261 lines
7.1 KiB
C
261 lines
7.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Helper functions for MMC regulators.
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*/
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/log2.h>
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#include <linux/regulator/consumer.h>
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#include <linux/mmc/host.h>
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#include "core.h"
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#include "host.h"
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#ifdef CONFIG_REGULATOR
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/**
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* mmc_ocrbitnum_to_vdd - Convert a OCR bit number to its voltage
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* @vdd_bit: OCR bit number
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* @min_uV: minimum voltage value (mV)
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* @max_uV: maximum voltage value (mV)
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*
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* This function returns the voltage range according to the provided OCR
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* bit number. If conversion is not possible a negative errno value returned.
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*/
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static int mmc_ocrbitnum_to_vdd(int vdd_bit, int *min_uV, int *max_uV)
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{
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int tmp;
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if (!vdd_bit)
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return -EINVAL;
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/*
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* REVISIT mmc_vddrange_to_ocrmask() may have set some
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* bits this regulator doesn't quite support ... don't
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* be too picky, most cards and regulators are OK with
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* a 0.1V range goof (it's a small error percentage).
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*/
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tmp = vdd_bit - ilog2(MMC_VDD_165_195);
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if (tmp == 0) {
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*min_uV = 1650 * 1000;
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*max_uV = 1950 * 1000;
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} else {
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*min_uV = 1900 * 1000 + tmp * 100 * 1000;
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*max_uV = *min_uV + 100 * 1000;
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}
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return 0;
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}
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/**
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* mmc_regulator_get_ocrmask - return mask of supported voltages
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* @supply: regulator to use
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*
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* This returns either a negative errno, or a mask of voltages that
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* can be provided to MMC/SD/SDIO devices using the specified voltage
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* regulator. This would normally be called before registering the
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* MMC host adapter.
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*/
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static int mmc_regulator_get_ocrmask(struct regulator *supply)
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{
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int result = 0;
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int count;
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int i;
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int vdd_uV;
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int vdd_mV;
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count = regulator_count_voltages(supply);
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if (count < 0)
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return count;
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for (i = 0; i < count; i++) {
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vdd_uV = regulator_list_voltage(supply, i);
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if (vdd_uV <= 0)
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continue;
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vdd_mV = vdd_uV / 1000;
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result |= mmc_vddrange_to_ocrmask(vdd_mV, vdd_mV);
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}
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if (!result) {
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vdd_uV = regulator_get_voltage(supply);
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if (vdd_uV <= 0)
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return vdd_uV;
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vdd_mV = vdd_uV / 1000;
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result = mmc_vddrange_to_ocrmask(vdd_mV, vdd_mV);
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}
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return result;
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}
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/**
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* mmc_regulator_set_ocr - set regulator to match host->ios voltage
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* @mmc: the host to regulate
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* @supply: regulator to use
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* @vdd_bit: zero for power off, else a bit number (host->ios.vdd)
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*
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* Returns zero on success, else negative errno.
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*
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* MMC host drivers may use this to enable or disable a regulator using
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* a particular supply voltage. This would normally be called from the
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* set_ios() method.
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*/
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int mmc_regulator_set_ocr(struct mmc_host *mmc,
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struct regulator *supply,
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unsigned short vdd_bit)
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{
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int result = 0;
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int min_uV, max_uV;
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if (vdd_bit) {
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mmc_ocrbitnum_to_vdd(vdd_bit, &min_uV, &max_uV);
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result = regulator_set_voltage(supply, min_uV, max_uV);
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if (result == 0 && !mmc->regulator_enabled) {
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result = regulator_enable(supply);
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if (!result)
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mmc->regulator_enabled = true;
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}
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} else if (mmc->regulator_enabled) {
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result = regulator_disable(supply);
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if (result == 0)
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mmc->regulator_enabled = false;
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}
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if (result)
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dev_err(mmc_dev(mmc),
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"could not set regulator OCR (%d)\n", result);
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return result;
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}
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EXPORT_SYMBOL_GPL(mmc_regulator_set_ocr);
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static int mmc_regulator_set_voltage_if_supported(struct regulator *regulator,
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int min_uV, int target_uV,
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int max_uV)
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{
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/*
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* Check if supported first to avoid errors since we may try several
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* signal levels during power up and don't want to show errors.
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*/
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if (!regulator_is_supported_voltage(regulator, min_uV, max_uV))
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return -EINVAL;
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return regulator_set_voltage_triplet(regulator, min_uV, target_uV,
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max_uV);
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}
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/**
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* mmc_regulator_set_vqmmc - Set VQMMC as per the ios
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*
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* For 3.3V signaling, we try to match VQMMC to VMMC as closely as possible.
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* That will match the behavior of old boards where VQMMC and VMMC were supplied
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* by the same supply. The Bus Operating conditions for 3.3V signaling in the
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* SD card spec also define VQMMC in terms of VMMC.
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* If this is not possible we'll try the full 2.7-3.6V of the spec.
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*
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* For 1.2V and 1.8V signaling we'll try to get as close as possible to the
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* requested voltage. This is definitely a good idea for UHS where there's a
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* separate regulator on the card that's trying to make 1.8V and it's best if
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* we match.
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*
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* This function is expected to be used by a controller's
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* start_signal_voltage_switch() function.
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*/
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int mmc_regulator_set_vqmmc(struct mmc_host *mmc, struct mmc_ios *ios)
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{
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struct device *dev = mmc_dev(mmc);
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int ret, volt, min_uV, max_uV;
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/* If no vqmmc supply then we can't change the voltage */
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if (IS_ERR(mmc->supply.vqmmc))
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return -EINVAL;
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switch (ios->signal_voltage) {
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case MMC_SIGNAL_VOLTAGE_120:
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return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
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1100000, 1200000, 1300000);
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case MMC_SIGNAL_VOLTAGE_180:
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return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
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1700000, 1800000, 1950000);
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case MMC_SIGNAL_VOLTAGE_330:
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ret = mmc_ocrbitnum_to_vdd(mmc->ios.vdd, &volt, &max_uV);
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if (ret < 0)
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return ret;
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dev_dbg(dev, "%s: found vmmc voltage range of %d-%duV\n",
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__func__, volt, max_uV);
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min_uV = max(volt - 300000, 2700000);
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max_uV = min(max_uV + 200000, 3600000);
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/*
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* Due to a limitation in the current implementation of
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* regulator_set_voltage_triplet() which is taking the lowest
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* voltage possible if below the target, search for a suitable
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* voltage in two steps and try to stay close to vmmc
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* with a 0.3V tolerance at first.
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*/
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if (!mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
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min_uV, volt, max_uV))
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return 0;
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return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
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2700000, volt, 3600000);
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default:
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return -EINVAL;
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}
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}
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EXPORT_SYMBOL_GPL(mmc_regulator_set_vqmmc);
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#else
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static inline int mmc_regulator_get_ocrmask(struct regulator *supply)
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{
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return 0;
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}
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#endif /* CONFIG_REGULATOR */
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/**
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* mmc_regulator_get_supply - try to get VMMC and VQMMC regulators for a host
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* @mmc: the host to regulate
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*
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* Returns 0 or errno. errno should be handled, it is either a critical error
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* or -EPROBE_DEFER. 0 means no critical error but it does not mean all
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* regulators have been found because they all are optional. If you require
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* certain regulators, you need to check separately in your driver if they got
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* populated after calling this function.
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*/
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int mmc_regulator_get_supply(struct mmc_host *mmc)
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{
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struct device *dev = mmc_dev(mmc);
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int ret;
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mmc->supply.vmmc = devm_regulator_get_optional(dev, "vmmc");
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mmc->supply.vqmmc = devm_regulator_get_optional(dev, "vqmmc");
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if (IS_ERR(mmc->supply.vmmc)) {
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if (PTR_ERR(mmc->supply.vmmc) == -EPROBE_DEFER)
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return -EPROBE_DEFER;
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dev_dbg(dev, "No vmmc regulator found\n");
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} else {
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ret = mmc_regulator_get_ocrmask(mmc->supply.vmmc);
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if (ret > 0)
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mmc->ocr_avail = ret;
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else
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dev_warn(dev, "Failed getting OCR mask: %d\n", ret);
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}
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if (IS_ERR(mmc->supply.vqmmc)) {
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if (PTR_ERR(mmc->supply.vqmmc) == -EPROBE_DEFER)
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return -EPROBE_DEFER;
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dev_dbg(dev, "No vqmmc regulator found\n");
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(mmc_regulator_get_supply);
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