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Diffstat (limited to 'Documentation/devicetree/bindings/clock/lpc1850-cgu.txt')
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diff --git a/Documentation/devicetree/bindings/clock/lpc1850-cgu.txt b/Documentation/devicetree/bindings/clock/lpc1850-cgu.txt new file mode 100644 index 000000000..2cc32a9a9 --- /dev/null +++ b/Documentation/devicetree/bindings/clock/lpc1850-cgu.txt @@ -0,0 +1,131 @@ +* NXP LPC1850 Clock Generation Unit (CGU) + +The CGU generates multiple independent clocks for the core and the +peripheral blocks of the LPC18xx. Each independent clock is called +a base clock and itself is one of the inputs to the two Clock +Control Units (CCUs) which control the branch clocks to the +individual peripherals. + +The CGU selects the inputs to the clock generators from multiple +clock sources, controls the clock generation, and routes the outputs +of the clock generators through the clock source bus to the output +stages. Each output stage provides an independent clock source and +corresponds to one of the base clocks for the LPC18xx. + + - Above text taken from NXP LPC1850 User Manual. + + +This binding uses the common clock binding: + Documentation/devicetree/bindings/clock/clock-bindings.txt + +Required properties: +- compatible: + Should be "nxp,lpc1850-cgu" +- reg: + Shall define the base and range of the address space + containing clock control registers +- #clock-cells: + Shall have value <1>. The permitted clock-specifier values + are the base clock numbers defined below. +- clocks: + Shall contain a list of phandles for the external input + sources to the CGU. The list shall be in the following + order: xtal, 32khz, enet_rx_clk, enet_tx_clk, gp_clkin. +- clock-indices: + Shall be an ordered list of numbers defining the base clock + number provided by the CGU. +- clock-output-names: + Shall be an ordered list of strings defining the names of + the clocks provided by the CGU. + +Which base clocks that are available on the CGU depends on the +specific LPC part. Base clocks are numbered from 0 to 27. + +Number: Name: Description: + 0 BASE_SAFE_CLK Base safe clock (always on) for WWDT + 1 BASE_USB0_CLK Base clock for USB0 + 2 BASE_PERIPH_CLK Base clock for Cortex-M0SUB subsystem, + SPI, and SGPIO + 3 BASE_USB1_CLK Base clock for USB1 + 4 BASE_CPU_CLK System base clock for ARM Cortex-M core + and APB peripheral blocks #0 and #2 + 5 BASE_SPIFI_CLK Base clock for SPIFI + 6 BASE_SPI_CLK Base clock for SPI + 7 BASE_PHY_RX_CLK Base clock for Ethernet PHY Receive clock + 8 BASE_PHY_TX_CLK Base clock for Ethernet PHY Transmit clock + 9 BASE_APB1_CLK Base clock for APB peripheral block # 1 +10 BASE_APB3_CLK Base clock for APB peripheral block # 3 +11 BASE_LCD_CLK Base clock for LCD +12 BASE_ADCHS_CLK Base clock for ADCHS +13 BASE_SDIO_CLK Base clock for SD/MMC +14 BASE_SSP0_CLK Base clock for SSP0 +15 BASE_SSP1_CLK Base clock for SSP1 +16 BASE_UART0_CLK Base clock for UART0 +17 BASE_UART1_CLK Base clock for UART1 +18 BASE_UART2_CLK Base clock for UART2 +19 BASE_UART3_CLK Base clock for UART3 +20 BASE_OUT_CLK Base clock for CLKOUT pin +24-21 - Reserved +25 BASE_AUDIO_CLK Base clock for audio system (I2S) +26 BASE_CGU_OUT0_CLK Base clock for CGU_OUT0 clock output +27 BASE_CGU_OUT1_CLK Base clock for CGU_OUT1 clock output + +BASE_PERIPH_CLK and BASE_SPI_CLK is only available on LPC43xx. +BASE_ADCHS_CLK is only available on LPC4370. + + +Example board file: + +/ { + clocks { + xtal: xtal { + compatible = "fixed-clock"; + #clock-cells = <0>; + clock-frequency = <12000000>; + }; + + xtal32: xtal32 { + compatible = "fixed-clock"; + #clock-cells = <0>; + clock-frequency = <32768>; + }; + + enet_rx_clk: enet_rx_clk { + compatible = "fixed-clock"; + #clock-cells = <0>; + clock-frequency = <0>; + clock-output-names = "enet_rx_clk"; + }; + + enet_tx_clk: enet_tx_clk { + compatible = "fixed-clock"; + #clock-cells = <0>; + clock-frequency = <0>; + clock-output-names = "enet_tx_clk"; + }; + + gp_clkin: gp_clkin { + compatible = "fixed-clock"; + #clock-cells = <0>; + clock-frequency = <0>; + clock-output-names = "gp_clkin"; + }; + }; + + soc { + cgu: clock-controller@40050000 { + compatible = "nxp,lpc1850-cgu"; + reg = <0x40050000 0x1000>; + #clock-cells = <1>; + clocks = <&xtal>, <&creg_clk 1>, <&enet_rx_clk>, <&enet_tx_clk>, <&gp_clkin>; + }; + + /* A CGU and CCU clock consumer */ + lcdc: lcdc@40008000 { + ... + clocks = <&cgu BASE_LCD_CLK>, <&ccu1 CLK_CPU_LCD>; + clock-names = "clcdclk", "apb_pclk"; + ... + }; + }; +}; |