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doc: dt: add documentation for lpc1850-ccu clk driver
Add DT binding documentation for lpc1850-ccu clk driver.
Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
authored by
Joachim Eastwood
and committed by
Michael Turquette
ddfb1574
472cd304
+77
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Documentation/devicetree/bindings/clock/lpc1850-ccu.txt
+77
Documentation/devicetree/bindings/clock/lpc1850-ccu.txt
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* NXP LPC1850 Clock Control Unit (CCU)
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Each CGU base clock has several clock branches which can be turned on
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or off independently by the Clock Control Units CCU1 or CCU2. The
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branch clocks are distributed between CCU1 and CCU2.
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- Above text taken from NXP LPC1850 User Manual.
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This binding uses the common clock binding:
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Documentation/devicetree/bindings/clock/clock-bindings.txt
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Required properties:
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- compatible:
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Should be "nxp,lpc1850-ccu"
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- reg:
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Shall define the base and range of the address space
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containing clock control registers
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- #clock-cells:
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Shall have value <1>. The permitted clock-specifier values
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are the branch clock names defined in table below.
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- clocks:
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Shall contain a list of phandles for the base clocks routed
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from the CGU to the specific CCU. See mapping of base clocks
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and CCU in table below.
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- clock-names:
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Shall contain a list of names for the base clock routed
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from the CGU to the specific CCU. Valid CCU clock names:
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"base_usb0_clk", "base_periph_clk", "base_usb1_clk",
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"base_cpu_clk", "base_spifi_clk", "base_spi_clk",
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"base_apb1_clk", "base_apb3_clk", "base_adchs_clk",
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"base_sdio_clk", "base_ssp0_clk", "base_ssp1_clk",
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"base_uart0_clk", "base_uart1_clk", "base_uart2_clk",
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"base_uart3_clk", "base_audio_clk"
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Which branch clocks that are available on the CCU depends on the
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specific LPC part. Check the user manual for your specific part.
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A list of CCU clocks can be found in dt-bindings/clock/lpc18xx-ccu.h.
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Example board file:
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soc {
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ccu1: clock-controller@40051000 {
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compatible = "nxp,lpc1850-ccu";
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reg = <0x40051000 0x1000>;
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#clock-cells = <1>;
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clocks = <&cgu BASE_APB3_CLK>, <&cgu BASE_APB1_CLK>,
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<&cgu BASE_SPIFI_CLK>, <&cgu BASE_CPU_CLK>,
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<&cgu BASE_PERIPH_CLK>, <&cgu BASE_USB0_CLK>,
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<&cgu BASE_USB1_CLK>, <&cgu BASE_SPI_CLK>;
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clock-names = "base_apb3_clk", "base_apb1_clk",
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"base_spifi_clk", "base_cpu_clk",
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"base_periph_clk", "base_usb0_clk",
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"base_usb1_clk", "base_spi_clk";
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};
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ccu2: clock-controller@40052000 {
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compatible = "nxp,lpc1850-ccu";
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reg = <0x40052000 0x1000>;
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#clock-cells = <1>;
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clocks = <&cgu BASE_AUDIO_CLK>, <&cgu BASE_UART3_CLK>,
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<&cgu BASE_UART2_CLK>, <&cgu BASE_UART1_CLK>,
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<&cgu BASE_UART0_CLK>, <&cgu BASE_SSP1_CLK>,
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<&cgu BASE_SSP0_CLK>, <&cgu BASE_SDIO_CLK>;
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clock-names = "base_audio_clk", "base_uart3_clk",
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"base_uart2_clk", "base_uart1_clk",
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"base_uart0_clk", "base_ssp1_clk",
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"base_ssp0_clk", "base_sdio_clk";
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};
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/* A user of CCU brach clocks */
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uart1: serial@40082000 {
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...
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clocks = <&ccu2 CLK_APB0_UART1>, <&ccu1 CLK_CPU_UART1>;
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...
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};
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};