regulator_check_voltage
if (regulator_check_voltage(helper->vqmmc_supply, 1200000) == 0)
if (regulator_check_voltage(helper->vqmmc_supply, 1800000) == 0)
if (regulator_check_voltage(helper->vqmmc_supply, 3300000) == 0)
int regulator_check_voltage(regulator_t reg, int uvolt);