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diff --git a/Documentation/devicetree/bindings/bus/imx-weim.txt b/Documentation/devicetree/bindings/bus/imx-weim.txt new file mode 100644 index 000000000..e7f502070 --- /dev/null +++ b/Documentation/devicetree/bindings/bus/imx-weim.txt @@ -0,0 +1,117 @@ +Device tree bindings for i.MX Wireless External Interface Module (WEIM) + +The term "wireless" does not imply that the WEIM is literally an interface +without wires. It simply means that this module was originally designed for +wireless and mobile applications that use low-power technology. + +The actual devices are instantiated from the child nodes of a WEIM node. + +Required properties: + + - compatible: Should contain one of the following: + "fsl,imx1-weim" + "fsl,imx27-weim" + "fsl,imx51-weim" + "fsl,imx50-weim" + "fsl,imx6q-weim" + - reg: A resource specifier for the register space + (see the example below) + - clocks: the clock, see the example below. + - #address-cells: Must be set to 2 to allow memory address translation + - #size-cells: Must be set to 1 to allow CS address passing + - ranges: Must be set up to reflect the memory layout with four + integer values for each chip-select line in use: + + <cs-number> 0 <physical address of mapping> <size> + +Optional properties: + + - fsl,weim-cs-gpr: For "fsl,imx50-weim" and "fsl,imx6q-weim" type of + devices, it should be the phandle to the system General + Purpose Register controller that contains WEIM CS GPR + register, e.g. IOMUXC_GPR1 on i.MX6Q. IOMUXC_GPR1[11:0] + should be set up as one of the following 4 possible + values depending on the CS space configuration. + + IOMUXC_GPR1[11:0] CS0 CS1 CS2 CS3 + --------------------------------------------- + 05 128M 0M 0M 0M + 033 64M 64M 0M 0M + 0113 64M 32M 32M 0M + 01111 32M 32M 32M 32M + + In case that the property is absent, the reset value or + what bootloader sets up in IOMUXC_GPR1[11:0] will be + used. + + - fsl,burst-clk-enable For "fsl,imx50-weim" and "fsl,imx6q-weim" type of + devices, the presence of this property indicates that + the weim bus should operate in Burst Clock Mode. + + - fsl,continuous-burst-clk Make Burst Clock to output continuous clock. + Without this option Burst Clock will output clock + only when necessary. This takes effect only if + "fsl,burst-clk-enable" is set. + +Timing property for child nodes. It is mandatory, not optional. + + - fsl,weim-cs-timing: The timing array, contains timing values for the + child node. We get the CS indexes from the address + ranges in the child node's "reg" property. + The number of registers depends on the selected chip: + For i.MX1, i.MX21 ("fsl,imx1-weim") there are two + registers: CSxU, CSxL. + For i.MX25, i.MX27, i.MX31 and i.MX35 ("fsl,imx27-weim") + there are three registers: CSCRxU, CSCRxL, CSCRxA. + For i.MX50, i.MX53 ("fsl,imx50-weim"), + i.MX51 ("fsl,imx51-weim") and i.MX6Q ("fsl,imx6q-weim") + there are six registers: CSxGCR1, CSxGCR2, CSxRCR1, + CSxRCR2, CSxWCR1, CSxWCR2. + +Example for an imx6q-sabreauto board, the NOR flash connected to the WEIM: + + weim: weim@21b8000 { + compatible = "fsl,imx6q-weim"; + reg = <0x021b8000 0x4000>; + clocks = <&clks 196>; + #address-cells = <2>; + #size-cells = <1>; + ranges = <0 0 0x08000000 0x08000000>; + fsl,weim-cs-gpr = <&gpr>; + + nor@0,0 { + compatible = "cfi-flash"; + reg = <0 0 0x02000000>; + #address-cells = <1>; + #size-cells = <1>; + bank-width = <2>; + fsl,weim-cs-timing = <0x00620081 0x00000001 0x1c022000 + 0x0000c000 0x1404a38e 0x00000000>; + }; + }; + +Example for an imx6q-based board, a multi-chipselect device connected to WEIM: + +In this case, both chip select 0 and 1 will be configured with the same timing +array values. + + weim: weim@21b8000 { + compatible = "fsl,imx6q-weim"; + reg = <0x021b8000 0x4000>; + clocks = <&clks 196>; + #address-cells = <2>; + #size-cells = <1>; + ranges = <0 0 0x08000000 0x02000000 + 1 0 0x0a000000 0x02000000 + 2 0 0x0c000000 0x02000000 + 3 0 0x0e000000 0x02000000>; + fsl,weim-cs-gpr = <&gpr>; + + acme@0 { + compatible = "acme,whatever"; + reg = <0 0 0x100>, <0 0x400000 0x800>, + <1 0x400000 0x800>; + fsl,weim-cs-timing = <0x024400b1 0x00001010 0x20081100 + 0x00000000 0xa0000240 0x00000000>; + }; + }; |