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