“ADC device tree configuration”的版本间的差异

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=== DT configuration example ===
 
=== DT configuration example ===
The example below shows how to configure ADC1:
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下面的示例显示如何配置ADC1:
* Input pin: use [[Pinctrl device tree configuration]] to configure PF12 as analog input.
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* 输入引脚:使用[[Pinctrl device tree configuration]]将PF12配置为模拟输入。
* Analog supply: it is provided by one of the [[PMIC hardware components|PMIC]] LDO regulators.
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* 模拟电源:由 [[PMIC hardware components|PMIC]] LDO稳压器之一提供。
* Voltage reference: it is provided by the [[Regulator_overview#Microprocessor device internal regulators|VREFBUF internal regulator]].
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* 参考电压:由[[Regulator_overview#Microprocessor device internal regulators|VREFBUF internal regulator]]提供。
* Input channel: configure ADC1_IN6 (e.g on PF12).
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* 输入通道:配置ADC1_IN6(例如在PF12上)。
* Sampling time: the minimum sampling time is 10 µs.
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* 采样时间:最短采样时间为10 µs。
  
 
  # part of pin-controller dt node
 
  # part of pin-controller dt node

2020年11月9日 (一) 14:48的版本

Article purpose

本文的目的是解释在将外围设备分配给Linux® OS时如何配置模数转换器(“ ADC”)[1]

  • 如何配置ADC外围设备
  • 如何配置board,例如 ADC参考电压调节器,通道,引脚和采样时间。

使用设备树机制执行配置[2].

ADC Linux driver 使用它在 IIO framework中注册相关信息,例如每个ADC的IIO设备,通道和电压标度。

如果外围设备已分配给另一个执行上下文,请参阅 How to assign an internal peripheral to a runtime context 文章,以获取有关外围设备分配和配置的准则。

DT bindings documentation

"STM32 ADC设备树绑定"[3] 描述所有必需和可选功能。

DT configuration

该硬件描述是STM32微处理器和电路板设备树文件的组合。 有关设备树文件分割的更多说明,请参见Device treeSTM32CubeMX可用于生成板卡设备树。 有关更多详细信息,请参考 How to configure the DT using STM32CubeMX

ADC common resources ADC common resources ADC common resources ADC private resources ADC private resources Regulator Pinctrl How to setup TIM or LPTIM triggers
ADC DT configuration

DT configuration (STM32 level)

ADC节点在stm32mp157c.dtsi中声明[4].

  • DT根节点('adc')描述ADC硬件模块参数,例如寄存器区域,时钟和中断。
  • DT子节点('adc1'和'adc2')独立描述ADC1和ADC2。
adc: adc@address {
	compatible = "st,stm32mp1-adc-core";
	...                                      /* common resources in 'adc' root node. */
	adc1: adc@0 {
		compatible = "st,stm32mp1-adc";
		...                              /* private resources in 'adc1' child node. */
	};
	adc2: adc@100 {
		compatible = "st,stm32mp1-adc";
		...                              /* private resources in 'adc2' child node. */
	};
};
Warning.png 该设备树部分与STM32微处理器有关。 它必须保持原样,而不能由最终用户修改。

DT configuration (board level)

请按照以下章节中描述的顺序在板上配置和启用ADC。

Common resources for all ADCs

必须填写DT根节点('adc'):

  • 通过设置status =“ okay”。来启用ADC模块。
  • 通过pinctrl,pinctrl-0pinctrl-names配置正在使用的引脚。
  • 通过设置vdda-supply = <&your_vdda_regulator>来配置模拟电源稳压器[5]
  • 通过设置vref-supply = <&your_vref_regulator>来配置模拟参考电压调节器[5]
Info.png ADC可以使用内部VREFBUF[6] 或任何其他连接到VREF +引脚的外部稳压器[5]

Resources dedicated to ADC1 and ADC2

DT子节点('adc1'和/或'adc2')必须填写:

  • 通过设置status =“ okay”。来启用'adc1'和/或'adc2'。
  • 通过设置st,adc-channels = <0 1 2 ...>。来启用单端通道(<vinp ...>
  • 通过设置st,adc-diff-channels = <1 0>,<2 6>,....来启用差分通道对(<vinp vinn>,...)。
  • 设置最小采样时间 [7] 通过设置st,min-sample-time-nsecs = <10000>(可选)为每个或所有通道设置。
  • 通过设置assigned-resolution-bits = <12>(可选)来设置分辨率。

DT configuration example

下面的示例显示如何配置ADC1:

# part of pin-controller dt node
adc1_in6_pins_a: adc1-in6 {
	pins {
		pinmux = <STM32_PINMUX('F', 12, ANALOG)>; /* configure 'PF12' as ANALOG */
	};
};
&adc {
	/* ADC1 & ADC2 common resources */
	pinctrl-names = "default";
	pinctrl-0 = <&adc1_in6_pins_a>;              /* Use PF12 pin as ANALOG */
	vdda-supply = <&vdda>;                       /* Example to supply vdda pin by using a PMIC regulator
	vref-supply = <&vrefbuf>;                    /* Example to use VREFBUF (It needs to be enabled as well) */
	status = "okay";                             /* Enable ADC12 block */
	adc1: adc@0 {
		/* private resources for ADC1 */
		st,adc-channels = <6>;               /* ADC1 in6 channel is used */
		st,min-sample-time-nsecs = <10000>;  /* 10µs sampling time */
		status = "okay";                     /* Enable ADC1 */
	};
	adc2: adc@100 {
		/* private resources for ADC2 */
		...
	};
};

How to configure the DT using STM32CubeMX

The STM32CubeMX tool can be used to configure the STM32MPU device and get the corresponding platform configuration device tree files.
The STM32CubeMX may not support all the properties described in the above DT bindings documentation paragraph. If so, the tool inserts user sections in the generated device tree. These sections can then be edited to add some properties and they are preserved from one generation to another. Refer to STM32CubeMX user manual for further information.