regulator.c (7537B)
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 */ 27static 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 */ 61static 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 */ 106int 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} 133EXPORT_SYMBOL_GPL(mmc_regulator_set_ocr); 134 135static 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 */ 179int 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} 224EXPORT_SYMBOL_GPL(mmc_regulator_set_vqmmc); 225 226#else 227 228static 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 */ 245int 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} 273EXPORT_SYMBOL_GPL(mmc_regulator_get_supply);