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Linux/drivers/regulator/gpio-regulator.c

  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.h>
 34 #include <linux/slab.h>
 35 #include <linux/of.h>
 36 #include <linux/of_gpio.h>
 37 
 38 struct gpio_regulator_data {
 39         struct regulator_desc desc;
 40         struct regulator_dev *dev;
 41 
 42         struct gpio *gpios;
 43         int nr_gpios;
 44 
 45         struct gpio_regulator_state *states;
 46         int nr_states;
 47 
 48         int state;
 49 };
 50 
 51 static int gpio_regulator_get_value(struct regulator_dev *dev)
 52 {
 53         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 54         int ptr;
 55 
 56         for (ptr = 0; ptr < data->nr_states; ptr++)
 57                 if (data->states[ptr].gpios == data->state)
 58                         return data->states[ptr].value;
 59 
 60         return -EINVAL;
 61 }
 62 
 63 static int gpio_regulator_set_voltage(struct regulator_dev *dev,
 64                                         int min_uV, int max_uV,
 65                                         unsigned *selector)
 66 {
 67         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 68         int ptr, target = 0, state, best_val = INT_MAX;
 69 
 70         for (ptr = 0; ptr < data->nr_states; ptr++)
 71                 if (data->states[ptr].value < best_val &&
 72                     data->states[ptr].value >= min_uV &&
 73                     data->states[ptr].value <= max_uV) {
 74                         target = data->states[ptr].gpios;
 75                         best_val = data->states[ptr].value;
 76                         if (selector)
 77                                 *selector = ptr;
 78                 }
 79 
 80         if (best_val == INT_MAX)
 81                 return -EINVAL;
 82 
 83         for (ptr = 0; ptr < data->nr_gpios; ptr++) {
 84                 state = (target & (1 << ptr)) >> ptr;
 85                 gpio_set_value_cansleep(data->gpios[ptr].gpio, state);
 86         }
 87         data->state = target;
 88 
 89         return 0;
 90 }
 91 
 92 static int gpio_regulator_list_voltage(struct regulator_dev *dev,
 93                                       unsigned selector)
 94 {
 95         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 96 
 97         if (selector >= data->nr_states)
 98                 return -EINVAL;
 99 
100         return data->states[selector].value;
101 }
102 
103 static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
104                                         int min_uA, int max_uA)
105 {
106         struct gpio_regulator_data *data = rdev_get_drvdata(dev);
107         int ptr, target = 0, state, best_val = 0;
108 
109         for (ptr = 0; ptr < data->nr_states; ptr++)
110                 if (data->states[ptr].value > best_val &&
111                     data->states[ptr].value >= min_uA &&
112                     data->states[ptr].value <= max_uA) {
113                         target = data->states[ptr].gpios;
114                         best_val = data->states[ptr].value;
115                 }
116 
117         if (best_val == 0)
118                 return -EINVAL;
119 
120         for (ptr = 0; ptr < data->nr_gpios; ptr++) {
121                 state = (target & (1 << ptr)) >> ptr;
122                 gpio_set_value_cansleep(data->gpios[ptr].gpio, state);
123         }
124         data->state = target;
125 
126         return 0;
127 }
128 
129 static struct regulator_ops gpio_regulator_voltage_ops = {
130         .get_voltage = gpio_regulator_get_value,
131         .set_voltage = gpio_regulator_set_voltage,
132         .list_voltage = gpio_regulator_list_voltage,
133 };
134 
135 static struct gpio_regulator_config *
136 of_get_gpio_regulator_config(struct device *dev, struct device_node *np,
137                              const struct regulator_desc *desc)
138 {
139         struct gpio_regulator_config *config;
140         const char *regtype;
141         int proplen, gpio, i;
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-active-high"))
157                 config->enable_high = true;
158 
159         if (of_property_read_bool(np, "enable-at-boot"))
160                 config->enabled_at_boot = true;
161 
162         of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
163 
164         config->enable_gpio = of_get_named_gpio(np, "enable-gpio", 0);
165         if (config->enable_gpio == -EPROBE_DEFER)
166                 return ERR_PTR(-EPROBE_DEFER);
167 
168         /* Fetch GPIOs. - optional property*/
169         ret = of_gpio_count(np);
170         if ((ret < 0) && (ret != -ENOENT))
171                 return ERR_PTR(ret);
172 
173         if (ret > 0) {
174                 config->nr_gpios = ret;
175                 config->gpios = devm_kzalloc(dev,
176                                         sizeof(struct gpio) * config->nr_gpios,
177                                         GFP_KERNEL);
178                 if (!config->gpios)
179                         return ERR_PTR(-ENOMEM);
180 
181                 proplen = of_property_count_u32_elems(np, "gpios-states");
182                 /* optional property */
183                 if (proplen < 0)
184                         proplen = 0;
185 
186                 if (proplen > 0 && proplen != config->nr_gpios) {
187                         dev_warn(dev, "gpios <-> gpios-states mismatch\n");
188                         proplen = 0;
189                 }
190 
191                 for (i = 0; i < config->nr_gpios; i++) {
192                         gpio = of_get_named_gpio(np, "gpios", i);
193                         if (gpio < 0)
194                                 break;
195                         config->gpios[i].gpio = gpio;
196                         if (proplen > 0) {
197                                 of_property_read_u32_index(np, "gpios-states",
198                                                            i, &ret);
199                                 if (ret)
200                                         config->gpios[i].flags =
201                                                            GPIOF_OUT_INIT_HIGH;
202                         }
203                 }
204         }
205 
206         /* Fetch states. */
207         proplen = of_property_count_u32_elems(np, "states");
208         if (proplen < 0) {
209                 dev_err(dev, "No 'states' property found\n");
210                 return ERR_PTR(-EINVAL);
211         }
212 
213         config->states = devm_kzalloc(dev,
214                                 sizeof(struct gpio_regulator_state)
215                                 * (proplen / 2),
216                                 GFP_KERNEL);
217         if (!config->states)
218                 return ERR_PTR(-ENOMEM);
219 
220         for (i = 0; i < proplen / 2; i++) {
221                 of_property_read_u32_index(np, "states", i * 2,
222                                            &config->states[i].value);
223                 of_property_read_u32_index(np, "states", i * 2 + 1,
224                                            &config->states[i].gpios);
225         }
226         config->nr_states = i;
227 
228         config->type = REGULATOR_VOLTAGE;
229         ret = of_property_read_string(np, "regulator-type", &regtype);
230         if (ret >= 0) {
231                 if (!strncmp("voltage", regtype, 7))
232                         config->type = REGULATOR_VOLTAGE;
233                 else if (!strncmp("current", regtype, 7))
234                         config->type = REGULATOR_CURRENT;
235                 else
236                         dev_warn(dev, "Unknown regulator-type '%s'\n",
237                                  regtype);
238         }
239 
240         return config;
241 }
242 
243 static struct regulator_ops gpio_regulator_current_ops = {
244         .get_current_limit = gpio_regulator_get_value,
245         .set_current_limit = gpio_regulator_set_current_limit,
246 };
247 
248 static int gpio_regulator_probe(struct platform_device *pdev)
249 {
250         struct gpio_regulator_config *config = dev_get_platdata(&pdev->dev);
251         struct device_node *np = pdev->dev.of_node;
252         struct gpio_regulator_data *drvdata;
253         struct regulator_config cfg = { };
254         int ptr, ret, state;
255 
256         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
257                                GFP_KERNEL);
258         if (drvdata == NULL)
259                 return -ENOMEM;
260 
261         if (np) {
262                 config = of_get_gpio_regulator_config(&pdev->dev, np,
263                                                       &drvdata->desc);
264                 if (IS_ERR(config))
265                         return PTR_ERR(config);
266         }
267 
268         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
269         if (drvdata->desc.name == NULL) {
270                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
271                 ret = -ENOMEM;
272                 goto err;
273         }
274 
275         if (config->nr_gpios != 0) {
276                 drvdata->gpios = kmemdup(config->gpios,
277                                          config->nr_gpios * sizeof(struct gpio),
278                                          GFP_KERNEL);
279                 if (drvdata->gpios == NULL) {
280                         dev_err(&pdev->dev, "Failed to allocate gpio data\n");
281                         ret = -ENOMEM;
282                         goto err_name;
283                 }
284 
285                 drvdata->nr_gpios = config->nr_gpios;
286                 ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
287                 if (ret) {
288                         if (ret != -EPROBE_DEFER)
289                                 dev_err(&pdev->dev,
290                                         "Could not obtain regulator setting GPIOs: %d\n",
291                                         ret);
292                         goto err_memstate;
293                 }
294         }
295 
296         drvdata->states = kmemdup(config->states,
297                                   config->nr_states *
298                                          sizeof(struct gpio_regulator_state),
299                                   GFP_KERNEL);
300         if (drvdata->states == NULL) {
301                 dev_err(&pdev->dev, "Failed to allocate state data\n");
302                 ret = -ENOMEM;
303                 goto err_memgpio;
304         }
305         drvdata->nr_states = config->nr_states;
306 
307         drvdata->desc.owner = THIS_MODULE;
308         drvdata->desc.enable_time = config->startup_delay;
309 
310         /* handle regulator type*/
311         switch (config->type) {
312         case REGULATOR_VOLTAGE:
313                 drvdata->desc.type = REGULATOR_VOLTAGE;
314                 drvdata->desc.ops = &gpio_regulator_voltage_ops;
315                 drvdata->desc.n_voltages = config->nr_states;
316                 break;
317         case REGULATOR_CURRENT:
318                 drvdata->desc.type = REGULATOR_CURRENT;
319                 drvdata->desc.ops = &gpio_regulator_current_ops;
320                 break;
321         default:
322                 dev_err(&pdev->dev, "No regulator type set\n");
323                 ret = -EINVAL;
324                 goto err_memgpio;
325         }
326 
327         /* build initial state from gpio init data. */
328         state = 0;
329         for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
330                 if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
331                         state |= (1 << ptr);
332         }
333         drvdata->state = state;
334 
335         cfg.dev = &pdev->dev;
336         cfg.init_data = config->init_data;
337         cfg.driver_data = drvdata;
338         cfg.of_node = np;
339 
340         if (gpio_is_valid(config->enable_gpio)) {
341                 cfg.ena_gpio = config->enable_gpio;
342                 cfg.ena_gpio_initialized = true;
343         }
344         cfg.ena_gpio_invert = !config->enable_high;
345         if (config->enabled_at_boot) {
346                 if (config->enable_high)
347                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
348                 else
349                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
350         } else {
351                 if (config->enable_high)
352                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
353                 else
354                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
355         }
356 
357         drvdata->dev = regulator_register(&drvdata->desc, &cfg);
358         if (IS_ERR(drvdata->dev)) {
359                 ret = PTR_ERR(drvdata->dev);
360                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
361                 goto err_stategpio;
362         }
363 
364         platform_set_drvdata(pdev, drvdata);
365 
366         return 0;
367 
368 err_stategpio:
369         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
370 err_memstate:
371         kfree(drvdata->states);
372 err_memgpio:
373         kfree(drvdata->gpios);
374 err_name:
375         kfree(drvdata->desc.name);
376 err:
377         return ret;
378 }
379 
380 static int gpio_regulator_remove(struct platform_device *pdev)
381 {
382         struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
383 
384         regulator_unregister(drvdata->dev);
385 
386         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
387 
388         kfree(drvdata->states);
389         kfree(drvdata->gpios);
390 
391         kfree(drvdata->desc.name);
392 
393         return 0;
394 }
395 
396 #if defined(CONFIG_OF)
397 static const struct of_device_id regulator_gpio_of_match[] = {
398         { .compatible = "regulator-gpio", },
399         {},
400 };
401 MODULE_DEVICE_TABLE(of, regulator_gpio_of_match);
402 #endif
403 
404 static struct platform_driver gpio_regulator_driver = {
405         .probe          = gpio_regulator_probe,
406         .remove         = gpio_regulator_remove,
407         .driver         = {
408                 .name           = "gpio-regulator",
409                 .of_match_table = of_match_ptr(regulator_gpio_of_match),
410         },
411 };
412 
413 static int __init gpio_regulator_init(void)
414 {
415         return platform_driver_register(&gpio_regulator_driver);
416 }
417 subsys_initcall(gpio_regulator_init);
418 
419 static void __exit gpio_regulator_exit(void)
420 {
421         platform_driver_unregister(&gpio_regulator_driver);
422 }
423 module_exit(gpio_regulator_exit);
424 
425 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
426 MODULE_DESCRIPTION("gpio voltage regulator");
427 MODULE_LICENSE("GPL");
428 MODULE_ALIAS("platform:gpio-regulator");
429 

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