對于嵌入式設備來說，合適的電源管理，不僅可以延長電池的壽命，而且可以省電，延長設備運行時間，在提高用戶體驗方面有很大的好處。所以，各個soc廠家在這方面花了很多的功夫。下面，我們可以看看linux是如何處理電源管理驅動的。
1、代碼目錄
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drivers/regulator |
2、查看目錄下的Kconfig文件
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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、閱讀文件，得知REGULATOR是最核心的模塊macro，那我們可以找一個設備的macro看看
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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、沒有找到s3c，可以看一下stm32芯片的依賴屬性，接著看Makefile
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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、看的出來stm32只依賴于stm32-verfbuf.c文件，繼續查看
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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、確認驅動為platform驅動，尋找regulator特有的數據結構
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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、由代碼得知，regulator_ops和regulator_desc才是特有的regulator數據結構，當然也少不了注冊函數
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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、進一步確認of_device_id是不是真實存在，可以在arch/arm/boot/dts/stm32h743.dtsi找到對應內容
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vrefbuf: regulator@58003C00 { compatible = "st,stm32-vrefbuf"; reg = <0x58003C00 0x8>; clocks = <&rcc VREF_CK>; regulator-min-microvolt = <1500000>; regulator-max-microvolt = <2500000>; status = "disabled"; }; |
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持服務器之家。
原文鏈接：https://blog.csdn.net/feixiaoxing/article/details/79874311
