215 lines
7.8 KiB
YAML
215 lines
7.8 KiB
YAML
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# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/gpio/nvidia,tegra186-gpio.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: NVIDIA Tegra GPIO Controller (Tegra186 and later)
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maintainers:
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- Thierry Reding <thierry.reding@gmail.com>
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- Jon Hunter <jonathanh@nvidia.com>
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description: |
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Tegra186 contains two GPIO controllers; a main controller and an "AON"
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controller. This binding document applies to both controllers. The register
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layouts for the controllers share many similarities, but also some
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significant differences. Hence, this document describes closely related but
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different bindings and compatible values.
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The Tegra186 GPIO controller allows software to set the IO direction of,
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and read/write the value of, numerous GPIO signals. Routing of GPIO signals
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to package balls is under the control of a separate pin controller hardware
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block. Two major sets of registers exist:
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a) Security registers, which allow configuration of allowed access to the
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GPIO register set. These registers exist in a single contiguous block
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of physical address space. The size of this block, and the security
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features available, varies between the different GPIO controllers.
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Access to this set of registers is not necessary in all circumstances.
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Code that wishes to configure access to the GPIO registers needs access
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to these registers to do so. Code which simply wishes to read or write
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GPIO data does not need access to these registers.
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b) GPIO registers, which allow manipulation of the GPIO signals. In some
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GPIO controllers, these registers are exposed via multiple "physical
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aliases" in address space, each of which access the same underlying
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state. See the hardware documentation for rationale. Any particular
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GPIO client is expected to access just one of these physical aliases.
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Tegra HW documentation describes a unified naming convention for all GPIOs
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implemented by the SoC. Each GPIO is assigned to a port, and a port may
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control a number of GPIOs. Thus, each GPIO is named according to an
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alphabetical port name and an integer GPIO name within the port. For
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example, GPIO_PA0, GPIO_PN6, or GPIO_PCC3.
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The number of ports implemented by each GPIO controller varies. The number
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of implemented GPIOs within each port varies. GPIO registers within a
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controller are grouped and laid out according to the port they affect.
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The mapping from port name to the GPIO controller that implements that
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port, and the mapping from port name to register offset within a
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controller, are both extremely non-linear. The header file
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<dt-bindings/gpio/tegra186-gpio.h> describes the port-level mapping. In
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that file, the naming convention for ports matches the HW documentation.
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The values chosen for the names are alphabetically sorted within a
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particular controller. Drivers need to map between the DT GPIO IDs and HW
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register offsets using a lookup table.
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Each GPIO controller can generate a number of interrupt signals. Each
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signal represents the aggregate status for all GPIOs within a set of
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ports. Thus, the number of interrupt signals generated by a controller
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varies as a rough function of the number of ports it implements. Note
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that the HW documentation refers to both the overall controller HW
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module and the sets-of-ports as "controllers".
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Each GPIO controller in fact generates multiple interrupts signals for
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each set of ports. Each GPIO may be configured to feed into a specific
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one of the interrupt signals generated by a set-of-ports. The intent is
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for each generated signal to be routed to a different CPU, thus allowing
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different CPUs to each handle subsets of the interrupts within a port.
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The status of each of these per-port-set signals is reported via a
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separate register. Thus, a driver needs to know which status register to
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observe. This binding currently defines no configuration mechanism for
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this. By default, drivers should use register
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GPIO_${port}_INTERRUPT_STATUS_G1_0. Future revisions to the binding could
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define a property to configure this.
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properties:
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compatible:
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enum:
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- nvidia,tegra186-gpio
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- nvidia,tegra186-gpio-aon
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- nvidia,tegra194-gpio
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- nvidia,tegra194-gpio-aon
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- nvidia,tegra234-gpio
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- nvidia,tegra234-gpio-aon
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reg-names:
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items:
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- const: security
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- const: gpio
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minItems: 1
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reg:
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items:
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- description: Security configuration registers.
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- description: |
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GPIO control registers. This may cover either:
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a) The single physical alias that this OS should use.
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b) All physical aliases that exist in the controller. This is
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appropriate when the OS is responsible for managing assignment
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of the physical aliases.
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minItems: 1
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interrupts:
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description: The interrupt outputs from the HW block, one per set of
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ports, in the order the HW manual describes them. The number of entries
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required varies depending on compatible value.
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gpio-controller: true
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"#gpio-cells":
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description: |
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Indicates how many cells are used in a consumer's GPIO specifier. In the
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specifier:
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- The first cell is the pin number.
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See <dt-bindings/gpio/tegra186-gpio.h>.
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- The second cell contains flags:
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- Bit 0 specifies polarity
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- 0: Active-high (normal).
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- 1: Active-low (inverted).
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const: 2
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interrupt-controller: true
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"#interrupt-cells":
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description: |
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Indicates how many cells are used in a consumer's interrupt specifier.
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In the specifier:
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- The first cell is the GPIO number.
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See <dt-bindings/gpio/tegra186-gpio.h>.
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- The second cell is contains flags:
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- Bits [3:0] indicate trigger type and level:
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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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const: 2
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allOf:
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- if:
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properties:
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compatible:
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contains:
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enum:
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- nvidia,tegra186-gpio
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- nvidia,tegra194-gpio
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- nvidia,tegra234-gpio
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then:
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properties:
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interrupts:
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minItems: 6
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maxItems: 48
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- if:
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properties:
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compatible:
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contains:
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enum:
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- nvidia,tegra186-gpio-aon
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- nvidia,tegra194-gpio-aon
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- nvidia,tegra234-gpio-aon
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then:
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properties:
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interrupts:
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minItems: 1
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maxItems: 4
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required:
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- compatible
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- reg
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- reg-names
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- interrupts
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additionalProperties: false
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examples:
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- |
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#include <dt-bindings/interrupt-controller/irq.h>
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gpio@2200000 {
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compatible = "nvidia,tegra186-gpio";
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reg-names = "security", "gpio";
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reg = <0x2200000 0x10000>,
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<0x2210000 0x10000>;
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interrupts = <0 47 IRQ_TYPE_LEVEL_HIGH>,
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<0 50 IRQ_TYPE_LEVEL_HIGH>,
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<0 53 IRQ_TYPE_LEVEL_HIGH>,
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<0 56 IRQ_TYPE_LEVEL_HIGH>,
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<0 59 IRQ_TYPE_LEVEL_HIGH>,
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<0 180 IRQ_TYPE_LEVEL_HIGH>;
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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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gpio@c2f0000 {
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compatible = "nvidia,tegra186-gpio-aon";
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reg-names = "security", "gpio";
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reg = <0xc2f0000 0x1000>,
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<0xc2f1000 0x1000>;
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interrupts = <0 60 IRQ_TYPE_LEVEL_HIGH>;
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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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