From: John Feeney <jfeeney@redhat.com>
Date: Mon, 17 Dec 2007 15:53:42 -0500
Subject: [acpi] docking/undocking: add sysfs support
Message-id: 4766E1D6.8020504@redhat.com
O-Subject: RHEL-5.2 PATCH 2/5] Docking/undocking support
Bugzilla: 252214

bz252214 FEAT: RHEL 5.2 hot dock / undock support for mobile
w/docking station
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=252214

Problem:
The sysfs functionality is not present.

Solution:
The sysfs functionality was added by a string (7) of patches
as follows:
a. ACPI: dock: Make the dock station driver a platform device
driver.
    Make the dock station driver a platform device driver so that
    we can create sysfs entries under /sys/device/platform.

b. ACPI: dock: fix build warning
    drivers/acpi/dock.c:689: warning: too many arguments for format

c. 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.

d. ACPI: dock: add access to ACPI docking station UID
       It is useful to know whether your laptop is docked or not,
       but it is even more useful to know which docking station it's
       docked to. Attached patch adds "uid" file to sysfs.

e. ACPI: dock: use NULL for pointer
       Use NULL instead of 0 for pointers:
           drivers/acpi/dock.c:677:75: warning: Using plain integer as
NULL pointer

f. ACPI: dock: cleanup the uid patch
      Make uid sysfs file error path free memory, and cleanup sysfs file
      when removing driver.  Also fix CodingStyle violations.

g. ACPI: dock: fix opps after dock driver fails to initialize
     The driver tests the dock_station pointer for nonnull
      to check whether it has initialized properly. But in
      some cases dock_station will be non-null after being
      freed when driver init fails. Fix by zeroing the
      pointer after freeing.

Upstream Status:
All patches were taken from upstream. The commits will be
provided.
   a. commit: 671adbec210efc15cef81b4616adae8bcd667296
   b. commit: e67beb37df7a9da9d5d1e59c5358654d007a97c5
   c. commit: c80fdbe81a617c82e2f95233f8ddcf046ffe21b3
   d. commit: ac122bb64b0d51f0512185d3522a75f3f3a80bc9
   e. commit: 62a6d7fd9bc1d85f9aae734c46234e88fa839db0
   f. commit: 38ff4ffc039ba5a5878f2dcbb03d87c3a1f02f1b
   g. commit: 22fe4c2114e29477ca6738729c074ee8f60d3b73

Testing:
The sysfs patches in this series were successfully tested by me on
a T60p.

As always, acks would be appreciated.

diff --git a/drivers/acpi/dock.c b/drivers/acpi/dock.c
index c7df2a1..2630f06 100644
--- a/drivers/acpi/dock.c
+++ b/drivers/acpi/dock.c
@@ -27,6 +27,8 @@
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/notifier.h>
+#include <linux/platform_device.h>
+#include <linux/stddef.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
 
@@ -38,6 +40,8 @@ MODULE_DESCRIPTION(ACPI_DOCK_DRIVER_NAME);
 MODULE_LICENSE("GPL");
 
 static struct atomic_notifier_head dock_notifier_list;
+static struct platform_device dock_device;
+static char dock_device_name[] = "dock";
 
 struct dock_station {
 	acpi_handle handle;
@@ -511,6 +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
@@ -518,9 +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)
 {
@@ -552,19 +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);
@@ -603,6 +624,49 @@ 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);
+
+/*
+ * show_dock_uid - read method for "uid" file in sysfs
+ */
+static ssize_t show_dock_uid(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	unsigned long lbuf;
+	acpi_status status = acpi_evaluate_integer(dock_station->handle, 
+				"_UID", NULL, &lbuf);
+	if(ACPI_FAILURE(status)) 
+		return 0;
+
+	return snprintf(buf, PAGE_SIZE, "%lx\n", lbuf);
+}
+DEVICE_ATTR(uid, S_IRUGO, show_dock_uid, NULL);
+
 /**
  * dock_add - add a new dock station
  * @handle: the dock station handle
@@ -628,6 +692,44 @@ static int dock_add(acpi_handle handle)
 	mutex_init(&dock_station->hp_lock);
 	ATOMIC_INIT_NOTIFIER_HEAD(&dock_notifier_list);
 
+	/* initialize platform device stuff */
+	dock_device.name = dock_device_name;
+	ret = platform_device_register(&dock_device);
+	if (ret) {
+		printk(KERN_ERR PREFIX "Error %d registering dock device\n", ret);
+		kfree(dock_station);
+		dock_station = NULL;
+		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);
+		dock_station = NULL;
+		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);
+		dock_station = NULL;
+		return ret;
+	}
+
+	ret = device_create_file(&dock_device.dev, &dev_attr_uid);
+	if (ret) {
+		printk("Error %d adding sysfs file\n", ret);
+		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);
+		dock_station = NULL;
+		return ret;
+	}
+
 	/* Find dependent devices */
 	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 			    ACPI_UINT32_MAX, find_dock_devices, dock_station,
@@ -637,7 +739,9 @@ static int dock_add(acpi_handle handle)
 	dd = alloc_dock_dependent_device(handle);
 	if (!dd) {
 		kfree(dock_station);
-		return -ENOMEM;
+		dock_station = NULL;
+		ret = -ENOMEM;
+		goto dock_add_err_unregister;
 	}
 	add_dock_dependent_device(dock_station, dd);
 
@@ -657,8 +761,14 @@ static int dock_add(acpi_handle handle)
 	return 0;
 
 dock_add_err:
-	kfree(dock_station);
 	kfree(dd);
+dock_add_err_unregister:
+	device_remove_file(&dock_device.dev, &dev_attr_docked);
+	device_remove_file(&dock_device.dev, &dev_attr_undock);
+	device_remove_file(&dock_device.dev, &dev_attr_uid);
+	platform_device_unregister(&dock_device);
+	kfree(dock_station);
+	dock_station = NULL;
 	return ret;
 }
 
@@ -685,8 +795,15 @@ static int dock_remove(void)
 	if (ACPI_FAILURE(status))
 		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);
+	device_remove_file(&dock_device.dev, &dev_attr_uid);
+	platform_device_unregister(&dock_device);
+
 	/* free dock station memory */
 	kfree(dock_station);
+	dock_station = NULL;
 	return 0;
 }