| Tom Rini | 53633a8 | 2024-02-29 12:33:36 -0500 | [diff] [blame] | 1 | Lantiq SoC External Bus memory mapped GPIO controller |
| 2 | |
| 3 | By attaching hardware latches to the EBU it is possible to create output |
| 4 | only gpios. This driver configures a special memory address, which when |
| 5 | written to outputs 16 bit to the latches. |
| 6 | |
| 7 | The node describing the memory mapped GPIOs needs to be a child of the node |
| 8 | describing the "lantiq,localbus". |
| 9 | |
| 10 | Required properties: |
| 11 | - compatible : Should be "lantiq,gpio-mm-lantiq" |
| 12 | - reg : Address and length of the register set for the device |
| 13 | - #gpio-cells : Should be two. The first cell is the pin number and |
| 14 | the second cell is used to specify optional parameters (currently |
| 15 | unused). |
| 16 | - gpio-controller : Marks the device node as a gpio controller. |
| 17 | |
| 18 | Optional properties: |
| 19 | - lantiq,shadow : The default value that we shall assume as already set on the |
| 20 | shift register cascade. |
| 21 | |
| 22 | Example: |
| 23 | |
| 24 | localbus@0 { |
| 25 | #address-cells = <2>; |
| 26 | #size-cells = <1>; |
| 27 | ranges = <0 0 0x0 0x3ffffff /* addrsel0 */ |
| 28 | 1 0 0x4000000 0x4000010>; /* addsel1 */ |
| 29 | compatible = "lantiq,localbus", "simple-bus"; |
| 30 | |
| 31 | gpio_mm0: gpio@4000000 { |
| 32 | compatible = "lantiq,gpio-mm"; |
| 33 | reg = <1 0x0 0x10>; |
| 34 | gpio-controller; |
| 35 | #gpio-cells = <2>; |
| 36 | lantiq,shadow = <0x77f> |
| 37 | }; |
| 38 | } |