diff options
Diffstat (limited to 'drivers/mmc')
| -rw-r--r-- | drivers/mmc/core/core.c | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 7aa3b305b65d..5ae89e48fd85 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -1394,6 +1394,84 @@ int mmc_regulator_set_ocr(struct mmc_host *mmc, } EXPORT_SYMBOL_GPL(mmc_regulator_set_ocr); +static int mmc_regulator_set_voltage_if_supported(struct regulator *regulator, + int min_uV, int target_uV, + int max_uV) +{ + /* + * Check if supported first to avoid errors since we may try several + * signal levels during power up and don't want to show errors. + */ + if (!regulator_is_supported_voltage(regulator, min_uV, max_uV)) + return -EINVAL; + + return regulator_set_voltage_triplet(regulator, min_uV, target_uV, + max_uV); +} + +/** + * mmc_regulator_set_vqmmc - Set VQMMC as per the ios + * + * For 3.3V signaling, we try to match VQMMC to VMMC as closely as possible. + * That will match the behavior of old boards where VQMMC and VMMC were supplied + * by the same supply. The Bus Operating conditions for 3.3V signaling in the + * SD card spec also define VQMMC in terms of VMMC. + * If this is not possible we'll try the full 2.7-3.6V of the spec. + * + * For 1.2V and 1.8V signaling we'll try to get as close as possible to the + * requested voltage. This is definitely a good idea for UHS where there's a + * separate regulator on the card that's trying to make 1.8V and it's best if + * we match. + * + * This function is expected to be used by a controller's + * start_signal_voltage_switch() function. + */ +int mmc_regulator_set_vqmmc(struct mmc_host *mmc, struct mmc_ios *ios) +{ + struct device *dev = mmc_dev(mmc); + int ret, volt, min_uV, max_uV; + + /* If no vqmmc supply then we can't change the voltage */ + if (IS_ERR(mmc->supply.vqmmc)) + return -EINVAL; + + switch (ios->signal_voltage) { + case MMC_SIGNAL_VOLTAGE_120: + return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc, + 1100000, 1200000, 1300000); + case MMC_SIGNAL_VOLTAGE_180: + return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc, + 1700000, 1800000, 1950000); + case MMC_SIGNAL_VOLTAGE_330: + ret = mmc_ocrbitnum_to_vdd(mmc->ios.vdd, &volt, &max_uV); + if (ret < 0) + return ret; + + dev_dbg(dev, "%s: found vmmc voltage range of %d-%duV\n", + __func__, volt, max_uV); + + min_uV = max(volt - 300000, 2700000); + max_uV = min(max_uV + 200000, 3600000); + + /* + * Due to a limitation in the current implementation of + * regulator_set_voltage_triplet() which is taking the lowest + * voltage possible if below the target, search for a suitable + * voltage in two steps and try to stay close to vmmc + * with a 0.3V tolerance at first. + */ + if (!mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc, + min_uV, volt, max_uV)) + return 0; + + return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc, + 2700000, volt, 3600000); + default: + return -EINVAL; + } +} +EXPORT_SYMBOL_GPL(mmc_regulator_set_vqmmc); + #endif /* CONFIG_REGULATOR */ int mmc_regulator_get_supply(struct mmc_host *mmc) |