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-rw-r--r-- | Documentation/devicetree/bindings/clock/st,stm32h7-rcc.txt | 71 |
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diff --git a/Documentation/devicetree/bindings/clock/st,stm32h7-rcc.txt b/Documentation/devicetree/bindings/clock/st,stm32h7-rcc.txt new file mode 100644 index 000000000..cac24ee10 --- /dev/null +++ b/Documentation/devicetree/bindings/clock/st,stm32h7-rcc.txt @@ -0,0 +1,71 @@ +STMicroelectronics STM32H7 Reset and Clock Controller +===================================================== + +The RCC IP is both a reset and a clock controller. + +Please refer to clock-bindings.txt for common clock controller binding usage. +Please also refer to reset.txt for common reset controller binding usage. + +Required properties: +- compatible: Should be: + "st,stm32h743-rcc" + +- reg: should be register base and length as documented in the + datasheet + +- #reset-cells: 1, see below + +- #clock-cells : from common clock binding; shall be set to 1 + +- clocks: External oscillator clock phandle + - high speed external clock signal (HSE) + - low speed external clock signal (LSE) + - external I2S clock (I2S_CKIN) + +Optional properties: +- st,syscfg: phandle for pwrcfg, mandatory to disable/enable backup domain + write protection (RTC clock). + +Example: + + rcc: reset-clock-controller@58024400 { + compatible = "st,stm32h743-rcc", "st,stm32-rcc"; + reg = <0x58024400 0x400>; + #reset-cells = <1>; + #clock-cells = <1>; + clocks = <&clk_hse>, <&clk_lse>, <&clk_i2s_ckin>; + + st,syscfg = <&pwrcfg>; +}; + +The peripheral clock consumer should specify the desired clock by +having the clock ID in its "clocks" phandle cell. + +Example: + + timer5: timer@40000c00 { + compatible = "st,stm32-timer"; + reg = <0x40000c00 0x400>; + interrupts = <50>; + clocks = <&rcc TIM5_CK>; + }; + +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, for CRC reset: + crc = AHB4RSTR_offset / 4 * 32 + CRCRST_bit_offset = 0x88 / 4 * 32 + 19 = 1107 + +Example: + + timer2 { + resets = <&rcc STM32H7_APB1L_RESET(TIM2)>; + }; |