Re: [PATCH 2/7] ARM: shmobile: r8a7740 dtsi: Add missing "gpio-ranges" to gpio node

[Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>]

Hi Geert,

Thank you for the patch.

On Tuesday 30 June 2015 09:45:22 Geert Uytterhoeven wrote:
> If a GPIO driver uses gpiochip_add_pin_range() (which is usually the
> case for GPIO/PFC combos), the GPIO hogging mechanism configured from DT
> doesn't work:
> 
>     requesting hog GPIO lcd0 (chip r8a7740_pfc, offset 176) failed
> 
> The actual error code is -517 == -EPROBE_DEFER.
> 
> The problem is that PFC+GPIO registration is handled in multiple steps:
>   1. pinctrl_register(),
>   2. gpiochip_add(),
>   3. gpiochip_add_pin_range().
> 
> Configuration of the hogs is handled in gpiochip_add():
> 
>     gpiochip_add
>         of_gpiochip_add
>             of_gpiochip_scan_hogs
>                 gpiod_hog
>                     gpiochip_request_own_desc
>                         __gpiod_request
>                             chip->request
>                                 pinctrl_request_gpio
>                                     pinctrl_get_device_gpio_range
> 
> However, at this point the GPIO controller hasn't been added to
> pinctrldev_list yet, so the range can't be found, and the operation fails
> with -EPROBE_DEFER.
> 
> To fix this, add a "gpio-ranges" property to the gpio device node, so
> the range is added by of_gpiochip_add_pin_range(), which is called by
> of_gpiochip_add() before the call to of_gpiochip_scan_hogs().
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>

This looks sane to me, even though referencing the same DT node seems a bit 
dodgy. I'll let Linus comment on that, but for the implementation itself,

Acked-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>

> ---
>  arch/arm/boot/dts/r8a7740.dtsi | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/arm/boot/dts/r8a7740.dtsi b/arch/arm/boot/dts/r8a7740.dtsi
> index 3aaab195132bfc2c..15977b5834de9579 100644
> --- a/arch/arm/boot/dts/r8a7740.dtsi
> +++ b/arch/arm/boot/dts/r8a7740.dtsi
> @@ -316,6 +316,7 @@
>  		      <0xe605800c 0x20>;
>  		gpio-controller;
>  		#gpio-cells = <2>;
> +		gpio-ranges = <&pfc 0 0 212>;
>  		interrupts-extended =
>  			<&irqpin0 0 0>, <&irqpin0 1 0>, <&irqpin0 2 0>, <&irqpin0 3 0>,
>  			<&irqpin0 4 0>, <&irqpin0 5 0>, <&irqpin0 6 0>, <&irqpin0 7 0>,

-- 
Regards,

Laurent Pinchart

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