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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)
{
/*
* 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);
#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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