summaryrefslogtreecommitdiffstats
path: root/drivers/regulator/gpio-regulator.c
blob: 5927d4f3eabd751489c71275452d597f14a6f4fc (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
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * gpio-regulator.c
 *
 * Copyright 2011 Heiko Stuebner <heiko@sntech.de>
 *
 * based on fixed.c
 *
 * Copyright 2008 Wolfson Microelectronics PLC.
 *
 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
 *
 * Copyright (c) 2009 Nokia Corporation
 * Roger Quadros <ext-roger.quadros@nokia.com>
 *
 * This is useful for systems with mixed controllable and
 * non-controllable regulators, as well as for allowing testing on
 * systems with no controllable regulators.
 */

#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/of_regulator.h>
#include <linux/regulator/gpio-regulator.h>
#include <linux/gpio/consumer.h>
#include <linux/slab.h>
#include <linux/of.h>

struct gpio_regulator_data {
	struct regulator_desc desc;

	struct gpio_desc **gpiods;
	int nr_gpios;

	struct gpio_regulator_state *states;
	int nr_states;

	int state;
};

static int gpio_regulator_get_value(struct regulator_dev *dev)
{
	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
	int ptr;

	for (ptr = 0; ptr < data->nr_states; ptr++)
		if (data->states[ptr].gpios == data->state)
			return data->states[ptr].value;

	return -EINVAL;
}

static int gpio_regulator_set_voltage(struct regulator_dev *dev,
					int min_uV, int max_uV,
					unsigned *selector)
{
	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
	int ptr, target = 0, state, best_val = INT_MAX;

	for (ptr = 0; ptr < data->nr_states; ptr++)
		if (data->states[ptr].value < best_val &&
		    data->states[ptr].value >= min_uV &&
		    data->states[ptr].value <= max_uV) {
			target = data->states[ptr].gpios;
			best_val = data->states[ptr].value;
			if (selector)
				*selector = ptr;
		}

	if (best_val == INT_MAX)
		return -EINVAL;

	for (ptr = 0; ptr < data->nr_gpios; ptr++) {
		state = (target & (1 << ptr)) >> ptr;
		gpiod_set_value_cansleep(data->gpiods[ptr], state);
	}
	data->state = target;

	return 0;
}

static int gpio_regulator_list_voltage(struct regulator_dev *dev,
				      unsigned selector)
{
	struct gpio_regulator_data *data = rdev_get_drvdata(dev);

	if (selector >= data->nr_states)
		return -EINVAL;

	return data->states[selector].value;
}

static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
					int min_uA, int max_uA)
{
	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
	int ptr, target = 0, state, best_val = 0;

	for (ptr = 0; ptr < data->nr_states; ptr++)
		if (data->states[ptr].value > best_val &&
		    data->states[ptr].value >= min_uA &&
		    data->states[ptr].value <= max_uA) {
			target = data->states[ptr].gpios;
			best_val = data->states[ptr].value;
		}

	if (best_val == 0)
		return -EINVAL;

	for (ptr = 0; ptr < data->nr_gpios; ptr++) {
		state = (target & (1 << ptr)) >> ptr;
		gpiod_set_value_cansleep(data->gpiods[ptr], state);
	}
	data->state = target;

	return 0;
}

static const struct regulator_ops gpio_regulator_voltage_ops = {
	.get_voltage = gpio_regulator_get_value,
	.set_voltage = gpio_regulator_set_voltage,
	.list_voltage = gpio_regulator_list_voltage,
};

static struct gpio_regulator_config *
of_get_gpio_regulator_config(struct device *dev, struct device_node *np,
			     const struct regulator_desc *desc)
{
	struct gpio_regulator_config *config;
	const char *regtype;
	int proplen, i;
	int ngpios;
	int ret;

	config = devm_kzalloc(dev,
			sizeof(struct gpio_regulator_config),
			GFP_KERNEL);
	if (!config)
		return ERR_PTR(-ENOMEM);

	config->init_data = of_get_regulator_init_data(dev, np, desc);
	if (!config->init_data)
		return ERR_PTR(-EINVAL);

	config->supply_name = config->init_data->constraints.name;

	if (config->init_data->constraints.boot_on)
		config->enabled_at_boot = true;

	/*
	 * Do not use: undocumented device tree property.
	 * This is kept around solely for device tree ABI stability.
	 */
	if (of_property_read_bool(np, "enable-at-boot"))
		config->enabled_at_boot = true;

	of_property_read_u32(np, "startup-delay-us", &config->startup_delay);

	/* Fetch GPIO init levels */
	ngpios = gpiod_count(dev, NULL);
	if (ngpios > 0) {
		config->gflags = devm_kzalloc(dev,
					      sizeof(enum gpiod_flags)
					      * ngpios,
					      GFP_KERNEL);
		if (!config->gflags)
			return ERR_PTR(-ENOMEM);

		for (i = 0; i < ngpios; i++) {
			u32 val;

			ret = of_property_read_u32_index(np, "gpios-states", i,
							 &val);

			/* Default to high per specification */
			if (ret)
				config->gflags[i] = GPIOD_OUT_HIGH;
			else
				config->gflags[i] =
					val ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
		}
	}
	config->ngpios = ngpios;

	/* Fetch states. */
	proplen = of_property_count_u32_elems(np, "states");
	if (proplen < 0) {
		dev_err(dev, "No 'states' property found\n");
		return ERR_PTR(-EINVAL);
	}

	config->states = devm_kcalloc(dev,
				proplen / 2,
				sizeof(struct gpio_regulator_state),
				GFP_KERNEL);
	if (!config->states)
		return ERR_PTR(-ENOMEM);

	for (i = 0; i < proplen / 2; i++) {
		of_property_read_u32_index(np, "states", i * 2,
					   &config->states[i].value);
		of_property_read_u32_index(np, "states", i * 2 + 1,
					   &config->states[i].gpios);
	}
	config->nr_states = i;

	config->type = REGULATOR_VOLTAGE;
	ret = of_property_read_string(np, "regulator-type", &regtype);
	if (ret >= 0) {
		if (!strncmp("voltage", regtype, 7))
			config->type = REGULATOR_VOLTAGE;
		else if (!strncmp("current", regtype, 7))
			config->type = REGULATOR_CURRENT;
		else
			dev_warn(dev, "Unknown regulator-type '%s'\n",
				 regtype);
	}

	return config;
}

static const struct regulator_ops gpio_regulator_current_ops = {
	.get_current_limit = gpio_regulator_get_value,
	.set_current_limit = gpio_regulator_set_current_limit,
};

static int gpio_regulator_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct gpio_regulator_config *config = dev_get_platdata(dev);
	struct device_node *np = dev->of_node;
	struct gpio_regulator_data *drvdata;
	struct regulator_config cfg = { };
	struct regulator_dev *rdev;
	enum gpiod_flags gflags;
	int ptr, ret, state, i;

	drvdata = devm_kzalloc(dev, sizeof(struct gpio_regulator_data),
			       GFP_KERNEL);
	if (drvdata == NULL)
		return -ENOMEM;

	if (np) {
		config = of_get_gpio_regulator_config(dev, np,
						      &drvdata->desc);
		if (IS_ERR(config))
			return PTR_ERR(config);
	}

	drvdata->desc.name = devm_kstrdup(dev, config->supply_name, GFP_KERNEL);
	if (drvdata->desc.name == NULL) {
		dev_err(dev, "Failed to allocate supply name\n");
		return -ENOMEM;
	}

	drvdata->gpiods = devm_kzalloc(dev, sizeof(struct gpio_desc *),
				       GFP_KERNEL);
	if (!drvdata->gpiods)
		return -ENOMEM;
	for (i = 0; i < config->ngpios; i++) {
		drvdata->gpiods[i] = devm_gpiod_get_index(dev,
							  NULL,
							  i,
							  config->gflags[i]);
		if (IS_ERR(drvdata->gpiods[i]))
			return PTR_ERR(drvdata->gpiods[i]);
		/* This is good to know */
		gpiod_set_consumer_name(drvdata->gpiods[i], drvdata->desc.name);
	}
	drvdata->nr_gpios = config->ngpios;

	drvdata->states = devm_kmemdup(dev,
				       config->states,
				       config->nr_states *
				       sizeof(struct gpio_regulator_state),
				       GFP_KERNEL);
	if (drvdata->states == NULL) {
		dev_err(dev, "Failed to allocate state data\n");
		return -ENOMEM;
	}
	drvdata->nr_states = config->nr_states;

	drvdata->desc.owner = THIS_MODULE;
	drvdata->desc.enable_time = config->startup_delay;

	/* handle regulator type*/
	switch (config->type) {
	case REGULATOR_VOLTAGE:
		drvdata->desc.type = REGULATOR_VOLTAGE;
		drvdata->desc.ops = &gpio_regulator_voltage_ops;
		drvdata->desc.n_voltages = config->nr_states;
		break;
	case REGULATOR_CURRENT:
		drvdata->desc.type = REGULATOR_CURRENT;
		drvdata->desc.ops = &gpio_regulator_current_ops;
		break;
	default:
		dev_err(dev, "No regulator type set\n");
		return -EINVAL;
	}

	/* build initial state from gpio init data. */
	state = 0;
	for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
		if (config->gflags[ptr] == GPIOD_OUT_HIGH)
			state |= (1 << ptr);
	}
	drvdata->state = state;

	cfg.dev = dev;
	cfg.init_data = config->init_data;
	cfg.driver_data = drvdata;
	cfg.of_node = np;

	/*
	 * The signal will be inverted by the GPIO core if flagged so in the
	 * descriptor.
	 */
	if (config->enabled_at_boot)
		gflags = GPIOD_OUT_HIGH | GPIOD_FLAGS_BIT_NONEXCLUSIVE;
	else
		gflags = GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE;

	cfg.ena_gpiod = gpiod_get_optional(dev, "enable", gflags);
	if (IS_ERR(cfg.ena_gpiod))
		return PTR_ERR(cfg.ena_gpiod);

	rdev = devm_regulator_register(dev, &drvdata->desc, &cfg);
	if (IS_ERR(rdev)) {
		ret = PTR_ERR(rdev);
		dev_err(dev, "Failed to register regulator: %d\n", ret);
		return ret;
	}

	platform_set_drvdata(pdev, drvdata);

	return 0;
}

#if defined(CONFIG_OF)
static const struct of_device_id regulator_gpio_of_match[] = {
	{ .compatible = "regulator-gpio", },
	{},
};
MODULE_DEVICE_TABLE(of, regulator_gpio_of_match);
#endif

static struct platform_driver gpio_regulator_driver = {
	.probe		= gpio_regulator_probe,
	.driver		= {
		.name		= "gpio-regulator",
		.of_match_table = of_match_ptr(regulator_gpio_of_match),
	},
};

static int __init gpio_regulator_init(void)
{
	return platform_driver_register(&gpio_regulator_driver);
}
subsys_initcall(gpio_regulator_init);

static void __exit gpio_regulator_exit(void)
{
	platform_driver_unregister(&gpio_regulator_driver);
}
module_exit(gpio_regulator_exit);

MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
MODULE_DESCRIPTION("gpio voltage regulator");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:gpio-regulator");