drivers/base/power/sysfs.c

   1 /*
   2  * drivers/base/power/sysfs.c - sysfs entries for device PM
   3  */
   4
   5 #include <linux/device.h>
   6 #include <linux/string.h>
   7 #include <linux/pm_runtime.h>
   8 #include <asm/atomic.h>
   9 #include <linux/jiffies.h>
  10 #include "power.h"
  11
  12 /*
  13  *      control - Report/change current runtime PM setting of the device
  14  *
  15  *      Runtime power management of a device can be blocked with the help of
  16  *      this attribute.  All devices have one of the following two values for
  17  *      the power/control file:
  18  *
  19  *       + "auto\n" to allow the device to be power managed at run time;
  20  *       + "on\n" to prevent the device from being power managed at run time;
  21  *
  22  *      The default for all devices is "auto", which means that devices may be
  23  *      subject to automatic power management, depending on their drivers.
  24  *      Changing this attribute to "on" prevents the driver from power managing
  25  *      the device at run time.  Doing that while the device is suspended causes
  26  *      it to be woken up.
  27  *
  28  *      wakeup - Report/change current wakeup option for device
  29  *
  30  *      Some devices support "wakeup" events, which are hardware signals
  31  *      used to activate devices from suspended or low power states.  Such
  32  *      devices have one of three values for the sysfs power/wakeup file:
  33  *
  34  *       + "enabled\n" to issue the events;
  35  *       + "disabled\n" not to do so; or
  36  *       + "\n" for temporary or permanent inability to issue wakeup.
  37  *
  38  *      (For example, unconfigured USB devices can't issue wakeups.)
  39  *
  40  *      Familiar examples of devices that can issue wakeup events include
  41  *      keyboards and mice (both PS2 and USB styles), power buttons, modems,
  42  *      "Wake-On-LAN" Ethernet links, GPIO lines, and more.  Some events
  43  *      will wake the entire system from a suspend state; others may just
  44  *      wake up the device (if the system as a whole is already active).
  45  *      Some wakeup events use normal IRQ lines; other use special out
  46  *      of band signaling.
  47  *
  48  *      It is the responsibility of device drivers to enable (or disable)
  49  *      wakeup signaling as part of changing device power states, respecting
  50  *      the policy choices provided through the driver model.
  51  *
  52  *      Devices may not be able to generate wakeup events from all power
  53  *      states.  Also, the events may be ignored in some configurations;
  54  *      for example, they might need help from other devices that aren't
  55  *      active, or which may have wakeup disabled.  Some drivers rely on
  56  *      wakeup events internally (unless they are disabled), keeping
  57  *      their hardware in low power modes whenever they're unused.  This
  58  *      saves runtime power, without requiring system-wide sleep states.
  59  *
  60  *      async - Report/change current async suspend setting for the device
  61  *
  62  *      Asynchronous suspend and resume of the device during system-wide power
  63  *      state transitions can be enabled by writing "enabled" to this file.
  64  *      Analogously, if "disabled" is written to this file, the device will be
  65  *      suspended and resumed synchronously.
  66  *
  67  *      All devices have one of the following two values for power/async:
  68  *
  69  *       + "enabled\n" to permit the asynchronous suspend/resume of the device;
  70  *       + "disabled\n" to forbid it;
  71  *
  72  *      NOTE: It generally is unsafe to permit the asynchronous suspend/resume
  73  *      of a device unless it is certain that all of the PM dependencies of the
  74  *      device are known to the PM core.  However, for some devices this
  75  *      attribute is set to "enabled" by bus type code or device drivers and in
  76  *      that cases it should be safe to leave the default value.
  77  *
  78  *      wakeup_count - Report the number of wakeup events related to the device
  79  */
  80
  81 static const char enabled[] = "enabled";
  82 static const char disabled[] = "disabled";
  83
  84 #ifdef CONFIG_PM_RUNTIME
  85 static const char ctrl_auto[] = "auto";
  86 static const char ctrl_on[] = "on";
  87
  88 static ssize_t control_show(struct device *dev, struct device_attribute *attr,
  89                             char *buf)
  90 {
  91         return sprintf(buf, "%s\n",
  92                                 dev->power.runtime_auto ? ctrl_auto : ctrl_on);
  93 }
  94
  95 static ssize_t control_store(struct device * dev, struct device_attribute *attr,
  96                              const char * buf, size_t n)
  97 {
  98         char *cp;
  99         int len = n;
 100
 101         cp = memchr(buf, '\n', n);
 102         if (cp)
 103                 len = cp - buf;
 104         if (len == sizeof ctrl_auto - 1 && strncmp(buf, ctrl_auto, len) == 0)
 105                 pm_runtime_allow(dev);
 106         else if (len == sizeof ctrl_on - 1 && strncmp(buf, ctrl_on, len) == 0)
 107                 pm_runtime_forbid(dev);
 108         else
 109                 return -EINVAL;
 110         return n;
 111 }
 112
 113 static DEVICE_ATTR(control, 0644, control_show, control_store);
 114
 115 static ssize_t rtpm_active_time_show(struct device *dev,
 116                                 struct device_attribute *attr, char *buf)
 117 {
 118         int ret;
 119         spin_lock_irq(&dev->power.lock);
 120         update_pm_runtime_accounting(dev);
 121         ret = sprintf(buf, "%i\n", jiffies_to_msecs(dev->power.active_jiffies));
 122         spin_unlock_irq(&dev->power.lock);
 123         return ret;
 124 }
 125
 126 static DEVICE_ATTR(runtime_active_time, 0444, rtpm_active_time_show, NULL);
 127
 128 static ssize_t rtpm_suspended_time_show(struct device *dev,
 129                                 struct device_attribute *attr, char *buf)
 130 {
 131         int ret;
 132         spin_lock_irq(&dev->power.lock);
 133         update_pm_runtime_accounting(dev);
 134         ret = sprintf(buf, "%i\n",
 135                 jiffies_to_msecs(dev->power.suspended_jiffies));
 136         spin_unlock_irq(&dev->power.lock);
 137         return ret;
 138 }
 139
 140 static DEVICE_ATTR(runtime_suspended_time, 0444, rtpm_suspended_time_show, NULL);
 141
 142 static ssize_t rtpm_status_show(struct device *dev,
 143                                 struct device_attribute *attr, char *buf)
 144 {
 145         const char *p;
 146
 147         if (dev->power.runtime_error) {
 148                 p = "error\n";
 149         } else if (dev->power.disable_depth) {
 150                 p = "unsupported\n";
 151         } else {
 152                 switch (dev->power.runtime_status) {
 153                 case RPM_SUSPENDED:
 154                         p = "suspended\n";
 155                         break;
 156                 case RPM_SUSPENDING:
 157                         p = "suspending\n";
 158                         break;
 159                 case RPM_RESUMING:
 160                         p = "resuming\n";
 161                         break;
 162                 case RPM_ACTIVE:
 163                         p = "active\n";
 164                         break;
 165                 default:
 166                         return -EIO;
 167                 }
 168         }
 169         return sprintf(buf, p);
 170 }
 171
 172 static DEVICE_ATTR(runtime_status, 0444, rtpm_status_show, NULL);
 173 #endif
 174
 175 static ssize_t
 176 wake_show(struct device * dev, struct device_attribute *attr, char * buf)
 177 {
 178         return sprintf(buf, "%s\n", device_can_wakeup(dev)
 179                 ? (device_may_wakeup(dev) ? enabled : disabled)
 180                 : "");
 181 }
 182
 183 static ssize_t
 184 wake_store(struct device * dev, struct device_attribute *attr,
 185         const char * buf, size_t n)
 186 {
 187         char *cp;
 188         int len = n;
 189
 190         if (!device_can_wakeup(dev))
 191                 return -EINVAL;
 192
 193         cp = memchr(buf, '\n', n);
 194         if (cp)
 195                 len = cp - buf;
 196         if (len == sizeof enabled - 1
 197                         && strncmp(buf, enabled, sizeof enabled - 1) == 0)
 198                 device_set_wakeup_enable(dev, 1);
 199         else if (len == sizeof disabled - 1
 200                         && strncmp(buf, disabled, sizeof disabled - 1) == 0)
 201                 device_set_wakeup_enable(dev, 0);
 202         else
 203                 return -EINVAL;
 204         return n;
 205 }
 206
 207 static DEVICE_ATTR(wakeup, 0644, wake_show, wake_store);
 208
 209 #ifdef CONFIG_PM_SLEEP
 210 static ssize_t wakeup_count_show(struct device *dev,
 211                                 struct device_attribute *attr, char *buf)
 212 {
 213         return sprintf(buf, "%lu\n", dev->power.wakeup_count);
 214 }
 215
 216 static DEVICE_ATTR(wakeup_count, 0444, wakeup_count_show, NULL);
 217 #endif
 218
 219 #ifdef CONFIG_PM_ADVANCED_DEBUG
 220 #ifdef CONFIG_PM_RUNTIME
 221
 222 static ssize_t rtpm_usagecount_show(struct device *dev,
 223                                     struct device_attribute *attr, char *buf)
 224 {
 225         return sprintf(buf, "%d\n", atomic_read(&dev->power.usage_count));
 226 }
 227
 228 static ssize_t rtpm_children_show(struct device *dev,
 229                                   struct device_attribute *attr, char *buf)
 230 {
 231         return sprintf(buf, "%d\n", dev->power.ignore_children ?
 232                 0 : atomic_read(&dev->power.child_count));
 233 }
 234
 235 static ssize_t rtpm_enabled_show(struct device *dev,
 236                                  struct device_attribute *attr, char *buf)
 237 {
 238         if ((dev->power.disable_depth) && (dev->power.runtime_auto == false))
 239                 return sprintf(buf, "disabled & forbidden\n");
 240         else if (dev->power.disable_depth)
 241                 return sprintf(buf, "disabled\n");
 242         else if (dev->power.runtime_auto == false)
 243                 return sprintf(buf, "forbidden\n");
 244         return sprintf(buf, "enabled\n");
 245 }
 246
 247 static DEVICE_ATTR(runtime_usage, 0444, rtpm_usagecount_show, NULL);
 248 static DEVICE_ATTR(runtime_active_kids, 0444, rtpm_children_show, NULL);
 249 static DEVICE_ATTR(runtime_enabled, 0444, rtpm_enabled_show, NULL);
 250
 251 #endif
 252
 253 static ssize_t async_show(struct device *dev, struct device_attribute *attr,
 254                           char *buf)
 255 {
 256         return sprintf(buf, "%s\n",
 257                         device_async_suspend_enabled(dev) ? enabled : disabled);
 258 }
 259
 260 static ssize_t async_store(struct device *dev, struct device_attribute *attr,
 261                            const char *buf, size_t n)
 262 {
 263         char *cp;
 264         int len = n;
 265
 266         cp = memchr(buf, '\n', n);
 267         if (cp)
 268                 len = cp - buf;
 269         if (len == sizeof enabled - 1 && strncmp(buf, enabled, len) == 0)
 270                 device_enable_async_suspend(dev);
 271         else if (len == sizeof disabled - 1 && strncmp(buf, disabled, len) == 0)
 272                 device_disable_async_suspend(dev);
 273         else
 274                 return -EINVAL;
 275         return n;
 276 }
 277
 278 static DEVICE_ATTR(async, 0644, async_show, async_store);
 279 #endif /* CONFIG_PM_ADVANCED_DEBUG */
 280
 281 static struct attribute * power_attrs[] = {
 282 #ifdef CONFIG_PM_RUNTIME
 283         &dev_attr_control.attr,
 284         &dev_attr_runtime_status.attr,
 285         &dev_attr_runtime_suspended_time.attr,
 286         &dev_attr_runtime_active_time.attr,
 287 #endif
 288         &dev_attr_wakeup.attr,
 289 #ifdef CONFIG_PM_SLEEP
 290         &dev_attr_wakeup_count.attr,
 291 #endif
 292 #ifdef CONFIG_PM_ADVANCED_DEBUG
 293         &dev_attr_async.attr,
 294 #ifdef CONFIG_PM_RUNTIME
 295         &dev_attr_runtime_usage.attr,
 296         &dev_attr_runtime_active_kids.attr,
 297         &dev_attr_runtime_enabled.attr,
 298 #endif
 299 #endif
 300         NULL,
 301 };
 302 static struct attribute_group pm_attr_group = {
 303         .name   = "power",
 304         .attrs  = power_attrs,
 305 };
 306
 307 int dpm_sysfs_add(struct device * dev)
 308 {
 309         return sysfs_create_group(&dev->kobj, &pm_attr_group);
 310 }
 311
 312 void dpm_sysfs_remove(struct device * dev)
 313 {
 314         sysfs_remove_group(&dev->kobj, &pm_attr_group);
 315 }