1Rockchip RK3328 GRF (General Register Files) GPIO controller. 2 3In Rockchip RK3328, the output only GPIO_MUTE pin, originally for codec mute 4control, can also be used for general purpose. It is manipulated by the 5GRF_SOC_CON10 register in GRF. Aside from the GPIO_MUTE pin, the HDMI pins can 6also be set in the same way. 7 8Currently this GPIO controller only supports the mute pin. If needed in the 9future, the HDMI pins support can also be added. 10 11Required properties: 12- compatible: Should contain "rockchip,rk3328-grf-gpio". 13- gpio-controller: Marks the device node as a gpio controller. 14- #gpio-cells: Should be 2. The first cell is the pin number and 15 the second cell is used to specify the gpio polarity: 16 0 = Active high, 17 1 = Active low. 18 19Example: 20 21 grf: syscon@ff100000 { 22 compatible = "rockchip,rk3328-grf", "syscon", "simple-mfd"; 23 24 grf_gpio: grf-gpio { 25 compatible = "rockchip,rk3328-grf-gpio"; 26 gpio-controller; 27 #gpio-cells = <2>; 28 }; 29 }; 30 31Note: The grf_gpio node should be declared as the child of the GRF (General 32Register File) node. The GPIO_MUTE pin is referred to as <&grf_gpio 0>. 33