linux-kernel - [PATCH 4/4] arm64: dts: qcom: x1e80100: describe uefi rtc offset

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Message-ID: <20250423075143.11157-5-johan+linaro@kernel.org>
Date: Wed, 23 Apr 2025 09:51:43 +0200
From: Johan Hovold <johan+linaro@...nel.org>
To: Alexandre Belloni <alexandre.belloni@...tlin.com>,
	Bjorn Andersson <andersson@...nel.org>
Cc: Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Konrad Dybcio <konradybcio@...nel.org>,
	linux-arm-msm@...r.kernel.org,
	linux-rtc@...r.kernel.org,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Johan Hovold <johan+linaro@...nel.org>
Subject: [PATCH 4/4] arm64: dts: qcom: x1e80100: describe uefi rtc offset

On many Qualcomm platforms the PMIC RTC control and time registers are
read-only so that the RTC time can not be updated. Instead an offset
needs be stored in some machine-specific non-volatile memory, which a
driver can take into account.

On platforms where the offset is stored in a Qualcomm specific UEFI
variable the variables are also accessed in a non-standard way, which
means that the OS cannot assume that the variable service is available
by the time the RTC driver probes.

Use the new 'qcom,uefi-rtc-info' property to indicate that the offset is
stored in a UEFI variable so that the OS can determine whether to wait
for it to become available.

Fixes: b53c2c23d3c2 ("arm64: dts: qcom: x1e80100: enable rtc")
Signed-off-by: Johan Hovold <johan+linaro@...nel.org>
---
 arch/arm64/boot/dts/qcom/x1e80100-pmics.dtsi | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/boot/dts/qcom/x1e80100-pmics.dtsi b/arch/arm64/boot/dts/qcom/x1e80100-pmics.dtsi
index a59aa8e7642d..5a170238e74d 100644
--- a/arch/arm64/boot/dts/qcom/x1e80100-pmics.dtsi
+++ b/arch/arm64/boot/dts/qcom/x1e80100-pmics.dtsi
@@ -224,6 +224,7 @@ pmk8550_rtc: rtc@...0 {
 			reg-names = "rtc", "alarm";
 			interrupts = <0x0 0x62 0x1 IRQ_TYPE_EDGE_RISING>;
 			qcom,no-alarm; /* alarm owned by ADSP */
+			qcom,uefi-rtc-info;
 		};

 		pmk8550_sdam_2: nvram@...0 {
-- 
2.49.0