| Simon Glass | 46db51f | 2015-01-05 20:05:24 -0700 | [diff] [blame^] | 1 | Samsung Exynos4 GPIO Controller |
| 2 | |
| 3 | Required properties: |
| 4 | - compatible: Compatible property value should be "samsung,exynos4-gpio>". |
| 5 | |
| 6 | - reg: Physical base address of the controller and length of memory mapped |
| 7 | region. |
| 8 | |
| 9 | - #gpio-cells: Should be 4. The syntax of the gpio specifier used by client nodes |
| 10 | should be the following with values derived from the SoC user manual. |
| 11 | <[phandle of the gpio controller node] |
| 12 | [pin number within the gpio controller] |
| 13 | [mux function] |
| 14 | [flags and pull up/down] |
| 15 | [drive strength]> |
| 16 | |
| 17 | Values for gpio specifier: |
| 18 | - Pin number: is a value between 0 to 7. |
| 19 | - Flags and Pull Up/Down: 0 - Pull Up/Down Disabled. |
| 20 | 1 - Pull Down Enabled. |
| 21 | 3 - Pull Up Enabled. |
| 22 | Bit 16 (0x00010000) - Input is active low. |
| 23 | - Drive Strength: 0 - 1x, |
| 24 | 1 - 3x, |
| 25 | 2 - 2x, |
| 26 | 3 - 4x |
| 27 | |
| 28 | - gpio-controller: Specifies that the node is a gpio controller. |
| 29 | - #address-cells: should be 1. |
| 30 | - #size-cells: should be 1. |
| 31 | |
| 32 | Example: |
| 33 | |
| 34 | gpa0: gpio-controller@11400000 { |
| 35 | #address-cells = <1>; |
| 36 | #size-cells = <1>; |
| 37 | compatible = "samsung,exynos4-gpio"; |
| 38 | reg = <0x11400000 0x20>; |
| 39 | #gpio-cells = <4>; |
| 40 | gpio-controller; |
| 41 | }; |