1*4882a593SmuzhiyunSamsung Exynos4 GPIO Controller 2*4882a593Smuzhiyun 3*4882a593SmuzhiyunRequired properties: 4*4882a593Smuzhiyun- compatible: Compatible property value should be "samsung,exynos4-gpio>". 5*4882a593Smuzhiyun 6*4882a593Smuzhiyun- reg: Physical base address of the controller and length of memory mapped 7*4882a593Smuzhiyun region. 8*4882a593Smuzhiyun 9*4882a593Smuzhiyun- #gpio-cells: Should be 4. The syntax of the gpio specifier used by client nodes 10*4882a593Smuzhiyun should be the following with values derived from the SoC user manual. 11*4882a593Smuzhiyun <[phandle of the gpio controller node] 12*4882a593Smuzhiyun [pin number within the gpio controller] 13*4882a593Smuzhiyun [mux function] 14*4882a593Smuzhiyun [flags and pull up/down] 15*4882a593Smuzhiyun [drive strength]> 16*4882a593Smuzhiyun 17*4882a593Smuzhiyun Values for gpio specifier: 18*4882a593Smuzhiyun - Pin number: is a value between 0 to 7. 19*4882a593Smuzhiyun - Flags and Pull Up/Down: 0 - Pull Up/Down Disabled. 20*4882a593Smuzhiyun 1 - Pull Down Enabled. 21*4882a593Smuzhiyun 3 - Pull Up Enabled. 22*4882a593Smuzhiyun Bit 16 (0x00010000) - Input is active low. 23*4882a593Smuzhiyun - Drive Strength: 0 - 1x, 24*4882a593Smuzhiyun 1 - 3x, 25*4882a593Smuzhiyun 2 - 2x, 26*4882a593Smuzhiyun 3 - 4x 27*4882a593Smuzhiyun 28*4882a593Smuzhiyun- gpio-controller: Specifies that the node is a gpio controller. 29*4882a593Smuzhiyun- #address-cells: should be 1. 30*4882a593Smuzhiyun- #size-cells: should be 1. 31*4882a593Smuzhiyun 32*4882a593SmuzhiyunExample: 33*4882a593Smuzhiyun 34*4882a593Smuzhiyun gpa0: gpio-controller@11400000 { 35*4882a593Smuzhiyun #address-cells = <1>; 36*4882a593Smuzhiyun #size-cells = <1>; 37*4882a593Smuzhiyun compatible = "samsung,exynos4-gpio"; 38*4882a593Smuzhiyun reg = <0x11400000 0x20>; 39*4882a593Smuzhiyun #gpio-cells = <4>; 40*4882a593Smuzhiyun gpio-controller; 41*4882a593Smuzhiyun }; 42