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         struct property *prop;
 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);
 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. */
 167         config->nr_gpios = of_gpio_count(np);
 168
 169         config->gpios = devm_kzalloc(dev,
 170                                 sizeof(struct gpio) * config->nr_gpios,
 171                                 GFP_KERNEL);
 172         if (!config->gpios)
 173                 return ERR_PTR(-ENOMEM);
 174
 175         for (i = 0; i < config->nr_gpios; i++) {
 176                 gpio = of_get_named_gpio(np, "gpios", i);
 177                 if (gpio < 0)
 178                         break;
 179                 config->gpios[i].gpio = gpio;
 180         }
 181
 182         /* Fetch states. */
 183         prop = of_find_property(np, "states", NULL);
 184         if (!prop) {
 185                 dev_err(dev, "No 'states' property found\n");
 186                 return ERR_PTR(-EINVAL);
 187         }
 188
 189         proplen = prop->length / sizeof(int);
 190
 191         config->states = devm_kzalloc(dev,
 192                                 sizeof(struct gpio_regulator_state)
 193                                 * (proplen / 2),
 194                                 GFP_KERNEL);
 195         if (!config->states)
 196                 return ERR_PTR(-ENOMEM);
 197
 198         for (i = 0; i < proplen / 2; i++) {
 199                 config->states[i].value =
 200                         be32_to_cpup((int *)prop->value + (i * 2));
 201                 config->states[i].gpios =
 202                         be32_to_cpup((int *)prop->value + (i * 2 + 1));
 203         }
 204         config->nr_states = i;
 205
 206         config->type = REGULATOR_VOLTAGE;
 207         ret = of_property_read_string(np, "regulator-type", &regtype);
 208         if (ret >= 0) {
 209                 if (!strncmp("voltage", regtype, 7))
 210                         config->type = REGULATOR_VOLTAGE;
 211                 else if (!strncmp("current", regtype, 7))
 212                         config->type = REGULATOR_CURRENT;
 213                 else
 214                         dev_warn(dev, "Unknown regulator-type '%s'\n",
 215                                  regtype);
 216         }
 217
 218         return config;
 219 }
 220
 221 static struct regulator_ops gpio_regulator_current_ops = {
 222         .get_current_limit = gpio_regulator_get_value,
 223         .set_current_limit = gpio_regulator_set_current_limit,
 224 };
 225
 226 static int gpio_regulator_probe(struct platform_device *pdev)
 227 {
 228         struct gpio_regulator_config *config = dev_get_platdata(&pdev->dev);
 229         struct device_node *np = pdev->dev.of_node;
 230         struct gpio_regulator_data *drvdata;
 231         struct regulator_config cfg = { };
 232         int ptr, ret, state;
 233
 234         if (np) {
 235                 config = of_get_gpio_regulator_config(&pdev->dev, np);
 236                 if (IS_ERR(config))
 237                         return PTR_ERR(config);
 238         }
 239
 240         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
 241                                GFP_KERNEL);
 242         if (drvdata == NULL) {
 243                 dev_err(&pdev->dev, "Failed to allocate device data\n");
 244                 return -ENOMEM;
 245         }
 246
 247         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
 248         if (drvdata->desc.name == NULL) {
 249                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
 250                 ret = -ENOMEM;
 251                 goto err;
 252         }
 253
 254         drvdata->gpios = kmemdup(config->gpios,
 255                                  config->nr_gpios * sizeof(struct gpio),
 256                                  GFP_KERNEL);
 257         if (drvdata->gpios == NULL) {
 258                 dev_err(&pdev->dev, "Failed to allocate gpio data\n");
 259                 ret = -ENOMEM;
 260                 goto err_name;
 261         }
 262
 263         drvdata->states = kmemdup(config->states,
 264                                   config->nr_states *
 265                                          sizeof(struct gpio_regulator_state),
 266                                   GFP_KERNEL);
 267         if (drvdata->states == NULL) {
 268                 dev_err(&pdev->dev, "Failed to allocate state data\n");
 269                 ret = -ENOMEM;
 270                 goto err_memgpio;
 271         }
 272         drvdata->nr_states = config->nr_states;
 273
 274         drvdata->desc.owner = THIS_MODULE;
 275         drvdata->desc.enable_time = config->startup_delay;
 276
 277         /* handle regulator type*/
 278         switch (config->type) {
 279         case REGULATOR_VOLTAGE:
 280                 drvdata->desc.type = REGULATOR_VOLTAGE;
 281                 drvdata->desc.ops = &gpio_regulator_voltage_ops;
 282                 drvdata->desc.n_voltages = config->nr_states;
 283                 break;
 284         case REGULATOR_CURRENT:
 285                 drvdata->desc.type = REGULATOR_CURRENT;
 286                 drvdata->desc.ops = &gpio_regulator_current_ops;
 287                 break;
 288         default:
 289                 dev_err(&pdev->dev, "No regulator type set\n");
 290                 ret = -EINVAL;
 291                 goto err_memgpio;
 292         }
 293
 294         drvdata->nr_gpios = config->nr_gpios;
 295         ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
 296         if (ret) {
 297                 dev_err(&pdev->dev,
 298                    "Could not obtain regulator setting GPIOs: %d\n", ret);
 299                 goto err_memstate;
 300         }
 301
 302         /* build initial state from gpio init data. */
 303         state = 0;
 304         for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
 305                 if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
 306                         state |= (1 << ptr);
 307         }
 308         drvdata->state = state;
 309
 310         cfg.dev = &pdev->dev;
 311         cfg.init_data = config->init_data;
 312         cfg.driver_data = drvdata;
 313         cfg.of_node = np;
 314
 315         if (config->enable_gpio >= 0)
 316                 cfg.ena_gpio = config->enable_gpio;
 317         cfg.ena_gpio_invert = !config->enable_high;
 318         if (config->enabled_at_boot) {
 319                 if (config->enable_high)
 320                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 321                 else
 322                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 323         } else {
 324                 if (config->enable_high)
 325                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
 326                 else
 327                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
 328         }
 329
 330         drvdata->dev = regulator_register(&drvdata->desc, &cfg);
 331         if (IS_ERR(drvdata->dev)) {
 332                 ret = PTR_ERR(drvdata->dev);
 333                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
 334                 goto err_stategpio;
 335         }
 336
 337         platform_set_drvdata(pdev, drvdata);
 338
 339         return 0;
 340
 341 err_stategpio:
 342         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 343 err_memstate:
 344         kfree(drvdata->states);
 345 err_memgpio:
 346         kfree(drvdata->gpios);
 347 err_name:
 348         kfree(drvdata->desc.name);
 349 err:
 350         return ret;
 351 }
 352
 353 static int gpio_regulator_remove(struct platform_device *pdev)
 354 {
 355         struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
 356
 357         regulator_unregister(drvdata->dev);
 358
 359         gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
 360
 361         kfree(drvdata->states);
 362         kfree(drvdata->gpios);
 363
 364         kfree(drvdata->desc.name);
 365
 366         return 0;
 367 }
 368
 369 #if defined(CONFIG_OF)
 370 static const struct of_device_id regulator_gpio_of_match[] = {
 371         { .compatible = "regulator-gpio", },
 372         {},
 373 };
 374 #endif
 375
 376 static struct platform_driver gpio_regulator_driver = {
 377         .probe          = gpio_regulator_probe,
 378         .remove         = gpio_regulator_remove,
 379         .driver         = {
 380                 .name           = "gpio-regulator",
 381                 .owner          = THIS_MODULE,
 382                 .of_match_table = of_match_ptr(regulator_gpio_of_match),
 383         },
 384 };
 385
 386 static int __init gpio_regulator_init(void)
 387 {
 388         return platform_driver_register(&gpio_regulator_driver);
 389 }
 390 subsys_initcall(gpio_regulator_init);
 391
 392 static void __exit gpio_regulator_exit(void)
 393 {
 394         platform_driver_unregister(&gpio_regulator_driver);
 395 }
 396 module_exit(gpio_regulator_exit);
 397
 398 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
 399 MODULE_DESCRIPTION("gpio voltage regulator");
 400 MODULE_LICENSE("GPL");
 401 MODULE_ALIAS("platform:gpio-regulator");