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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#include <linux/workqueue.h>
11
12#include <linux/mmc/host.h>
13
14#include "core.h"
15#include "host.h"
16
17#ifdef CONFIG_REGULATOR
18
19/**
20 * mmc_ocrbitnum_to_vdd - Convert a OCR bit number to its voltage
21 * @vdd_bit: OCR bit number
22 * @min_uV: minimum voltage value (mV)
23 * @max_uV: maximum voltage value (mV)
24 *
25 * This function returns the voltage range according to the provided OCR
26 * bit number. If conversion is not possible a negative errno value returned.
27 */
28static int mmc_ocrbitnum_to_vdd(int vdd_bit, int *min_uV, int *max_uV)
29{
30 int tmp;
31
32 if (!vdd_bit)
33 return -EINVAL;
34
35 /*
36 * REVISIT mmc_vddrange_to_ocrmask() may have set some
37 * bits this regulator doesn't quite support ... don't
38 * be too picky, most cards and regulators are OK with
39 * a 0.1V range goof (it's a small error percentage).
40 */
41 tmp = vdd_bit - ilog2(MMC_VDD_165_195);
42 if (tmp == 0) {
43 *min_uV = 1650 * 1000;
44 *max_uV = 1950 * 1000;
45 } else {
46 *min_uV = 1900 * 1000 + tmp * 100 * 1000;
47 *max_uV = *min_uV + 100 * 1000;
48 }
49
50 return 0;
51}
52
53/**
54 * mmc_regulator_get_ocrmask - return mask of supported voltages
55 * @supply: regulator to use
56 *
57 * This returns either a negative errno, or a mask of voltages that
58 * can be provided to MMC/SD/SDIO devices using the specified voltage
59 * regulator. This would normally be called before registering the
60 * MMC host adapter.
61 */
62static int mmc_regulator_get_ocrmask(struct regulator *supply)
63{
64 int result = 0;
65 int count;
66 int i;
67 int vdd_uV;
68 int vdd_mV;
69
70 count = regulator_count_voltages(supply);
71 if (count < 0)
72 return count;
73
74 for (i = 0; i < count; i++) {
75 vdd_uV = regulator_list_voltage(supply, i);
76 if (vdd_uV <= 0)
77 continue;
78
79 vdd_mV = vdd_uV / 1000;
80 result |= mmc_vddrange_to_ocrmask(vdd_mV, vdd_mV);
81 }
82
83 if (!result) {
84 vdd_uV = regulator_get_voltage(supply);
85 if (vdd_uV <= 0)
86 return vdd_uV;
87
88 vdd_mV = vdd_uV / 1000;
89 result = mmc_vddrange_to_ocrmask(vdd_mV, vdd_mV);
90 }
91
92 return result;
93}
94
95/**
96 * mmc_regulator_set_ocr - set regulator to match host->ios voltage
97 * @mmc: the host to regulate
98 * @supply: regulator to use
99 * @vdd_bit: zero for power off, else a bit number (host->ios.vdd)
100 *
101 * Returns zero on success, else negative errno.
102 *
103 * MMC host drivers may use this to enable or disable a regulator using
104 * a particular supply voltage. This would normally be called from the
105 * set_ios() method.
106 */
107int mmc_regulator_set_ocr(struct mmc_host *mmc,
108 struct regulator *supply,
109 unsigned short vdd_bit)
110{
111 int result = 0;
112 int min_uV, max_uV;
113
114 if (IS_ERR(supply))
115 return 0;
116
117 if (vdd_bit) {
118 mmc_ocrbitnum_to_vdd(vdd_bit, &min_uV, &max_uV);
119
120 result = regulator_set_voltage(supply, min_uV, max_uV);
121 if (result == 0 && !mmc->regulator_enabled) {
122 result = regulator_enable(supply);
123 if (!result)
124 mmc->regulator_enabled = true;
125 }
126 } else if (mmc->regulator_enabled) {
127 result = regulator_disable(supply);
128 if (result == 0)
129 mmc->regulator_enabled = false;
130 }
131
132 if (result)
133 dev_err(mmc_dev(mmc),
134 "could not set regulator OCR (%d)\n", result);
135 return result;
136}
137EXPORT_SYMBOL_GPL(mmc_regulator_set_ocr);
138
139static int mmc_regulator_set_voltage_if_supported(struct regulator *regulator,
140 int min_uV, int target_uV,
141 int max_uV)
142{
143 int current_uV;
144
145 /*
146 * Check if supported first to avoid errors since we may try several
147 * signal levels during power up and don't want to show errors.
148 */
149 if (!regulator_is_supported_voltage(regulator, min_uV, max_uV))
150 return -EINVAL;
151
152 /*
153 * The voltage is already set, no need to switch.
154 * Return 1 to indicate that no switch happened.
155 */
156 current_uV = regulator_get_voltage(regulator);
157 if (current_uV == target_uV)
158 return 1;
159
160 return regulator_set_voltage_triplet(regulator, min_uV, target_uV,
161 max_uV);
162}
163
164/**
165 * mmc_regulator_set_vqmmc - Set VQMMC as per the ios
166 * @mmc: the host to regulate
167 * @ios: io bus settings
168 *
169 * For 3.3V signaling, we try to match VQMMC to VMMC as closely as possible.
170 * That will match the behavior of old boards where VQMMC and VMMC were supplied
171 * by the same supply. The Bus Operating conditions for 3.3V signaling in the
172 * SD card spec also define VQMMC in terms of VMMC.
173 * If this is not possible we'll try the full 2.7-3.6V of the spec.
174 *
175 * For 1.2V and 1.8V signaling we'll try to get as close as possible to the
176 * requested voltage. This is definitely a good idea for UHS where there's a
177 * separate regulator on the card that's trying to make 1.8V and it's best if
178 * we match.
179 *
180 * This function is expected to be used by a controller's
181 * start_signal_voltage_switch() function.
182 */
183int mmc_regulator_set_vqmmc(struct mmc_host *mmc, struct mmc_ios *ios)
184{
185 struct device *dev = mmc_dev(mmc);
186 int ret, volt, min_uV, max_uV;
187
188 /* If no vqmmc supply then we can't change the voltage */
189 if (IS_ERR(mmc->supply.vqmmc))
190 return -EINVAL;
191
192 switch (ios->signal_voltage) {
193 case MMC_SIGNAL_VOLTAGE_120:
194 return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
195 1100000, 1200000, 1300000);
196 case MMC_SIGNAL_VOLTAGE_180:
197 return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
198 1700000, 1800000, 1950000);
199 case MMC_SIGNAL_VOLTAGE_330:
200 ret = mmc_ocrbitnum_to_vdd(mmc->ios.vdd, &volt, &max_uV);
201 if (ret < 0)
202 return ret;
203
204 dev_dbg(dev, "%s: found vmmc voltage range of %d-%duV\n",
205 __func__, volt, max_uV);
206
207 min_uV = max(volt - 300000, 2700000);
208 max_uV = min(max_uV + 200000, 3600000);
209
210 /*
211 * Due to a limitation in the current implementation of
212 * regulator_set_voltage_triplet() which is taking the lowest
213 * voltage possible if below the target, search for a suitable
214 * voltage in two steps and try to stay close to vmmc
215 * with a 0.3V tolerance at first.
216 */
217 ret = mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
218 min_uV, volt, max_uV);
219 if (ret >= 0)
220 return ret;
221
222 return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
223 2700000, volt, 3600000);
224 default:
225 return -EINVAL;
226 }
227}
228EXPORT_SYMBOL_GPL(mmc_regulator_set_vqmmc);
229
230/**
231 * mmc_regulator_set_vqmmc2 - Set vqmmc2 as per the ios->vqmmc2_voltage
232 * @mmc: The mmc host to regulate
233 * @ios: The io bus settings
234 *
235 * Sets a new voltage level for the vqmmc2 regulator, which may correspond to
236 * the vdd2 regulator for an SD UHS-II interface. This function is expected to
237 * be called by mmc host drivers.
238 *
239 * Returns a negative error code on failure, zero if the voltage level was
240 * changed successfully or a positive value if the level didn't need to change.
241 */
242int mmc_regulator_set_vqmmc2(struct mmc_host *mmc, struct mmc_ios *ios)
243{
244 if (IS_ERR(mmc->supply.vqmmc2))
245 return -EINVAL;
246
247 switch (ios->vqmmc2_voltage) {
248 case MMC_VQMMC2_VOLTAGE_180:
249 return mmc_regulator_set_voltage_if_supported(
250 mmc->supply.vqmmc2, 1700000, 1800000, 1950000);
251 default:
252 return -EINVAL;
253 }
254}
255EXPORT_SYMBOL_GPL(mmc_regulator_set_vqmmc2);
256
257#else
258
259static inline int mmc_regulator_get_ocrmask(struct regulator *supply)
260{
261 return 0;
262}
263
264#endif /* CONFIG_REGULATOR */
265
266/* To be called from a high-priority workqueue */
267void mmc_undervoltage_workfn(struct work_struct *work)
268{
269 struct mmc_supply *supply;
270 struct mmc_host *host;
271
272 supply = container_of(work, struct mmc_supply, uv_work);
273 host = container_of(supply, struct mmc_host, supply);
274
275 mmc_handle_undervoltage(host);
276}
277
278static int mmc_handle_regulator_event(struct notifier_block *nb,
279 unsigned long event, void *data)
280{
281 struct mmc_supply *supply = container_of(nb, struct mmc_supply,
282 vmmc_nb);
283 struct mmc_host *host = container_of(supply, struct mmc_host, supply);
284 unsigned long flags;
285
286 switch (event) {
287 case REGULATOR_EVENT_UNDER_VOLTAGE:
288 spin_lock_irqsave(&host->lock, flags);
289 if (host->undervoltage) {
290 spin_unlock_irqrestore(&host->lock, flags);
291 return NOTIFY_OK;
292 }
293
294 host->undervoltage = true;
295 spin_unlock_irqrestore(&host->lock, flags);
296
297 queue_work(system_highpri_wq, &host->supply.uv_work);
298 break;
299 default:
300 return NOTIFY_DONE;
301 }
302
303 return NOTIFY_OK;
304}
305
306/**
307 * mmc_regulator_register_undervoltage_notifier - Register for undervoltage
308 * events
309 * @host: MMC host
310 *
311 * To be called by a bus driver when a card supporting graceful shutdown
312 * is attached.
313 */
314void mmc_regulator_register_undervoltage_notifier(struct mmc_host *host)
315{
316 int ret;
317
318 if (IS_ERR_OR_NULL(host->supply.vmmc))
319 return;
320
321 host->supply.vmmc_nb.notifier_call = mmc_handle_regulator_event;
322 ret = regulator_register_notifier(host->supply.vmmc,
323 &host->supply.vmmc_nb);
324 if (ret)
325 dev_warn(mmc_dev(host), "Failed to register vmmc notifier: %d\n", ret);
326}
327
328/**
329 * mmc_regulator_unregister_undervoltage_notifier - Unregister undervoltage
330 * notifier
331 * @host: MMC host
332 */
333void mmc_regulator_unregister_undervoltage_notifier(struct mmc_host *host)
334{
335 if (IS_ERR_OR_NULL(host->supply.vmmc))
336 return;
337
338 regulator_unregister_notifier(host->supply.vmmc, &host->supply.vmmc_nb);
339 cancel_work_sync(&host->supply.uv_work);
340}
341
342/**
343 * mmc_regulator_get_supply - try to get VMMC and VQMMC regulators for a host
344 * @mmc: the host to regulate
345 *
346 * Returns 0 or errno. errno should be handled, it is either a critical error
347 * or -EPROBE_DEFER. 0 means no critical error but it does not mean all
348 * regulators have been found because they all are optional. If you require
349 * certain regulators, you need to check separately in your driver if they got
350 * populated after calling this function.
351 */
352int mmc_regulator_get_supply(struct mmc_host *mmc)
353{
354 struct device *dev = mmc_dev(mmc);
355 int ret;
356
357 mmc->supply.vmmc = devm_regulator_get_optional(dev, "vmmc");
358 mmc->supply.vqmmc = devm_regulator_get_optional(dev, "vqmmc");
359 mmc->supply.vqmmc2 = devm_regulator_get_optional(dev, "vqmmc2");
360
361 if (IS_ERR(mmc->supply.vmmc)) {
362 if (PTR_ERR(mmc->supply.vmmc) == -EPROBE_DEFER)
363 return dev_err_probe(dev, -EPROBE_DEFER,
364 "vmmc regulator not available\n");
365
366 dev_dbg(dev, "No vmmc regulator found\n");
367 } else {
368 ret = mmc_regulator_get_ocrmask(mmc->supply.vmmc);
369 if (ret > 0)
370 mmc->ocr_avail = ret;
371 else
372 dev_warn(dev, "Failed getting OCR mask: %d\n", ret);
373 }
374
375 if (IS_ERR(mmc->supply.vqmmc)) {
376 if (PTR_ERR(mmc->supply.vqmmc) == -EPROBE_DEFER)
377 return dev_err_probe(dev, -EPROBE_DEFER,
378 "vqmmc regulator not available\n");
379
380 dev_dbg(dev, "No vqmmc regulator found\n");
381 }
382
383 if (IS_ERR(mmc->supply.vqmmc2)) {
384 if (PTR_ERR(mmc->supply.vqmmc2) == -EPROBE_DEFER)
385 return -EPROBE_DEFER;
386 dev_dbg(dev, "No vqmmc2 regulator found\n");
387 }
388
389 return 0;
390}
391EXPORT_SYMBOL_GPL(mmc_regulator_get_supply);
392
393/**
394 * mmc_regulator_enable_vqmmc - enable VQMMC regulator for a host
395 * @mmc: the host to regulate
396 *
397 * Returns 0 or errno. Enables the regulator for vqmmc.
398 * Keeps track of the enable status for ensuring that calls to
399 * regulator_enable/disable are balanced.
400 */
401int mmc_regulator_enable_vqmmc(struct mmc_host *mmc)
402{
403 int ret = 0;
404
405 if (!IS_ERR(mmc->supply.vqmmc) && !mmc->vqmmc_enabled) {
406 ret = regulator_enable(mmc->supply.vqmmc);
407 if (ret < 0)
408 dev_err(mmc_dev(mmc), "enabling vqmmc regulator failed\n");
409 else
410 mmc->vqmmc_enabled = true;
411 }
412
413 return ret;
414}
415EXPORT_SYMBOL_GPL(mmc_regulator_enable_vqmmc);
416
417/**
418 * mmc_regulator_disable_vqmmc - disable VQMMC regulator for a host
419 * @mmc: the host to regulate
420 *
421 * Returns 0 or errno. Disables the regulator for vqmmc.
422 * Keeps track of the enable status for ensuring that calls to
423 * regulator_enable/disable are balanced.
424 */
425void mmc_regulator_disable_vqmmc(struct mmc_host *mmc)
426{
427 if (!IS_ERR(mmc->supply.vqmmc) && mmc->vqmmc_enabled) {
428 regulator_disable(mmc->supply.vqmmc);
429 mmc->vqmmc_enabled = false;
430 }
431}
432EXPORT_SYMBOL_GPL(mmc_regulator_disable_vqmmc);