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Linux/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 (kstrtol(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 (kstrtol(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 (kstrtol(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 (kstrtol(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 regulator_virtual_probe(struct platform_device *pdev)
289 {
290         char *reg_id = dev_get_platdata(&pdev->dev);
291         struct virtual_consumer_data *drvdata;
292         int ret;
293 
294         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct virtual_consumer_data),
295                                GFP_KERNEL);
296         if (drvdata == NULL)
297                 return -ENOMEM;
298 
299         mutex_init(&drvdata->lock);
300 
301         drvdata->regulator = devm_regulator_get(&pdev->dev, reg_id);
302         if (IS_ERR(drvdata->regulator)) {
303                 ret = PTR_ERR(drvdata->regulator);
304                 dev_err(&pdev->dev, "Failed to obtain supply '%s': %d\n",
305                         reg_id, ret);
306                 return ret;
307         }
308 
309         ret = sysfs_create_group(&pdev->dev.kobj,
310                                  &regulator_virtual_attr_group);
311         if (ret != 0) {
312                 dev_err(&pdev->dev,
313                         "Failed to create attribute group: %d\n", ret);
314                 return ret;
315         }
316 
317         drvdata->mode = regulator_get_mode(drvdata->regulator);
318 
319         platform_set_drvdata(pdev, drvdata);
320 
321         return 0;
322 }
323 
324 static int regulator_virtual_remove(struct platform_device *pdev)
325 {
326         struct virtual_consumer_data *drvdata = platform_get_drvdata(pdev);
327 
328         sysfs_remove_group(&pdev->dev.kobj, &regulator_virtual_attr_group);
329 
330         if (drvdata->enabled)
331                 regulator_disable(drvdata->regulator);
332 
333         return 0;
334 }
335 
336 static struct platform_driver regulator_virtual_consumer_driver = {
337         .probe          = regulator_virtual_probe,
338         .remove         = regulator_virtual_remove,
339         .driver         = {
340                 .name           = "reg-virt-consumer",
341                 .owner          = THIS_MODULE,
342         },
343 };
344 
345 module_platform_driver(regulator_virtual_consumer_driver);
346 
347 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
348 MODULE_DESCRIPTION("Virtual regulator consumer");
349 MODULE_LICENSE("GPL");
350 MODULE_ALIAS("platform:reg-virt-consumer");
351 

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