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