xref: /OK3568_Linux_fs/u-boot/doc/device-tree-bindings/exynos/dwmmc.txt (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun* Exynos DWC_mobile_storage
2*4882a593Smuzhiyun
3*4882a593SmuzhiyunThe Exynos provides DWC_mobile_storage interface which supports
4*4882a593Smuzhiyun. Embedded Multimedia Cards (EMMC-version 4.5)
5*4882a593Smuzhiyun. Secure Digital memory (SD mem-version 2.0)
6*4882a593Smuzhiyun. Secure Digital I/O (SDIO-version 3.0)
7*4882a593Smuzhiyun. Consumer Electronics Advanced Transport Architecture (CE-ATA-version 1.1)
8*4882a593Smuzhiyun
9*4882a593SmuzhiyunThe Exynos DWC_mobile_storage provides four channels.
10*4882a593SmuzhiyunSOC specific and Board specific properties are channel specific.
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12*4882a593SmuzhiyunRequired SoC Specific Properties:
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun- compatible: should be
15*4882a593Smuzhiyun	- samsung,exynos-dwmmc: for exynos platforms
16*4882a593Smuzhiyun
17*4882a593Smuzhiyun- reg: physical base address of the controller and length of memory mapped
18*4882a593Smuzhiyun	region.
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun- interrupts: The interrupt number to the cpu.
21*4882a593Smuzhiyun
22*4882a593SmuzhiyunRequired Board Specific Properties:
23*4882a593Smuzhiyun
24*4882a593Smuzhiyun- #address-cells: should be 1.
25*4882a593Smuzhiyun- #size-cells: should be 0.
26*4882a593Smuzhiyun- samsung,bus-width: The width of the bus used to interface the devices
27*4882a593Smuzhiyun	supported by DWC_mobile_storage (SD-MMC/EMMC/SDIO).
28*4882a593Smuzhiyun	. Typically the bus width is 4 or 8.
29*4882a593Smuzhiyun- samsung,timing: The timing values to be written into the
30*4882a593Smuzhiyun	Drv/sample clock selection register of corresponding channel.
31*4882a593Smuzhiyun	. It is comprised of 3 values corresponding to the 3 fileds
32*4882a593Smuzhiyun	  'SelClk_sample', 'SelClk_drv' and 'DIVRATIO' of CLKSEL register.
33*4882a593Smuzhiyun	. SelClk_sample: Select sample clock among 8 shifted clocks.
34*4882a593Smuzhiyun	. SelClk_drv: Select drv clock among 8 shifted clocks.
35*4882a593Smuzhiyun	. DIVRATIO: Clock Divide ratio select.
36*4882a593Smuzhiyun	. The above 3 values are used by the clock phase shifter.
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38*4882a593SmuzhiyunExample:
39*4882a593Smuzhiyun
40*4882a593Smuzhiyunmmc@12200000 {
41*4882a593Smuzhiyun	samsung,bus-width = <8>;
42*4882a593Smuzhiyun	samsung,timing = <1 3 3>;
43*4882a593Smuzhiyun	samsung,removable = <1>;
44*4882a593Smuzhiyun}
45*4882a593SmuzhiyunIn the above example,
46*4882a593Smuzhiyun	. The bus width is 8
47*4882a593Smuzhiyun	. Timing is comprised of 3 values as explained below
48*4882a593Smuzhiyun		1 - SelClk_sample
49*4882a593Smuzhiyun		3 - SelClk_drv
50*4882a593Smuzhiyun		3 - DIVRATIO
51*4882a593Smuzhiyun	. The 'removable' flag indicates whether the the particilar device
52*4882a593Smuzhiyun	  cannot be removed (always present) or it is a removable device.
53*4882a593Smuzhiyun		1 - Indicates that the device is removable.
54*4882a593Smuzhiyun		0 - Indicates that the device cannot be removed.
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