summaryrefslogtreecommitdiffstats
path: root/drivers/mmc/core/regulator.c
blob: 609201a467ef954e64c9ebc71c57a0f3a7b976d1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
// SPDX-License-Identifier: GPL-2.0
/*
 * Helper functions for MMC regulators.
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/log2.h>
#include <linux/regulator/consumer.h>

#include <linux/mmc/host.h>

#include "core.h"
#include "host.h"

#ifdef CONFIG_REGULATOR

/**
 * mmc_ocrbitnum_to_vdd - Convert a OCR bit number to its voltage
 * @vdd_bit:	OCR bit number
 * @min_uV:	minimum voltage value (mV)
 * @max_uV:	maximum voltage value (mV)
 *
 * This function returns the voltage range according to the provided OCR
 * bit number. If conversion is not possible a negative errno value returned.
 */
static int mmc_ocrbitnum_to_vdd(int vdd_bit, int *min_uV, int *max_uV)
{
	int		tmp;

	if (!vdd_bit)
		return -EINVAL;

	/*
	 * REVISIT mmc_vddrange_to_ocrmask() may have set some
	 * bits this regulator doesn't quite support ... don't
	 * be too picky, most cards and regulators are OK with
	 * a 0.1V range goof (it's a small error percentage).
	 */
	tmp = vdd_bit - ilog2(MMC_VDD_165_195);
	if (tmp == 0) {
		*min_uV = 1650 * 1000;
		*max_uV = 1950 * 1000;
	} else {
		*min_uV = 1900 * 1000 + tmp * 100 * 1000;
		*max_uV = *min_uV + 100 * 1000;
	}

	return 0;
}

/**
 * mmc_regulator_get_ocrmask - return mask of supported voltages
 * @supply: regulator to use
 *
 * This returns either a negative errno, or a mask of voltages that
 * can be provided to MMC/SD/SDIO devices using the specified voltage
 * regulator.  This would normally be called before registering the
 * MMC host adapter.
 */
static int mmc_regulator_get_ocrmask(struct regulator *supply)
{
	int			result = 0;
	int			count;
	int			i;
	int			vdd_uV;
	int			vdd_mV;

	count = regulator_count_voltages(supply);
	if (count < 0)
		return count;

	for (i = 0; i < count; i++) {
		vdd_uV = regulator_list_voltage(supply, i);
		if (vdd_uV <= 0)
			continue;

		vdd_mV = vdd_uV / 1000;
		result |= mmc_vddrange_to_ocrmask(vdd_mV, vdd_mV);
	}

	if (!result) {
		vdd_uV = regulator_get_voltage(supply);
		if (vdd_uV <= 0)
			return vdd_uV;

		vdd_mV = vdd_uV / 1000;
		result = mmc_vddrange_to_ocrmask(vdd_mV, vdd_mV);
	}

	return result;
}

/**
 * mmc_regulator_set_ocr - set regulator to match host->ios voltage
 * @mmc: the host to regulate
 * @supply: regulator to use
 * @vdd_bit: zero for power off, else a bit number (host->ios.vdd)
 *
 * Returns zero on success, else negative errno.
 *
 * MMC host drivers may use this to enable or disable a regulator using
 * a particular supply voltage.  This would normally be called from the
 * set_ios() method.
 */
int mmc_regulator_set_ocr(struct mmc_host *mmc,
			struct regulator *supply,
			unsigned short vdd_bit)
{
	int			result = 0;
	int			min_uV, max_uV;

	if (vdd_bit) {
		mmc_ocrbitnum_to_vdd(vdd_bit, &min_uV, &max_uV);

		result = regulator_set_voltage(supply, min_uV, max_uV);
		if (result == 0 && !mmc->regulator_enabled) {
			result = regulator_enable(supply);
			if (!result)
				mmc->regulator_enabled = true;
		}
	} else if (mmc->regulator_enabled) {
		result = regulator_disable(supply);
		if (result == 0)
			mmc->regulator_enabled = false;
	}

	if (result)
		dev_err(mmc_dev(mmc),
			"could not set regulator OCR (%d)\n", result);
	return result;
}
EXPORT_SYMBOL_GPL(mmc_regulator_set_ocr);

static int mmc_regulator_set_voltage_if_supported(struct regulator *regulator,
						  int min_uV, int target_uV,
						  int max_uV)
{
	int current_uV;

	/*
	 * Check if supported first to avoid errors since we may try several
	 * signal levels during power up and don't want to show errors.
	 */
	if (!regulator_is_supported_voltage(regulator, min_uV, max_uV))
		return -EINVAL;

	/*
	 * The voltage is already set, no need to switch.
	 * Return 1 to indicate that no switch happened.
	 */
	current_uV = regulator_get_voltage(regulator);
	if (current_uV == target_uV)
		return 1;

	return regulator_set_voltage_triplet(regulator, min_uV, target_uV,
					     max_uV);
}

/**
 * mmc_regulator_set_vqmmc - Set VQMMC as per the ios
 * @mmc: the host to regulate
 * @ios: io bus settings
 *
 * For 3.3V signaling, we try to match VQMMC to VMMC as closely as possible.
 * That will match the behavior of old boards where VQMMC and VMMC were supplied
 * by the same supply.  The Bus Operating conditions for 3.3V signaling in the
 * SD card spec also define VQMMC in terms of VMMC.
 * If this is not possible we'll try the full 2.7-3.6V of the spec.
 *
 * For 1.2V and 1.8V signaling we'll try to get as close as possible to the
 * requested voltage.  This is definitely a good idea for UHS where there's a
 * separate regulator on the card that's trying to make 1.8V and it's best if
 * we match.
 *
 * This function is expected to be used by a controller's
 * start_signal_voltage_switch() function.
 */
int mmc_regulator_set_vqmmc(struct mmc_host *mmc, struct mmc_ios *ios)
{
	struct device *dev = mmc_dev(mmc);
	int ret, volt, min_uV, max_uV;

	/* If no vqmmc supply then we can't change the voltage */
	if (IS_ERR(mmc->supply.vqmmc))
		return -EINVAL;

	switch (ios->signal_voltage) {
	case MMC_SIGNAL_VOLTAGE_120:
		return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
						1100000, 1200000, 1300000);
	case MMC_SIGNAL_VOLTAGE_180:
		return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
						1700000, 1800000, 1950000);
	case MMC_SIGNAL_VOLTAGE_330:
		ret = mmc_ocrbitnum_to_vdd(mmc->ios.vdd, &volt, &max_uV);
		if (ret < 0)
			return ret;

		dev_dbg(dev, "%s: found vmmc voltage range of %d-%duV\n",
			__func__, volt, max_uV);

		min_uV = max(volt - 300000, 2700000);
		max_uV = min(max_uV + 200000, 3600000);

		/*
		 * Due to a limitation in the current implementation of
		 * regulator_set_voltage_triplet() which is taking the lowest
		 * voltage possible if below the target, search for a suitable
		 * voltage in two steps and try to stay close to vmmc
		 * with a 0.3V tolerance at first.
		 */
		ret = mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
							min_uV, volt, max_uV);
		if (ret >= 0)
			return ret;

		return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
						2700000, volt, 3600000);
	default:
		return -EINVAL;
	}
}
EXPORT_SYMBOL_GPL(mmc_regulator_set_vqmmc);

#else

static inline int mmc_regulator_get_ocrmask(struct regulator *supply)
{
	return 0;
}

#endif /* CONFIG_REGULATOR */

/**
 * mmc_regulator_get_supply - try to get VMMC and VQMMC regulators for a host
 * @mmc: the host to regulate
 *
 * Returns 0 or errno. errno should be handled, it is either a critical error
 * or -EPROBE_DEFER. 0 means no critical error but it does not mean all
 * regulators have been found because they all are optional. If you require
 * certain regulators, you need to check separately in your driver if they got
 * populated after calling this function.
 */
int mmc_regulator_get_supply(struct mmc_host *mmc)
{
	struct device *dev = mmc_dev(mmc);
	int ret;

	mmc->supply.vmmc = devm_regulator_get_optional(dev, "vmmc");
	mmc->supply.vqmmc = devm_regulator_get_optional(dev, "vqmmc");

	if (IS_ERR(mmc->supply.vmmc)) {
		if (PTR_ERR(mmc->supply.vmmc) == -EPROBE_DEFER)
			return -EPROBE_DEFER;
		dev_dbg(dev, "No vmmc regulator found\n");
	} else {
		ret = mmc_regulator_get_ocrmask(mmc->supply.vmmc);
		if (ret > 0)
			mmc->ocr_avail = ret;
		else
			dev_warn(dev, "Failed getting OCR mask: %d\n", ret);
	}

	if (IS_ERR(mmc->supply.vqmmc)) {
		if (PTR_ERR(mmc->supply.vqmmc) == -EPROBE_DEFER)
			return -EPROBE_DEFER;
		dev_dbg(dev, "No vqmmc regulator found\n");
	}

	return 0;
}
EXPORT_SYMBOL_GPL(mmc_regulator_get_supply);