ARM: dts: exynos: Correct S3C RTC bindings and enable it in Galaxy I9100

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-i9100.dt.yaml: rtc@10070000: clocks: [[5, 346]] is too short
  arch/arm/boot/dts/exynos4210-i9100.dt.yaml: rtc@10070000: clock-names: ['rtc'] is too short

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200830135200.24304-3-krzk@kernel.org

1 files changed, 18 insertions, 0 deletions

diff --git a/arch/arm/boot/dts/exynos4210-i9100.dts b/arch/arm/boot/dts/exynos4210-i9100.dts
index 6fa57d1fa1d7..d63274c8539d 100644
--- a/arch/arm/boot/dts/exynos4210-i9100.dts
+++ b/arch/arm/boot/dts/exynos4210-i9100.dts
@@ -209,6 +209,13 @@
 			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>;
+		};
 	};
 
 	thermal-zones {
@@ -568,6 +575,11 @@
 				regulator-max-microvolt = <4100000>;
 				regulator-always-on;
 			};
+
+			EN32KHZ_AP {
+				regulator-name = "EN32KHZ_AP";
+				regulator-always-on;
+			};
 		};
 	};
 };
@@ -688,6 +700,12 @@
 	};
 };
 
+&rtc {
+	status = "okay";
+	clocks = <&clock CLK_RTC>, <&pmic_ap_clk>;
+	clock-names = "rtc", "rtc_src";
+};
+
 &sdhci_0 {
 	status = "okay";