From 605add0c7bbf5ecb9eeef02c605e47dfd2980acb Mon Sep 17 00:00:00 2001 From: Gabriel Fernandez Date: Thu, 8 Mar 2018 17:53:54 +0100 Subject: [PATCH] dt-bindings: Document STM32MP1 Reset Clock Controller (RCC) bindings The RCC block is responsible of the management of the clock and reset generation for the complete circuit. Signed-off-by: Gabriel Fernandez Reviewed-by: Rob Herring Signed-off-by: Michael Turquette --- .../devicetree/bindings/clock/st,stm32mp1-rcc.txt | 60 ++++++++++++++++++++++ 1 file changed, 60 insertions(+) create mode 100644 Documentation/devicetree/bindings/clock/st,stm32mp1-rcc.txt diff --git a/Documentation/devicetree/bindings/clock/st,stm32mp1-rcc.txt b/Documentation/devicetree/bindings/clock/st,stm32mp1-rcc.txt new file mode 100644 index 000000000000..fb9495ea582c --- /dev/null +++ b/Documentation/devicetree/bindings/clock/st,stm32mp1-rcc.txt @@ -0,0 +1,60 @@ +STMicroelectronics STM32 Peripheral Reset Clock Controller +========================================================== + +The RCC IP is both a reset and a clock controller. + +RCC makes also power management (resume/supend and wakeup interrupt). + +Please also refer to reset.txt for common reset controller binding usage. + +Please also refer to clock-bindings.txt for common clock controller +binding usage. + + +Required properties: +- compatible: "st,stm32mp1-rcc", "syscon" +- reg: should be register base and length as documented in the datasheet +- #clock-cells: 1, device nodes should specify the clock in their + "clocks" property, containing a phandle to the clock device node, + an index specifying the clock to use. +- #reset-cells: Shall be 1 +- interrupts: Should contain a general interrupt line and a interrupt line + to the wake-up of processor (CSTOP). + +Example: + rcc: rcc@50000000 { + compatible = "st,stm32mp1-rcc", "syscon"; + reg = <0x50000000 0x1000>; + #clock-cells = <1>; + #reset-cells = <1>; + interrupts = , + ; + }; + +Specifying clocks +================= + +All available clocks are defined as preprocessor macros in +dt-bindings/clock/stm32mp1-clks.h header and can be used in device +tree sources. + +Specifying softreset control of devices +======================================= + +Device nodes should specify the reset channel required in their "resets" +property, containing a phandle to the reset device node and an index specifying +which channel to use. +The index is the bit number within the RCC registers bank, starting from RCC +base address. +It is calculated as: index = register_offset / 4 * 32 + bit_offset. +Where bit_offset is the bit offset within the register. + +For example on STM32MP1, for LTDC reset: + ltdc = APB4_RSTSETR_offset / 4 * 32 + LTDC_bit_offset + = 0x180 / 4 * 32 + 0 = 3072 + +The list of valid indices for STM32MP1 is available in: +include/dt-bindings/reset-controller/stm32mp1-resets.h + +This file implements defines like: +#define LTDC_R 3072 -- 2.11.0