2 files changed, 31 insertions, 4 deletions

diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index 51f677215f1d..6d81a02463a3 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -553,6 +553,32 @@ int drm_mode_height(struct drm_display_mode *mode)
 }
 EXPORT_SYMBOL(drm_mode_height);
 
+/** drm_mode_hsync - get the hsync of a mode
+ * @mode: mode
+ *
+ * LOCKING:
+ * None.
+ *
+ * Return @modes's hsync rate in kHz, rounded to the nearest int.
+ */
+int drm_mode_hsync(struct drm_display_mode *mode)
+{
+        unsigned int calc_val;
+
+        if (mode->hsync)
+                return mode->hsync;
+
+        if (mode->htotal < 0)
+                return 0;
+
+        calc_val = (mode->clock * 1000) / mode->htotal; /* hsync in Hz */
+        calc_val += 500;                                /* round to 1000Hz */
+        calc_val /= 1000;                               /* truncate to kHz */
+
+        return calc_val;
+}
+EXPORT_SYMBOL(drm_mode_hsync);
+
 /**
  * drm_mode_vrefresh - get the vrefresh of a mode
  * @mode: mode
@@ -560,7 +586,7 @@ EXPORT_SYMBOL(drm_mode_height);
  * LOCKING:
  * None.
  *
- * Return @mode's vrefresh rate or calculate it if necessary.
+ * Return @mode's vrefresh rate in Hz or calculate it if necessary.
  *
  * FIXME: why is this needed?  shouldn't vrefresh be set already?
  *
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index d84fba15c9d8..938f327a2a3b 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -123,7 +123,7 @@ struct drm_display_mode {
         int type;
 
         /* Proposed mode values */
-        int clock;
+        int clock;              /* in kHz */
         int hdisplay;
         int hsync_start;
         int hsync_end;
@@ -164,8 +164,8 @@ struct drm_display_mode {
         int *private;
         int private_flags;
 
-        int vrefresh;
-        float hsync;
+        int vrefresh;           /* in Hz */
+        int hsync;              /* in kHz */
 };
 
 enum drm_connector_status {
@@ -681,6 +681,7 @@ extern void drm_mode_validate_size(struct drm_device *dev,
 extern void drm_mode_prune_invalid(struct drm_device *dev,
                                    struct list_head *mode_list, bool verbose);
 extern void drm_mode_sort(struct list_head *mode_list);
+extern int drm_mode_hsync(struct drm_display_mode *mode);
 extern int drm_mode_vrefresh(struct drm_display_mode *mode);
 extern void drm_mode_set_crtcinfo(struct drm_display_mode *p,
                                   int adjust_flags);