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# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/bus/intel,ixp4xx-expansion-bus-controller.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Intel IXP4xx Expansion Bus Controller
description: |
The IXP4xx expansion bus controller handles access to devices on the
memory-mapped expansion bus on the Intel IXP4xx family of system on chips,
including IXP42x, IXP43x, IXP45x and IXP46x.
maintainers:
- Linus Walleij <linus.walleij@linaro.org>
properties:
$nodename:
pattern: '^bus@[0-9a-f]+$'
compatible:
items:
- enum:
- intel,ixp42x-expansion-bus-controller
- intel,ixp43x-expansion-bus-controller
- intel,ixp45x-expansion-bus-controller
- intel,ixp46x-expansion-bus-controller
- const: syscon
reg:
description: Control registers for the expansion bus, these are not
inside the memory range handled by the expansion bus.
maxItems: 1
native-endian:
$ref: /schemas/types.yaml#/definitions/flag
description: The IXP4xx has a peculiar MMIO access scheme, as it changes
the access pattern for words (swizzling) on the bus depending on whether
the SoC is running in big-endian or little-endian mode. Thus the
registers must always be accessed using native endianness.
"#address-cells":
description: |
The first cell is the chip select number.
The second cell is the address offset within the bank.
const: 2
"#size-cells":
const: 1
ranges: true
dma-ranges: true
patternProperties:
"^.*@[0-7],[0-9a-f]+$":
description: Devices attached to chip selects are represented as
subnodes.
type: object
properties:
intel,ixp4xx-eb-t1:
description: Address timing, extend address phase with n cycles.
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 3
intel,ixp4xx-eb-t2:
description: Setup chip select timing, extend setup phase with n cycles.
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 3
intel,ixp4xx-eb-t3:
description: Strobe timing, extend strobe phase with n cycles.
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 15
intel,ixp4xx-eb-t4:
description: Hold timing, extend hold phase with n cycles.
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 3
intel,ixp4xx-eb-t5:
description: Recovery timing, extend recovery phase with n cycles.
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 15
intel,ixp4xx-eb-cycle-type:
description: The type of cycles to use on the expansion bus for this
chip select. 0 = Intel cycles, 1 = Motorola cycles, 2 = HPI cycles.
$ref: /schemas/types.yaml#/definitions/uint32
enum: [0, 1, 2]
intel,ixp4xx-eb-byte-access-on-halfword:
description: Allow byte read access on half word devices.
$ref: /schemas/types.yaml#/definitions/uint32
enum: [0, 1]
intel,ixp4xx-eb-hpi-hrdy-pol-high:
description: Set HPI HRDY polarity to active high when using HPI.
$ref: /schemas/types.yaml#/definitions/uint32
enum: [0, 1]
intel,ixp4xx-eb-mux-address-and-data:
description: Multiplex address and data on the data bus.
$ref: /schemas/types.yaml#/definitions/uint32
enum: [0, 1]
intel,ixp4xx-eb-ahb-split-transfers:
description: Enable AHB split transfers.
$ref: /schemas/types.yaml#/definitions/uint32
enum: [0, 1]
intel,ixp4xx-eb-write-enable:
description: Enable write cycles.
$ref: /schemas/types.yaml#/definitions/uint32
enum: [0, 1]
intel,ixp4xx-eb-byte-access:
description: Expansion bus uses only 8 bits. The default is to use
16 bits.
$ref: /schemas/types.yaml#/definitions/uint32
enum: [0, 1]
required:
- compatible
- reg
- native-endian
- "#address-cells"
- "#size-cells"
- ranges
- dma-ranges
additionalProperties: false
examples:
- |
#include <dt-bindings/interrupt-controller/irq.h>
bus@50000000 {
compatible = "intel,ixp42x-expansion-bus-controller", "syscon";
reg = <0xc4000000 0x28>;
native-endian;
#address-cells = <2>;
#size-cells = <1>;
ranges = <0 0x0 0x50000000 0x01000000>,
<1 0x0 0x51000000 0x01000000>;
dma-ranges = <0 0x0 0x50000000 0x01000000>,
<1 0x0 0x51000000 0x01000000>;
flash@0,0 {
compatible = "intel,ixp4xx-flash", "cfi-flash";
bank-width = <2>;
reg = <0 0x00000000 0x1000000>;
intel,ixp4xx-eb-t3 = <3>;
intel,ixp4xx-eb-cycle-type = <0>;
intel,ixp4xx-eb-byte-access-on-halfword = <1>;
intel,ixp4xx-eb-write-enable = <1>;
intel,ixp4xx-eb-byte-access = <0>;
};
serial@1,0 {
compatible = "exar,xr16l2551", "ns8250";
reg = <1 0x00000000 0x10>;
interrupt-parent = <&gpio0>;
interrupts = <4 IRQ_TYPE_LEVEL_LOW>;
clock-frequency = <1843200>;
intel,ixp4xx-eb-t3 = <3>;
intel,ixp4xx-eb-cycle-type = <1>;
intel,ixp4xx-eb-write-enable = <1>;
intel,ixp4xx-eb-byte-access = <1>;
};
};
|
