[media] vivid-tpg: add const where appropriate

Added 'const' to several functions where that is possible to do.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/platform/vivid/vivid-tpg.c

@@ -1241,7 +1241,7 @@ static void tpg_precalculate_line(struct tpg_data *tpg)
 /* need this to do rgb24 rendering */
 typedef struct { u16 __; u8 _; } __packed x24;
 
-void tpg_gen_text(struct tpg_data *tpg, u8 *basep[TPG_MAX_PLANES][2],
+void tpg_gen_text(const struct tpg_data *tpg, u8 *basep[TPG_MAX_PLANES][2],
 		  int y, int x, char *text)
 {
 	int line;
@@ -1389,7 +1389,7 @@ void tpg_update_mv_step(struct tpg_data *tpg)
 }
 
 /* Map the line number relative to the crop rectangle to a frame line number */
-static unsigned tpg_calc_frameline(struct tpg_data *tpg, unsigned src_y,
+static unsigned tpg_calc_frameline(const struct tpg_data *tpg, unsigned src_y,
 				    unsigned field)
 {
 	switch (field) {
@@ -1406,7 +1406,7 @@ static unsigned tpg_calc_frameline(struct tpg_data *tpg, unsigned src_y,
  * Map the line number relative to the compose rectangle to a destination
  * buffer line number.
  */
-static unsigned tpg_calc_buffer_line(struct tpg_data *tpg, unsigned y,
+static unsigned tpg_calc_buffer_line(const struct tpg_data *tpg, unsigned y,
 				    unsigned field)
 {
 	y += tpg->compose.top;

drivers/media/platform/vivid/vivid-tpg.h

@@ -193,12 +193,14 @@ void tpg_reset_source(struct tpg_data *tpg, unsigned width, unsigned height,
 		       u32 field);
 
 void tpg_set_font(const u8 *f);
-void tpg_gen_text(struct tpg_data *tpg,
+void tpg_gen_text(const struct tpg_data *tpg,
 		u8 *basep[TPG_MAX_PLANES][2], int y, int x, char *text);
 void tpg_calc_text_basep(struct tpg_data *tpg,
 		u8 *basep[TPG_MAX_PLANES][2], unsigned p, u8 *vbuf);
-void tpg_fill_plane_buffer(struct tpg_data *tpg, v4l2_std_id std, unsigned p, u8 *vbuf);
-void tpg_fillbuffer(struct tpg_data *tpg, v4l2_std_id std, unsigned p, u8 *vbuf);
+void tpg_fill_plane_buffer(struct tpg_data *tpg, v4l2_std_id std,
+			   unsigned p, u8 *vbuf);
+void tpg_fillbuffer(struct tpg_data *tpg, v4l2_std_id std,
+		    unsigned p, u8 *vbuf);
 bool tpg_s_fourcc(struct tpg_data *tpg, u32 fourcc);
 void tpg_s_crop_compose(struct tpg_data *tpg, const struct v4l2_rect *crop,
 		const struct v4l2_rect *compose);