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Diffstat (limited to 'Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt')
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diff --git a/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt new file mode 100644 index 000000000..aad984427 --- /dev/null +++ b/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt @@ -0,0 +1,93 @@ +* Samsung Exynos specific extensions to the Synopsys Designware Mobile + Storage Host Controller + +The Synopsys designware mobile storage host controller is used to interface +a SoC with storage medium such as eMMC or SD/MMC cards. This file documents +differences between the core Synopsys dw mshc controller properties described +by synopsys-dw-mshc.txt and the properties used by the Samsung Exynos specific +extensions to the Synopsys Designware Mobile Storage Host Controller. + +Required Properties: + +* compatible: should be + - "samsung,exynos4210-dw-mshc": for controllers with Samsung Exynos4210 + specific extensions. + - "samsung,exynos4412-dw-mshc": for controllers with Samsung Exynos4412 + specific extensions. + - "samsung,exynos5250-dw-mshc": for controllers with Samsung Exynos5250 + specific extensions. + - "samsung,exynos5420-dw-mshc": for controllers with Samsung Exynos5420 + specific extensions. + - "samsung,exynos7-dw-mshc": for controllers with Samsung Exynos7 + specific extensions. + - "samsung,exynos7-dw-mshc-smu": for controllers with Samsung Exynos7 + specific extensions having an SMU. + +* samsung,dw-mshc-ciu-div: Specifies the divider value for the card interface + unit (ciu) clock. This property is applicable only for Exynos5 SoC's and + ignored for Exynos4 SoC's. The valid range of divider value is 0 to 7. + +* samsung,dw-mshc-sdr-timing: Specifies the value of CIU clock phase shift value + in transmit mode and CIU clock phase shift value in receive mode for single + data rate mode operation. Refer notes below for the order of the cells and the + valid values. + +* samsung,dw-mshc-ddr-timing: Specifies the value of CUI clock phase shift value + in transmit mode and CIU clock phase shift value in receive mode for double + data rate mode operation. Refer notes below for the order of the cells and the + valid values. +* samsung,dw-mshc-hs400-timing: Specifies the value of CIU TX and RX clock phase + shift value for hs400 mode operation. + + Notes for the sdr-timing and ddr-timing values: + + The order of the cells should be + - First Cell: CIU clock phase shift value for tx mode. + - Second Cell: CIU clock phase shift value for rx mode. + + Valid values for SDR and DDR CIU clock timing for Exynos5250: + - valid value for tx phase shift and rx phase shift is 0 to 7. + - when CIU clock divider value is set to 3, all possible 8 phase shift + values can be used. + - if CIU clock divider value is 0 (that is divide by 1), both tx and rx + phase shift clocks should be 0. + +* samsung,read-strobe-delay: RCLK (Data strobe) delay to control HS400 mode + (Latency value for delay line in Read path) + +Required properties for a slot (Deprecated - Recommend to use one slot per host): + +* gpios: specifies a list of gpios used for command, clock and data bus. The + first gpio is the command line and the second gpio is the clock line. The + rest of the gpios (depending on the bus-width property) are the data lines in + no particular order. The format of the gpio specifier depends on the gpio + controller. +(Deprecated - Refer to Documentation/devicetree/binding/pinctrl/samsung-pinctrl.txt) + +Example: + + The MSHC controller node can be split into two portions, SoC specific and + board specific portions as listed below. + + dwmmc0@12200000 { + compatible = "samsung,exynos5250-dw-mshc"; + reg = <0x12200000 0x1000>; + interrupts = <0 75 0>; + #address-cells = <1>; + #size-cells = <0>; + }; + + dwmmc0@12200000 { + num-slots = <1>; + cap-mmc-highspeed; + cap-sd-highspeed; + broken-cd; + fifo-depth = <0x80>; + card-detect-delay = <200>; + samsung,dw-mshc-ciu-div = <3>; + samsung,dw-mshc-sdr-timing = <2 3>; + samsung,dw-mshc-ddr-timing = <1 2>; + samsung,dw-mshc-hs400-timing = <0 2>; + samsung,read-strobe-delay = <90>; + bus-width = <8>; + }; |