linux-kernel - Re: [PATCH] ARM64: dts: meson-gx: use specific compatible for the AO pwms

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Message-ID: <b3812e40-cb59-a30f-9558-2926ca49a29a@baylibre.com>
Date:   Wed, 7 Jun 2017 15:52:28 +0200
From:   Neil Armstrong <narmstrong@...libre.com>
To:     Jerome Brunet <jbrunet@...libre.com>,
        Kevin Hilman <khilman@...libre.com>, devicetree@...r.kernel.org
Cc:     Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        linux-kernel@...r.kernel.org, Carlo Caione <carlo@...one.org>,
        linux-amlogic@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] ARM64: dts: meson-gx: use specific compatible for the AO
 pwms

On 06/07/2017 03:48 PM, Jerome Brunet wrote:
> Use the specific compatiable for AO pwms so the pwms input can
-----------------------/\
s/compatiable/compatible/

> be correctly set
> 
> FDIV4 is not present on the pwm A0, so change kadhas vim input
> clocks to xtal.
> 
> Signed-off-by: Jerome Brunet <jbrunet@...libre.com>
> ---
> This patch depends on the pwm patchset available here [0]
> 
> On the Khadas Vim I chose to replace FDIV4 with the crytal.
> Only PWM_AO_B is actually used and It is used for led dimming.
> The frequency, as long as it is high enough, does not matter.
> Only the duty cycle does. After testing, xtal seems to be fast
> enough.
> 
> PWM_AO_A is outputed on the general purpose header, but no usage is
> defined for it.

Seems we will need to define what to enable by default on these SBC
headers somehow, and leave future out-of-tree DT overlays do the work.

> 
> It might be bit late for that but I wonder why it defined and enabled ?
> Same goes for the other peripherals activated on this general purpose
> header.
> 
> I know that's what shows the schematics but one could choose to do
> anything else possible with it ? like use in GPIO mode, or another
> function. In addition, we never which setting will be required ? (eg
> which clock source ?).
> 
> Should we keep those ? or remove them ?
> 
> [0]: https://lkml.kernel.org/r/20170607133013.4766-1-jbrunet@baylibre.com
> 
>  arch/arm64/boot/dts/amlogic/meson-gx.dtsi                  | 2 +-
>  arch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts | 4 ++--
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/amlogic/meson-gx.dtsi b/arch/arm64/boot/dts/amlogic/meson-gx.dtsi
> index 436b875060e7..fbaa6b598fca 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-gx.dtsi
> +++ b/arch/arm64/boot/dts/amlogic/meson-gx.dtsi
> @@ -391,7 +391,7 @@
>  			};
>  
>  			pwm_AO_ab: pwm@550 {
> -				compatible = "amlogic,meson-gx-pwm", "amlogic,meson-gxbb-pwm";
> +				compatible = "amlogic,meson-gx-ao-pwm", "amlogic,meson-gxbb-ao-pwm";
>  				reg = <0x0 0x00550 0x0 0x10>;
>  				#pwm-cells = <3>;
>  				status = "disabled";
> diff --git a/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts b/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts
> index 6a81f0168da5..371f43cdd3ab 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts
> +++ b/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts
> @@ -86,8 +86,8 @@
>  	status = "okay";
>  	pinctrl-0 = <&pwm_ao_a_3_pins>, <&pwm_ao_b_pins>;
>  	pinctrl-names = "default";
> -	clocks = <&clkc CLKID_FCLK_DIV4>;
> -	clock-names = "clkin0";
> +	clocks = <&xtal> , <&xtal>;
> +	clock-names = "clkin0", "clkin1" ;
>  };
>  
>  &pwm_ef {
> 

Reviewed-by: Neil Armstrong <narmstrong@...libre.com>