1*35ea1bfdSSimon GlassSamsung Exynos4 GPIO Controller 2*35ea1bfdSSimon Glass 3*35ea1bfdSSimon GlassRequired properties: 4*35ea1bfdSSimon Glass- compatible: Compatible property value should be "samsung,exynos4-gpio>". 5*35ea1bfdSSimon Glass 6*35ea1bfdSSimon Glass- reg: Physical base address of the controller and length of memory mapped 7*35ea1bfdSSimon Glass region. 8*35ea1bfdSSimon Glass 9*35ea1bfdSSimon Glass- #gpio-cells: Should be 4. The syntax of the gpio specifier used by client nodes 10*35ea1bfdSSimon Glass should be the following with values derived from the SoC user manual. 11*35ea1bfdSSimon Glass <[phandle of the gpio controller node] 12*35ea1bfdSSimon Glass [pin number within the gpio controller] 13*35ea1bfdSSimon Glass [mux function] 14*35ea1bfdSSimon Glass [flags and pull up/down] 15*35ea1bfdSSimon Glass [drive strength]> 16*35ea1bfdSSimon Glass 17*35ea1bfdSSimon Glass Values for gpio specifier: 18*35ea1bfdSSimon Glass - Pin number: is a value between 0 to 7. 19*35ea1bfdSSimon Glass - Flags and Pull Up/Down: 0 - Pull Up/Down Disabled. 20*35ea1bfdSSimon Glass 1 - Pull Down Enabled. 21*35ea1bfdSSimon Glass 3 - Pull Up Enabled. 22*35ea1bfdSSimon Glass Bit 16 (0x00010000) - Input is active low. 23*35ea1bfdSSimon Glass - Drive Strength: 0 - 1x, 24*35ea1bfdSSimon Glass 1 - 3x, 25*35ea1bfdSSimon Glass 2 - 2x, 26*35ea1bfdSSimon Glass 3 - 4x 27*35ea1bfdSSimon Glass 28*35ea1bfdSSimon Glass- gpio-controller: Specifies that the node is a gpio controller. 29*35ea1bfdSSimon Glass- #address-cells: should be 1. 30*35ea1bfdSSimon Glass- #size-cells: should be 1. 31*35ea1bfdSSimon Glass 32*35ea1bfdSSimon GlassExample: 33*35ea1bfdSSimon Glass 34*35ea1bfdSSimon Glass gpa0: gpio-controller@11400000 { 35*35ea1bfdSSimon Glass #address-cells = <1>; 36*35ea1bfdSSimon Glass #size-cells = <1>; 37*35ea1bfdSSimon Glass compatible = "samsung,exynos4-gpio"; 38*35ea1bfdSSimon Glass reg = <0x11400000 0x20>; 39*35ea1bfdSSimon Glass #gpio-cells = <4>; 40*35ea1bfdSSimon Glass gpio-controller; 41*35ea1bfdSSimon Glass }; 42