From cdfd5daf90af8363fb1f58e08c829a775b2e2fc5 Mon Sep 17 00:00:00 2001 From: Claudiu Beznea Date: Fri, 1 Nov 2024 11:57:12 +0200 Subject: [PATCH] dt-bindings: clock: renesas,r9a08g045-vbattb: Document VBATTB The VBATTB IP of the Renesas RZ/G3S SoC controls the clock for RTC, the tamper detector and a small general usage memory of 128B. The VBATTB controller controls the clock for the RTC on the Renesas RZ/G3S. The HW block diagram for the clock logic is as follows: +----------+ XC `\ RTXIN --->| |----->| \ +----+ VBATTCLK | 32K clock| | |----->|gate|-----------> | osc | XBYP | | +----+ RTXOUT --->| |----->| / +----------+ ,/ One could connect as input to this HW block either a crystal or an external clock device. This is board specific. After discussions w/ Stephen Boyd the clock tree associated with this hardware block was exported in Linux as: input-xtal xbyp xc mux vbattclk where: - input-xtal is the input clock (connected to RTXIN, RTXOUT pins) - xc, xbyp are mux inputs - mux is the internal mux - vbattclk is the gate clock that feeds in the end the RTC to allow selecting the input of the MUX though assigned-clock DT properties, using the already existing clock drivers and avoid adding other DT properties. This allows select the input of the mux based on the type of the connected input clock: - if the 32768 crystal is connected as input for the VBATTB, the input of the mux should be xc - if an external clock device is connected as input for the VBATTB the input of the mux should be xbyp Add bindings for the VBATTB controller. Reviewed-by: Geert Uytterhoeven Reviewed-by: Krzysztof Kozlowski Signed-off-by: Claudiu Beznea Link: https://lore.kernel.org/20241101095720.2247815-2-claudiu.beznea.uj@bp.renesas.com Signed-off-by: Geert Uytterhoeven --- .../clock/renesas,r9a08g045-vbattb.yaml | 84 +++++++++++++++++++ .../clock/renesas,r9a08g045-vbattb.h | 13 +++ 2 files changed, 97 insertions(+) create mode 100644 Documentation/devicetree/bindings/clock/renesas,r9a08g045-vbattb.yaml create mode 100644 include/dt-bindings/clock/renesas,r9a08g045-vbattb.h diff --git a/Documentation/devicetree/bindings/clock/renesas,r9a08g045-vbattb.yaml b/Documentation/devicetree/bindings/clock/renesas,r9a08g045-vbattb.yaml new file mode 100644 index 0000000000000..3707e4118949d --- /dev/null +++ b/Documentation/devicetree/bindings/clock/renesas,r9a08g045-vbattb.yaml @@ -0,0 +1,84 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/clock/renesas,r9a08g045-vbattb.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Renesas Battery Backup Function (VBATTB) + +description: + Renesas VBATTB is an always on powered module (backed by battery) which + controls the RTC clock (VBATTCLK), tamper detection logic and a small + general usage memory (128B). + +maintainers: + - Claudiu Beznea + +properties: + compatible: + const: renesas,r9a08g045-vbattb + + reg: + maxItems: 1 + + interrupts: + items: + - description: tamper detector interrupt + + clocks: + items: + - description: VBATTB module clock + - description: RTC input clock (crystal or external clock device) + + clock-names: + items: + - const: bclk + - const: rtx + + '#clock-cells': + const: 1 + + power-domains: + maxItems: 1 + + resets: + items: + - description: VBATTB module reset + + quartz-load-femtofarads: + description: load capacitance of the on board crystal + enum: [ 4000, 7000, 9000, 12500 ] + default: 4000 + +required: + - compatible + - reg + - interrupts + - clocks + - clock-names + - '#clock-cells' + - power-domains + - resets + +additionalProperties: false + +examples: + - | + #include + #include + #include + #include + + clock-controller@1005c000 { + compatible = "renesas,r9a08g045-vbattb"; + reg = <0x1005c000 0x1000>; + interrupts = ; + clocks = <&cpg CPG_MOD R9A08G045_VBAT_BCLK>, <&vbattb_xtal>; + clock-names = "bclk", "rtx"; + assigned-clocks = <&vbattb VBATTB_MUX>; + assigned-clock-parents = <&vbattb VBATTB_XC>; + #clock-cells = <1>; + power-domains = <&cpg>; + resets = <&cpg R9A08G045_VBAT_BRESETN>; + quartz-load-femtofarads = <12500>; + }; diff --git a/include/dt-bindings/clock/renesas,r9a08g045-vbattb.h b/include/dt-bindings/clock/renesas,r9a08g045-vbattb.h new file mode 100644 index 0000000000000..67774eafad062 --- /dev/null +++ b/include/dt-bindings/clock/renesas,r9a08g045-vbattb.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + * + * Copyright (C) 2024 Renesas Electronics Corp. + */ +#ifndef __DT_BINDINGS_CLOCK_R9A08G045_VBATTB_H__ +#define __DT_BINDINGS_CLOCK_R9A08G045_VBATTB_H__ + +#define VBATTB_XC 0 +#define VBATTB_XBYP 1 +#define VBATTB_MUX 2 +#define VBATTB_VBATTCLK 3 + +#endif /* __DT_BINDINGS_CLOCK_R9A08G045_VBATTB_H__ */ -- 2.39.5