ARM: dts: exynos: Correct S3C RTC bindings and enable it in Universal C210

The S3C RTC requires 32768 Hz clock as input which is provided by PMIC.
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 - add a fixed-clock to fill missing clock phandle
reference in S3C RTC.  The "clock" regulator in PMIC is already present
and enabled.

This allows to enable the S3C RTC and fixes dtbs_check warnings:

  arch/arm/boot/dts/exynos4210-universal_c210.dt.yaml: rtc@10070000: clocks: [[5, 346]] is too short
  arch/arm/boot/dts/exynos4210-universal_c210.dt.yaml: rtc@10070000: clock-names: ['rtc'] is too short

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20200830135200.24304-6-krzk@kernel.org

diff --git a/arch/arm/boot/dts/exynos4210-universal_c210.dts b/arch/arm/boot/dts/exynos4210-universal_c210.dts
index 99ce53b120ac3acaf3d613c492affbfd6752baf7..9479e41bdc2af9f9a7c2562aa755ea7a57e3a914 100644 (file)
--- a/arch/arm/boot/dts/exynos4210-universal_c210.dts
+++ b/arch/arm/boot/dts/exynos4210-universal_c210.dts
@@ -39,6 +39,13 @@
                        compatible = "samsung,clock-xusbxti";
                        clock-frequency = <24000000>;
                };
+
+               pmic_ap_clk: pmic-ap-clk {
+                       /* Workaround for missing clock on PMIC */
+                       compatible = "fixed-clock";
+                       #clock-cells = <0>;
+                       clock-frequency = <32768>;
+               };
        };
 
        vemmc_reg: voltage-regulator {
@@ -537,6 +544,12 @@
        status = "okay";
 };
 
+&rtc {
+       status = "okay";
+       clocks = <&clock CLK_RTC>, <&pmic_ap_clk>;
+       clock-names = "rtc", "rtc_src";
+};
+
 &sdhci_0 {
        bus-width = <8>;
        non-removable;