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         int current_uV;
 140
 141         /*
 142          * Check if supported first to avoid errors since we may try several
 143          * signal levels during power up and don't want to show errors.
 144          */
 145         if (!regulator_is_supported_voltage(regulator, min_uV, max_uV))
 146                 return -EINVAL;
 147
 148         /*
 149          * The voltage is already set, no need to switch.
 150          * Return 1 to indicate that no switch happened.
 151          */
 152         current_uV = regulator_get_voltage(regulator);
 153         if (current_uV == target_uV)
 154                 return 1;
 155
 156         return regulator_set_voltage_triplet(regulator, min_uV, target_uV,
 157                                              max_uV);
 158 }
 159
 160 /**
 161  * mmc_regulator_set_vqmmc - Set VQMMC as per the ios
 162  * @mmc: the host to regulate
 163  * @ios: io bus settings
 164  *
 165  * For 3.3V signaling, we try to match VQMMC to VMMC as closely as possible.
 166  * That will match the behavior of old boards where VQMMC and VMMC were supplied
 167  * by the same supply.  The Bus Operating conditions for 3.3V signaling in the
 168  * SD card spec also define VQMMC in terms of VMMC.
 169  * If this is not possible we'll try the full 2.7-3.6V of the spec.
 170  *
 171  * For 1.2V and 1.8V signaling we'll try to get as close as possible to the
 172  * requested voltage.  This is definitely a good idea for UHS where there's a
 173  * separate regulator on the card that's trying to make 1.8V and it's best if
 174  * we match.
 175  *
 176  * This function is expected to be used by a controller's
 177  * start_signal_voltage_switch() function.
 178  */
 179 int mmc_regulator_set_vqmmc(struct mmc_host *mmc, struct mmc_ios *ios)
 180 {
 181         struct device *dev = mmc_dev(mmc);
 182         int ret, volt, min_uV, max_uV;
 183
 184         /* If no vqmmc supply then we can't change the voltage */
 185         if (IS_ERR(mmc->supply.vqmmc))
 186                 return -EINVAL;
 187
 188         switch (ios->signal_voltage) {
 189         case MMC_SIGNAL_VOLTAGE_120:
 190                 return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
 191                                                 1100000, 1200000, 1300000);
 192         case MMC_SIGNAL_VOLTAGE_180:
 193                 return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
 194                                                 1700000, 1800000, 1950000);
 195         case MMC_SIGNAL_VOLTAGE_330:
 196                 ret = mmc_ocrbitnum_to_vdd(mmc->ios.vdd, &volt, &max_uV);
 197                 if (ret < 0)
 198                         return ret;
 199
 200                 dev_dbg(dev, "%s: found vmmc voltage range of %d-%duV\n",
 201                         __func__, volt, max_uV);
 202
 203                 min_uV = max(volt - 300000, 2700000);
 204                 max_uV = min(max_uV + 200000, 3600000);
 205
 206                 /*
 207                  * Due to a limitation in the current implementation of
 208                  * regulator_set_voltage_triplet() which is taking the lowest
 209                  * voltage possible if below the target, search for a suitable
 210                  * voltage in two steps and try to stay close to vmmc
 211                  * with a 0.3V tolerance at first.
 212                  */
 213                 ret = mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
 214                                                         min_uV, volt, max_uV);
 215                 if (ret >= 0)
 216                         return ret;
 217
 218                 return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
 219                                                 2700000, volt, 3600000);
 220         default:
 221                 return -EINVAL;
 222         }
 223 }
 224 EXPORT_SYMBOL_GPL(mmc_regulator_set_vqmmc);
 225
 226 #else
 227
 228 static inline int mmc_regulator_get_ocrmask(struct regulator *supply)
 229 {
 230         return 0;
 231 }
 232
 233 #endif /* CONFIG_REGULATOR */
 234
 235 /**
 236  * mmc_regulator_get_supply - try to get VMMC and VQMMC regulators for a host
 237  * @mmc: the host to regulate
 238  *
 239  * Returns 0 or errno. errno should be handled, it is either a critical error
 240  * or -EPROBE_DEFER. 0 means no critical error but it does not mean all
 241  * regulators have been found because they all are optional. If you require
 242  * certain regulators, you need to check separately in your driver if they got
 243  * populated after calling this function.
 244  */
 245 int mmc_regulator_get_supply(struct mmc_host *mmc)
 246 {
 247         struct device *dev = mmc_dev(mmc);
 248         int ret;
 249
 250         mmc->supply.vmmc = devm_regulator_get_optional(dev, "vmmc");
 251         mmc->supply.vqmmc = devm_regulator_get_optional(dev, "vqmmc");
 252
 253         if (IS_ERR(mmc->supply.vmmc)) {
 254                 if (PTR_ERR(mmc->supply.vmmc) == -EPROBE_DEFER)
 255                         return -EPROBE_DEFER;
 256                 dev_dbg(dev, "No vmmc regulator found\n");
 257         } else {
 258                 ret = mmc_regulator_get_ocrmask(mmc->supply.vmmc);
 259                 if (ret > 0)
 260                         mmc->ocr_avail = ret;
 261                 else
 262                         dev_warn(dev, "Failed getting OCR mask: %d\n", ret);
 263         }
 264
 265         if (IS_ERR(mmc->supply.vqmmc)) {
 266                 if (PTR_ERR(mmc->supply.vqmmc) == -EPROBE_DEFER)
 267                         return -EPROBE_DEFER;
 268                 dev_dbg(dev, "No vqmmc regulator found\n");
 269         }
 270
 271         return 0;
 272 }
 273 EXPORT_SYMBOL_GPL(mmc_regulator_get_supply);