[PATCH 1/6] dt-bindings: rtc: stm32: add st,lsco optional property to select output

[Valentin Caron <valentin.caron@foss.st.com>]

From: Amelie Delaunay <amelie.delaunay@foss.st.com>

STM32 RTC has three output pins: RTC_OUT1, RTC_OUT2 or RTC_OUT2_RMP.

RTC Low-Speed Clock Output (LSCO) can be output on RTC_OUT1 or
RTC_OUT2_RMP.

This patch adds constants for RTC output bindings and adds st,lsco
optional property for stm32 rtc driver, to select and enable LSCO.
A pinctrl state is also optional to reserve pin for RTC output.

Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
---
 .../devicetree/bindings/rtc/st,stm32-rtc.yaml | 20 +++++++++++++++++++
 include/dt-bindings/rtc/rtc-stm32.h           | 14 +++++++++++++
 2 files changed, 34 insertions(+)
 create mode 100644 include/dt-bindings/rtc/rtc-stm32.h

diff --git a/Documentation/devicetree/bindings/rtc/st,stm32-rtc.yaml b/Documentation/devicetree/bindings/rtc/st,stm32-rtc.yaml
index 764717ce1873..56d46ea35c5d 100644
--- a/Documentation/devicetree/bindings/rtc/st,stm32-rtc.yaml
+++ b/Documentation/devicetree/bindings/rtc/st,stm32-rtc.yaml
@@ -52,6 +52,13 @@ properties:
       override default rtc_ck parent clock phandle of the new parent clock of rtc_ck
     maxItems: 1
 
+  st,lsco:
+    $ref: "/schemas/types.yaml#/definitions/uint32"
+    description: |
+      To select and enable RTC Low Speed Clock Output.
+      Refer to <include/dt-bindings/rtc/rtc-stm32.h> for the supported values.
+      Pinctrl state named "default" may be defined to reserve pin for RTC output.
+
 allOf:
   - if:
       properties:
@@ -65,6 +72,9 @@ allOf:
           minItems: 1
           maxItems: 1
 
+        st,lsco:
+          maxItems: 0
+
         clock-names: false
 
       required:
@@ -82,6 +92,9 @@ allOf:
           minItems: 2
           maxItems: 2
 
+        st,lsco:
+          maxItems: 0
+
       required:
         - clock-names
         - st,syscfg
@@ -101,6 +114,9 @@ allOf:
         assigned-clocks: false
         assigned-clock-parents: false
 
+        st,lsco:
+          maxItems: 1
+
       required:
         - clock-names
 
@@ -130,12 +146,16 @@ examples:
   - |
     #include <dt-bindings/interrupt-controller/arm-gic.h>
     #include <dt-bindings/clock/stm32mp1-clks.h>
+    #include <dt-bindings/rtc/rtc-stm32.h>
     rtc@5c004000 {
       compatible = "st,stm32mp1-rtc";
       reg = <0x5c004000 0x400>;
       clocks = <&rcc RTCAPB>, <&rcc RTC>;
       clock-names = "pclk", "rtc_ck";
       interrupts = <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>;
+      st,lsco = <RTC_OUT2_RMP>;
+      pinctrl-0 = <&rtc_out2_rmp_pins_a>;
+      pinctrl-names = "default";
     };
 
 ...
diff --git a/include/dt-bindings/rtc/rtc-stm32.h b/include/dt-bindings/rtc/rtc-stm32.h
new file mode 100644
index 000000000000..2fd78c2e62d4
--- /dev/null
+++ b/include/dt-bindings/rtc/rtc-stm32.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * This header provides constants for STM32_RTC bindings.
+ */
+
+#ifndef _DT_BINDINGS_RTC_RTC_STM32_H
+#define _DT_BINDINGS_RTC_RTC_STM32_H
+
+#define RTC_NO_OUT	0
+#define RTC_OUT1	1
+#define RTC_OUT2	2
+#define RTC_OUT2_RMP	3
+
+#endif
-- 
2.25.1