102 lines
2.2 KiB
Plaintext
102 lines
2.2 KiB
Plaintext
$FreeBSD$
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GPIO configuration.
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===================
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1. Properties for GPIO Controllers
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1.1 #gpio-cells
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Property: #gpio-cells
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Value type: <u32>
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Description: The #gpio-cells property defines the number of cells required
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to encode a gpio specifier.
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1.2 gpio-controller
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Property: gpio-controller
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Value type: <empty>
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Description: The presence of a gpio-controller property defines a node as a
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GPIO controller node.
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1.3 pin-count
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Property: pin-count
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Value type: <u32>
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Description: The pin-count property defines the number of GPIO pins.
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1.4 Example
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GPIO: gpio@10100 {
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#gpio-cells = <3>;
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compatible = "mrvl,gpio";
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reg = <0x10100 0x20>;
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gpio-controller;
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interrupts = <6 7 8 9>;
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interrupt-parent = <&PIC>;
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pin-count = <50>
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};
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2. Properties for GPIO consumer nodes.
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2.1 gpios
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Property: gpios
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Value type: <prop-encoded-array> encoded as arbitrary number of GPIO
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specifiers.
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Description: The gpios property of a device node defines the GPIO or GPIOs
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that are used by the device. The value of the gpios property
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consists of an arbitrary number of GPIO specifiers.
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The first cell of the GPIO specifier is phandle of the node's
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parent GPIO controller and remaining cells are defined by the
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binding describing the GPIO parent, typically include
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information like pin number, direction and various flags.
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Example:
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gpios = <&GPIO 0 1 0 /* GPIO[0]: IN, NONE */
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&GPIO 1 2 0>; /* GPIO[1]: OUT, NONE */
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3. "mrvl,gpio" controller GPIO specifier
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<phandle pin dir flags>
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pin: 0-MAX GPIO pin number.
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dir:
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1 IN Input direction.
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2 OUT Output direction.
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flags:
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0x0000---- IN_NONE
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0x0001---- IN_POL_LOW Polarity low (active-low).
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0x0002---- IN_IRQ_EDGE Interrupt, edge triggered.
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0x0004---- IN_IRQ_LEVEL Interrupt, level triggered.
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0x----0000 OUT_NONE
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0x----0001 OUT_BLINK Blink on the pin.
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0x----0002 OUT_OPEN_DRAIN Open drain output line.
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0x----0004 OUT_OPEN_SRC Open source output line.
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Example:
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gpios = <&GPIO 0 1 0x00000000 /* GPIO[0]: IN */
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&GPIO 1 2 0x00000000 /* GPIO[1]: OUT */
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&GPIO 2 1 0x00020000 /* GPIO[2]: IN, IRQ (edge) */
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&GPIO 3 1 0x00040000 /* GPIO[3]: IN, IRQ (level) */
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...
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&GPIO 10 2 0x00000001>; /* GPIO[10]: OUT, blink */
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