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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 (IS_ERR(supply))
114 return 0;
115
116 if (vdd_bit) {
117 mmc_ocrbitnum_to_vdd(vdd_bit, &min_uV, &max_uV);
118
119 result = regulator_set_voltage(supply, min_uV, max_uV);
120 if (result == 0 && !mmc->regulator_enabled) {
121 result = regulator_enable(supply);
122 if (!result)
123 mmc->regulator_enabled = true;
124 }
125 } else if (mmc->regulator_enabled) {
126 result = regulator_disable(supply);
127 if (result == 0)
128 mmc->regulator_enabled = false;
129 }
130
131 if (result)
132 dev_err(mmc_dev(mmc),
133 "could not set regulator OCR (%d)\n", result);
134 return result;
135}
136EXPORT_SYMBOL_GPL(mmc_regulator_set_ocr);
137
138static int mmc_regulator_set_voltage_if_supported(struct regulator *regulator,
139 int min_uV, int target_uV,
140 int max_uV)
141{
142 int current_uV;
143
144 /*
145 * Check if supported first to avoid errors since we may try several
146 * signal levels during power up and don't want to show errors.
147 */
148 if (!regulator_is_supported_voltage(regulator, min_uV, max_uV))
149 return -EINVAL;
150
151 /*
152 * The voltage is already set, no need to switch.
153 * Return 1 to indicate that no switch happened.
154 */
155 current_uV = regulator_get_voltage(regulator);
156 if (current_uV == target_uV)
157 return 1;
158
159 return regulator_set_voltage_triplet(regulator, min_uV, target_uV,
160 max_uV);
161}
162
163/**
164 * mmc_regulator_set_vqmmc - Set VQMMC as per the ios
165 * @mmc: the host to regulate
166 * @ios: io bus settings
167 *
168 * For 3.3V signaling, we try to match VQMMC to VMMC as closely as possible.
169 * That will match the behavior of old boards where VQMMC and VMMC were supplied
170 * by the same supply. The Bus Operating conditions for 3.3V signaling in the
171 * SD card spec also define VQMMC in terms of VMMC.
172 * If this is not possible we'll try the full 2.7-3.6V of the spec.
173 *
174 * For 1.2V and 1.8V signaling we'll try to get as close as possible to the
175 * requested voltage. This is definitely a good idea for UHS where there's a
176 * separate regulator on the card that's trying to make 1.8V and it's best if
177 * we match.
178 *
179 * This function is expected to be used by a controller's
180 * start_signal_voltage_switch() function.
181 */
182int mmc_regulator_set_vqmmc(struct mmc_host *mmc, struct mmc_ios *ios)
183{
184 struct device *dev = mmc_dev(mmc);
185 int ret, volt, min_uV, max_uV;
186
187 /* If no vqmmc supply then we can't change the voltage */
188 if (IS_ERR(mmc->supply.vqmmc))
189 return -EINVAL;
190
191 switch (ios->signal_voltage) {
192 case MMC_SIGNAL_VOLTAGE_120:
193 return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
194 1100000, 1200000, 1300000);
195 case MMC_SIGNAL_VOLTAGE_180:
196 return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
197 1700000, 1800000, 1950000);
198 case MMC_SIGNAL_VOLTAGE_330:
199 ret = mmc_ocrbitnum_to_vdd(mmc->ios.vdd, &volt, &max_uV);
200 if (ret < 0)
201 return ret;
202
203 dev_dbg(dev, "%s: found vmmc voltage range of %d-%duV\n",
204 __func__, volt, max_uV);
205
206 min_uV = max(volt - 300000, 2700000);
207 max_uV = min(max_uV + 200000, 3600000);
208
209 /*
210 * Due to a limitation in the current implementation of
211 * regulator_set_voltage_triplet() which is taking the lowest
212 * voltage possible if below the target, search for a suitable
213 * voltage in two steps and try to stay close to vmmc
214 * with a 0.3V tolerance at first.
215 */
216 ret = mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
217 min_uV, volt, max_uV);
218 if (ret >= 0)
219 return ret;
220
221 return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
222 2700000, volt, 3600000);
223 default:
224 return -EINVAL;
225 }
226}
227EXPORT_SYMBOL_GPL(mmc_regulator_set_vqmmc);
228
229#else
230
231static inline int mmc_regulator_get_ocrmask(struct regulator *supply)
232{
233 return 0;
234}
235
236#endif /* CONFIG_REGULATOR */
237
238/**
239 * mmc_regulator_get_supply - try to get VMMC and VQMMC regulators for a host
240 * @mmc: the host to regulate
241 *
242 * Returns 0 or errno. errno should be handled, it is either a critical error
243 * or -EPROBE_DEFER. 0 means no critical error but it does not mean all
244 * regulators have been found because they all are optional. If you require
245 * certain regulators, you need to check separately in your driver if they got
246 * populated after calling this function.
247 */
248int mmc_regulator_get_supply(struct mmc_host *mmc)
249{
250 struct device *dev = mmc_dev(mmc);
251 int ret;
252
253 mmc->supply.vmmc = devm_regulator_get_optional(dev, "vmmc");
254 mmc->supply.vqmmc = devm_regulator_get_optional(dev, "vqmmc");
255
256 if (IS_ERR(mmc->supply.vmmc)) {
257 if (PTR_ERR(mmc->supply.vmmc) == -EPROBE_DEFER)
258 return -EPROBE_DEFER;
259 dev_dbg(dev, "No vmmc regulator found\n");
260 } else {
261 ret = mmc_regulator_get_ocrmask(mmc->supply.vmmc);
262 if (ret > 0)
263 mmc->ocr_avail = ret;
264 else
265 dev_warn(dev, "Failed getting OCR mask: %d\n", ret);
266 }
267
268 if (IS_ERR(mmc->supply.vqmmc)) {
269 if (PTR_ERR(mmc->supply.vqmmc) == -EPROBE_DEFER)
270 return -EPROBE_DEFER;
271 dev_dbg(dev, "No vqmmc regulator found\n");
272 }
273
274 return 0;
275}
276EXPORT_SYMBOL_GPL(mmc_regulator_get_supply);
277
278/**
279 * mmc_regulator_enable_vqmmc - enable VQMMC regulator for a host
280 * @mmc: the host to regulate
281 *
282 * Returns 0 or errno. Enables the regulator for vqmmc.
283 * Keeps track of the enable status for ensuring that calls to
284 * regulator_enable/disable are balanced.
285 */
286int mmc_regulator_enable_vqmmc(struct mmc_host *mmc)
287{
288 int ret = 0;
289
290 if (!IS_ERR(mmc->supply.vqmmc) && !mmc->vqmmc_enabled) {
291 ret = regulator_enable(mmc->supply.vqmmc);
292 if (ret < 0)
293 dev_err(mmc_dev(mmc), "enabling vqmmc regulator failed\n");
294 else
295 mmc->vqmmc_enabled = true;
296 }
297
298 return ret;
299}
300EXPORT_SYMBOL_GPL(mmc_regulator_enable_vqmmc);
301
302/**
303 * mmc_regulator_disable_vqmmc - disable VQMMC regulator for a host
304 * @mmc: the host to regulate
305 *
306 * Returns 0 or errno. Disables the regulator for vqmmc.
307 * Keeps track of the enable status for ensuring that calls to
308 * regulator_enable/disable are balanced.
309 */
310void mmc_regulator_disable_vqmmc(struct mmc_host *mmc)
311{
312 if (!IS_ERR(mmc->supply.vqmmc) && mmc->vqmmc_enabled) {
313 regulator_disable(mmc->supply.vqmmc);
314 mmc->vqmmc_enabled = false;
315 }
316}
317EXPORT_SYMBOL_GPL(mmc_regulator_disable_vqmmc);