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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 
166         /* Fetch GPIOs. - optional property*/
167         ret = of_gpio_count(np);
168         if ((ret < 0) && (ret != -ENOENT))
169                 return ERR_PTR(ret);
170 
171         if (ret > 0) {
172                 config->nr_gpios = ret;
173                 config->gpios = devm_kzalloc(dev,
174                                         sizeof(struct gpio) * config->nr_gpios,
175                                         GFP_KERNEL);
176                 if (!config->gpios)
177                         return ERR_PTR(-ENOMEM);
178 
179                 proplen = of_property_count_u32_elems(np, "gpios-states");
180                 /* optional property */
181                 if (proplen < 0)
182                         proplen = 0;
183 
184                 if (proplen > 0 && proplen != config->nr_gpios) {
185                         dev_warn(dev, "gpios <-> gpios-states mismatch\n");
186                         proplen = 0;
187                 }
188 
189                 for (i = 0; i < config->nr_gpios; i++) {
190                         gpio = of_get_named_gpio(np, "gpios", i);
191                         if (gpio < 0)
192                                 break;
193                         config->gpios[i].gpio = gpio;
194                         if (proplen > 0) {
195                                 of_property_read_u32_index(np, "gpios-states",
196                                                            i, &ret);
197                                 if (ret)
198                                         config->gpios[i].flags =
199                                                            GPIOF_OUT_INIT_HIGH;
200                         }
201                 }
202         }
203 
204         /* Fetch states. */
205         proplen = of_property_count_u32_elems(np, "states");
206         if (proplen < 0) {
207                 dev_err(dev, "No 'states' property found\n");
208                 return ERR_PTR(-EINVAL);
209         }
210 
211         config->states = devm_kzalloc(dev,
212                                 sizeof(struct gpio_regulator_state)
213                                 * (proplen / 2),
214                                 GFP_KERNEL);
215         if (!config->states)
216                 return ERR_PTR(-ENOMEM);
217 
218         for (i = 0; i < proplen / 2; i++) {
219                 of_property_read_u32_index(np, "states", i * 2,
220                                            &config->states[i].value);
221                 of_property_read_u32_index(np, "states", i * 2 + 1,
222                                            &config->states[i].gpios);
223         }
224         config->nr_states = i;
225 
226         config->type = REGULATOR_VOLTAGE;
227         ret = of_property_read_string(np, "regulator-type", &regtype);
228         if (ret >= 0) {
229                 if (!strncmp("voltage", regtype, 7))
230                         config->type = REGULATOR_VOLTAGE;
231                 else if (!strncmp("current", regtype, 7))
232                         config->type = REGULATOR_CURRENT;
233                 else
234                         dev_warn(dev, "Unknown regulator-type '%s'\n",
235                                  regtype);
236         }
237 
238         return config;
239 }
240 
241 static struct regulator_ops gpio_regulator_current_ops = {
242         .get_current_limit = gpio_regulator_get_value,
243         .set_current_limit = gpio_regulator_set_current_limit,
244 };
245 
246 static int gpio_regulator_probe(struct platform_device *pdev)
247 {
248         struct gpio_regulator_config *config = dev_get_platdata(&pdev->dev);
249         struct device_node *np = pdev->dev.of_node;
250         struct gpio_regulator_data *drvdata;
251         struct regulator_config cfg = { };
252         int ptr, ret, state;
253 
254         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
255                                GFP_KERNEL);
256         if (drvdata == NULL)
257                 return -ENOMEM;
258 
259         if (np) {
260                 config = of_get_gpio_regulator_config(&pdev->dev, np,
261                                                       &drvdata->desc);
262                 if (IS_ERR(config))
263                         return PTR_ERR(config);
264         }
265 
266         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
267         if (drvdata->desc.name == NULL) {
268                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
269                 ret = -ENOMEM;
270                 goto err;
271         }
272 
273         if (config->nr_gpios != 0) {
274                 drvdata->gpios = kmemdup(config->gpios,
275                                          config->nr_gpios * sizeof(struct gpio),
276                                          GFP_KERNEL);
277                 if (drvdata->gpios == NULL) {
278                         dev_err(&pdev->dev, "Failed to allocate gpio data\n");
279                         ret = -ENOMEM;
280                         goto err_name;
281                 }
282 
283                 drvdata->nr_gpios = config->nr_gpios;
284                 ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
285                 if (ret) {
286                         dev_err(&pdev->dev,
287                         "Could not obtain regulator setting GPIOs: %d\n", ret);
288                         goto err_memstate;
289                 }
290         }
291 
292         drvdata->states = kmemdup(config->states,
293                                   config->nr_states *
294                                          sizeof(struct gpio_regulator_state),
295                                   GFP_KERNEL);
296         if (drvdata->states == NULL) {
297                 dev_err(&pdev->dev, "Failed to allocate state data\n");
298                 ret = -ENOMEM;
299                 goto err_memgpio;
300         }
301         drvdata->nr_states = config->nr_states;
302 
303         drvdata->desc.owner = THIS_MODULE;
304         drvdata->desc.enable_time = config->startup_delay;
305 
306         /* handle regulator type*/
307         switch (config->type) {
308         case REGULATOR_VOLTAGE:
309                 drvdata->desc.type = REGULATOR_VOLTAGE;
310                 drvdata->desc.ops = &gpio_regulator_voltage_ops;
311                 drvdata->desc.n_voltages = config->nr_states;
312                 break;
313         case REGULATOR_CURRENT:
314                 drvdata->desc.type = REGULATOR_CURRENT;
315                 drvdata->desc.ops = &gpio_regulator_current_ops;
316                 break;
317         default:
318                 dev_err(&pdev->dev, "No regulator type set\n");
319                 ret = -EINVAL;
320                 goto err_memgpio;
321         }
322 
323         /* build initial state from gpio init data. */
324         state = 0;
325         for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
326                 if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
327                         state |= (1 << ptr);
328         }
329         drvdata->state = state;
330 
331         cfg.dev = &pdev->dev;
332         cfg.init_data = config->init_data;
333         cfg.driver_data = drvdata;
334         cfg.of_node = np;
335 
336         if (gpio_is_valid(config->enable_gpio)) {
337                 cfg.ena_gpio = config->enable_gpio;
338                 cfg.ena_gpio_initialized = true;
339         }
340         cfg.ena_gpio_invert = !config->enable_high;
341         if (config->enabled_at_boot) {
342                 if (config->enable_high)
343                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
344                 else
345                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
346         } else {
347                 if (config->enable_high)
348                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
349                 else
350                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
351         }
352 
353         drvdata->dev = regulator_register(&drvdata->desc, &cfg);
354         if (IS_ERR(drvdata->dev)) {
355                 ret = PTR_ERR(drvdata->dev);
356                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
357                 goto err_stategpio;
358         }
359 
360         platform_set_drvdata(pdev, drvdata);
361 
362         return 0;
363 
364 err_stategpio:
365         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
366 err_memstate:
367         kfree(drvdata->states);
368 err_memgpio:
369         kfree(drvdata->gpios);
370 err_name:
371         kfree(drvdata->desc.name);
372 err:
373         return ret;
374 }
375 
376 static int gpio_regulator_remove(struct platform_device *pdev)
377 {
378         struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
379 
380         regulator_unregister(drvdata->dev);
381 
382         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
383 
384         kfree(drvdata->states);
385         kfree(drvdata->gpios);
386 
387         kfree(drvdata->desc.name);
388 
389         return 0;
390 }
391 
392 #if defined(CONFIG_OF)
393 static const struct of_device_id regulator_gpio_of_match[] = {
394         { .compatible = "regulator-gpio", },
395         {},
396 };
397 #endif
398 
399 static struct platform_driver gpio_regulator_driver = {
400         .probe          = gpio_regulator_probe,
401         .remove         = gpio_regulator_remove,
402         .driver         = {
403                 .name           = "gpio-regulator",
404                 .of_match_table = of_match_ptr(regulator_gpio_of_match),
405         },
406 };
407 
408 static int __init gpio_regulator_init(void)
409 {
410         return platform_driver_register(&gpio_regulator_driver);
411 }
412 subsys_initcall(gpio_regulator_init);
413 
414 static void __exit gpio_regulator_exit(void)
415 {
416         platform_driver_unregister(&gpio_regulator_driver);
417 }
418 module_exit(gpio_regulator_exit);
419 
420 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
421 MODULE_DESCRIPTION("gpio voltage regulator");
422 MODULE_LICENSE("GPL");
423 MODULE_ALIAS("platform:gpio-regulator");
424 

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