diff options
Diffstat (limited to 'drivers/mmc/core/regulator.c')
| -rw-r--r-- | drivers/mmc/core/regulator.c | 314 |
1 files changed, 314 insertions, 0 deletions
diff --git a/drivers/mmc/core/regulator.c b/drivers/mmc/core/regulator.c new file mode 100644 index 000000000..4dcbc2281 --- /dev/null +++ b/drivers/mmc/core/regulator.c @@ -0,0 +1,314 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Helper functions for MMC regulators. + */ + +#include <linux/device.h> +#include <linux/err.h> +#include <linux/log2.h> +#include <linux/regulator/consumer.h> + +#include <linux/mmc/host.h> + +#include "core.h" +#include "host.h" + +#ifdef CONFIG_REGULATOR + +/** + * mmc_ocrbitnum_to_vdd - Convert a OCR bit number to its voltage + * @vdd_bit: OCR bit number + * @min_uV: minimum voltage value (mV) + * @max_uV: maximum voltage value (mV) + * + * This function returns the voltage range according to the provided OCR + * bit number. If conversion is not possible a negative errno value returned. + */ +static int mmc_ocrbitnum_to_vdd(int vdd_bit, int *min_uV, int *max_uV) +{ + int tmp; + + if (!vdd_bit) + return -EINVAL; + + /* + * REVISIT mmc_vddrange_to_ocrmask() may have set some + * bits this regulator doesn't quite support ... don't + * be too picky, most cards and regulators are OK with + * a 0.1V range goof (it's a small error percentage). + */ + tmp = vdd_bit - ilog2(MMC_VDD_165_195); + if (tmp == 0) { + *min_uV = 1650 * 1000; + *max_uV = 1950 * 1000; + } else { + *min_uV = 1900 * 1000 + tmp * 100 * 1000; + *max_uV = *min_uV + 100 * 1000; + } + + return 0; +} + +/** + * mmc_regulator_get_ocrmask - return mask of supported voltages + * @supply: regulator to use + * + * This returns either a negative errno, or a mask of voltages that + * can be provided to MMC/SD/SDIO devices using the specified voltage + * regulator. This would normally be called before registering the + * MMC host adapter. + */ +static int mmc_regulator_get_ocrmask(struct regulator *supply) +{ + int result = 0; + int count; + int i; + int vdd_uV; + int vdd_mV; + + count = regulator_count_voltages(supply); + if (count < 0) + return count; + + for (i = 0; i < count; i++) { + vdd_uV = regulator_list_voltage(supply, i); + if (vdd_uV <= 0) + continue; + + vdd_mV = vdd_uV / 1000; + result |= mmc_vddrange_to_ocrmask(vdd_mV, vdd_mV); + } + + if (!result) { + vdd_uV = regulator_get_voltage(supply); + if (vdd_uV <= 0) + return vdd_uV; + + vdd_mV = vdd_uV / 1000; + result = mmc_vddrange_to_ocrmask(vdd_mV, vdd_mV); + } + + return result; +} + +/** + * mmc_regulator_set_ocr - set regulator to match host->ios voltage + * @mmc: the host to regulate + * @supply: regulator to use + * @vdd_bit: zero for power off, else a bit number (host->ios.vdd) + * + * Returns zero on success, else negative errno. + * + * MMC host drivers may use this to enable or disable a regulator using + * a particular supply voltage. This would normally be called from the + * set_ios() method. + */ +int mmc_regulator_set_ocr(struct mmc_host *mmc, + struct regulator *supply, + unsigned short vdd_bit) +{ + int result = 0; + int min_uV, max_uV; + + if (vdd_bit) { + mmc_ocrbitnum_to_vdd(vdd_bit, &min_uV, &max_uV); + + result = regulator_set_voltage(supply, min_uV, max_uV); + if (result == 0 && !mmc->regulator_enabled) { + result = regulator_enable(supply); + if (!result) + mmc->regulator_enabled = true; + } + } else if (mmc->regulator_enabled) { + result = regulator_disable(supply); + if (result == 0) + mmc->regulator_enabled = false; + } + + if (result) + dev_err(mmc_dev(mmc), + "could not set regulator OCR (%d)\n", result); + return result; +} +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) +{ + int current_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; + + /* + * The voltage is already set, no need to switch. + * Return 1 to indicate that no switch happened. + */ + current_uV = regulator_get_voltage(regulator); + if (current_uV == target_uV) + return 1; + + return regulator_set_voltage_triplet(regulator, min_uV, target_uV, + max_uV); +} + +/** + * mmc_regulator_set_vqmmc - Set VQMMC as per the ios + * @mmc: the host to regulate + * @ios: io bus settings + * + * 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. + */ + ret = mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc, + min_uV, volt, max_uV); + if (ret >= 0) + return ret; + + return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc, + 2700000, volt, 3600000); + default: + return -EINVAL; + } +} +EXPORT_SYMBOL_GPL(mmc_regulator_set_vqmmc); + +#else + +static inline int mmc_regulator_get_ocrmask(struct regulator *supply) +{ + return 0; +} + +#endif /* CONFIG_REGULATOR */ + +/** + * mmc_regulator_get_supply - try to get VMMC and VQMMC regulators for a host + * @mmc: the host to regulate + * + * Returns 0 or errno. errno should be handled, it is either a critical error + * or -EPROBE_DEFER. 0 means no critical error but it does not mean all + * regulators have been found because they all are optional. If you require + * certain regulators, you need to check separately in your driver if they got + * populated after calling this function. + */ +int mmc_regulator_get_supply(struct mmc_host *mmc) +{ + struct device *dev = mmc_dev(mmc); + int ret; + + mmc->supply.vmmc = devm_regulator_get_optional(dev, "vmmc"); + mmc->supply.vqmmc = devm_regulator_get_optional(dev, "vqmmc"); + + if (IS_ERR(mmc->supply.vmmc)) { + if (PTR_ERR(mmc->supply.vmmc) == -EPROBE_DEFER) + return -EPROBE_DEFER; + dev_dbg(dev, "No vmmc regulator found\n"); + } else { + ret = mmc_regulator_get_ocrmask(mmc->supply.vmmc); + if (ret > 0) + mmc->ocr_avail = ret; + else + dev_warn(dev, "Failed getting OCR mask: %d\n", ret); + } + + if (IS_ERR(mmc->supply.vqmmc)) { + if (PTR_ERR(mmc->supply.vqmmc) == -EPROBE_DEFER) + return -EPROBE_DEFER; + dev_dbg(dev, "No vqmmc regulator found\n"); + } + + return 0; +} +EXPORT_SYMBOL_GPL(mmc_regulator_get_supply); + +/** + * mmc_regulator_enable_vqmmc - enable VQMMC regulator for a host + * @mmc: the host to regulate + * + * Returns 0 or errno. Enables the regulator for vqmmc. + * Keeps track of the enable status for ensuring that calls to + * regulator_enable/disable are balanced. + */ +int mmc_regulator_enable_vqmmc(struct mmc_host *mmc) +{ + int ret = 0; + + if (!IS_ERR(mmc->supply.vqmmc) && !mmc->vqmmc_enabled) { + ret = regulator_enable(mmc->supply.vqmmc); + if (ret < 0) + dev_err(mmc_dev(mmc), "enabling vqmmc regulator failed\n"); + else + mmc->vqmmc_enabled = true; + } + + return ret; +} +EXPORT_SYMBOL_GPL(mmc_regulator_enable_vqmmc); + +/** + * mmc_regulator_disable_vqmmc - disable VQMMC regulator for a host + * @mmc: the host to regulate + * + * Returns 0 or errno. Disables the regulator for vqmmc. + * Keeps track of the enable status for ensuring that calls to + * regulator_enable/disable are balanced. + */ +void mmc_regulator_disable_vqmmc(struct mmc_host *mmc) +{ + if (!IS_ERR(mmc->supply.vqmmc) && mmc->vqmmc_enabled) { + regulator_disable(mmc->supply.vqmmc); + mmc->vqmmc_enabled = false; + } +} +EXPORT_SYMBOL_GPL(mmc_regulator_disable_vqmmc); |