linux/Documentation/devicetree/bindings/serial/qcom,msm-uartdm.yaml
Stephan Gerhold 692079bda7 dt-bindings: serial: qcom,msm-uartdm: Vote for shared resources
Document power-domains, operating-points-v2 and interconnects to allow
making performance state votes for certain clock frequencies of the UART
DM controller. The interconnect path to DRAM is needed when UART DM is
used together with a DMA engine.

Voting for these shared resources is necessary to guarantee performance
with power management enabled. Otherwise these resources might run at
minimal performance state which is not sufficient for certain UART
baud rates.

Signed-off-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20231128-serial-msm-dvfs-v1-1-4f290d20a4be@kernkonzept.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-08 12:02:37 +01:00

126 lines
3.2 KiB
YAML

# SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
%YAML 1.2
---
$id: http://devicetree.org/schemas/serial/qcom,msm-uartdm.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Qualcomm MSM Serial UARTDM
maintainers:
- Andy Gross <agross@kernel.org>
- Bjorn Andersson <bjorn.andersson@linaro.org>
- Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
description: |
The MSM serial UARTDM hardware is designed for high-speed use cases where the
transmit and/or receive channels can be offloaded to a dma-engine. From a
software perspective it's mostly compatible with the MSM serial UART except
that it supports reading and writing multiple characters at a time.
Note:: Aliases may be defined to ensure the correct ordering of the UARTs.
The alias serialN will result in the UART being assigned port N. If any
serialN alias exists, then an alias must exist for each enabled UART. The
serialN aliases should be in a .dts file instead of in a .dtsi file.
properties:
compatible:
items:
- enum:
- qcom,msm-uartdm-v1.1
- qcom,msm-uartdm-v1.2
- qcom,msm-uartdm-v1.3
- qcom,msm-uartdm-v1.4
- const: qcom,msm-uartdm
clocks:
maxItems: 2
clock-names:
items:
- const: core
- const: iface
dmas:
maxItems: 2
dma-names:
items:
- const: tx
- const: rx
interconnects:
maxItems: 1
interrupts:
maxItems: 1
operating-points-v2: true
power-domains:
maxItems: 1
qcom,rx-crci:
$ref: /schemas/types.yaml#/definitions/uint32
description:
Identificator for Client Rate Control Interface to be used with RX DMA
channel. Required when using DMA for reception with UARTDM v1.3 and
below.
qcom,tx-crci:
$ref: /schemas/types.yaml#/definitions/uint32
description:
Identificator for Client Rate Control Interface to be used with TX DMA
channel. Required when using DMA for transmission with UARTDM v1.3 and
below.
reg:
minItems: 1
items:
- description: Main control registers
- description: An optional second register location shall specify the GSBI control region.
required:
- compatible
- clock-names
- clocks
- interrupts
- reg
allOf:
- $ref: /schemas/serial/serial.yaml#
- if:
properties:
compatible:
contains:
const: qcom,msm-uartdm-v1.3
then:
properties:
reg:
minItems: 2
else:
properties:
reg:
maxItems: 1
unevaluatedProperties: false
examples:
- |
#include <dt-bindings/interconnect/qcom,msm8996.h>
#include <dt-bindings/interrupt-controller/arm-gic.h>
#include <dt-bindings/power/qcom-rpmpd.h>
serial@f991e000 {
compatible = "qcom,msm-uartdm-v1.4", "qcom,msm-uartdm";
reg = <0xf991e000 0x1000>;
interrupts = <GIC_SPI 108 IRQ_TYPE_LEVEL_HIGH>;
clocks = <&blsp1_uart2_apps_cxc>, <&blsp1_ahb_cxc>;
clock-names = "core", "iface";
dmas = <&dma0 0>, <&dma0 1>;
dma-names = "tx", "rx";
power-domains = <&rpmpd MSM8996_VDDCX>;
operating-points-v2 = <&uart_opp_table>;
interconnects = <&pnoc MASTER_BLSP_1 &bimc SLAVE_EBI_CH0>;
};