drm/amd/display: do not use drm middle layer for debugfs

Use debugfs API directly instead of drm middle layer.

v2: * checkpatch.pl: use '0444' instead of S_IRUGO.
    * remove S_IFREG from mode.
    * remove mode variable.

Signed-off-by: Nirmoy Das <nirmoy.das@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c

@@ -1645,10 +1645,8 @@ int amdgpu_debugfs_init(struct amdgpu_device *adev)
 		DRM_ERROR("registering firmware debugfs failed (%d).\n", r);
 
 #if defined(CONFIG_DRM_AMD_DC)
-	if (amdgpu_device_has_dc_support(adev)) {
-		if (dtn_debugfs_init(adev))
-			DRM_ERROR("amdgpu: failed initialize dtn debugfs support.\n");
-	}
+	if (amdgpu_device_has_dc_support(adev))
+		dtn_debugfs_init(adev);
 #endif
 
 	for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c

@@ -25,8 +25,6 @@
 
 #include <linux/uaccess.h>
 
-#include <drm/drm_debugfs.h>
-
 #include "dc.h"
 #include "amdgpu.h"
 #include "amdgpu_dm.h"
@@ -2450,11 +2448,9 @@ static ssize_t dtn_log_write(
  * As written to display, taking ABM and backlight lut into account.
  * Ranges from 0x0 to 0x10000 (= 100% PWM)
  */
-static int current_backlight_read(struct seq_file *m, void *data)
+static int current_backlight_show(struct seq_file *m, void *unused)
 {
-	struct drm_info_node *node = (struct drm_info_node *)m->private;
-	struct drm_device *dev = node->minor->dev;
-	struct amdgpu_device *adev = drm_to_adev(dev);
+	struct amdgpu_device *adev = (struct amdgpu_device *)m->private;
 	struct amdgpu_display_manager *dm = &adev->dm;
 
 	unsigned int backlight = dc_link_get_backlight_level(dm->backlight_link);
@@ -2468,11 +2464,9 @@ static int current_backlight_read(struct seq_file *m, void *data)
  * As written to display, taking ABM and backlight lut into account.
  * Ranges from 0x0 to 0x10000 (= 100% PWM)
  */
-static int target_backlight_read(struct seq_file *m, void *data)
+static int target_backlight_show(struct seq_file *m, void *unused)
 {
-	struct drm_info_node *node = (struct drm_info_node *)m->private;
-	struct drm_device *dev = node->minor->dev;
-	struct amdgpu_device *adev = drm_to_adev(dev);
+	struct amdgpu_device *adev = (struct amdgpu_device *)m->private;
 	struct amdgpu_display_manager *dm = &adev->dm;
 
 	unsigned int backlight = dc_link_get_target_backlight_pwm(dm->backlight_link);
@@ -2481,10 +2475,10 @@ static int target_backlight_read(struct seq_file *m, void *data)
 	return 0;
 }
 
-static int mst_topo(struct seq_file *m, void *unused)
+static int mst_topo_show(struct seq_file *m, void *unused)
 {
-	struct drm_info_node *node = (struct drm_info_node *)m->private;
-	struct drm_device *dev = node->minor->dev;
+	struct amdgpu_device *adev = (struct amdgpu_device *)m->private;
+	struct drm_device *dev = adev_to_drm(adev);
 	struct drm_connector *connector;
 	struct drm_connector_list_iter conn_iter;
 	struct amdgpu_dm_connector *aconnector;
@@ -2504,12 +2498,6 @@ static int mst_topo(struct seq_file *m, void *unused)
 	return 0;
 }
 
-static const struct drm_info_list amdgpu_dm_debugfs_list[] = {
-	{"amdgpu_current_backlight_pwm", &current_backlight_read},
-	{"amdgpu_target_backlight_pwm", &target_backlight_read},
-	{"amdgpu_mst_topology", &mst_topo},
-};
-
 /*
  * Sets the force_timing_sync debug optino from the given string.
  * All connected displays will be force synchronized immediately.
@@ -2568,10 +2556,13 @@ static int visual_confirm_get(void *data, u64 *val)
 	return 0;
 }
 
+DEFINE_SHOW_ATTRIBUTE(current_backlight);
+DEFINE_SHOW_ATTRIBUTE(target_backlight);
+DEFINE_SHOW_ATTRIBUTE(mst_topo);
 DEFINE_DEBUGFS_ATTRIBUTE(visual_confirm_fops, visual_confirm_get,
 			 visual_confirm_set, "%llu\n");
 
-int dtn_debugfs_init(struct amdgpu_device *adev)
+void dtn_debugfs_init(struct amdgpu_device *adev)
 {
 	static const struct file_operations dtn_log_fops = {
 		.owner = THIS_MODULE,
@@ -2582,13 +2573,13 @@ int dtn_debugfs_init(struct amdgpu_device *adev)
 
 	struct drm_minor *minor = adev_to_drm(adev)->primary;
 	struct dentry *root = minor->debugfs_root;
-	int ret;
-
-	ret = amdgpu_debugfs_add_files(adev, amdgpu_dm_debugfs_list,
-				ARRAY_SIZE(amdgpu_dm_debugfs_list));
-	if (ret)
-		return ret;
 
+	debugfs_create_file("amdgpu_current_backlight_pwm", 0444,
+			    root, adev, &current_backlight_fops);
+	debugfs_create_file("amdgpu_target_backlight_pwm", 0444,
+			    root, adev, &target_backlight_fops);
+	debugfs_create_file("amdgpu_mst_topology", 0444, root,
+			    adev, &mst_topo_fops);
 	debugfs_create_file("amdgpu_dm_dtn_log", 0644, root, adev,
 			    &dtn_log_fops);
 
@@ -2603,6 +2594,4 @@ int dtn_debugfs_init(struct amdgpu_device *adev)
 
 	debugfs_create_file_unsafe("amdgpu_dm_force_timing_sync", 0644, root,
 				   adev, &force_timing_sync_ops);
-
-	return 0;
 }

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.h

@@ -30,6 +30,6 @@
 #include "amdgpu_dm.h"
 
 void connector_debugfs_init(struct amdgpu_dm_connector *connector);
-int dtn_debugfs_init(struct amdgpu_device *adev);
+void dtn_debugfs_init(struct amdgpu_device *adev);
 
 #endif