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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 < 0 && config->enable_gpio != -ENOENT)
166                 return ERR_PTR(config->enable_gpio);
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                                 if (gpio != -ENOENT)
195                                         return ERR_PTR(gpio);
196                                 break;
197                         }
198                         config->gpios[i].gpio = gpio;
199                         if (proplen > 0) {
200                                 of_property_read_u32_index(np, "gpios-states",
201                                                            i, &ret);
202                                 if (ret)
203                                         config->gpios[i].flags =
204                                                            GPIOF_OUT_INIT_HIGH;
205                         }
206                 }
207         }
208 
209         /* Fetch states. */
210         proplen = of_property_count_u32_elems(np, "states");
211         if (proplen < 0) {
212                 dev_err(dev, "No 'states' property found\n");
213                 return ERR_PTR(-EINVAL);
214         }
215 
216         config->states = devm_kzalloc(dev,
217                                 sizeof(struct gpio_regulator_state)
218                                 * (proplen / 2),
219                                 GFP_KERNEL);
220         if (!config->states)
221                 return ERR_PTR(-ENOMEM);
222 
223         for (i = 0; i < proplen / 2; i++) {
224                 of_property_read_u32_index(np, "states", i * 2,
225                                            &config->states[i].value);
226                 of_property_read_u32_index(np, "states", i * 2 + 1,
227                                            &config->states[i].gpios);
228         }
229         config->nr_states = i;
230 
231         config->type = REGULATOR_VOLTAGE;
232         ret = of_property_read_string(np, "regulator-type", &regtype);
233         if (ret >= 0) {
234                 if (!strncmp("voltage", regtype, 7))
235                         config->type = REGULATOR_VOLTAGE;
236                 else if (!strncmp("current", regtype, 7))
237                         config->type = REGULATOR_CURRENT;
238                 else
239                         dev_warn(dev, "Unknown regulator-type '%s'\n",
240                                  regtype);
241         }
242 
243         return config;
244 }
245 
246 static struct regulator_ops gpio_regulator_current_ops = {
247         .get_current_limit = gpio_regulator_get_value,
248         .set_current_limit = gpio_regulator_set_current_limit,
249 };
250 
251 static int gpio_regulator_probe(struct platform_device *pdev)
252 {
253         struct gpio_regulator_config *config = dev_get_platdata(&pdev->dev);
254         struct device_node *np = pdev->dev.of_node;
255         struct gpio_regulator_data *drvdata;
256         struct regulator_config cfg = { };
257         int ptr, ret, state;
258 
259         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
260                                GFP_KERNEL);
261         if (drvdata == NULL)
262                 return -ENOMEM;
263 
264         if (np) {
265                 config = of_get_gpio_regulator_config(&pdev->dev, np,
266                                                       &drvdata->desc);
267                 if (IS_ERR(config))
268                         return PTR_ERR(config);
269         }
270 
271         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
272         if (drvdata->desc.name == NULL) {
273                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
274                 ret = -ENOMEM;
275                 goto err;
276         }
277 
278         if (config->nr_gpios != 0) {
279                 drvdata->gpios = kmemdup(config->gpios,
280                                          config->nr_gpios * sizeof(struct gpio),
281                                          GFP_KERNEL);
282                 if (drvdata->gpios == NULL) {
283                         dev_err(&pdev->dev, "Failed to allocate gpio data\n");
284                         ret = -ENOMEM;
285                         goto err_name;
286                 }
287 
288                 drvdata->nr_gpios = config->nr_gpios;
289                 ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
290                 if (ret) {
291                         if (ret != -EPROBE_DEFER)
292                                 dev_err(&pdev->dev,
293                                         "Could not obtain regulator setting GPIOs: %d\n",
294                                         ret);
295                         goto err_memstate;
296                 }
297         }
298 
299         drvdata->states = kmemdup(config->states,
300                                   config->nr_states *
301                                          sizeof(struct gpio_regulator_state),
302                                   GFP_KERNEL);
303         if (drvdata->states == NULL) {
304                 dev_err(&pdev->dev, "Failed to allocate state data\n");
305                 ret = -ENOMEM;
306                 goto err_memgpio;
307         }
308         drvdata->nr_states = config->nr_states;
309 
310         drvdata->desc.owner = THIS_MODULE;
311         drvdata->desc.enable_time = config->startup_delay;
312 
313         /* handle regulator type*/
314         switch (config->type) {
315         case REGULATOR_VOLTAGE:
316                 drvdata->desc.type = REGULATOR_VOLTAGE;
317                 drvdata->desc.ops = &gpio_regulator_voltage_ops;
318                 drvdata->desc.n_voltages = config->nr_states;
319                 break;
320         case REGULATOR_CURRENT:
321                 drvdata->desc.type = REGULATOR_CURRENT;
322                 drvdata->desc.ops = &gpio_regulator_current_ops;
323                 break;
324         default:
325                 dev_err(&pdev->dev, "No regulator type set\n");
326                 ret = -EINVAL;
327                 goto err_memgpio;
328         }
329 
330         /* build initial state from gpio init data. */
331         state = 0;
332         for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
333                 if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
334                         state |= (1 << ptr);
335         }
336         drvdata->state = state;
337 
338         cfg.dev = &pdev->dev;
339         cfg.init_data = config->init_data;
340         cfg.driver_data = drvdata;
341         cfg.of_node = np;
342 
343         if (gpio_is_valid(config->enable_gpio)) {
344                 cfg.ena_gpio = config->enable_gpio;
345                 cfg.ena_gpio_initialized = true;
346         }
347         cfg.ena_gpio_invert = !config->enable_high;
348         if (config->enabled_at_boot) {
349                 if (config->enable_high)
350                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
351                 else
352                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
353         } else {
354                 if (config->enable_high)
355                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
356                 else
357                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
358         }
359 
360         drvdata->dev = regulator_register(&drvdata->desc, &cfg);
361         if (IS_ERR(drvdata->dev)) {
362                 ret = PTR_ERR(drvdata->dev);
363                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
364                 goto err_stategpio;
365         }
366 
367         platform_set_drvdata(pdev, drvdata);
368 
369         return 0;
370 
371 err_stategpio:
372         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
373 err_memstate:
374         kfree(drvdata->states);
375 err_memgpio:
376         kfree(drvdata->gpios);
377 err_name:
378         kfree(drvdata->desc.name);
379 err:
380         return ret;
381 }
382 
383 static int gpio_regulator_remove(struct platform_device *pdev)
384 {
385         struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
386 
387         regulator_unregister(drvdata->dev);
388 
389         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
390 
391         kfree(drvdata->states);
392         kfree(drvdata->gpios);
393 
394         kfree(drvdata->desc.name);
395 
396         return 0;
397 }
398 
399 #if defined(CONFIG_OF)
400 static const struct of_device_id regulator_gpio_of_match[] = {
401         { .compatible = "regulator-gpio", },
402         {},
403 };
404 MODULE_DEVICE_TABLE(of, regulator_gpio_of_match);
405 #endif
406 
407 static struct platform_driver gpio_regulator_driver = {
408         .probe          = gpio_regulator_probe,
409         .remove         = gpio_regulator_remove,
410         .driver         = {
411                 .name           = "gpio-regulator",
412                 .of_match_table = of_match_ptr(regulator_gpio_of_match),
413         },
414 };
415 
416 static int __init gpio_regulator_init(void)
417 {
418         return platform_driver_register(&gpio_regulator_driver);
419 }
420 subsys_initcall(gpio_regulator_init);
421 
422 static void __exit gpio_regulator_exit(void)
423 {
424         platform_driver_unregister(&gpio_regulator_driver);
425 }
426 module_exit(gpio_regulator_exit);
427 
428 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
429 MODULE_DESCRIPTION("gpio voltage regulator");
430 MODULE_LICENSE("GPL");
431 MODULE_ALIAS("platform:gpio-regulator");
432 

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