1Broadcom BCM2835 GPIO (and pinmux) controller 2 3The BCM2835 GPIO module is a combined GPIO controller, (GPIO) interrupt 4controller, and pinmux/control device. 5 6Required properties: 7- compatible: "brcm,bcm2835-gpio" 8- reg: Should contain the physical address of the GPIO module's registers. 9- gpio-controller: Marks the device node as a GPIO controller. 10- #gpio-cells : Should be two. The first cell is the pin number and the 11 second cell is used to specify optional parameters: 12 - bit 0 specifies polarity (0 for normal, 1 for inverted) 13- interrupts : The interrupt outputs from the controller. One interrupt per 14 individual bank followed by the "all banks" interrupt. 15- interrupt-controller: Marks the device node as an interrupt controller. 16- #interrupt-cells : Should be 2. 17 The first cell is the GPIO number. 18 The second cell is used to specify flags: 19 bits[3:0] trigger type and level flags: 20 1 = low-to-high edge triggered. 21 2 = high-to-low edge triggered. 22 4 = active high level-sensitive. 23 8 = active low level-sensitive. 24 Valid combinations are 1, 2, 3, 4, 8. 25 26Please refer to ../gpio/gpio.txt for a general description of GPIO bindings. 27 28Please refer to pinctrl-bindings.txt in this directory for details of the 29common pinctrl bindings used by client devices, including the meaning of the 30phrase "pin configuration node". 31 32Each pin configuration node lists the pin(s) to which it applies, and one or 33more of the mux function to select on those pin(s), and pull-up/down 34configuration. Each subnode only affects those parameters that are explicitly 35listed. In other words, a subnode that lists only a mux function implies no 36information about any pull configuration. Similarly, a subnode that lists only 37a pul parameter implies no information about the mux function. 38 39Required subnode-properties: 40- brcm,pins: An array of cells. Each cell contains the ID of a pin. Valid IDs 41 are the integer GPIO IDs; 0==GPIO0, 1==GPIO1, ... 53==GPIO53. 42 43Optional subnode-properties: 44- brcm,function: Integer, containing the function to mux to the pin(s): 45 0: GPIO in 46 1: GPIO out 47 2: alt5 48 3: alt4 49 4: alt0 50 5: alt1 51 6: alt2 52 7: alt3 53- brcm,pull: Integer, representing the pull-down/up to apply to the pin(s): 54 0: none 55 1: down 56 2: up 57 58Each of brcm,function and brcm,pull may contain either a single value which 59will be applied to all pins in brcm,pins, or 1 value for each entry in 60brcm,pins. 61 62Example: 63 64 gpio: gpio { 65 compatible = "brcm,bcm2835-gpio"; 66 reg = <0x2200000 0xb4>; 67 interrupts = <2 17>, <2 19>, <2 18>, <2 20>; 68 69 gpio-controller; 70 #gpio-cells = <2>; 71 72 interrupt-controller; 73 #interrupt-cells = <2>; 74 }; 75