drivers/regulator/virtual.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * reg-virtual-consumer.c
   4  *
   5  * Copyright 2008 Wolfson Microelectronics PLC.
   6  *
   7  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   8  */
   9
  10 #include <linux/err.h>
  11 #include <linux/mutex.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/regulator/consumer.h>
  14 #include <linux/slab.h>
  15 #include <linux/module.h>
  16 #include <linux/of.h>
  17
  18 struct virtual_consumer_data {
  19         struct mutex lock;
  20         struct regulator *regulator;
  21         bool enabled;
  22         int min_uV;
  23         int max_uV;
  24         int min_uA;
  25         int max_uA;
  26         unsigned int mode;
  27 };
  28
  29 static void update_voltage_constraints(struct device *dev,
  30                                        struct virtual_consumer_data *data)
  31 {
  32         int ret;
  33
  34         if (data->min_uV && data->max_uV
  35             && data->min_uV <= data->max_uV) {
  36                 dev_dbg(dev, "Requesting %d-%duV\n",
  37                         data->min_uV, data->max_uV);
  38                 ret = regulator_set_voltage(data->regulator,
  39                                         data->min_uV, data->max_uV);
  40                 if (ret != 0) {
  41                         dev_err(dev,
  42                                 "regulator_set_voltage() failed: %d\n", ret);
  43                         return;
  44                 }
  45         }
  46
  47         if (data->min_uV && data->max_uV && !data->enabled) {
  48                 dev_dbg(dev, "Enabling regulator\n");
  49                 ret = regulator_enable(data->regulator);
  50                 if (ret == 0)
  51                         data->enabled = true;
  52                 else
  53                         dev_err(dev, "regulator_enable() failed: %d\n",
  54                                 ret);
  55         }
  56
  57         if (!(data->min_uV && data->max_uV) && data->enabled) {
  58                 dev_dbg(dev, "Disabling regulator\n");
  59                 ret = regulator_disable(data->regulator);
  60                 if (ret == 0)
  61                         data->enabled = false;
  62                 else
  63                         dev_err(dev, "regulator_disable() failed: %d\n",
  64                                 ret);
  65         }
  66 }
  67
  68 static void update_current_limit_constraints(struct device *dev,
  69                                           struct virtual_consumer_data *data)
  70 {
  71         int ret;
  72
  73         if (data->max_uA
  74             && data->min_uA <= data->max_uA) {
  75                 dev_dbg(dev, "Requesting %d-%duA\n",
  76                         data->min_uA, data->max_uA);
  77                 ret = regulator_set_current_limit(data->regulator,
  78                                         data->min_uA, data->max_uA);
  79                 if (ret != 0) {
  80                         dev_err(dev,
  81                                 "regulator_set_current_limit() failed: %d\n",
  82                                 ret);
  83                         return;
  84                 }
  85         }
  86
  87         if (data->max_uA && !data->enabled) {
  88                 dev_dbg(dev, "Enabling regulator\n");
  89                 ret = regulator_enable(data->regulator);
  90                 if (ret == 0)
  91                         data->enabled = true;
  92                 else
  93                         dev_err(dev, "regulator_enable() failed: %d\n",
  94                                 ret);
  95         }
  96
  97         if (!(data->min_uA && data->max_uA) && data->enabled) {
  98                 dev_dbg(dev, "Disabling regulator\n");
  99                 ret = regulator_disable(data->regulator);
 100                 if (ret == 0)
 101                         data->enabled = false;
 102                 else
 103                         dev_err(dev, "regulator_disable() failed: %d\n",
 104                                 ret);
 105         }
 106 }
 107
 108 static ssize_t show_min_uV(struct device *dev,
 109                            struct device_attribute *attr, char *buf)
 110 {
 111         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 112         return sprintf(buf, "%d\n", data->min_uV);
 113 }
 114
 115 static ssize_t set_min_uV(struct device *dev, struct device_attribute *attr,
 116                           const char *buf, size_t count)
 117 {
 118         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 119         long val;
 120
 121         if (kstrtol(buf, 10, &val) != 0)
 122                 return count;
 123
 124         mutex_lock(&data->lock);
 125
 126         data->min_uV = val;
 127         update_voltage_constraints(dev, data);
 128
 129         mutex_unlock(&data->lock);
 130
 131         return count;
 132 }
 133
 134 static ssize_t show_max_uV(struct device *dev,
 135                            struct device_attribute *attr, char *buf)
 136 {
 137         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 138         return sprintf(buf, "%d\n", data->max_uV);
 139 }
 140
 141 static ssize_t set_max_uV(struct device *dev, struct device_attribute *attr,
 142                           const char *buf, size_t count)
 143 {
 144         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 145         long val;
 146
 147         if (kstrtol(buf, 10, &val) != 0)
 148                 return count;
 149
 150         mutex_lock(&data->lock);
 151
 152         data->max_uV = val;
 153         update_voltage_constraints(dev, data);
 154
 155         mutex_unlock(&data->lock);
 156
 157         return count;
 158 }
 159
 160 static ssize_t show_min_uA(struct device *dev,
 161                            struct device_attribute *attr, char *buf)
 162 {
 163         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 164         return sprintf(buf, "%d\n", data->min_uA);
 165 }
 166
 167 static ssize_t set_min_uA(struct device *dev, struct device_attribute *attr,
 168                           const char *buf, size_t count)
 169 {
 170         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 171         long val;
 172
 173         if (kstrtol(buf, 10, &val) != 0)
 174                 return count;
 175
 176         mutex_lock(&data->lock);
 177
 178         data->min_uA = val;
 179         update_current_limit_constraints(dev, data);
 180
 181         mutex_unlock(&data->lock);
 182
 183         return count;
 184 }
 185
 186 static ssize_t show_max_uA(struct device *dev,
 187                            struct device_attribute *attr, char *buf)
 188 {
 189         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 190         return sprintf(buf, "%d\n", data->max_uA);
 191 }
 192
 193 static ssize_t set_max_uA(struct device *dev, struct device_attribute *attr,
 194                           const char *buf, size_t count)
 195 {
 196         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 197         long val;
 198
 199         if (kstrtol(buf, 10, &val) != 0)
 200                 return count;
 201
 202         mutex_lock(&data->lock);
 203
 204         data->max_uA = val;
 205         update_current_limit_constraints(dev, data);
 206
 207         mutex_unlock(&data->lock);
 208
 209         return count;
 210 }
 211
 212 static ssize_t show_mode(struct device *dev,
 213                          struct device_attribute *attr, char *buf)
 214 {
 215         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 216
 217         switch (data->mode) {
 218         case REGULATOR_MODE_FAST:
 219                 return sprintf(buf, "fast\n");
 220         case REGULATOR_MODE_NORMAL:
 221                 return sprintf(buf, "normal\n");
 222         case REGULATOR_MODE_IDLE:
 223                 return sprintf(buf, "idle\n");
 224         case REGULATOR_MODE_STANDBY:
 225                 return sprintf(buf, "standby\n");
 226         default:
 227                 return sprintf(buf, "unknown\n");
 228         }
 229 }
 230
 231 static ssize_t set_mode(struct device *dev, struct device_attribute *attr,
 232                         const char *buf, size_t count)
 233 {
 234         struct virtual_consumer_data *data = dev_get_drvdata(dev);
 235         unsigned int mode;
 236         int ret;
 237
 238         /*
 239          * sysfs_streq() doesn't need the \n's, but we add them so the strings
 240          * will be shared with show_mode(), above.
 241          */
 242         if (sysfs_streq(buf, "fast\n"))
 243                 mode = REGULATOR_MODE_FAST;
 244         else if (sysfs_streq(buf, "normal\n"))
 245                 mode = REGULATOR_MODE_NORMAL;
 246         else if (sysfs_streq(buf, "idle\n"))
 247                 mode = REGULATOR_MODE_IDLE;
 248         else if (sysfs_streq(buf, "standby\n"))
 249                 mode = REGULATOR_MODE_STANDBY;
 250         else {
 251                 dev_err(dev, "Configuring invalid mode\n");
 252                 return count;
 253         }
 254
 255         mutex_lock(&data->lock);
 256         ret = regulator_set_mode(data->regulator, mode);
 257         if (ret == 0)
 258                 data->mode = mode;
 259         else
 260                 dev_err(dev, "Failed to configure mode: %d\n", ret);
 261         mutex_unlock(&data->lock);
 262
 263         return count;
 264 }
 265
 266 static DEVICE_ATTR(min_microvolts, 0664, show_min_uV, set_min_uV);
 267 static DEVICE_ATTR(max_microvolts, 0664, show_max_uV, set_max_uV);
 268 static DEVICE_ATTR(min_microamps, 0664, show_min_uA, set_min_uA);
 269 static DEVICE_ATTR(max_microamps, 0664, show_max_uA, set_max_uA);
 270 static DEVICE_ATTR(mode, 0664, show_mode, set_mode);
 271
 272 static struct attribute *regulator_virtual_attributes[] = {
 273         &dev_attr_min_microvolts.attr,
 274         &dev_attr_max_microvolts.attr,
 275         &dev_attr_min_microamps.attr,
 276         &dev_attr_max_microamps.attr,
 277         &dev_attr_mode.attr,
 278         NULL
 279 };
 280
 281 static const struct attribute_group regulator_virtual_attr_group = {
 282         .attrs  = regulator_virtual_attributes,
 283 };
 284
 285 #ifdef CONFIG_OF
 286 static const struct of_device_id regulator_virtual_consumer_of_match[] = {
 287         { .compatible = "regulator-virtual-consumer" },
 288         {},
 289 };
 290 MODULE_DEVICE_TABLE(of, regulator_virtual_consumer_of_match);
 291 #endif
 292
 293 static int regulator_virtual_probe(struct platform_device *pdev)
 294 {
 295         char *reg_id = dev_get_platdata(&pdev->dev);
 296         struct virtual_consumer_data *drvdata;
 297         static bool warned;
 298         int ret;
 299
 300         if (!warned) {
 301                 warned = true;
 302                 pr_warn("**********************************************************\n");
 303                 pr_warn("**   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **\n");
 304                 pr_warn("**                                                      **\n");
 305                 pr_warn("** regulator-virtual-consumer is only for testing and   **\n");
 306                 pr_warn("** debugging.  Do not use it in a production kernel.    **\n");
 307                 pr_warn("**                                                      **\n");
 308                 pr_warn("**   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **\n");
 309                 pr_warn("**********************************************************\n");
 310         }
 311
 312         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct virtual_consumer_data),
 313                                GFP_KERNEL);
 314         if (drvdata == NULL)
 315                 return -ENOMEM;
 316
 317         /*
 318          * This virtual consumer does not have any hardware-defined supply
 319          * name, so just allow the regulator to be specified in a property
 320          * named "default-supply" when we're being probed from devicetree.
 321          */
 322         if (!reg_id && pdev->dev.of_node)
 323                 reg_id = "default";
 324
 325         mutex_init(&drvdata->lock);
 326
 327         drvdata->regulator = devm_regulator_get(&pdev->dev, reg_id);
 328         if (IS_ERR(drvdata->regulator))
 329                 return dev_err_probe(&pdev->dev, PTR_ERR(drvdata->regulator),
 330                                      "Failed to obtain supply '%s'\n",
 331                                      reg_id);
 332
 333         ret = sysfs_create_group(&pdev->dev.kobj,
 334                                  &regulator_virtual_attr_group);
 335         if (ret != 0) {
 336                 dev_err(&pdev->dev,
 337                         "Failed to create attribute group: %d\n", ret);
 338                 return ret;
 339         }
 340
 341         drvdata->mode = regulator_get_mode(drvdata->regulator);
 342
 343         platform_set_drvdata(pdev, drvdata);
 344
 345         return 0;
 346 }
 347
 348 static int regulator_virtual_remove(struct platform_device *pdev)
 349 {
 350         struct virtual_consumer_data *drvdata = platform_get_drvdata(pdev);
 351
 352         sysfs_remove_group(&pdev->dev.kobj, &regulator_virtual_attr_group);
 353
 354         if (drvdata->enabled)
 355                 regulator_disable(drvdata->regulator);
 356
 357         return 0;
 358 }
 359
 360 static struct platform_driver regulator_virtual_consumer_driver = {
 361         .probe          = regulator_virtual_probe,
 362         .remove         = regulator_virtual_remove,
 363         .driver         = {
 364                 .name           = "reg-virt-consumer",
 365                 .of_match_table = of_match_ptr(regulator_virtual_consumer_of_match),
 366         },
 367 };
 368
 369 module_platform_driver(regulator_virtual_consumer_driver);
 370
 371 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 372 MODULE_DESCRIPTION("Virtual regulator consumer");
 373 MODULE_LICENSE("GPL");
 374 MODULE_ALIAS("platform:reg-virt-consumer");