[PATCH] arm64: dts: meson: enable rtc node on Khadas VIM1/VIM2 boards

[Christian Hewitt]

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@xxxxxxxxxx>
Signed-off-by: Christian Hewitt <christianshewitt@xxxxxxxxx>
---

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@xxxxxxxxxx/
[1] https://patchwork.kernel.org/project/linux-amlogic/patch/20200925033017.1790973-9-art@xxxxxxxxxx/

 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>;
-- 
2.17.1