rtc: apple: Add Abbey PMU counter and wake alarm support

Documentation/devicetree/bindings/rtc/apple,abbey-pmu-rtc.yaml

@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: GPL-2.0-only
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/rtc/apple,abbey-pmu-rtc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Apple Abbey SPMI PMU real-time clock
+
+maintainers:
+  - Dj <hey@djdev.me>
+
+description: |
+  The Abbey PMU exposes a 48-bit 65536 Hz counter and a signed 48-bit
+  wall-clock offset in units of 1/32768 second. Its alarm comparator uses
+  32-bit counter seconds. NVMEM cells use little-endian byte order.
+  The one-byte alarm control has event bit 1, monitor bit 0 and enable
+  bit 6. The one-byte interrupt mask has the alarm mask in bit 0.
+  This layout is distinct from the Baku PMU RTC.
+
+allOf:
+  - $ref: rtc.yaml#
+
+properties:
+  compatible:
+    const: apple,abbey-pmu-rtc
+
+  interrupts:
+    maxItems: 1
+    description: Alarm event interrupt from the SPMI controller
+
+  nvmem-cells:
+    minItems: 5
+    maxItems: 5
+    description: Counter (6), offset (6), alarm (4), control (1), mask (1) bytes
+
+  nvmem-cell-names:
+    items:
+      - const: counter
+      - const: rtc_offset
+      - const: alarm
+      - const: alarm_ctrl
+      - const: irq_mask
+
+  wakeup-source: true
+
+required:
+  - compatible
+  - nvmem-cells
+  - nvmem-cell-names
+
+unevaluatedProperties: false

MAINTAINERS

@@ -4359,6 +4359,13 @@ F:	rust/helpers/auxiliary.c
 F:	rust/kernel/auxiliary.rs
 F:	samples/rust/rust_driver_auxiliary.rs
 
+AURORA APPLE SPMI PMU RTC
+M:	Dj <hey@djdev.me>
+L:	linux-rtc@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/rtc/apple,abbey-pmu-rtc.yaml
+F:	drivers/rtc/rtc-apple-spmi-pmu.c
+
 AURORA PLATFORM MMIO INTERFACE
 M:	Dj <hey@djdev.me>
 S:	Maintained

arch/arm64/configs/aurora-apif.config

@@ -12,3 +12,9 @@ CONFIG_PCIE_APPLE_APIF=y
 CONFIG_PM=y
 CONFIG_RUST=y
 CONFIG_APPLE_PMP=y
+CONFIG_SPMI=y
+CONFIG_SPMI_APPLE=y
+CONFIG_NVMEM=y
+CONFIG_NVMEM_APPLE_SPMI=y
+CONFIG_RTC_CLASS=y
+CONFIG_RTC_DRV_APPLE_SPMI_PMU=y

drivers/rtc/Kconfig

@@ -2111,6 +2111,15 @@ config RTC_DRV_APPLE_PMU
 
 	  This driver can be built as the module rtc-apple-pmu.
 
+config RTC_DRV_APPLE_SPMI_PMU
+	tristate "Apple Abbey SPMI PMU RTC"
+	depends on ARCH_APPLE || COMPILE_TEST
+	depends on NVMEM && OF
+	help
+	  Access the Abbey PMU counter, signed wall-clock offset and wake alarm
+	  through named NVMEM cells. This uses a different register layout from
+	  the J700 Baku PMU RTC.
+
 config RTC_DRV_MACSMC
 	tristate "Apple Mac System Management Controller RTC"
 	depends on MFD_MACSMC

drivers/rtc/Makefile

@@ -201,3 +201,5 @@ obj-$(CONFIG_RTC_DRV_WM8350)	+= rtc-wm8350.o
 obj-$(CONFIG_RTC_DRV_X1205)	+= rtc-x1205.o
 obj-$(CONFIG_RTC_DRV_XGENE)	+= rtc-xgene.o
 obj-$(CONFIG_RTC_DRV_ZYNQMP)	+= rtc-zynqmp.o
+
+obj-$(CONFIG_RTC_DRV_APPLE_SPMI_PMU) += rtc-apple-spmi-pmu.o