drm/sti: set mixer background color through module param

Add bkgcolor module parameter that allow to change the background
color of the mixer. It can be set with an RGB value coded as 0xRRGGBB.
The default value is black.

Signed-off-by: Vincent Abriou <vincent.abriou@st.com>
Signed-off-by: Nicolas VANHAELEWYN <nicolas.vanhaelewyn@st.com>

drivers/gpu/drm/sti/sti_mixer.c

@@ -10,6 +10,11 @@
 #include "sti_mixer.h"
 #include "sti_vtg.h"
 
+/* Module parameter to set the background color of the mixer */
+static unsigned int bkg_color = 0x000000;
+MODULE_PARM_DESC(bkgcolor, "Value of the background color 0xRRGGBB");
+module_param_named(bkgcolor, bkg_color, int, 0644);
+
 /* Identity: G=Y , B=Cb , R=Cr */
 static const u32 mixerColorSpaceMatIdentity[] = {
 	0x10000000, 0x00000000, 0x10000000, 0x00001000,
@@ -80,11 +85,9 @@ void sti_mixer_set_background_status(struct sti_mixer *mixer, bool enable)
 }
 
 static void sti_mixer_set_background_color(struct sti_mixer *mixer,
-					   u8 red, u8 green, u8 blue)
+					   unsigned int rgb)
 {
-	u32 val = (red << 16) | (green << 8) | blue;
-
-	sti_mixer_reg_write(mixer, GAM_MIXER_BKC, val);
+	sti_mixer_reg_write(mixer, GAM_MIXER_BKC, rgb);
 }
 
 static void sti_mixer_set_background_area(struct sti_mixer *mixer,
@@ -174,7 +177,7 @@ int sti_mixer_active_video_area(struct sti_mixer *mixer,
 	sti_mixer_reg_write(mixer, GAM_MIXER_AVO, ydo << 16 | xdo);
 	sti_mixer_reg_write(mixer, GAM_MIXER_AVS, yds << 16 | xds);
 
-	sti_mixer_set_background_color(mixer, 0xFF, 0, 0);
+	sti_mixer_set_background_color(mixer, bkg_color);
 
 	sti_mixer_set_background_area(mixer, mode);
 	sti_mixer_set_background_status(mixer, true);