Messages in this thread | | | Date | Mon, 27 Jun 2022 09:57:05 +0200 | Subject | Re: [PATCH v5 1/3] dt-bindings: leds: Add bindings for the TLC5925 controller | From | Jean-Jacques Hiblot <> |
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On 18/06/2022 01:19, Rob Herring wrote: > On Tue, Jun 14, 2022 at 05:42:43PM +0200, Jean-Jacques Hiblot wrote: >> Add bindings documentation for the TLC5925 LED controller. >> >> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com> >> --- >> .../devicetree/bindings/leds/ti,tlc5925.yaml | 107 ++++++++++++++++++ >> 1 file changed, 107 insertions(+) >> create mode 100644 Documentation/devicetree/bindings/leds/ti,tlc5925.yaml >> >> diff --git a/Documentation/devicetree/bindings/leds/ti,tlc5925.yaml b/Documentation/devicetree/bindings/leds/ti,tlc5925.yaml >> new file mode 100644 >> index 000000000000..12a71e48f854 >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/leds/ti,tlc5925.yaml >> @@ -0,0 +1,107 @@ >> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause >> +%YAML 1.2 >> +--- >> +$id: http://devicetree.org/schemas/leds/ti,tlc5925.yaml# >> +$schema: http://devicetree.org/meta-schemas/core.yaml# >> + >> +title: LEDs connected to TI TLC5925 controller >> + >> +maintainers: >> + - Jean-Jacques Hiblot <jjhiblot@traphandler.com> >> + >> +description: | >> + The TLC5925 is a low-power 16-channel constant-current LED sink driver. >> + It is controlled through a SPI interface. >> + It is built around a shift register and latches which convert serial >> + input data into a parallel output. Several TLC5925 can be chained to >> + control more than 16 LEDs with a single chip-select. >> + The brightness level cannot be controlled, each LED is either on or off. >> + >> + Each LED is represented as a sub-node of the ti,tlc5925 device. >> + >> +$ref: /schemas/spi/spi-peripheral-props.yaml# >> + >> +properties: >> + compatible: >> + const: ti,tlc5925 >> + >> + ti,shift-register-length: >> + $ref: /schemas/types.yaml#/definitions/uint32 >> + minimum: 8 >> + description: | > Don't need '|' if no formatting to preserve. > >> + The length of the shift register. If several TLC5925 are chained, >> + shift_register_length should be set to 16 times the number of TLC5925. >> + The value must be a multiple of 8. > multipleOf: 8 > > Though I'm confused why it's not 16.
The reason why it is 8 instead of 16, is that there exists other LEDs controllers that are compatible with this driver and use only a 8-bits shift register.
The main reason is that the granularity of the size of a SPI transfer is 8 bits.
>> + >> + "#address-cells": >> + const: 1 >> + >> + "#size-cells": >> + const: 0 >> + >> + output-enable-b-gpios: >> + $ref: /schemas/types.yaml#/definitions/phandle-array > Already has a type. > >> + description: | >> + Optional GPIO pins to enable/disable the parallel output. They describe >> + the GPIOs connected to the OE/ pin of the TLC5925s. >> + >> +patternProperties: >> + "@[0-9a-f]+$": >> + type: object >> + $ref: common.yaml# > unevaluatedProperties: false > >> + >> + properties: >> + reg: >> + $ref: /schemas/types.yaml#/definitions/uint32 > Don't need a type here. > >> + description: | >> + LED pin number (must be lower than ti,shift-register-length). >> + The furthest LED down the chain has the pin number 0. >> + >> + required: >> + - reg >> + >> +required: >> + - "#address-cells" >> + - "#size-cells" >> + - ti,shift-register-length > Is there not a default when not chained?
A default value could be used indeed. I'll rework the driver to use a default value of 16
Thanks
Jean-Jacques
> >> + >> +unevaluatedProperties: false >> + >> +examples: >> + - | >> + #include <dt-bindings/gpio/gpio.h> >> + #include <dt-bindings/leds/common.h> >> + >> + spi0 { > spi { > >> + #address-cells = <1>; >> + #size-cells = <0>; >> + >> + leds@2 { >> + compatible = "ti,tlc5925"; >> + reg = <0x02>; >> + spi-max-frequency = <30000000>; >> + ti,shift-register-length = <32>; >> + output-enable-b-gpios = <&gpio0b 9 GPIO_ACTIVE_HIGH>, <&gpio0b 7 GPIO_ACTIVE_HIGH>; >> + #address-cells = <1>; >> + #size-cells = <0>; >> + >> + led@0 { >> + reg = <0>; >> + function = LED_FUNCTION_STATUS; >> + color = <LED_COLOR_ID_GREEN>; >> + }; >> + >> + led@4 { >> + reg = <4>; >> + function = LED_FUNCTION_STATUS; >> + color = <LED_COLOR_ID_RED>; >> + }; >> + >> + led@1f { >> + reg = <31>; >> + function = LED_FUNCTION_PANIC; >> + color = <LED_COLOR_ID_RED>; >> + }; >> + }; >> + >> + }; >> -- >> 2.25.1 >> >>
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