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- // 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);
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