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273 lines
7.4 KiB
273 lines
7.4 KiB
// 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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int current_uV; |
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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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/* |
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* The voltage is already set, no need to switch. |
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* Return 1 to indicate that no switch happened. |
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*/ |
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current_uV = regulator_get_voltage(regulator); |
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if (current_uV == target_uV) |
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return 1; |
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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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* @mmc: the host to regulate |
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* @ios: io bus settings |
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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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ret = mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc, |
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min_uV, volt, max_uV); |
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if (ret >= 0) |
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return ret; |
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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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