From aac343ebb35e3428cf3b101cc16f8aa082817b37 Mon Sep 17 00:00:00 2001 From: Shawn Lin Date: Wed, 16 Nov 2016 16:49:21 +0800 Subject: dt-bindings: add documentation for rk1108 cru This adds the dt-binding documentation for the clock and reset unit found on Rockchip rk1108 SoCs. Signed-off-by: Shawn Lin Signed-off-by: Heiko Stuebner --- .../bindings/clock/rockchip,rk1108-cru.txt | 59 ++++++++++++++++++++++ 1 file changed, 59 insertions(+) create mode 100644 Documentation/devicetree/bindings/clock/rockchip,rk1108-cru.txt (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/clock/rockchip,rk1108-cru.txt b/Documentation/devicetree/bindings/clock/rockchip,rk1108-cru.txt new file mode 100644 index 000000000000..4da126116cf0 --- /dev/null +++ b/Documentation/devicetree/bindings/clock/rockchip,rk1108-cru.txt @@ -0,0 +1,59 @@ +* Rockchip RK1108 Clock and Reset Unit + +The RK1108 clock controller generates and supplies clock to various +controllers within the SoC and also implements a reset controller for SoC +peripherals. + +Required Properties: + +- compatible: should be "rockchip,rk1108-cru" +- reg: physical base address of the controller and length of memory mapped + region. +- #clock-cells: should be 1. +- #reset-cells: should be 1. + +Optional Properties: + +- rockchip,grf: phandle to the syscon managing the "general register files" + If missing pll rates are not changeable, due to the missing pll lock status. + +Each clock is assigned an identifier and client nodes can use this identifier +to specify the clock which they consume. All available clocks are defined as +preprocessor macros in the dt-bindings/clock/rk1108-cru.h headers and can be +used in device tree sources. Similar macros exist for the reset sources in +these files. + +External clocks: + +There are several clocks that are generated outside the SoC. It is expected +that they are defined using standard clock bindings with following +clock-output-names: + - "xin24m" - crystal input - required, + - "ext_vip" - external VIP clock - optional + - "ext_i2s" - external I2S clock - optional + - "ext_gmac" - external GMAC clock - optional + - "hdmiphy" - external clock input derived from HDMI PHY - optional + - "usbphy" - external clock input derived from USB PHY - optional + +Example: Clock controller node: + + cru: cru@20200000 { + compatible = "rockchip,rk1108-cru"; + reg = <0x20200000 0x1000>; + rockchip,grf = <&grf>; + + #clock-cells = <1>; + #reset-cells = <1>; + }; + +Example: UART controller node that consumes the clock generated by the clock + controller: + + uart0: serial@10230000 { + compatible = "rockchip,rk1108-uart", "snps,dw-apb-uart"; + reg = <0x10230000 0x100>; + interrupts = ; + reg-shift = <2>; + reg-io-width = <4>; + clocks = <&cru SCLK_UART0>; + }; -- cgit v1.2.3