
 delete mode 100644 Documentation/devicetree/bindings/leds/leds-ktd2692.txt

-- 
2.35.1

[PATCH v5 1/2] dt-bindings: leds: convert ktd2692 bindings to yaml

[Markuss Broks]

This patch converts the leds-ktd2692.txt bindings to modern yaml
style device-tree bindings.

Signed-off-by: Markuss Broks <markuss.broks@gmail.com>
---
 .../bindings/leds/kinetic,ktd2692.yaml        | 87 +++++++++++++++++++
 .../devicetree/bindings/leds/leds-ktd2692.txt | 50 -----------
 2 files changed, 87 insertions(+), 50 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/leds/kinetic,ktd2692.yaml
 delete mode 100644 Documentation/devicetree/bindings/leds/leds-ktd2692.txt

diff --git a/Documentation/devicetree/bindings/leds/kinetic,ktd2692.yaml b/Documentation/devicetree/bindings/leds/kinetic,ktd2692.yaml
new file mode 100644
index 000000000000..bac95a51afa1
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/kinetic,ktd2692.yaml
@@ -0,0 +1,87 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/kinetic,ktd2692.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: KTD2692 Flash LED Driver from Kinetic Technologies
+
+maintainers:
+  - Markuss Broks <markuss.broks@gmail.com>
+
+description: |
+  KTD2692 is the ideal power solution for high-power flash LEDs.
+  It uses ExpressWire single-wire programming for maximum flexibility.
+
+  The ExpressWire interface through CTRL pin can control LED on/off and
+  enable/disable the IC, Movie(max 1/3 of Flash current) / Flash mode current,
+  Flash timeout, LVP(low voltage protection).
+
+  Also, When the AUX pin is pulled high while CTRL pin is high,
+  LED current will be ramped up to the flash-mode current level.
+
+properties:
+  compatible:
+    const: kinetic,ktd2692
+
+  ctrl-gpios:
+    maxItems: 1
+    description: Specifier of the GPIO connected to CTRL pin.
+
+  aux-gpios:
+    maxItems: 1
+    description: Specifier of the GPIO connected to CTRL pin.
+
+  vin-supply:
+    description: LED supply (2.7V to 5.5V).
+
+  led:
+    type: object
+    $ref: common.yaml#
+    description: Properties for the LED.
+    properties:
+      function: true
+      color: true
+      flash-max-timeout-us:
+        description: Flash LED maximum timeout.
+
+      led-max-microamp:
+        maximum: 300000
+        description: Minimum Threshold for Timer protection
+          is defined internally (Maximum 300mA).
+
+      flash-max-microamp:
+        maximum: 300000
+        description: Flash LED maximum current
+          Formula - I(uA) = 15000000 / Rset.
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - ctrl-gpios
+  - led
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/leds/common.h>
+
+    ktd2692 {
+      compatible = "kinetic,ktd2692";
+      ctrl-gpios = <&gpc0 1 0>;
+      aux-gpios = <&gpc0 2 0>;
+      vin-supply = <&vbat>;
+
+      led {
+        function = LED_FUNCTION_FLASH;
+        color = <LED_COLOR_ID_WHITE>;
+        flash-max-timeout-us = <250000>;
+        flash-max-microamp = <150000>;
+        led-max-microamp = <25000>;
+      };
+    };
+
+...
diff --git a/Documentation/devicetree/bindings/leds/leds-ktd2692.txt b/Documentation/devicetree/bindings/leds/leds-ktd2692.txt
deleted file mode 100644
index 853737452580..000000000000
--- a/Documentation/devicetree/bindings/leds/leds-ktd2692.txt
+++ /dev/null
@@ -1,50 +0,0 @@
-* Kinetic Technologies - KTD2692 Flash LED Driver
-
-KTD2692 is the ideal power solution for high-power flash LEDs.
-It uses ExpressWire single-wire programming for maximum flexibility.
-
-The ExpressWire interface through CTRL pin can control LED on/off and
-enable/disable the IC, Movie(max 1/3 of Flash current) / Flash mode current,
-Flash timeout, LVP(low voltage protection).
-
-Also, When the AUX pin is pulled high while CTRL pin is high,
-LED current will be ramped up to the flash-mode current level.
-
-Required properties:
-- compatible : Should be "kinetic,ktd2692".
-- ctrl-gpios : Specifier of the GPIO connected to CTRL pin.
-- aux-gpios : Specifier of the GPIO connected to AUX pin.
-
-Optional properties:
-- vin-supply : "vin" LED supply (2.7V to 5.5V).
-  See Documentation/devicetree/bindings/regulator/regulator.txt
-
-A discrete LED element connected to the device must be represented by a child
-node - See Documentation/devicetree/bindings/leds/common.txt
-
-Required properties for flash LED child nodes:
-  See Documentation/devicetree/bindings/leds/common.txt
-- led-max-microamp : Minimum Threshold for Timer protection
-  is defined internally (Maximum 300mA).
-- flash-max-microamp : Flash LED maximum current
-  Formula : I(mA) = 15000 / Rset.
-- flash-max-timeout-us : Flash LED maximum timeout.
-
-Optional properties for flash LED child nodes:
-- label : See Documentation/devicetree/bindings/leds/common.txt
-
-Example:
-
-ktd2692 {
-	compatible = "kinetic,ktd2692";
-	ctrl-gpios = <&gpc0 1 0>;
-	aux-gpios = <&gpc0 2 0>;
-	vin-supply = <&vbat>;
-
-	flash-led {
-		label = "ktd2692-flash";
-		led-max-microamp = <300000>;
-		flash-max-microamp = <1500000>;
-		flash-max-timeout-us = <1835000>;
-	};
-};
-- 
2.35.1

[PATCH v5 2/2] leds: ktd2692: Make aux-gpios optional

[Markuss Broks]

Make the AUX pin optional, since it isn't a core part of functionality,
and the device is designed to be operational with only one CTRL pin.

Also pick up maintenance for the LED driver and the yaml bindings.

Signed-off-by: Markuss Broks <markuss.broks@gmail.com>
---
 MAINTAINERS                       | 6 ++++++
 drivers/leds/flash/leds-ktd2692.c | 4 ++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/MAINTAINERS b/MAINTAINERS
index 2db49ea7ae55..8ef5667a1d98 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10479,6 +10479,12 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/leds/backlight/kinetic,ktd253.yaml
 F:	drivers/video/backlight/ktd253-backlight.c
 
+KTD2692 FLASH LED DRIVER
+M:	Markuss Broks <markuss.broks@gmail.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/leds/backlight/kinetic,ktd2692.yaml
+F:	drivers/leds/flash/leds-ktd2692.yaml
+
 KTEST
 M:	Steven Rostedt <rostedt@goodmis.org>
 M:	John Hawley <warthog9@eaglescrag.net>
diff --git a/drivers/leds/flash/leds-ktd2692.c b/drivers/leds/flash/leds-ktd2692.c
index f341da1503a4..fc9c2e441caa 100644
--- a/drivers/leds/flash/leds-ktd2692.c
+++ b/drivers/leds/flash/leds-ktd2692.c
@@ -284,8 +284,8 @@ static int ktd2692_parse_dt(struct ktd2692_context *led, struct device *dev,
 		return ret;
 	}
 
-	led->aux_gpio = devm_gpiod_get(dev, "aux", GPIOD_ASIS);
-	ret = PTR_ERR_OR_ZERO(led->aux_gpio);
+	led->aux_gpio = devm_gpiod_get_optional(dev, "aux", GPIOD_ASIS);
+	ret = PTR_ERR(led->aux_gpio);
 	if (ret) {
 		dev_err(dev, "cannot get aux-gpios %d\n", ret);
 		return ret;
-- 
2.35.1

Re: [PATCH v5 2/2] leds: ktd2692: Make aux-gpios optional

[Marion & Christophe JAILLET]

Le 08/04/2022 à 19:59, Markuss Broks a écrit :
> Make the AUX pin optional, since it isn't a core part of functionality,
> and the device is designed to be operational with only one CTRL pin.
>
> Also pick up maintenance for the LED driver and the yaml bindings.
>
> Signed-off-by: Markuss Broks <markuss.broks@gmail.com>
> ---
>   MAINTAINERS                       | 6 ++++++
>   drivers/leds/flash/leds-ktd2692.c | 4 ++--
>   2 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 2db49ea7ae55..8ef5667a1d98 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -10479,6 +10479,12 @@ S:	Maintained
>   F:	Documentation/devicetree/bindings/leds/backlight/kinetic,ktd253.yaml
>   F:	drivers/video/backlight/ktd253-backlight.c
>   
> +KTD2692 FLASH LED DRIVER
> +M:	Markuss Broks <markuss.broks@gmail.com>
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/leds/backlight/kinetic,ktd2692.yaml
> +F:	drivers/leds/flash/leds-ktd2692.yaml
> +
>   KTEST
>   M:	Steven Rostedt <rostedt@goodmis.org>
>   M:	John Hawley <warthog9@eaglescrag.net>
> diff --git a/drivers/leds/flash/leds-ktd2692.c b/drivers/leds/flash/leds-ktd2692.c
> index f341da1503a4..fc9c2e441caa 100644
> --- a/drivers/leds/flash/leds-ktd2692.c
> +++ b/drivers/leds/flash/leds-ktd2692.c
> @@ -284,8 +284,8 @@ static int ktd2692_parse_dt(struct ktd2692_context *led, struct device *dev,
>   		return ret;
>   	}
>   
> -	led->aux_gpio = devm_gpiod_get(dev, "aux", GPIOD_ASIS);
> -	ret = PTR_ERR_OR_ZERO(led->aux_gpio);
> +	led->aux_gpio = devm_gpiod_get_optional(dev, "aux", GPIOD_ASIS);
> +	ret = PTR_ERR(led->aux_gpio);
>   	if (ret) {
>   		dev_err(dev, "cannot get aux-gpios %d\n", ret);
>   		return ret;

Hi,

Sorry if I was unclear. What I was meaning is below.

This v5 is just wrong. If 'led->aux_gpio' is a valid pointer, then 
'PTR_ERR(led->aux_gpio)' will be non-0 and you will bail-out with a 
pointless error value.

PTR_ERR(x) is a valid error value if IS_ERR(x) is true. Otherwise it is 
just 'x' casted as a long. So if 'x' is valid, it can be anything.


What I had in mind was more something like:

@@ -284,10 +284,9 @@ static int ktd2692_parse_dt(struct ktd2692_context *led, struct device *dev,
  		return ret;
  	}
  
-	led->aux_gpio = devm_gpiod_get(dev, "aux", GPIOD_ASIS);
-	ret = PTR_ERR_OR_ZERO(led->aux_gpio);
-	if (ret) {
-		dev_err(dev, "cannot get aux-gpios %d\n", ret);
+	led->aux_gpio = devm_gpiod_get_optional(dev, "aux", GPIOD_ASIS);
+	if (IS_ERR(led->aux_gpio)) {
+		ret = PTR_ERR(led->aux_gpio);
+		dev_err(dev, "cannot get aux-gpios: %d\n", ret);
  		return ret;
  	}
  


I guess that using PTR_ERR_OR_ZERO() is an option (like in the original 
code) but personally I find it less readable (but it is just a matter of 
taste)

CJ