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Message-ID: <9e790744-c966-0ed6-349e-b1e0013f5193@baylibre.com>
Date: Mon, 16 Nov 2020 09:36:07 +0100
From: Neil Armstrong <narmstrong@...libre.com>
To: Christian Hewitt <christianshewitt@...il.com>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Kevin Hilman <khilman@...libre.com>,
devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-amlogic@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc: Artem Lapkin <art@...das.com>
Subject: Re: [PATCH] arm64: dts: meson: enable rtc node on Khadas VIM1/VIM2
boards
On 16/11/2020 07:41, Christian Hewitt wrote:
> Enable the rtc node on VIM1/VIM2 boards so users can simply attach a power
> cell and use the on-board RTC without modifying the device-tree.
>
> Cold boot with no cell attached is gracefully handled:
>
> VIM2:~ # dmesg | grep rtc
> [ 7.716150] rtc-hym8563 1-0051: no valid clock/calendar values available
> [ 7.716957] rtc-hym8563 1-0051: registered as rtc0
> [ 7.729850] rtc-hym8563 1-0051: no valid clock/calendar values available
> [ 7.729877] rtc-hym8563 1-0051: hctosys: unable to read the hardware clock
> [ 8.126768] rtc-hym8563 1-0051: no valid clock/calendar values available
>
> Warm boot (and any boot with cell attached) recalls stored values resulting
> in consistently faster (re)boot times:
>
> VIM2:~ # dmesg | grep rtc
> [ 7.441671] rtc-hym8563 1-0051: registered as rtc0
> [ 7.442663] rtc-hym8563 1-0051: setting system clock to 2020-11-16T05:49:59 UTC (1605505799)
>
> Suggested-by: Artem Lapkin <art@...das.com>
> Signed-off-by: Christian Hewitt <christianshewitt@...il.com>
> ---
>
> This supersedes other recent attempts by Art to make the same change [0]
> and [1] which were rejected for lack of justification for the change and
> leaving comments behind. I have been using the same changes in my own
> tree for a while.
>
> Christian
>
> [0] https://patchwork.kernel.org/project/linux-amlogic/patch/20200925033017.1790973-8-art@khadas.com/
> [1] https://patchwork.kernel.org/project/linux-amlogic/patch/20200925033017.1790973-9-art@khadas.com/
>
> arch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts | 3 +--
> arch/arm64/boot/dts/amlogic/meson-gxm-khadas-vim2.dts | 3 +--
> 2 files changed, 2 insertions(+), 4 deletions(-)
>
> 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 8bcdffdf55d0..638a5992d760 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
> @@ -97,8 +97,7 @@
> pinctrl-names = "default";
>
> rtc: rtc@51 {
> - /* has to be enabled manually when a battery is connected: */
> - status = "disabled";
> + status = "okay";
> compatible = "haoyu,hym8563";
> reg = <0x51>;
> #clock-cells = <0>;
> diff --git a/arch/arm64/boot/dts/amlogic/meson-gxm-khadas-vim2.dts b/arch/arm64/boot/dts/amlogic/meson-gxm-khadas-vim2.dts
> index bff8ec2c1c70..da000c10b945 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-gxm-khadas-vim2.dts
> +++ b/arch/arm64/boot/dts/amlogic/meson-gxm-khadas-vim2.dts
> @@ -228,8 +228,7 @@
> pinctrl-names = "default";
>
> rtc: rtc@51 {
> - /* has to be enabled manually when a battery is connected: */
> - status = "disabled";
> + status = "okay";
> compatible = "haoyu,hym8563";
> reg = <0x51>;
> #clock-cells = <0>;
>
Reviewed-by: Neil Armstrong <narmstrong@...libre.com>
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