1/*
2 * gpio-regulator.c
3 *
4 * Copyright 2011 Heiko Stuebner <heiko@sntech.de>
5 *
6 * based on fixed.c
7 *
8 * Copyright 2008 Wolfson Microelectronics PLC.
9 *
10 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
11 *
12 * Copyright (c) 2009 Nokia Corporation
13 * Roger Quadros <ext-roger.quadros@nokia.com>
14 *
15 * This program is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU General Public License as
17 * published by the Free Software Foundation; either version 2 of the
18 * License, or (at your option) any later version.
19 *
20 * This is useful for systems with mixed controllable and
21 * non-controllable regulators, as well as for allowing testing on
22 * systems with no controllable regulators.
23 */
24
25#include <linux/err.h>
26#include <linux/mutex.h>
27#include <linux/module.h>
28#include <linux/platform_device.h>
29#include <linux/regulator/driver.h>
30#include <linux/regulator/machine.h>
31#include <linux/regulator/of_regulator.h>
32#include <linux/regulator/gpio-regulator.h>
33#include <linux/gpio/consumer.h>
34#include <linux/slab.h>
35#include <linux/of.h>
36
37struct gpio_regulator_data {
38 struct regulator_desc desc;
39 struct regulator_dev *dev;
40
41 struct gpio_desc **gpiods;
42 int nr_gpios;
43
44 struct gpio_regulator_state *states;
45 int nr_states;
46
47 int state;
48};
49
50static int gpio_regulator_get_value(struct regulator_dev *dev)
51{
52 struct gpio_regulator_data *data = rdev_get_drvdata(dev);
53 int ptr;
54
55 for (ptr = 0; ptr < data->nr_states; ptr++)
56 if (data->states[ptr].gpios == data->state)
57 return data->states[ptr].value;
58
59 return -EINVAL;
60}
61
62static int gpio_regulator_set_voltage(struct regulator_dev *dev,
63 int min_uV, int max_uV,
64 unsigned *selector)
65{
66 struct gpio_regulator_data *data = rdev_get_drvdata(dev);
67 int ptr, target = 0, state, best_val = INT_MAX;
68
69 for (ptr = 0; ptr < data->nr_states; ptr++)
70 if (data->states[ptr].value < best_val &&
71 data->states[ptr].value >= min_uV &&
72 data->states[ptr].value <= max_uV) {
73 target = data->states[ptr].gpios;
74 best_val = data->states[ptr].value;
75 if (selector)
76 *selector = ptr;
77 }
78
79 if (best_val == INT_MAX)
80 return -EINVAL;
81
82 for (ptr = 0; ptr < data->nr_gpios; ptr++) {
83 state = (target & (1 << ptr)) >> ptr;
84 gpiod_set_value_cansleep(data->gpiods[ptr], state);
85 }
86 data->state = target;
87
88 return 0;
89}
90
91static int gpio_regulator_list_voltage(struct regulator_dev *dev,
92 unsigned selector)
93{
94 struct gpio_regulator_data *data = rdev_get_drvdata(dev);
95
96 if (selector >= data->nr_states)
97 return -EINVAL;
98
99 return data->states[selector].value;
100}
101
102static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
103 int min_uA, int max_uA)
104{
105 struct gpio_regulator_data *data = rdev_get_drvdata(dev);
106 int ptr, target = 0, state, best_val = 0;
107
108 for (ptr = 0; ptr < data->nr_states; ptr++)
109 if (data->states[ptr].value > best_val &&
110 data->states[ptr].value >= min_uA &&
111 data->states[ptr].value <= max_uA) {
112 target = data->states[ptr].gpios;
113 best_val = data->states[ptr].value;
114 }
115
116 if (best_val == 0)
117 return -EINVAL;
118
119 for (ptr = 0; ptr < data->nr_gpios; ptr++) {
120 state = (target & (1 << ptr)) >> ptr;
121 gpiod_set_value_cansleep(data->gpiods[ptr], state);
122 }
123 data->state = target;
124
125 return 0;
126}
127
128static struct regulator_ops gpio_regulator_voltage_ops = {
129 .get_voltage = gpio_regulator_get_value,
130 .set_voltage = gpio_regulator_set_voltage,
131 .list_voltage = gpio_regulator_list_voltage,
132};
133
134static struct gpio_regulator_config *
135of_get_gpio_regulator_config(struct device *dev, struct device_node *np,
136 const struct regulator_desc *desc)
137{
138 struct gpio_regulator_config *config;
139 const char *regtype;
140 int proplen, i;
141 int ngpios;
142 int ret;
143
144 config = devm_kzalloc(dev,
145 sizeof(struct gpio_regulator_config),
146 GFP_KERNEL);
147 if (!config)
148 return ERR_PTR(-ENOMEM);
149
150 config->init_data = of_get_regulator_init_data(dev, np, desc);
151 if (!config->init_data)
152 return ERR_PTR(-EINVAL);
153
154 config->supply_name = config->init_data->constraints.name;
155
156 if (of_property_read_bool(np, "enable-at-boot"))
157 config->enabled_at_boot = true;
158
159 of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
160
161 /* Fetch GPIO init levels */
162 ngpios = gpiod_count(dev, NULL);
163 if (ngpios > 0) {
164 config->gflags = devm_kzalloc(dev,
165 sizeof(enum gpiod_flags)
166 * ngpios,
167 GFP_KERNEL);
168 if (!config->gflags)
169 return ERR_PTR(-ENOMEM);
170
171 for (i = 0; i < ngpios; i++) {
172 u32 val;
173
174 ret = of_property_read_u32_index(np, "gpios-states", i,
175 &val);
176
177 /* Default to high per specification */
178 if (ret)
179 config->gflags[i] = GPIOD_OUT_HIGH;
180 else
181 config->gflags[i] =
182 val ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
183 }
184 }
185 config->ngpios = ngpios;
186
187 /* Fetch states. */
188 proplen = of_property_count_u32_elems(np, "states");
189 if (proplen < 0) {
190 dev_err(dev, "No 'states' property found\n");
191 return ERR_PTR(-EINVAL);
192 }
193
194 config->states = devm_kcalloc(dev,
195 proplen / 2,
196 sizeof(struct gpio_regulator_state),
197 GFP_KERNEL);
198 if (!config->states)
199 return ERR_PTR(-ENOMEM);
200
201 for (i = 0; i < proplen / 2; i++) {
202 of_property_read_u32_index(np, "states", i * 2,
203 &config->states[i].value);
204 of_property_read_u32_index(np, "states", i * 2 + 1,
205 &config->states[i].gpios);
206 }
207 config->nr_states = i;
208
209 config->type = REGULATOR_VOLTAGE;
210 ret = of_property_read_string(np, "regulator-type", &regtype);
211 if (ret >= 0) {
212 if (!strncmp("voltage", regtype, 7))
213 config->type = REGULATOR_VOLTAGE;
214 else if (!strncmp("current", regtype, 7))
215 config->type = REGULATOR_CURRENT;
216 else
217 dev_warn(dev, "Unknown regulator-type '%s'\n",
218 regtype);
219 }
220
221 return config;
222}
223
224static struct regulator_ops gpio_regulator_current_ops = {
225 .get_current_limit = gpio_regulator_get_value,
226 .set_current_limit = gpio_regulator_set_current_limit,
227};
228
229static int gpio_regulator_probe(struct platform_device *pdev)
230{
231 struct device *dev = &pdev->dev;
232 struct gpio_regulator_config *config = dev_get_platdata(dev);
233 struct device_node *np = dev->of_node;
234 struct gpio_regulator_data *drvdata;
235 struct regulator_config cfg = { };
236 enum gpiod_flags gflags;
237 int ptr, ret, state, i;
238
239 drvdata = devm_kzalloc(dev, sizeof(struct gpio_regulator_data),
240 GFP_KERNEL);
241 if (drvdata == NULL)
242 return -ENOMEM;
243
244 if (np) {
245 config = of_get_gpio_regulator_config(dev, np,
246 &drvdata->desc);
247 if (IS_ERR(config))
248 return PTR_ERR(config);
249 }
250
251 drvdata->desc.name = devm_kstrdup(dev, config->supply_name, GFP_KERNEL);
252 if (drvdata->desc.name == NULL) {
253 dev_err(dev, "Failed to allocate supply name\n");
254 return -ENOMEM;
255 }
256
257 drvdata->gpiods = devm_kzalloc(dev, sizeof(struct gpio_desc *),
258 GFP_KERNEL);
259 if (!drvdata->gpiods)
260 return -ENOMEM;
261 for (i = 0; i < config->ngpios; i++) {
262 drvdata->gpiods[i] = devm_gpiod_get_index(dev,
263 NULL,
264 i,
265 config->gflags[i]);
266 if (IS_ERR(drvdata->gpiods[i]))
267 return PTR_ERR(drvdata->gpiods[i]);
268 /* This is good to know */
269 gpiod_set_consumer_name(drvdata->gpiods[i], drvdata->desc.name);
270 }
271 drvdata->nr_gpios = config->ngpios;
272
273 drvdata->states = devm_kmemdup(dev,
274 config->states,
275 config->nr_states *
276 sizeof(struct gpio_regulator_state),
277 GFP_KERNEL);
278 if (drvdata->states == NULL) {
279 dev_err(dev, "Failed to allocate state data\n");
280 return -ENOMEM;
281 }
282 drvdata->nr_states = config->nr_states;
283
284 drvdata->desc.owner = THIS_MODULE;
285 drvdata->desc.enable_time = config->startup_delay;
286
287 /* handle regulator type*/
288 switch (config->type) {
289 case REGULATOR_VOLTAGE:
290 drvdata->desc.type = REGULATOR_VOLTAGE;
291 drvdata->desc.ops = &gpio_regulator_voltage_ops;
292 drvdata->desc.n_voltages = config->nr_states;
293 break;
294 case REGULATOR_CURRENT:
295 drvdata->desc.type = REGULATOR_CURRENT;
296 drvdata->desc.ops = &gpio_regulator_current_ops;
297 break;
298 default:
299 dev_err(dev, "No regulator type set\n");
300 return -EINVAL;
301 }
302
303 /* build initial state from gpio init data. */
304 state = 0;
305 for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
306 if (config->gflags[ptr] == GPIOD_OUT_HIGH)
307 state |= (1 << ptr);
308 }
309 drvdata->state = state;
310
311 cfg.dev = dev;
312 cfg.init_data = config->init_data;
313 cfg.driver_data = drvdata;
314 cfg.of_node = np;
315
316 /*
317 * The signal will be inverted by the GPIO core if flagged so in the
318 * decriptor.
319 */
320 if (config->enabled_at_boot)
321 gflags = GPIOD_OUT_HIGH | GPIOD_FLAGS_BIT_NONEXCLUSIVE;
322 else
323 gflags = GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE;
324
325 cfg.ena_gpiod = gpiod_get_optional(dev, "enable", gflags);
326 if (IS_ERR(cfg.ena_gpiod))
327 return PTR_ERR(cfg.ena_gpiod);
328
329 drvdata->dev = regulator_register(&drvdata->desc, &cfg);
330 if (IS_ERR(drvdata->dev)) {
331 ret = PTR_ERR(drvdata->dev);
332 dev_err(dev, "Failed to register regulator: %d\n", ret);
333 return ret;
334 }
335
336 platform_set_drvdata(pdev, drvdata);
337
338 return 0;
339}
340
341static int gpio_regulator_remove(struct platform_device *pdev)
342{
343 struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
344
345 regulator_unregister(drvdata->dev);
346
347 return 0;
348}
349
350#if defined(CONFIG_OF)
351static const struct of_device_id regulator_gpio_of_match[] = {
352 { .compatible = "regulator-gpio", },
353 {},
354};
355MODULE_DEVICE_TABLE(of, regulator_gpio_of_match);
356#endif
357
358static struct platform_driver gpio_regulator_driver = {
359 .probe = gpio_regulator_probe,
360 .remove = gpio_regulator_remove,
361 .driver = {
362 .name = "gpio-regulator",
363 .of_match_table = of_match_ptr(regulator_gpio_of_match),
364 },
365};
366
367static int __init gpio_regulator_init(void)
368{
369 return platform_driver_register(&gpio_regulator_driver);
370}
371subsys_initcall(gpio_regulator_init);
372
373static void __exit gpio_regulator_exit(void)
374{
375 platform_driver_unregister(&gpio_regulator_driver);
376}
377module_exit(gpio_regulator_exit);
378
379MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
380MODULE_DESCRIPTION("gpio voltage regulator");
381MODULE_LICENSE("GPL");
382MODULE_ALIAS("platform:gpio-regulator");
383