From c3665006eccd7d2326b7dc2c1d5ff2f545dee6c5 Mon Sep 17 00:00:00 2001 From: Thomas Abraham Date: Mon, 17 Sep 2012 18:16:43 +0000 Subject: mmc: dw_mmc: add support for exynos specific implementation of dw-mshc Samsung Exynos SoC's extend the dw-mshc controller for additional clock and bus control. Add support for these extensions and include provide device tree based discovery suppory as well. Signed-off-by: Thomas Abraham Acked-by: Will Newton Signed-off-by: Chris Ball --- .../devicetree/bindings/mmc/exynos-dw-mshc.txt | 87 ++++++++++++++++++++++ 1 file changed, 87 insertions(+) create mode 100644 Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt (limited to 'Documentation') 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 000000000000..792768953330 --- /dev/null +++ b/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt @@ -0,0 +1,87 @@ +* Samsung Exynos specific extensions to the Synopsis Designware Mobile + Storage Host Controller + +The Synopsis 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 Synopsis dw mshc controller properties described +by synposis-dw-mshc.txt and the properties used by the Samsung Exynos specific +extensions to the Synopsis Designware Mobile Storage Host Controller. + +Required Properties: + +* compatible: should be + - "samsung,exynos4210-dw-mshc": for controllers with Samsung Exynos4210 + specific extentions. + - "samsung,exynos4412-dw-mshc": for controllers with Samsung Exynos4412 + specific extentions. + - "samsung,exynos5250-dw-mshc": for controllers with Samsung Exynos5250 + specific extentions. + +* 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. + + 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. + +Required properties for a slot: + +* 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. + +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>; + supports-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>; + + slot@0 { + reg = <0>; + bus-width = <8>; + gpios = <&gpc0 0 2 0 3>, <&gpc0 1 2 0 3>, + <&gpc1 0 2 3 3>, <&gpc1 1 2 3 3>, + <&gpc1 2 2 3 3>, <&gpc1 3 2 3 3>, + <&gpc0 3 2 3 3>, <&gpc0 4 2 3 3>, + <&gpc0 5 2 3 3>, <&gpc0 6 2 3 3>; + }; + }; -- cgit v1.2.3