对于嵌入式设备来说,合适的电源管理,不仅可以延长电池的寿命,而且可以省电,延长设备运行时间,在提高用户体验方面有很大的好处。所以,各个soc厂家在这方面花了很多的功夫。下面,我们可以看看linux是如何处理电源管理驱动的。
1、代码目录
drivers/regulator
2、查看目录下的Kconfig文件
- menuconfig REGULATOR
- bool "Voltage and Current Regulator Support"
- help
- Generic Voltage and Current Regulator support.
- This framework is designed to provide a generic interface to voltage
- and current regulators within the Linux kernel. It‘s intended to
- provide voltage and current control to client or consumer drivers and
- also provide status information to user space applications through a
- sysfs interface.
- The intention is to allow systems to dynamically control regulator
- output in order to save power and prolong battery life. This applies
- to both voltage regulators (where voltage output is controllable) and
- current sinks (where current output is controllable).
- This framework safely compiles out if not selected so that client
- drivers can still be used in systems with no software controllable
- regulators.
- If unsure, say no.
3、阅读文件,得知REGULATOR是最核心的模块macro,那我们可以找一个设备的macro看看
- config REGULATOR_STM32_VREFBUF
- tristate "STMicroelectronics STM32 VREFBUF"
- depends on ARCH_STM32 || COMPILE_TEST
- help
- This driver supports STMicroelectronics STM32 VREFBUF (voltage
- reference buffer) which can be used as voltage reference for
- internal ADCs, DACs and also for external components through
- dedicated Vref+ pin.
- This driver can also be built as a module. If so, the module
- will be called stm32-vrefbuf.
4、没有找到s3c,可以看一下stm32芯片的依赖属性,接着看Makefile
- obj-$(CONFIG_REGULATOR) += core.o dummy.o fixed-helper.o helpers.o devres.o
- obj-$(CONFIG_OF) += of_regulator.o
- obj-$(CONFIG_REGULATOR_FIXED_VOLTAGE) += fixed.o
- obj-$(CONFIG_REGULATOR_VIRTUAL_CONSUMER) += virtual.o
- obj-$(CONFIG_REGULATOR_USERSPACE_CONSUMER) += userspace-consumer.o
- obj-$(CONFIG_REGULATOR_STM32_VREFBUF) += stm32-vrefbuf.o
5、看的出来stm32只依赖于stm32-verfbuf.c文件,继续查看
- static const struct of_device_id stm32_vrefbuf_of_match[] = {
- { .compatible = "st,stm32-vrefbuf", },
- {},
- };
- MODULE_DEVICE_TABLE(of, stm32_vrefbuf_of_match);
- static struct platform_driver stm32_vrefbuf_driver = {
- .probe = stm32_vrefbuf_probe,
- .remove = stm32_vrefbuf_remove,
- .driver = {
- .name = "stm32-vrefbuf",
- .of_match_table = of_match_ptr(stm32_vrefbuf_of_match),
- },
- };
- module_platform_driver(stm32_vrefbuf_driver);
6、确认驱动为platform驱动,寻找regulator特有的数据结构
- static const struct regulator_ops stm32_vrefbuf_volt_ops = {
- .enable = stm32_vrefbuf_enable,
- .disable = stm32_vrefbuf_disable,
- .is_enabled = stm32_vrefbuf_is_enabled,
- .get_voltage_sel = stm32_vrefbuf_get_voltage_sel,
- .set_voltage_sel = stm32_vrefbuf_set_voltage_sel,
- .list_voltage = regulator_list_voltage_table,
- };
- static const struct regulator_desc stm32_vrefbuf_regu = {
- .name = "vref",
- .supply_name = "vdda",
- .volt_table = stm32_vrefbuf_voltages,
- .n_voltages = ARRAY_SIZE(stm32_vrefbuf_voltages),
- .ops = &stm32_vrefbuf_volt_ops,
- .type = REGULATOR_VOLTAGE,
- .owner = THIS_MODULE,
- };
7、由代码得知,regulator_ops和regulator_desc才是特有的regulator数据结构,当然也少不了注册函数
- rdev = regulator_register(&stm32_vrefbuf_regu, &config);
- if (IS_ERR(rdev)) {
- ret = PTR_ERR(rdev);
- dev_err(&pdev->dev, "register failed with error %d\n", ret);
- goto err_clk_dis;
- }
- platform_set_drvdata(pdev, rdev);
8、进一步确认of_device_id是不是真实存在,可以在arch/arm/boot/dts/stm32h743.dtsi找到对应内容
- vrefbuf: [email protected]58003C00 {
- compatible = "st,stm32-vrefbuf";
- reg = <0x58003C00 0x8>;
- clocks = <&rcc VREF_CK>;
- regulator-min-microvolt = <1500000>;
- regulator-max-microvolt = <2500000>;
- status = "disabled";
- };
原文地址:https://www.cnblogs.com/wanghuaijun/p/9649102.html
时间: 2024-10-11 12:05:01