linux 使用regulator
简要说明一下在Rockchip平台regulator的使用方法
//在pmic这个节点中可以看到一个子节点vcc_sd，表明有一路电源从pmic中引出来连接到sdmmc的外设上，给sdmmc进行供电，那这一路电源如何使用呢？可以看下面的dts sdmmc 这个节点的vqmmc-supply
vcc_sd: LDO_REG4 {
regulator-always-on;
regulator-boot-on;
regulator-min-microvolt = <3000000>;
regulator-max-microvolt = <3000000>;
regulator-name = "vcc_sd";
regulator-state-mem {
regulator-on-in-suspend;
regulator-suspend-microvolt = <3000000>;
};
};
&sdmmc {
clock-frequency = <50000000>;
clock-freq-min-max = <400000 150000000>;
supports-sd;
bus-width = <4>;
cap-mmc-highspeed;
cap-sd-highspeed;
disable-wp;
num-slots = <1>;
//sd-uhs-sdr104;
vqmmc-supply = <&vcc_sd>; //指定vqmmc-supply 使用pmic是使用那一路电源
pinctrl-names = "default";
pinctrl-0 = <&sdmmc_clk &sdmmc_cmd &sdmmc_cd &sdmmc_bus4>;
status = "okay";
};
在代码中使用vqmmc-supply这一路电源代码调用如下：
kernel\drivers\mmc\host\dw_mmc-pltfm.c
//step 1
static const struct of_device_id dw_mci_rockchip_match[] = {
{
.compatible = "rockchip,rk2928-dw-mshc",
.data = &rk2928_drv_data },
{
.compatible = "rockchip,rk3288-dw-mshc",
.data = &rk3288_drv_data },
{
},
};
//step 2
static struct platform_driver dw_mci_rockchip_pltfm_driver = {
.probe = dw_mci_rockchip_probe,
.remove = dw_mci_pltfm_remove,
.driver = {
.name = "dwmmc_rockchip",
.of_match_table = dw_mci_rockchip_match,
.pm = &dw_mci_rockchip_pmops,
},
};
static int dw_mci_rockchip_probe(struct platform_device *pdev)
dw_mci_pltfm_register(pdev, drv_data);
dw_mci_probe(host);
ret = dw_mci_init_slot(host, i);
ret = mmc_regulator_get_supply(mmc);
mmc->supply.vmmc = devm_regulator_get_optional(dev, "vmmc");
mmc->supply.vqmmc = devm_regulator_get_optional(dev, "vqmmc");
/"代码里通过“vqmmc” 找到 vqmmc-supply = <&vcc_sd>;，从而找到vcc_sd，电源配置*/