68 lines
2.2 KiB
Plaintext
68 lines
2.2 KiB
Plaintext
* Rockchip RK3288 Clock and Reset Unit
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The RK3288 clock controller generates and supplies clock to various
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controllers within the SoC and also implements a reset controller for SoC
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peripherals.
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A revision of this SoC is available: rk3288w. The clock tree is a bit
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different so another dt-compatible is available. Noticed that it is only
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setting the difference but there is no automatic revision detection. This
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should be performed by bootloaders.
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Required Properties:
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- compatible: should be "rockchip,rk3288-cru" or "rockchip,rk3288w-cru" in
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case of this revision of Rockchip rk3288.
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- reg: physical base address of the controller and length of memory mapped
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region.
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- #clock-cells: should be 1.
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- #reset-cells: should be 1.
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Optional Properties:
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- rockchip,grf: phandle to the syscon managing the "general register files"
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If missing pll rates are not changeable, due to the missing pll lock status.
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Each clock is assigned an identifier and client nodes can use this identifier
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to specify the clock which they consume. All available clocks are defined as
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preprocessor macros in the dt-bindings/clock/rk3288-cru.h headers and can be
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used in device tree sources. Similar macros exist for the reset sources in
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these files.
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External clocks:
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There are several clocks that are generated outside the SoC. It is expected
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that they are defined using standard clock bindings with following
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clock-output-names:
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- "xin24m" - crystal input - required,
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- "xin32k" - rtc clock - optional,
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- "ext_i2s" - external I2S clock - optional,
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- "ext_hsadc" - external HSADC clock - optional,
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- "ext_edp_24m" - external display port clock - optional,
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- "ext_vip" - external VIP clock - optional,
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- "ext_isp" - external ISP clock - optional,
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- "ext_jtag" - external JTAG clock - optional
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Example: Clock controller node:
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cru: cru@20000000 {
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compatible = "rockchip,rk3188-cru";
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reg = <0x20000000 0x1000>;
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rockchip,grf = <&grf>;
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#clock-cells = <1>;
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#reset-cells = <1>;
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};
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Example: UART controller node that consumes the clock generated by the clock
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controller:
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uart0: serial@10124000 {
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compatible = "snps,dw-apb-uart";
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reg = <0x10124000 0x400>;
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interrupts = <GIC_SPI 34 IRQ_TYPE_LEVEL_HIGH>;
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reg-shift = <2>;
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reg-io-width = <1>;
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clocks = <&cru SCLK_UART0>;
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};
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