In the Linux kernel, pinctrl (pin control) is a mechanism used to manage and control pins in the system. It allows developers to configure a pin's functionality and properties to meet specific hardware needs. This article will introduce in detail the process and programming method of pinctrl in the Linux kernel, and provide corresponding source code examples.
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Overview of the pin control subsystem (pinctrl subsytem)
The pin control subsystem is a subsystem in the Linux kernel that is used to manage and control pin resources in the system. It provides an abstract way to configure and use hardware pins. The main components of the pin control subsystem include pin descriptor, pin function and pin property. -
Pin Description (Pin Descriptor)
Pin description is a data structure in the pin control subsystem, used to describe a pin resource. In the kernel, a pin description is represented by a unique integer value. Developers can use this integer value to reference and manipulate specific pins. -
Pin Function Pin function
defines the specific function of the pin in the system. A pin can have multiple functions such as input, output, interrupt, etc. Developers can configure pin functionality to meet system needs. In the Linux kernel, each pin function is identified by a unique name. -
Pin Property A
pin property is a set of parameters used to configure the characteristics of a pin. They control the pin's electrical characteristics, levels, and other related properties. Pin properties can be configured and modified based on system requirements. -
Pinctrl process analysis
In the Linux kernel, the pinctrl usage process mainly includes the following steps:
a. Initialize the pin control subsystem: Before using pinctrl, you need to initialize the pin control subsystem.