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);