drivers/regulator/virtual.c

   1 /*
   2  * reg-virtual-consumer.c
   3  *
   4  * Copyright 2008 Wolfson Microelectronics PLC.
   5  *
   6  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of the
  11  * License, or (at your option) any later version.
  12  */
  13
  14 #include <linux/err.h>
  15 #include <linux/mutex.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/regulator/consumer.h>
  18 #include <linux/slab.h>
  19
  20 struct virtual_consumer_data {
  21         struct mutex lock;
  22         struct regulator *regulator;
  23         bool enabled;
  24         int min_uV;
  25         int max_uV;
  26         int min_uA;
  27         int max_uA;
  28         unsigned int mode;
  29 };
  30
  31 static void update_voltage_constraints(struct device *dev,
  32                                        struct virtual_consumer_data *data)
  33 {
  34         int ret;
  35
  36         if (data->min_uV && data->max_uV
  37             && data->min_uV <= data->max_uV) {
  38                 dev_dbg(dev, "Requesting %d-%duV\n",
  39                         data->min_uV, data->max_uV);
  40                 ret = regulator_set_voltage(data->regulator,
  41                                         data->min_uV, data->max_uV);
  42                 if (ret != 0) {
  43                         dev_err(dev,
  44                                 "regulator_set_voltage() failed: %d\n", ret);
  45                         return;
  46                 }
  47         }
  48
  49         if (data->min_uV && data->max_uV && !data->enabled) {
  50                 dev_dbg(dev, "Enabling regulator\n");
  51                 ret = regulator_enable(data->regulator);
  52                 if (ret == 0)
  53                         data->enabled = true;
  54                 else
  55                         dev_err(dev, "regulator_enable() failed: %d\n",
  56                                 ret);
  57         }
  58
  59         if (!(data->min_uV && data->max_uV) && data->enabled) {
  60                 dev_dbg(dev, "Disabling regulator\n");
  61                 ret = regulator_disable(data->regulator);
  62                 if (ret == 0)
  63                         data->enabled = false;
  64                 else
  65                         dev_err(dev, "regulator_disable() failed: %d\n",
  66                                 ret);
  67         }
  68 }
  69
  70 static void update_current_limit_constraints(struct device *dev,
  71                                           struct virtual_consumer_data *data)
  72 {
  73         int ret;
  74
  75         if (data->max_uA
  76             && data->min_uA <= data->max_uA) {
  77                 dev_dbg(dev, "Requesting %d-%duA\n",
  78                         data->min_uA, data->max_uA);
  79                 ret = regulator_set_current_limit(data->regulator,
  80                                         data->min_uA, data->max_uA);
  81                 if (ret != 0) {
  82                         dev_err(dev,
  83                                 "regulator_set_current_limit() failed: %d\n",
  84                                 ret);
  85                         return;
  86                 }
  87         }
  88
  89         if (data->max_uA && !data->enabled) {
  90                 dev_dbg(dev, "Enabling regulator\n");
  91                 ret = regulator_enable(data->regulator);
  92                 if (ret == 0)
  93                         data->enabled = true;
  94                 else
  95                         dev_err(dev, "regulator_enable() failed: %d\n",
  96                                 ret);
  97         }
  98
  99         if (!(data->min_uA && data->max_uA) && data->enabled) {
 100                 dev_dbg(dev, "Disabling regulator\n");
 101                 ret = regulator_disable(data->regulator);
 102                 if (ret == 0)
 103                         data->enabled = false;
 104                 else
 105                         dev_err(dev, "regulator_disable() failed: %d\n",
 106                                 ret);
 107         }
 108 }
 109
 110 static ssize_t show_min_uV(struct device *dev,
 111                            struct device_attribute *attr, char *buf)
 112 {
 113         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 114         return sprintf(buf, "%d\n", data->min_uV);
 115 }
 116
 117 static ssize_t set_min_uV(struct device *dev, struct device_attribute *attr,
 118                           const char *buf, size_t count)
 119 {
 120         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 121         long val;
 122
 123         if (strict_strtol(buf, 10, &val) != 0)
 124                 return count;
 125
 126         mutex_lock(&data->lock);
 127
 128         data->min_uV = val;
 129         update_voltage_constraints(dev, data);
 130
 131         mutex_unlock(&data->lock);
 132
 133         return count;
 134 }
 135
 136 static ssize_t show_max_uV(struct device *dev,
 137                            struct device_attribute *attr, char *buf)
 138 {
 139         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 140         return sprintf(buf, "%d\n", data->max_uV);
 141 }
 142
 143 static ssize_t set_max_uV(struct device *dev, struct device_attribute *attr,
 144                           const char *buf, size_t count)
 145 {
 146         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 147         long val;
 148
 149         if (strict_strtol(buf, 10, &val) != 0)
 150                 return count;
 151
 152         mutex_lock(&data->lock);
 153
 154         data->max_uV = val;
 155         update_voltage_constraints(dev, data);
 156
 157         mutex_unlock(&data->lock);
 158
 159         return count;
 160 }
 161
 162 static ssize_t show_min_uA(struct device *dev,
 163                            struct device_attribute *attr, char *buf)
 164 {
 165         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 166         return sprintf(buf, "%d\n", data->min_uA);
 167 }
 168
 169 static ssize_t set_min_uA(struct device *dev, struct device_attribute *attr,
 170                           const char *buf, size_t count)
 171 {
 172         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 173         long val;
 174
 175         if (strict_strtol(buf, 10, &val) != 0)
 176                 return count;
 177
 178         mutex_lock(&data->lock);
 179
 180         data->min_uA = val;
 181         update_current_limit_constraints(dev, data);
 182
 183         mutex_unlock(&data->lock);
 184
 185         return count;
 186 }
 187
 188 static ssize_t show_max_uA(struct device *dev,
 189                            struct device_attribute *attr, char *buf)
 190 {
 191         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 192         return sprintf(buf, "%d\n", data->max_uA);
 193 }
 194
 195 static ssize_t set_max_uA(struct device *dev, struct device_attribute *attr,
 196                           const char *buf, size_t count)
 197 {
 198         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 199         long val;
 200
 201         if (strict_strtol(buf, 10, &val) != 0)
 202                 return count;
 203
 204         mutex_lock(&data->lock);
 205
 206         data->max_uA = val;
 207         update_current_limit_constraints(dev, data);
 208
 209         mutex_unlock(&data->lock);
 210
 211         return count;
 212 }
 213
 214 static ssize_t show_mode(struct device *dev,
 215                          struct device_attribute *attr, char *buf)
 216 {
 217         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 218
 219         switch (data->mode) {
 220         case REGULATOR_MODE_FAST:
 221                 return sprintf(buf, "fast\n");
 222         case REGULATOR_MODE_NORMAL:
 223                 return sprintf(buf, "normal\n");
 224         case REGULATOR_MODE_IDLE:
 225                 return sprintf(buf, "idle\n");
 226         case REGULATOR_MODE_STANDBY:
 227                 return sprintf(buf, "standby\n");
 228         default:
 229                 return sprintf(buf, "unknown\n");
 230         }
 231 }
 232
 233 static ssize_t set_mode(struct device *dev, struct device_attribute *attr,
 234                         const char *buf, size_t count)
 235 {
 236         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 237         unsigned int mode;
 238         int ret;
 239
 240         /*
 241          * sysfs_streq() doesn't need the \n's, but we add them so the strings
 242          * will be shared with show_mode(), above.
 243          */
 244         if (sysfs_streq(buf, "fast\n"))
 245                 mode = REGULATOR_MODE_FAST;
 246         else if (sysfs_streq(buf, "normal\n"))
 247                 mode = REGULATOR_MODE_NORMAL;
 248         else if (sysfs_streq(buf, "idle\n"))
 249                 mode = REGULATOR_MODE_IDLE;
 250         else if (sysfs_streq(buf, "standby\n"))
 251                 mode = REGULATOR_MODE_STANDBY;
 252         else {
 253                 dev_err(dev, "Configuring invalid mode\n");
 254                 return count;
 255         }
 256
 257         mutex_lock(&data->lock);
 258         ret = regulator_set_mode(data->regulator, mode);
 259         if (ret == 0)
 260                 data->mode = mode;
 261         else
 262                 dev_err(dev, "Failed to configure mode: %d\n", ret);
 263         mutex_unlock(&data->lock);
 264
 265         return count;
 266 }
 267
 268 static DEVICE_ATTR(min_microvolts, 0666, show_min_uV, set_min_uV);
 269 static DEVICE_ATTR(max_microvolts, 0666, show_max_uV, set_max_uV);
 270 static DEVICE_ATTR(min_microamps, 0666, show_min_uA, set_min_uA);
 271 static DEVICE_ATTR(max_microamps, 0666, show_max_uA, set_max_uA);
 272 static DEVICE_ATTR(mode, 0666, show_mode, set_mode);
 273
 274 static struct attribute *regulator_virtual_attributes[] = {
 275         &dev_attr_min_microvolts.attr,
 276         &dev_attr_max_microvolts.attr,
 277         &dev_attr_min_microamps.attr,
 278         &dev_attr_max_microamps.attr,
 279         &dev_attr_mode.attr,
 280         NULL
 281 };
 282
 283 static const struct attribute_group regulator_virtual_attr_group = {
 284         .attrs  = regulator_virtual_attributes,
 285 };
 286
 287 static int __devinit regulator_virtual_probe(struct platform_device *pdev)
 288 {
 289         char *reg_id = pdev->dev.platform_data;
 290         struct virtual_consumer_data *drvdata;
 291         int ret;
 292
 293         drvdata = kzalloc(sizeof(struct virtual_consumer_data), GFP_KERNEL);
 294         if (drvdata == NULL)
 295                 return -ENOMEM;
 296
 297         mutex_init(&drvdata->lock);
 298
 299         drvdata->regulator = regulator_get(&pdev->dev, reg_id);
 300         if (IS_ERR(drvdata->regulator)) {
 301                 ret = PTR_ERR(drvdata->regulator);
 302                 dev_err(&pdev->dev, "Failed to obtain supply '%s': %d\n",
 303                         reg_id, ret);
 304                 goto err;
 305         }
 306
 307         ret = sysfs_create_group(&pdev->dev.kobj,
 308                                  &regulator_virtual_attr_group);
 309         if (ret != 0) {
 310                 dev_err(&pdev->dev,
 311                         "Failed to create attribute group: %d\n", ret);
 312                 goto err_regulator;
 313         }
 314
 315         drvdata->mode = regulator_get_mode(drvdata->regulator);
 316
 317         platform_set_drvdata(pdev, drvdata);
 318
 319         return 0;
 320
 321 err_regulator:
 322         regulator_put(drvdata->regulator);
 323 err:
 324         kfree(drvdata);
 325         return ret;
 326 }
 327
 328 static int __devexit regulator_virtual_remove(struct platform_device *pdev)
 329 {
 330         struct virtual_consumer_data *drvdata = platform_get_drvdata(pdev);
 331
 332         sysfs_remove_group(&pdev->dev.kobj, &regulator_virtual_attr_group);
 333
 334         if (drvdata->enabled)
 335                 regulator_disable(drvdata->regulator);
 336         regulator_put(drvdata->regulator);
 337
 338         kfree(drvdata);
 339
 340         platform_set_drvdata(pdev, NULL);
 341
 342         return 0;
 343 }
 344
 345 static struct platform_driver regulator_virtual_consumer_driver = {
 346         .probe          = regulator_virtual_probe,
 347         .remove         = __devexit_p(regulator_virtual_remove),
 348         .driver         = {
 349                 .name           = "reg-virt-consumer",
 350                 .owner          = THIS_MODULE,
 351         },
 352 };
 353
 354 static int __init regulator_virtual_consumer_init(void)
 355 {
 356         return platform_driver_register(&regulator_virtual_consumer_driver);
 357 }
 358 module_init(regulator_virtual_consumer_init);
 359
 360 static void __exit regulator_virtual_consumer_exit(void)
 361 {
 362         platform_driver_unregister(&regulator_virtual_consumer_driver);
 363 }
 364 module_exit(regulator_virtual_consumer_exit);
 365
 366 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 367 MODULE_DESCRIPTION("Virtual regulator consumer");
 368 MODULE_LICENSE("GPL");
 369 MODULE_ALIAS("platform:reg-virt-consumer");