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  */
mmc_ocrbitnum_to_vdd(int vdd_bit,int * min_uV,int * max_uV)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  */
mmc_regulator_get_ocrmask(struct regulator * supply)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  */
mmc_regulator_set_ocr(struct mmc_host * mmc,struct regulator * supply,unsigned short vdd_bit)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 
mmc_regulator_set_voltage_if_supported(struct regulator * regulator,int min_uV,int target_uV,int max_uV)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  * @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  */
mmc_regulator_set_vqmmc(struct mmc_host * mmc,struct mmc_ios * ios)179 int 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 }
224 EXPORT_SYMBOL_GPL(mmc_regulator_set_vqmmc);
225 
226 #else
227 
mmc_regulator_get_ocrmask(struct regulator * supply)228 static 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  */
mmc_regulator_get_supply(struct mmc_host * mmc)245 int 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 }
273 EXPORT_SYMBOL_GPL(mmc_regulator_get_supply);
274