dt/bindings: memory: Add bindings for TI GPMC driver

GPMC stands for General Purpose Memory Controller and it is
present on many Texas Instruments SoCs.

It supports a number of Asynchronous and Synchronous interfaces
and has various settings to configure the bus interface.

The DT bindings define all the various GPMC settings.

As the GPMC supports multiple devices on the bus, each
device is represented as a child and the respective
GPMC settings are situated there. (see ti,gpmc-child.yaml)

These binding docs are picked up from the Linux kernel.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
This commit is contained in:
Roger Quadros 2022-10-20 16:30:48 +03:00 committed by Tom Rini
parent 3a82cd26ee
commit 37d6d1645a
2 changed files with 442 additions and 0 deletions

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# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/memory-controllers/ti,gpmc-child.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: device tree bindings for children of the Texas Instruments GPMC
maintainers:
- Tony Lindgren <tony@atomide.com>
- Roger Quadros <rogerq@kernel.org>
description:
This binding is meant for the child nodes of the GPMC node. The node
represents any device connected to the GPMC bus. It may be a Flash chip,
RAM chip or Ethernet controller, etc. These properties are meant for
configuring the GPMC settings/timings and will accompany the bindings
supported by the respective device.
properties:
reg: true
# GPMC Timing properties for child nodes. All are optional and default to 0.
gpmc,sync-clk-ps:
description: Minimum clock period for synchronous mode
default: 0
# Chip-select signal timings corresponding to GPMC_CONFIG2:
gpmc,cs-on-ns:
description: Assertion time
default: 0
gpmc,cs-rd-off-ns:
description: Read deassertion time
default: 0
gpmc,cs-wr-off-ns:
description: Write deassertion time
default: 0
# ADV signal timings corresponding to GPMC_CONFIG3:
gpmc,adv-on-ns:
description: Assertion time
default: 0
gpmc,adv-rd-off-ns:
description: Read deassertion time
default: 0
gpmc,adv-wr-off-ns:
description: Write deassertion time
default: 0
gpmc,adv-aad-mux-on-ns:
description: Assertion time for AAD
default: 0
gpmc,adv-aad-mux-rd-off-ns:
description: Read deassertion time for AAD
default: 0
gpmc,adv-aad-mux-wr-off-ns:
description: Write deassertion time for AAD
default: 0
# WE signals timings corresponding to GPMC_CONFIG4:
gpmc,we-on-ns:
description: Assertion time
default: 0
gpmc,we-off-ns:
description: Deassertion time
default: 0
# OE signals timings corresponding to GPMC_CONFIG4:
gpmc,oe-on-ns:
description: Assertion time
default: 0
gpmc,oe-off-ns:
description: Deassertion time
default: 0
gpmc,oe-aad-mux-on-ns:
description: Assertion time for AAD
default: 0
gpmc,oe-aad-mux-off-ns:
description: Deassertion time for AAD
default: 0
# Access time and cycle time timings (in nanoseconds) corresponding to
# GPMC_CONFIG5:
gpmc,page-burst-access-ns:
description: Multiple access word delay
default: 0
gpmc,access-ns:
description: Start-cycle to first data valid delay
default: 0
gpmc,rd-cycle-ns:
description: Total read cycle time
default: 0
gpmc,wr-cycle-ns:
description: Total write cycle time
default: 0
gpmc,bus-turnaround-ns:
description: Turn-around time between successive accesses
default: 0
gpmc,cycle2cycle-delay-ns:
description: Delay between chip-select pulses
default: 0
gpmc,clk-activation-ns:
description: GPMC clock activation time
default: 0
gpmc,wait-monitoring-ns:
description: Start of wait monitoring with regard to valid data
default: 0
# Boolean timing parameters. If property is present, parameter is enabled
# otherwise disabled.
gpmc,adv-extra-delay:
description: ADV signal is delayed by half GPMC clock
type: boolean
gpmc,cs-extra-delay:
description: CS signal is delayed by half GPMC clock
type: boolean
gpmc,cycle2cycle-diffcsen:
description: |
Add "cycle2cycle-delay" between successive accesses
to a different CS
type: boolean
gpmc,cycle2cycle-samecsen:
description: |
Add "cycle2cycle-delay" between successive accesses
to the same CS
type: boolean
gpmc,oe-extra-delay:
description: OE signal is delayed by half GPMC clock
type: boolean
gpmc,we-extra-delay:
description: WE signal is delayed by half GPMC clock
type: boolean
gpmc,time-para-granularity:
description: Multiply all access times by 2
type: boolean
# The following two properties are applicable only to OMAP3+ and AM335x:
gpmc,wr-access-ns:
description: |
In synchronous write mode, for single or
burst accesses, defines the number of
GPMC_FCLK cycles from start access time
to the GPMC_CLK rising edge used by the
memory device for the first data capture.
default: 0
gpmc,wr-data-mux-bus-ns:
description: |
In address-data multiplex mode, specifies
the time when the first data is driven on
the address-data bus.
default: 0
# GPMC chip-select settings properties for child nodes. All are optional.
gpmc,burst-length:
description: Page/burst length.
$ref: /schemas/types.yaml#/definitions/uint32
enum: [0, 4, 8, 16]
default: 0
gpmc,burst-wrap:
description: Enables wrap bursting
type: boolean
gpmc,burst-read:
description: Enables read page/burst mode
type: boolean
gpmc,burst-write:
description: Enables write page/burst mode
type: boolean
gpmc,device-width:
description: |
Total width of device(s) connected to a GPMC
chip-select in bytes. The GPMC supports 8-bit
and 16-bit devices and so this property must be
1 or 2.
$ref: /schemas/types.yaml#/definitions/uint32
enum: [1, 2]
default: 1
gpmc,mux-add-data:
description: |
Address and data multiplexing configuration.
Valid values are
0 for Non multiplexed mode
1 for address-address-data multiplexing mode and
2 for address-data multiplexing mode.
$ref: /schemas/types.yaml#/definitions/uint32
enum: [0, 1, 2]
gpmc,sync-read:
description: |
Enables synchronous read. Defaults to asynchronous
is this is not set.
type: boolean
gpmc,sync-write:
description: |
Enables synchronous writes. Defaults to asynchronous
is this is not set.
type: boolean
gpmc,wait-pin:
description: |
Wait-pin used by client. Must be less than "gpmc,num-waitpins".
$ref: /schemas/types.yaml#/definitions/uint32
gpmc,wait-pin-polarity:
description: |
Set the desired polarity for the selected wait pin.
0 for active low, 1 for active high.
$ref: /schemas/types.yaml#/definitions/uint32
enum: [0, 1]
gpmc,wait-on-read:
description: Enables wait monitoring on reads.
type: boolean
gpmc,wait-on-write:
description: Enables wait monitoring on writes.
type: boolean
required:
- reg
# the GPMC child will have its own native properties
additionalProperties: true

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# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/memory-controllers/ti,gpmc.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Texas Instruments GPMC Memory Controller device-tree bindings
maintainers:
- Tony Lindgren <tony@atomide.com>
- Roger Quadros <rogerq@kernel.org>
description:
The GPMC is a unified memory controller dedicated for interfacing
with external memory devices like
- Asynchronous SRAM-like memories and ASICs
- Asynchronous, synchronous, and page mode burst NOR flash
- NAND flash
- Pseudo-SRAM devices
properties:
compatible:
items:
- enum:
- ti,am3352-gpmc
- ti,am64-gpmc
- ti,omap2420-gpmc
- ti,omap2430-gpmc
- ti,omap3430-gpmc
- ti,omap4430-gpmc
reg:
minItems: 1
maxItems: 2
reg-names:
items:
- const: cfg
- const: data
interrupts:
maxItems: 1
clocks:
maxItems: 1
description: |
Functional clock. Used for bus timing calculations and
GPMC configuration.
clock-names:
items:
- const: fck
power-domains:
maxItems: 1
dmas:
items:
- description: DMA channel for GPMC NAND prefetch
dma-names:
items:
- const: rxtx
"#address-cells": true
"#size-cells": true
gpmc,num-cs:
description: maximum number of supported chip-select lines.
$ref: /schemas/types.yaml#/definitions/uint32
gpmc,num-waitpins:
description: maximum number of supported wait pins.
$ref: /schemas/types.yaml#/definitions/uint32
ranges:
minItems: 1
description: |
Must be set up to reflect the memory layout with four
integer values for each chip-select line in use,
<cs-number> 0 <physical address of mapping> <size>
items:
- description: NAND bank 0
- description: NOR/SRAM bank 0
- description: NOR/SRAM bank 1
'#interrupt-cells':
const: 2
interrupt-controller:
description: |
The GPMC driver implements and interrupt controller for
the NAND events "fifoevent" and "termcount" plus the
rising/falling edges on the GPMC_WAIT pins.
The interrupt number mapping is as follows
0 - NAND_fifoevent
1 - NAND_termcount
2 - GPMC_WAIT0 pin edge
3 - GPMC_WAIT1 pin edge, and so on.
'#gpio-cells':
const: 2
gpio-controller:
description: |
The GPMC driver implements a GPIO controller for the
GPMC WAIT pins that can be used as general purpose inputs.
0 maps to GPMC_WAIT0 pin.
ti,hwmods:
description:
Name of the HWMOD associated with GPMC. This is for legacy
omap2/3 platforms only.
$ref: /schemas/types.yaml#/definitions/string
deprecated: true
ti,no-idle-on-init:
description:
Prevent idling the module at init. This is for legacy omap2/3
platforms only.
type: boolean
deprecated: true
patternProperties:
"@[0-7],[a-f0-9]+$":
type: object
description: |
The child device node represents the device connected to the GPMC
bus. The device can be a NAND chip, SRAM device, NOR device
or an ASIC.
$ref: "ti,gpmc-child.yaml"
required:
- compatible
- reg
- gpmc,num-cs
- gpmc,num-waitpins
- "#address-cells"
- "#size-cells"
allOf:
- if:
properties:
compatible:
contains:
const: ti,am64-gpmc
then:
required:
- reg-names
- power-domains
additionalProperties: false
examples:
- |
#include <dt-bindings/interrupt-controller/arm-gic.h>
#include <dt-bindings/gpio/gpio.h>
gpmc: memory-controller@50000000 {
compatible = "ti,am3352-gpmc";
reg = <0x50000000 0x2000>;
interrupts = <100>;
clocks = <&l3s_clkctrl>;
clock-names = "fck";
dmas = <&edma 52 0>;
dma-names = "rxtx";
gpmc,num-cs = <8>;
gpmc,num-waitpins = <2>;
#address-cells = <2>;
#size-cells = <1>;
ranges = <0 0 0x08000000 0x10000000>; /* CS0 @addr 0x8000000, size 0x10000000 */
interrupt-controller;
#interrupt-cells = <2>;
gpio-controller;
#gpio-cells = <2>;
nand@0,0 {
compatible = "ti,omap2-nand";
reg = <0 0 4>;
interrupt-parent = <&gpmc>;
interrupts = <0 IRQ_TYPE_NONE>, /* fifoevent */
<1 IRQ_TYPE_NONE>; /* termcount */
ti,nand-xfer-type = "prefetch-dma";
ti,nand-ecc-opt = "bch16";
ti,elm-id = <&elm>;
rb-gpios = <&gpmc 0 GPIO_ACTIVE_HIGH>; /* gpmc_wait0 pin */
};
};