75 lines
2.6 KiB
Plaintext
75 lines
2.6 KiB
Plaintext
Broadcom BCM2835 GPIO (and pinmux) controller
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The BCM2835 GPIO module is a combined GPIO controller, (GPIO) interrupt
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controller, and pinmux/control device.
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Required properties:
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- compatible: "brcm,bcm2835-gpio"
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- reg: Should contain the physical address of the GPIO module's registers.
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- gpio-controller: Marks the device node as a GPIO controller.
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- #gpio-cells : Should be two. The first cell is the pin number and the
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second cell is used to specify optional parameters:
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- bit 0 specifies polarity (0 for normal, 1 for inverted)
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- interrupts : The interrupt outputs from the controller. One interrupt per
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individual bank followed by the "all banks" interrupt.
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- interrupt-controller: Marks the device node as an interrupt controller.
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- #interrupt-cells : Should be 2.
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The first cell is the GPIO number.
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The second cell is used to specify flags:
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bits[3:0] trigger type and level flags:
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1 = low-to-high edge triggered.
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2 = high-to-low edge triggered.
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4 = active high level-sensitive.
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8 = active low level-sensitive.
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Valid combinations are 1, 2, 3, 4, 8.
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Please refer to ../gpio/gpio.txt for a general description of GPIO bindings.
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Please refer to pinctrl-bindings.txt in this directory for details of the
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common pinctrl bindings used by client devices, including the meaning of the
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phrase "pin configuration node".
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Each pin configuration node lists the pin(s) to which it applies, and one or
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more of the mux function to select on those pin(s), and pull-up/down
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configuration. Each subnode only affects those parameters that are explicitly
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listed. In other words, a subnode that lists only a mux function implies no
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information about any pull configuration. Similarly, a subnode that lists only
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a pul parameter implies no information about the mux function.
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Required subnode-properties:
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- brcm,pins: An array of cells. Each cell contains the ID of a pin. Valid IDs
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are the integer GPIO IDs; 0==GPIO0, 1==GPIO1, ... 53==GPIO53.
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Optional subnode-properties:
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- brcm,function: Integer, containing the function to mux to the pin(s):
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0: GPIO in
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1: GPIO out
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2: alt5
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3: alt4
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4: alt0
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5: alt1
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6: alt2
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7: alt3
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- brcm,pull: Integer, representing the pull-down/up to apply to the pin(s):
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0: none
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1: down
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2: up
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Each of brcm,function and brcm,pull may contain either a single value which
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will be applied to all pins in brcm,pins, or 1 value for each entry in
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brcm,pins.
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Example:
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gpio: gpio {
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compatible = "brcm,bcm2835-gpio";
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reg = <0x2200000 0xb4>;
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interrupts = <2 17>, <2 19>, <2 18>, <2 20>;
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gpio-controller;
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#gpio-cells = <2>;
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interrupt-controller;
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#interrupt-cells = <2>;
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};
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