Re: [PATCH v3 1/2] Documentation: Add GPIO reset binding to reset binding documentation

From: Arnd Bergmann
Date: Wed Jan 08 2014 - 11:08:46 EST


On Wednesday 08 January 2014, Philipp Zabel wrote:
> += GPIO Reset consumers =
> +
> +For the common case of reset lines controlled by GPIOs, the GPIO binding
> +documented in devicetree/bindings/gpio/gpio.txt should be used:
> +
> +Required properties:
> +reset-gpios or Reset GPIO using standard GPIO bindings,
> +<name>-reset-gpios: optionally named to specify the reset line
> +
> +Optional properties:
> +reset-boot-asserted or Boolean. If set, the corresponding reset is
> +<name>-reset-boot-asserted: initially asserted and should be kept that way
> + until released by the driver.

I don't get this one. Why would you use a different reset binding for the case
where the reset line is connected to the gpio controller rather than a
specialized reset controller?

I was expecting to see the definition of a generic reset controller that
in turn uses gpio lines, like


reset {
compatible = "gpio-reset";
/* provides three reset lines through these GPIOs */
gpios = <&gpioA 1 &gpioB 7 <gpioD 17>;
#reset-cells = <1>;
};

foo {
...
resets = <&reset 0>; /* uses first reset line of the gpio-reset controller */
};

I realize it would be a little more verbose, but it also seems more
regular and wouldn't stand out from the rest of the reset interfaces.

Arnd
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