From 07049187e83072e187d7a9f3386286e59c83e8ee Mon Sep 17 00:00:00 2001 From: Sven Peter Date: Wed, 12 Nov 2025 21:16:47 +1000 Subject: [PATCH] dt-bindings: rtc: Add Apple SMC RTC Apple Silicon Macs (M1, etc.) have an RTC that is part of the PMU IC, but most of the PMU functionality is abstracted out by the SMC. An additional RTC offset stored inside NVMEM is required to compute the current date/time. Reviewed-by: Mark Kettenis Reviewed-by: Neal Gompa Reviewed-by: Rob Herring (Arm) Signed-off-by: Sven Peter Signed-off-by: James Calligeros Reviewd-by: Mark Kettenis Link: https://patch.msgid.link/20251112-macsmc-subdevs-v5-1-728e4b91fe81@gmail.com Signed-off-by: Alexandre Belloni --- .../devicetree/bindings/mfd/apple,smc.yaml | 9 +++++ .../bindings/rtc/apple,smc-rtc.yaml | 35 +++++++++++++++++++ MAINTAINERS | 1 + 3 files changed, 45 insertions(+) create mode 100644 Documentation/devicetree/bindings/rtc/apple,smc-rtc.yaml diff --git a/Documentation/devicetree/bindings/mfd/apple,smc.yaml b/Documentation/devicetree/bindings/mfd/apple,smc.yaml index 5429538f7e2e..0410e712c900 100644 --- a/Documentation/devicetree/bindings/mfd/apple,smc.yaml +++ b/Documentation/devicetree/bindings/mfd/apple,smc.yaml @@ -46,6 +46,9 @@ properties: reboot: $ref: /schemas/power/reset/apple,smc-reboot.yaml + rtc: + $ref: /schemas/rtc/apple,smc-rtc.yaml + additionalProperties: false required: @@ -80,5 +83,11 @@ examples: nvmem-cell-names = "shutdown_flag", "boot_stage", "boot_error_count", "panic_count"; }; + + rtc { + compatible = "apple,smc-rtc"; + nvmem-cells = <&rtc_offset>; + nvmem-cell-names = "rtc_offset"; + }; }; }; diff --git a/Documentation/devicetree/bindings/rtc/apple,smc-rtc.yaml b/Documentation/devicetree/bindings/rtc/apple,smc-rtc.yaml new file mode 100644 index 000000000000..607b610665a2 --- /dev/null +++ b/Documentation/devicetree/bindings/rtc/apple,smc-rtc.yaml @@ -0,0 +1,35 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/rtc/apple,smc-rtc.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Apple SMC RTC + +description: + Apple Silicon Macs (M1, etc.) have an RTC that is part of the PMU IC, + but most of the PMU functionality is abstracted out by the SMC. + An additional RTC offset stored inside NVMEM is required to compute + the current date/time. + +maintainers: + - Sven Peter + +properties: + compatible: + const: apple,smc-rtc + + nvmem-cells: + items: + - description: 48bit RTC offset, specified in 32768 (2^15) Hz clock ticks + + nvmem-cell-names: + items: + - const: rtc_offset + +required: + - compatible + - nvmem-cells + - nvmem-cell-names + +additionalProperties: false diff --git a/MAINTAINERS b/MAINTAINERS index 0a19e3171ad4..b93d26e60e99 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2435,6 +2435,7 @@ F: Documentation/devicetree/bindings/pinctrl/apple,pinctrl.yaml F: Documentation/devicetree/bindings/power/apple* F: Documentation/devicetree/bindings/power/reset/apple,smc-reboot.yaml F: Documentation/devicetree/bindings/pwm/apple,s5l-fpwm.yaml +F: Documentation/devicetree/bindings/rtc/apple,smc-rtc.yaml F: Documentation/devicetree/bindings/spi/apple,spi.yaml F: Documentation/devicetree/bindings/spmi/apple,spmi.yaml F: Documentation/devicetree/bindings/watchdog/apple,wdt.yaml -- 2.47.3