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