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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 {
138         struct gpio_regulator_config *config;
139         const char *regtype;
140         int proplen, gpio, i;
141         int ret;
142 
143         config = devm_kzalloc(dev,
144                         sizeof(struct gpio_regulator_config),
145                         GFP_KERNEL);
146         if (!config)
147                 return ERR_PTR(-ENOMEM);
148 
149         config->init_data = of_get_regulator_init_data(dev, np);
150         if (!config->init_data)
151                 return ERR_PTR(-EINVAL);
152 
153         config->supply_name = config->init_data->constraints.name;
154 
155         if (of_property_read_bool(np, "enable-active-high"))
156                 config->enable_high = true;
157 
158         if (of_property_read_bool(np, "enable-at-boot"))
159                 config->enabled_at_boot = true;
160 
161         of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
162 
163         config->enable_gpio = of_get_named_gpio(np, "enable-gpio", 0);
164 
165         /* Fetch GPIOs. */
166         config->nr_gpios = of_gpio_count(np);
167 
168         config->gpios = devm_kzalloc(dev,
169                                 sizeof(struct gpio) * config->nr_gpios,
170                                 GFP_KERNEL);
171         if (!config->gpios)
172                 return ERR_PTR(-ENOMEM);
173 
174         proplen = of_property_count_u32_elems(np, "gpios-states");
175         /* optional property */
176         if (proplen < 0)
177                 proplen = 0;
178 
179         if (proplen > 0 && proplen != config->nr_gpios) {
180                 dev_warn(dev, "gpios <-> gpios-states mismatch\n");
181                 proplen = 0;
182         }
183 
184         for (i = 0; i < config->nr_gpios; i++) {
185                 gpio = of_get_named_gpio(np, "gpios", i);
186                 if (gpio < 0)
187                         break;
188                 config->gpios[i].gpio = gpio;
189                 if (proplen > 0) {
190                         of_property_read_u32_index(np, "gpios-states", i, &ret);
191                         if (ret)
192                                 config->gpios[i].flags = GPIOF_OUT_INIT_HIGH;
193                 }
194         }
195 
196         /* Fetch states. */
197         proplen = of_property_count_u32_elems(np, "states");
198         if (proplen < 0) {
199                 dev_err(dev, "No 'states' property found\n");
200                 return ERR_PTR(-EINVAL);
201         }
202 
203         config->states = devm_kzalloc(dev,
204                                 sizeof(struct gpio_regulator_state)
205                                 * (proplen / 2),
206                                 GFP_KERNEL);
207         if (!config->states)
208                 return ERR_PTR(-ENOMEM);
209 
210         for (i = 0; i < proplen / 2; i++) {
211                 of_property_read_u32_index(np, "states", i * 2,
212                                            &config->states[i].value);
213                 of_property_read_u32_index(np, "states", i * 2 + 1,
214                                            &config->states[i].gpios);
215         }
216         config->nr_states = i;
217 
218         config->type = REGULATOR_VOLTAGE;
219         ret = of_property_read_string(np, "regulator-type", &regtype);
220         if (ret >= 0) {
221                 if (!strncmp("voltage", regtype, 7))
222                         config->type = REGULATOR_VOLTAGE;
223                 else if (!strncmp("current", regtype, 7))
224                         config->type = REGULATOR_CURRENT;
225                 else
226                         dev_warn(dev, "Unknown regulator-type '%s'\n",
227                                  regtype);
228         }
229 
230         return config;
231 }
232 
233 static struct regulator_ops gpio_regulator_current_ops = {
234         .get_current_limit = gpio_regulator_get_value,
235         .set_current_limit = gpio_regulator_set_current_limit,
236 };
237 
238 static int gpio_regulator_probe(struct platform_device *pdev)
239 {
240         struct gpio_regulator_config *config = dev_get_platdata(&pdev->dev);
241         struct device_node *np = pdev->dev.of_node;
242         struct gpio_regulator_data *drvdata;
243         struct regulator_config cfg = { };
244         int ptr, ret, state;
245 
246         if (np) {
247                 config = of_get_gpio_regulator_config(&pdev->dev, np);
248                 if (IS_ERR(config))
249                         return PTR_ERR(config);
250         }
251 
252         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
253                                GFP_KERNEL);
254         if (drvdata == NULL)
255                 return -ENOMEM;
256 
257         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
258         if (drvdata->desc.name == NULL) {
259                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
260                 ret = -ENOMEM;
261                 goto err;
262         }
263 
264         drvdata->gpios = kmemdup(config->gpios,
265                                  config->nr_gpios * sizeof(struct gpio),
266                                  GFP_KERNEL);
267         if (drvdata->gpios == NULL) {
268                 dev_err(&pdev->dev, "Failed to allocate gpio data\n");
269                 ret = -ENOMEM;
270                 goto err_name;
271         }
272 
273         drvdata->states = kmemdup(config->states,
274                                   config->nr_states *
275                                          sizeof(struct gpio_regulator_state),
276                                   GFP_KERNEL);
277         if (drvdata->states == NULL) {
278                 dev_err(&pdev->dev, "Failed to allocate state data\n");
279                 ret = -ENOMEM;
280                 goto err_memgpio;
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(&pdev->dev, "No regulator type set\n");
300                 ret = -EINVAL;
301                 goto err_memgpio;
302         }
303 
304         drvdata->nr_gpios = config->nr_gpios;
305         ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
306         if (ret) {
307                 dev_err(&pdev->dev,
308                    "Could not obtain regulator setting GPIOs: %d\n", ret);
309                 goto err_memstate;
310         }
311 
312         /* build initial state from gpio init data. */
313         state = 0;
314         for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
315                 if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
316                         state |= (1 << ptr);
317         }
318         drvdata->state = state;
319 
320         cfg.dev = &pdev->dev;
321         cfg.init_data = config->init_data;
322         cfg.driver_data = drvdata;
323         cfg.of_node = np;
324 
325         if (config->enable_gpio >= 0)
326                 cfg.ena_gpio = config->enable_gpio;
327         cfg.ena_gpio_invert = !config->enable_high;
328         if (config->enabled_at_boot) {
329                 if (config->enable_high)
330                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
331                 else
332                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
333         } else {
334                 if (config->enable_high)
335                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
336                 else
337                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
338         }
339 
340         drvdata->dev = regulator_register(&drvdata->desc, &cfg);
341         if (IS_ERR(drvdata->dev)) {
342                 ret = PTR_ERR(drvdata->dev);
343                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
344                 goto err_stategpio;
345         }
346 
347         platform_set_drvdata(pdev, drvdata);
348 
349         return 0;
350 
351 err_stategpio:
352         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
353 err_memstate:
354         kfree(drvdata->states);
355 err_memgpio:
356         kfree(drvdata->gpios);
357 err_name:
358         kfree(drvdata->desc.name);
359 err:
360         return ret;
361 }
362 
363 static int gpio_regulator_remove(struct platform_device *pdev)
364 {
365         struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
366 
367         regulator_unregister(drvdata->dev);
368 
369         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
370 
371         kfree(drvdata->states);
372         kfree(drvdata->gpios);
373 
374         kfree(drvdata->desc.name);
375 
376         return 0;
377 }
378 
379 #if defined(CONFIG_OF)
380 static const struct of_device_id regulator_gpio_of_match[] = {
381         { .compatible = "regulator-gpio", },
382         {},
383 };
384 #endif
385 
386 static struct platform_driver gpio_regulator_driver = {
387         .probe          = gpio_regulator_probe,
388         .remove         = gpio_regulator_remove,
389         .driver         = {
390                 .name           = "gpio-regulator",
391                 .owner          = THIS_MODULE,
392                 .of_match_table = of_match_ptr(regulator_gpio_of_match),
393         },
394 };
395 
396 static int __init gpio_regulator_init(void)
397 {
398         return platform_driver_register(&gpio_regulator_driver);
399 }
400 subsys_initcall(gpio_regulator_init);
401 
402 static void __exit gpio_regulator_exit(void)
403 {
404         platform_driver_unregister(&gpio_regulator_driver);
405 }
406 module_exit(gpio_regulator_exit);
407 
408 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
409 MODULE_DESCRIPTION("gpio voltage regulator");
410 MODULE_LICENSE("GPL");
411 MODULE_ALIAS("platform:gpio-regulator");
412 

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