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https://git.hardenedbsd.org/hardenedbsd/HardenedBSD.git
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106 lines
2.6 KiB
Plaintext
106 lines
2.6 KiB
Plaintext
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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 /* GPIO[0]: FLAGS */
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&GPIO 1 2>; /* GPIO[1]: FLAGS */
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3. GPIO controller specifier
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<phandle pin dir flags>
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pin: 0-MAX GPIO pin number.
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flags:
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Available flags are listed in sys/conf.h. Following combination
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can be supported by the controller. For details please refer
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to controller's GPIO reference manual.
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GPIO_PIN_INPUT 0x0001 Input direction
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GPIO_PIN_OUTPUT 0x0002 Output direction
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GPIO_PIN_OPENDRAIN 0x0004 Open-drain output
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GPIO_PIN_OPENSOURCE 0x0008 Open-source output
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GPIO_PIN_PUSHPULL 0x0010 Push-pull output
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GPIO_PIN_TRISTATE 0x0020 Output disabled
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GPIO_PIN_PULLUP 0x0040 Internal pull-up enabled
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GPIO_PIN_PULLDOWN 0x0080 Internal pull-down enabled
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GPIO_PIN_INVIN 0x0100 Invert input
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GPIO_PIN_INVOUT 0x0200 Invert output
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GPIO_PIN_PULSATE 0x0400 Pulsate in hardware
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GPIO_PIN_IRQ_POL_EDG 0x0800 IRQ active single edge
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GPIO_PIN_IRQ_POL_DBL 0x1000 IRQ active double edge
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GPIO_PIN_IRQ_POL_LVL 0x2000 IRQ active level
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GPIO_PIN_IRQ_DEBOUNCE 0x4000 Debounce on IRQ pin
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Example:
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gpios = <&GPIO 0 0x00000001 /* GPIO[0]: IN */
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&GPIO 1 0x00000002 /* GPIO[1]: OUT */
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&GPIO 2 0x00000801 /* GPIO[2]: IN, IRQ (edge) */
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&GPIO 3 0x00004001 /* GPIO[3]: IN, IRQ (level) */
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...
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&GPIO 10 0x00000401>; /* GPIO[10]: OUT, blink */
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