drivers/mmc/core/regulator.c

Source file repositories/reference/linux-study-clean/drivers/mmc/core/regulator.c

File Facts

System
Linux kernel
Corpus path
drivers/mmc/core/regulator.c
Extension
.c
Size
11904 bytes
Lines
433
Domain
Driver Families
Bucket
drivers/mmc
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

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);

		/*

Annotation

Implementation Notes