ACPI: dock: Add a docked sysfs file to the dock driver.

Add 2 sysfs files for user interface.
1) docked - 1/0 (read only) - indicates whether the software believes the
laptop is docked in a docking station.
2) undock - (write only) - writing to this file causes the software to
initiate an undock request to the firmware.

Signed-off-by: Brandon Philips <brandon@ifup.org>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 79 insertions, 16 deletions

diff --git a/drivers/acpi/dock.c b/drivers/acpi/dock.c
index 2c2f28db9fb2..e4c1a4ff4e31 100644
--- a/drivers/acpi/dock.c
+++ b/drivers/acpi/dock.c
@@ -515,6 +515,37 @@ void unregister_hotplug_dock_device(acpi_handle handle)
 EXPORT_SYMBOL_GPL(unregister_hotplug_dock_device);
 
 /**
+ * handle_eject_request - handle an undock request checking for error conditions
+ *
+ * Check to make sure the dock device is still present, then undock and
+ * hotremove all the devices that may need removing.
+ */
+static int handle_eject_request(struct dock_station *ds, u32 event)
+{
+        if (!dock_present(ds))
+                return -ENODEV;
+
+        if (dock_in_progress(ds))
+                return -EBUSY;
+
+        /*
+         * here we need to generate the undock
+         * event prior to actually doing the undock
+         * so that the device struct still exists.
+         */
+        dock_event(ds, event, UNDOCK_EVENT);
+        hotplug_dock_devices(ds, ACPI_NOTIFY_EJECT_REQUEST);
+        undock(ds);
+        eject_dock(ds);
+        if (dock_present(ds)) {
+                printk(KERN_ERR PREFIX "Unable to undock!\n");
+                return -EBUSY;
+        }
+
+        return 0;
+}
+
+/**
  * dock_notify - act upon an acpi dock notification
  * @handle: the dock station handle
  * @event: the acpi event
@@ -522,9 +553,7 @@ EXPORT_SYMBOL_GPL(unregister_hotplug_dock_device);
  *
  * If we are notified to dock, then check to see if the dock is
  * present and then dock.  Notify all drivers of the dock event,
- * and then hotplug and devices that may need hotplugging.  For undock
- * check to make sure the dock device is still present, then undock
- * and hotremove all the devices that may need removing.
+ * and then hotplug and devices that may need hotplugging.
  */
 static void dock_notify(acpi_handle handle, u32 event, void *data)
 {
@@ -556,19 +585,7 @@ static void dock_notify(acpi_handle handle, u32 event, void *data)
          * to the driver who wish to hotplug.
          */
         case ACPI_NOTIFY_EJECT_REQUEST:
-                if (!dock_in_progress(ds) && dock_present(ds)) {
-                        /*
-                         * here we need to generate the undock
-                         * event prior to actually doing the undock
-                         * so that the device struct still exists.
-                         */
-                        dock_event(ds, event, UNDOCK_EVENT);
-                        hotplug_dock_devices(ds, ACPI_NOTIFY_EJECT_REQUEST);
-                        undock(ds);
-                        eject_dock(ds);
-                        if (dock_present(ds))
-                                printk(KERN_ERR PREFIX "Unable to undock!\n");
-                }
+                handle_eject_request(ds, event);
                 break;
         default:
                 printk(KERN_ERR PREFIX "Unknown dock event %d\n", event);
@@ -607,6 +624,33 @@ find_dock_devices(acpi_handle handle, u32 lvl, void *context, void **rv)
         return AE_OK;
 }
 
+/*
+ * show_docked - read method for "docked" file in sysfs
+ */
+static ssize_t show_docked(struct device *dev,
+                           struct device_attribute *attr, char *buf)
+{
+        return snprintf(buf, PAGE_SIZE, "%d\n", dock_present(dock_station));
+
+}
+DEVICE_ATTR(docked, S_IRUGO, show_docked, NULL);
+
+/*
+ * write_undock - write method for "undock" file in sysfs
+ */
+static ssize_t write_undock(struct device *dev, struct device_attribute *attr,
+                           const char *buf, size_t count)
+{
+        int ret;
+
+        if (!count)
+                return -EINVAL;
+
+        ret = handle_eject_request(dock_station, ACPI_NOTIFY_EJECT_REQUEST);
+        return ret ? ret: count;
+}
+DEVICE_ATTR(undock, S_IWUSR, NULL, write_undock);
+
 /**
  * dock_add - add a new dock station
  * @handle: the dock station handle
@@ -640,6 +684,21 @@ static int dock_add(acpi_handle handle)
                 kfree(dock_station);
                 return ret;
         }
+        ret = device_create_file(&dock_device.dev, &dev_attr_docked);
+        if (ret) {
+                printk("Error %d adding sysfs file\n", ret);
+                platform_device_unregister(&dock_device);
+                kfree(dock_station);
+                return ret;
+        }
+        ret = device_create_file(&dock_device.dev, &dev_attr_undock);
+        if (ret) {
+                printk("Error %d adding sysfs file\n", ret);
+                device_remove_file(&dock_device.dev, &dev_attr_docked);
+                platform_device_unregister(&dock_device);
+                kfree(dock_station);
+                return ret;
+        }
 
         /* Find dependent devices */
         acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
@@ -673,6 +732,8 @@ static int dock_add(acpi_handle handle)
 dock_add_err:
         kfree(dd);
 dock_add_err_unregister:
+        device_remove_file(&dock_device.dev, &dev_attr_docked);
+        device_remove_file(&dock_device.dev, &dev_attr_undock);
         platform_device_unregister(&dock_device);
         kfree(dock_station);
         return ret;
@@ -702,6 +763,8 @@ static int dock_remove(void)
                 printk(KERN_ERR "Error removing notify handler\n");
 
         /* cleanup sysfs */
+        device_remove_file(&dock_device.dev, &dev_attr_docked);
+        device_remove_file(&dock_device.dev, &dev_attr_undock);
         platform_device_unregister(&dock_device);
 
         /* free dock station memory */