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Diffstat (limited to 'Documentation/devicetree/bindings/clock/pistachio-clock.txt')
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diff --git a/Documentation/devicetree/bindings/clock/pistachio-clock.txt b/Documentation/devicetree/bindings/clock/pistachio-clock.txt new file mode 100644 index 000000000..868db499e --- /dev/null +++ b/Documentation/devicetree/bindings/clock/pistachio-clock.txt @@ -0,0 +1,123 @@ +Imagination Technologies Pistachio SoC clock controllers +======================================================== + +Pistachio has four clock controllers (core clock, peripheral clock, peripheral +general control, and top general control) which are instantiated individually +from the device-tree. + +External clocks: +---------------- + +There are three external inputs to the clock controllers which should be +defined with the following clock-output-names: +- "xtal": External 52Mhz oscillator (required) +- "audio_clk_in": Alternate audio reference clock (optional) +- "enet_clk_in": Alternate ethernet PHY clock (optional) + +Core clock controller: +---------------------- + +The core clock controller generates clocks for the CPU, RPU (WiFi + BT +co-processor), audio, and several peripherals. + +Required properties: +- compatible: Must be "img,pistachio-clk". +- reg: Must contain the base address and length of the core clock controller. +- #clock-cells: Must be 1. The single cell is the clock identifier. + See dt-bindings/clock/pistachio-clk.h for the list of valid identifiers. +- clocks: Must contain an entry for each clock in clock-names. +- clock-names: Must include "xtal" (see "External clocks") and + "audio_clk_in_gate", "enet_clk_in_gate" which are generated by the + top-level general control. + +Example: + clk_core: clock-controller@18144000 { + compatible = "img,pistachio-clk"; + reg = <0x18144000 0x800>; + clocks = <&xtal>, <&cr_top EXT_CLK_AUDIO_IN>, + <&cr_top EXT_CLK_ENET_IN>; + clock-names = "xtal", "audio_clk_in_gate", "enet_clk_in_gate"; + + #clock-cells = <1>; + }; + +Peripheral clock controller: +---------------------------- + +The peripheral clock controller generates clocks for the DDR, ROM, and other +peripherals. The peripheral system clock ("periph_sys") generated by the core +clock controller is the input clock to the peripheral clock controller. + +Required properties: +- compatible: Must be "img,pistachio-periph-clk". +- reg: Must contain the base address and length of the peripheral clock + controller. +- #clock-cells: Must be 1. The single cell is the clock identifier. + See dt-bindings/clock/pistachio-clk.h for the list of valid identifiers. +- clocks: Must contain an entry for each clock in clock-names. +- clock-names: Must include "periph_sys", the peripheral system clock generated + by the core clock controller. + +Example: + clk_periph: clock-controller@18144800 { + compatible = "img,pistachio-clk-periph"; + reg = <0x18144800 0x800>; + clocks = <&clk_core CLK_PERIPH_SYS>; + clock-names = "periph_sys"; + + #clock-cells = <1>; + }; + +Peripheral general control: +--------------------------- + +The peripheral general control block generates system interface clocks and +resets for various peripherals. It also contains miscellaneous peripheral +control registers. The system clock ("sys") generated by the peripheral clock +controller is the input clock to the system clock controller. + +Required properties: +- compatible: Must include "img,pistachio-periph-cr" and "syscon". +- reg: Must contain the base address and length of the peripheral general + control registers. +- #clock-cells: Must be 1. The single cell is the clock identifier. + See dt-bindings/clock/pistachio-clk.h for the list of valid identifiers. +- clocks: Must contain an entry for each clock in clock-names. +- clock-names: Must include "sys", the system clock generated by the peripheral + clock controller. + +Example: + cr_periph: syscon@18144800 { + compatible = "img,pistachio-cr-periph", "syscon"; + reg = <0x18148000 0x1000>; + clocks = <&clock_periph PERIPH_CLK_PERIPH_SYS>; + clock-names = "sys"; + + #clock-cells = <1>; + }; + +Top-level general control: +-------------------------- + +The top-level general control block contains miscellaneous control registers and +gates for the external clocks "audio_clk_in" and "enet_clk_in". + +Required properties: +- compatible: Must include "img,pistachio-cr-top" and "syscon". +- reg: Must contain the base address and length of the top-level + control registers. +- clocks: Must contain an entry for each clock in clock-names. +- clock-names: Two optional clocks, "audio_clk_in" and "enet_clk_in" (see + "External clocks"). +- #clock-cells: Must be 1. The single cell is the clock identifier. + See dt-bindings/clock/pistachio-clk.h for the list of valid identifiers. + +Example: + cr_top: syscon@18144800 { + compatible = "img,pistachio-cr-top", "syscon"; + reg = <0x18149000 0x200>; + clocks = <&audio_refclk>, <&ext_enet_in>; + clock-names = "audio_clk_in", "enet_clk_in"; + + #clock-cells = <1>; + }; |