drivers/mmc/core/regulator.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Helper functions for MMC regulators.
   4  */
   5
   6 #include <linux/device.h>
   7 #include <linux/err.h>
   8 #include <linux/log2.h>
   9 #include <linux/regulator/consumer.h>
  10
  11 #include <linux/mmc/host.h>
  12
  13 #include "core.h"
  14 #include "host.h"
  15
  16 #ifdef CONFIG_REGULATOR
  17
  18 /**
  19  * mmc_ocrbitnum_to_vdd - Convert a OCR bit number to its voltage
  20  * @vdd_bit:    OCR bit number
  21  * @min_uV:     minimum voltage value (mV)
  22  * @max_uV:     maximum voltage value (mV)
  23  *
  24  * This function returns the voltage range according to the provided OCR
  25  * bit number. If conversion is not possible a negative errno value returned.
  26  */
  27 static int mmc_ocrbitnum_to_vdd(int vdd_bit, int *min_uV, int *max_uV)
  28 {
  29         int             tmp;
  30
  31         if (!vdd_bit)
  32                 return -EINVAL;
  33
  34         /*
  35          * REVISIT mmc_vddrange_to_ocrmask() may have set some
  36          * bits this regulator doesn't quite support ... don't
  37          * be too picky, most cards and regulators are OK with
  38          * a 0.1V range goof (it's a small error percentage).
  39          */
  40         tmp = vdd_bit - ilog2(MMC_VDD_165_195);
  41         if (tmp == 0) {
  42                 *min_uV = 1650 * 1000;
  43                 *max_uV = 1950 * 1000;
  44         } else {
  45                 *min_uV = 1900 * 1000 + tmp * 100 * 1000;
  46                 *max_uV = *min_uV + 100 * 1000;
  47         }
  48
  49         return 0;
  50 }
  51
  52 /**
  53  * mmc_regulator_get_ocrmask - return mask of supported voltages
  54  * @supply: regulator to use
  55  *
  56  * This returns either a negative errno, or a mask of voltages that
  57  * can be provided to MMC/SD/SDIO devices using the specified voltage
  58  * regulator.  This would normally be called before registering the
  59  * MMC host adapter.
  60  */
  61 static int mmc_regulator_get_ocrmask(struct regulator *supply)
  62 {
  63         int                     result = 0;
  64         int                     count;
  65         int                     i;
  66         int                     vdd_uV;
  67         int                     vdd_mV;
  68
  69         count = regulator_count_voltages(supply);
  70         if (count < 0)
  71                 return count;
  72
  73         for (i = 0; i < count; i++) {
  74                 vdd_uV = regulator_list_voltage(supply, i);
  75                 if (vdd_uV <= 0)
  76                         continue;
  77
  78                 vdd_mV = vdd_uV / 1000;
  79                 result |= mmc_vddrange_to_ocrmask(vdd_mV, vdd_mV);
  80         }
  81
  82         if (!result) {
  83                 vdd_uV = regulator_get_voltage(supply);
  84                 if (vdd_uV <= 0)
  85                         return vdd_uV;
  86
  87                 vdd_mV = vdd_uV / 1000;
  88                 result = mmc_vddrange_to_ocrmask(vdd_mV, vdd_mV);
  89         }
  90
  91         return result;
  92 }
  93
  94 /**
  95  * mmc_regulator_set_ocr - set regulator to match host->ios voltage
  96  * @mmc: the host to regulate
  97  * @supply: regulator to use
  98  * @vdd_bit: zero for power off, else a bit number (host->ios.vdd)
  99  *
 100  * Returns zero on success, else negative errno.
 101  *
 102  * MMC host drivers may use this to enable or disable a regulator using
 103  * a particular supply voltage.  This would normally be called from the
 104  * set_ios() method.
 105  */
 106 int mmc_regulator_set_ocr(struct mmc_host *mmc,
 107                         struct regulator *supply,
 108                         unsigned short vdd_bit)
 109 {
 110         int                     result = 0;
 111         int                     min_uV, max_uV;
 112
 113         if (vdd_bit) {
 114                 mmc_ocrbitnum_to_vdd(vdd_bit, &min_uV, &max_uV);
 115
 116                 result = regulator_set_voltage(supply, min_uV, max_uV);
 117                 if (result == 0 && !mmc->regulator_enabled) {
 118                         result = regulator_enable(supply);
 119                         if (!result)
 120                                 mmc->regulator_enabled = true;
 121                 }
 122         } else if (mmc->regulator_enabled) {
 123                 result = regulator_disable(supply);
 124                 if (result == 0)
 125                         mmc->regulator_enabled = false;
 126         }
 127
 128         if (result)
 129                 dev_err(mmc_dev(mmc),
 130                         "could not set regulator OCR (%d)\n", result);
 131         return result;
 132 }
 133 EXPORT_SYMBOL_GPL(mmc_regulator_set_ocr);
 134
 135 static int mmc_regulator_set_voltage_if_supported(struct regulator *regulator,
 136                                                   int min_uV, int target_uV,
 137                                                   int max_uV)
 138 {
 139         /*
 140          * Check if supported first to avoid errors since we may try several
 141          * signal levels during power up and don't want to show errors.
 142          */
 143         if (!regulator_is_supported_voltage(regulator, min_uV, max_uV))
 144                 return -EINVAL;
 145
 146         return regulator_set_voltage_triplet(regulator, min_uV, target_uV,
 147                                              max_uV);
 148 }
 149
 150 /**
 151  * mmc_regulator_set_vqmmc - Set VQMMC as per the ios
 152  *
 153  * For 3.3V signaling, we try to match VQMMC to VMMC as closely as possible.
 154  * That will match the behavior of old boards where VQMMC and VMMC were supplied
 155  * by the same supply.  The Bus Operating conditions for 3.3V signaling in the
 156  * SD card spec also define VQMMC in terms of VMMC.
 157  * If this is not possible we'll try the full 2.7-3.6V of the spec.
 158  *
 159  * For 1.2V and 1.8V signaling we'll try to get as close as possible to the
 160  * requested voltage.  This is definitely a good idea for UHS where there's a
 161  * separate regulator on the card that's trying to make 1.8V and it's best if
 162  * we match.
 163  *
 164  * This function is expected to be used by a controller's
 165  * start_signal_voltage_switch() function.
 166  */
 167 int mmc_regulator_set_vqmmc(struct mmc_host *mmc, struct mmc_ios *ios)
 168 {
 169         struct device *dev = mmc_dev(mmc);
 170         int ret, volt, min_uV, max_uV;
 171
 172         /* If no vqmmc supply then we can't change the voltage */
 173         if (IS_ERR(mmc->supply.vqmmc))
 174                 return -EINVAL;
 175
 176         switch (ios->signal_voltage) {
 177         case MMC_SIGNAL_VOLTAGE_120:
 178                 return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
 179                                                 1100000, 1200000, 1300000);
 180         case MMC_SIGNAL_VOLTAGE_180:
 181                 return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
 182                                                 1700000, 1800000, 1950000);
 183         case MMC_SIGNAL_VOLTAGE_330:
 184                 ret = mmc_ocrbitnum_to_vdd(mmc->ios.vdd, &volt, &max_uV);
 185                 if (ret < 0)
 186                         return ret;
 187
 188                 dev_dbg(dev, "%s: found vmmc voltage range of %d-%duV\n",
 189                         __func__, volt, max_uV);
 190
 191                 min_uV = max(volt - 300000, 2700000);
 192                 max_uV = min(max_uV + 200000, 3600000);
 193
 194                 /*
 195                  * Due to a limitation in the current implementation of
 196                  * regulator_set_voltage_triplet() which is taking the lowest
 197                  * voltage possible if below the target, search for a suitable
 198                  * voltage in two steps and try to stay close to vmmc
 199                  * with a 0.3V tolerance at first.
 200                  */
 201                 if (!mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
 202                                                 min_uV, volt, max_uV))
 203                         return 0;
 204
 205                 return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
 206                                                 2700000, volt, 3600000);
 207         default:
 208                 return -EINVAL;
 209         }
 210 }
 211 EXPORT_SYMBOL_GPL(mmc_regulator_set_vqmmc);
 212
 213 #else
 214
 215 static inline int mmc_regulator_get_ocrmask(struct regulator *supply)
 216 {
 217         return 0;
 218 }
 219
 220 #endif /* CONFIG_REGULATOR */
 221
 222 /**
 223  * mmc_regulator_get_supply - try to get VMMC and VQMMC regulators for a host
 224  * @mmc: the host to regulate
 225  *
 226  * Returns 0 or errno. errno should be handled, it is either a critical error
 227  * or -EPROBE_DEFER. 0 means no critical error but it does not mean all
 228  * regulators have been found because they all are optional. If you require
 229  * certain regulators, you need to check separately in your driver if they got
 230  * populated after calling this function.
 231  */
 232 int mmc_regulator_get_supply(struct mmc_host *mmc)
 233 {
 234         struct device *dev = mmc_dev(mmc);
 235         int ret;
 236
 237         mmc->supply.vmmc = devm_regulator_get_optional(dev, "vmmc");
 238         mmc->supply.vqmmc = devm_regulator_get_optional(dev, "vqmmc");
 239
 240         if (IS_ERR(mmc->supply.vmmc)) {
 241                 if (PTR_ERR(mmc->supply.vmmc) == -EPROBE_DEFER)
 242                         return -EPROBE_DEFER;
 243                 dev_dbg(dev, "No vmmc regulator found\n");
 244         } else {
 245                 ret = mmc_regulator_get_ocrmask(mmc->supply.vmmc);
 246                 if (ret > 0)
 247                         mmc->ocr_avail = ret;
 248                 else
 249                         dev_warn(dev, "Failed getting OCR mask: %d\n", ret);
 250         }
 251
 252         if (IS_ERR(mmc->supply.vqmmc)) {
 253                 if (PTR_ERR(mmc->supply.vqmmc) == -EPROBE_DEFER)
 254                         return -EPROBE_DEFER;
 255                 dev_dbg(dev, "No vqmmc regulator found\n");
 256         }
 257
 258         return 0;
 259 }
 260 EXPORT_SYMBOL_GPL(mmc_regulator_get_supply);