xref: /rk3399_rockchip-uboot/doc/device-tree-bindings/exynos/dwmmc.txt (revision dab5e3469d294a4e1ffed8407d296a78e02cc01f)
1*7d3ca0f8SJaehoon Chung* Exynos DWC_mobile_storage
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3*7d3ca0f8SJaehoon ChungThe Exynos provides DWC_mobile_storage interface which supports
407eb5f9cSAmar. Embedded Multimedia Cards (EMMC-version 4.5)
507eb5f9cSAmar. Secure Digital memory (SD mem-version 2.0)
607eb5f9cSAmar. Secure Digital I/O (SDIO-version 3.0)
707eb5f9cSAmar. Consumer Electronics Advanced Transport Architecture (CE-ATA-version 1.1)
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9*7d3ca0f8SJaehoon ChungThe Exynos DWC_mobile_storage provides four channels.
1007eb5f9cSAmarSOC specific and Board specific properties are channel specific.
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1207eb5f9cSAmarRequired SoC Specific Properties:
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1407eb5f9cSAmar- compatible: should be
15*7d3ca0f8SJaehoon Chung	- samsung,exynos-dwmmc: for exynos platforms
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1707eb5f9cSAmar- reg: physical base address of the controller and length of memory mapped
1807eb5f9cSAmar	region.
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2007eb5f9cSAmar- interrupts: The interrupt number to the cpu.
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2207eb5f9cSAmarRequired Board Specific Properties:
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2407eb5f9cSAmar- #address-cells: should be 1.
2507eb5f9cSAmar- #size-cells: should be 0.
2607eb5f9cSAmar- samsung,bus-width: The width of the bus used to interface the devices
2707eb5f9cSAmar	supported by DWC_mobile_storage (SD-MMC/EMMC/SDIO).
2807eb5f9cSAmar	. Typically the bus width is 4 or 8.
2907eb5f9cSAmar- samsung,timing: The timing values to be written into the
3007eb5f9cSAmar	Drv/sample clock selection register of corresponding channel.
3107eb5f9cSAmar	. It is comprised of 3 values corresponding to the 3 fileds
3207eb5f9cSAmar	  'SelClk_sample', 'SelClk_drv' and 'DIVRATIO' of CLKSEL register.
3307eb5f9cSAmar	. SelClk_sample: Select sample clock among 8 shifted clocks.
3407eb5f9cSAmar	. SelClk_drv: Select drv clock among 8 shifted clocks.
3507eb5f9cSAmar	. DIVRATIO: Clock Divide ratio select.
3607eb5f9cSAmar	. The above 3 values are used by the clock phase shifter.
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3807eb5f9cSAmarExample:
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4007eb5f9cSAmarmmc@12200000 {
4107eb5f9cSAmar	samsung,bus-width = <8>;
4207eb5f9cSAmar	samsung,timing = <1 3 3>;
4307eb5f9cSAmar	samsung,removable = <1>;
4407eb5f9cSAmar}
4507eb5f9cSAmarIn the above example,
4607eb5f9cSAmar	. The bus width is 8
4707eb5f9cSAmar	. Timing is comprised of 3 values as explained below
4807eb5f9cSAmar		1 - SelClk_sample
4907eb5f9cSAmar		3 - SelClk_drv
5007eb5f9cSAmar		3 - DIVRATIO
5107eb5f9cSAmar	. The 'removable' flag indicates whether the the particilar device
5207eb5f9cSAmar	  cannot be removed (always present) or it is a removable device.
5307eb5f9cSAmar		1 - Indicates that the device is removable.
5407eb5f9cSAmar		0 - Indicates that the device cannot be removed.
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