[PATCH 1/2] drm/dp_aux: Use non-cyclic idr, add suffix option for aux device

[sunpeng.li at amd.com]

From: Leo Li <sunpeng.li at amd.com>

In preparation for adding aux devices for DP MST:

1. A non-cyclic idr is used for the device minor version. That way,
   hotplug cycling MST devices won't needlessly increment the minor
   version index.
2. A suffix option is added to the aux device file name. It can be used
   to identify the corresponding MST device.

Signed-off-by: Leo Li <sunpeng.li at amd.com>
---
 drivers/gpu/drm/drm_crtc_helper_internal.h | 5 +++--
 drivers/gpu/drm/drm_dp_aux_dev.c           | 8 ++++----
 drivers/gpu/drm/drm_dp_helper.c            | 2 +-
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc_helper_internal.h b/drivers/gpu/drm/drm_crtc_helper_internal.h
index b5ac158..9f0907b 100644
--- a/drivers/gpu/drm/drm_crtc_helper_internal.h
+++ b/drivers/gpu/drm/drm_crtc_helper_internal.h
@@ -46,7 +46,7 @@ static inline int drm_fb_helper_modinit(void)
 #ifdef CONFIG_DRM_DP_AUX_CHARDEV
 int drm_dp_aux_dev_init(void);
 void drm_dp_aux_dev_exit(void);
-int drm_dp_aux_register_devnode(struct drm_dp_aux *aux);
+int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char *suffix);
 void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux);
 #else
 static inline int drm_dp_aux_dev_init(void)
@@ -58,7 +58,8 @@ static inline void drm_dp_aux_dev_exit(void)
 {
 }
 
-static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
+static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux,
+					      const char *suffix)
 {
 	return 0;
 }
diff --git a/drivers/gpu/drm/drm_dp_aux_dev.c b/drivers/gpu/drm/drm_dp_aux_dev.c
index 0e4f25d..2310a67 100644
--- a/drivers/gpu/drm/drm_dp_aux_dev.c
+++ b/drivers/gpu/drm/drm_dp_aux_dev.c
@@ -80,8 +80,7 @@ static struct drm_dp_aux_dev *alloc_drm_dp_aux_dev(struct drm_dp_aux *aux)
 	kref_init(&aux_dev->refcount);
 
 	mutex_lock(&aux_idr_mutex);
-	index = idr_alloc_cyclic(&aux_idr, aux_dev, 0, DRM_AUX_MINORS,
-				 GFP_KERNEL);
+	index = idr_alloc(&aux_idr, aux_dev, 0, DRM_AUX_MINORS, GFP_KERNEL);
 	mutex_unlock(&aux_idr_mutex);
 	if (index < 0) {
 		kfree(aux_dev);
@@ -290,7 +289,7 @@ void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux)
 	kref_put(&aux_dev->refcount, release_drm_dp_aux_dev);
 }
 
-int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
+int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char *suffix)
 {
 	struct drm_dp_aux_dev *aux_dev;
 	int res;
@@ -301,7 +300,8 @@ int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
 
 	aux_dev->dev = device_create(drm_dp_aux_dev_class, aux->dev,
 				     MKDEV(drm_dev_major, aux_dev->index), NULL,
-				     "drm_dp_aux%d", aux_dev->index);
+				     "drm_dp_aux%d%s", aux_dev->index,
+				     suffix ? suffix : "");
 	if (IS_ERR(aux_dev->dev)) {
 		res = PTR_ERR(aux_dev->dev);
 		aux_dev->dev = NULL;
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index e2266ac..13f1005 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -1143,7 +1143,7 @@ int drm_dp_aux_register(struct drm_dp_aux *aux)
 	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
 		sizeof(aux->ddc.name));
 
-	ret = drm_dp_aux_register_devnode(aux);
+	ret = drm_dp_aux_register_devnode(aux, NULL);
 	if (ret)
 		return ret;
 
-- 
2.7.4