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