Re: [PATCH 04/33] ARM: dts: exynos: Correct S3C RTC bindings and enable it in Origen

Marek Szyprowski
2020-08-31T09:49:27Z

On 30.08.2020 15:51, Krzysztof Kozlowski wrote:
> The S3C RTC requires 32768 Hz clock as input which is provided by PMIC
> (Maxim MAX8997). However there is no clock provided for the PMIC and
> the driver registers the clock as regulator. This is an old driver
> which will not be updated so add a workaround:
> 1. Enable the "clock" regulator in PMIC,
> 2. Add a fixed-clock to fill missing clock phandle reference in S3C RTC.
>
> This allows to enable the S3C RTC and fixes dtbs_check warnings:
>
> arch/arm/boot/dts/exynos4210-origen.dt.yaml: rtc@10070000: clocks: [[5, 346]] is too short
> arch/arm/boot/dts/exynos4210-origen.dt.yaml: rtc@10070000: clock-names: ['rtc'] is too short
>
> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

Confirmed, this workaround enables s3c-rtc driver operation on this board.

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

> ---
> arch/arm/boot/dts/exynos4210-origen.dts | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/arch/arm/boot/dts/exynos4210-origen.dts b/arch/arm/boot/dts/exynos4210-origen.dts
> index 890525b10d22..747221bbb856 100644
> --- a/arch/arm/boot/dts/exynos4210-origen.dts
> +++ b/arch/arm/boot/dts/exynos4210-origen.dts
> @@ -100,6 +100,13 @@
> compatible = "samsung,clock-xusbxti";
> clock-frequency = <24000000>;
> };
> +
> + pmic_ap_clk: pmic-ap-clk {
> + /* Workaround for missing clock on max8997 PMIC */
> + compatible = "fixed-clock";
> + #clock-cells = <0>;
> + clock-frequency = <32768>;
> + };
> };
>
> display-timings {
> @@ -286,6 +293,11 @@
> regulator-boot-on;
> regulator-always-on;
> };
> +
> + EN32KHZ_AP {
> + regulator-name = "EN32KHZ_AP";
> + regulator-always-on;
> + };
> };
> };
> };
> @@ -331,6 +343,8 @@
>
> &rtc {
> status = "okay";
> + clocks = <&clock CLK_RTC>, <&pmic_ap_clk>;
> + clock-names = "rtc", "rtc_src";
> };
>
> &tmu {

Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland