drivers/regulator 

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. 

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. 

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 

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); 

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, }; 

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); 

vrefbuf: regulator@58003C00 {   compatible = "st,stm32-vrefbuf";   reg = <0x58003C00 0x8>;   clocks = <&rcc VREF_CK>;   regulator-min-microvolt = <1500000>;   regulator-max-microvolt = <2500000>;   status = "disabled"; };