Kernel/SysFS: Add exposing interface for DisplayConnectors

Under normal conditions (when mounting SysFS in /sys), there will be a
new directory in the /sys/devices directory called "graphics".
For now, under that directory there will be only a sub-directory called
"connectors" which will contain all DisplayConnectors' details, each in
its own sub-directory too, distinguished in naming with its minor
number.

Therefore, /sys/devices/graphics/connectors/MINOR_NUMBER/ will contain:
- General device attributes such as mutable_mode_setting_capable,
  double_buffering_capable, flush_support, partial_flush_support and
  refresh_rate_support. These values are exposed in the ioctl interface
  of the DisplayConnector class too, but these can be useful later on
  for command line utilities that want/need to expose these basic
  settings.
- The EDID blob, simply named "edid". This will help userspace to fetch
  the edid without the need of using the ioctl interface later on.

1 files changed, 24 insertions, 2 deletions

diff --git a/Kernel/Graphics/DisplayConnector.cpp b/Kernel/Graphics/DisplayConnector.cpp
index e6462e33d1..9cf8f327b8 100644
--- a/Kernel/Graphics/DisplayConnector.cpp
+++ b/Kernel/Graphics/DisplayConnector.cpp
@@ -4,6 +4,9 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <Kernel/FileSystem/SysFS/Subsystems/DeviceIdentifiers/CharacterDevicesDirectory.h>
+#include <Kernel/FileSystem/SysFS/Subsystems/Devices/Graphics/DisplayConnector/DeviceDirectory.h>
+#include <Kernel/FileSystem/SysFS/Subsystems/Devices/Graphics/DisplayConnector/Directory.h>
 #include <Kernel/Graphics/DisplayConnector.h>
 #include <Kernel/Graphics/GraphicsManagement.h>
 #include <Kernel/Memory/MemoryManager.h>
@@ -57,12 +60,31 @@ ErrorOr<size_t> DisplayConnector::write(OpenFileDescription&, u64, UserOrKernelB
 void DisplayConnector::will_be_destroyed()
 {
     GraphicsManagement::the().detach_display_connector({}, *this);
-    Device::will_be_destroyed();
+
+    VERIFY(m_symlink_sysfs_component);
+    VERIFY(!is_block_device());
+    SysFSCharacterDevicesDirectory::the().m_child_components.with([&](auto& list) -> void {
+        list.remove(*m_symlink_sysfs_component);
+    });
+    m_symlink_sysfs_component.clear();
+    SysFSDisplayConnectorsDirectory::the().unplug({}, *m_sysfs_device_directory);
+    before_will_be_destroyed_remove_from_device_management();
 }
 
 void DisplayConnector::after_inserting()
 {
-    Device::after_inserting();
+    after_inserting_add_to_device_management();
+    auto sysfs_display_connector_device_directory = DisplayConnectorSysFSDirectory::create(SysFSDisplayConnectorsDirectory::the(), *this);
+    m_sysfs_device_directory = sysfs_display_connector_device_directory;
+    SysFSDisplayConnectorsDirectory::the().plug({}, *sysfs_display_connector_device_directory);
+    VERIFY(!m_symlink_sysfs_component);
+    auto sys_fs_component = MUST(SysFSSymbolicLinkDeviceComponent::try_create(SysFSDeviceIdentifiersDirectory::the(), *this, *m_sysfs_device_directory));
+    m_symlink_sysfs_component = sys_fs_component;
+    VERIFY(!is_block_device());
+    SysFSCharacterDevicesDirectory::the().m_child_components.with([&](auto& list) -> void {
+        list.append(*m_symlink_sysfs_component);
+    });
+
     auto rounded_size = MUST(Memory::page_round_up(m_framebuffer_resource_size));
 
     if (!m_framebuffer_at_arbitrary_physical_range) {