media: tpg: change char argument to const char

Change the argument of type char * to const char * for function
tpg_gen_text().

This function should take in a const char * as opposed to char * as it
does not make changes to the text. This issue was found while passing
the order of colors of tpg generated test image (which is a const char
*) to this function.
Signed-off-by: Kaaira Gupta <kgupta@es.iitr.ac.in>
Reviewed-by: Helen Koike <helen.koike@collabora.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/common/v4l2-tpg/v4l2-tpg-core.c

@@ -1927,34 +1927,34 @@ typedef struct { u16 __; u8 _; } __packed x24;
 
 static noinline void tpg_print_str_2(const struct tpg_data *tpg, u8 *basep[TPG_MAX_PLANES][2],
 			unsigned p, unsigned first, unsigned div, unsigned step,
-			int y, int x, char *text, unsigned len)
+			int y, int x, const char *text, unsigned len)
 {
 	PRINTSTR(u8);
 }
 
 static noinline void tpg_print_str_4(const struct tpg_data *tpg, u8 *basep[TPG_MAX_PLANES][2],
 			unsigned p, unsigned first, unsigned div, unsigned step,
-			int y, int x, char *text, unsigned len)
+			int y, int x, const char *text, unsigned len)
 {
 	PRINTSTR(u16);
 }
 
 static noinline void tpg_print_str_6(const struct tpg_data *tpg, u8 *basep[TPG_MAX_PLANES][2],
 			unsigned p, unsigned first, unsigned div, unsigned step,
-			int y, int x, char *text, unsigned len)
+			int y, int x, const char *text, unsigned len)
 {
 	PRINTSTR(x24);
 }
 
 static noinline void tpg_print_str_8(const struct tpg_data *tpg, u8 *basep[TPG_MAX_PLANES][2],
 			unsigned p, unsigned first, unsigned div, unsigned step,
-			int y, int x, char *text, unsigned len)
+			int y, int x, const char *text, unsigned len)
 {
 	PRINTSTR(u32);
 }
 
 void tpg_gen_text(const struct tpg_data *tpg, u8 *basep[TPG_MAX_PLANES][2],
-		  int y, int x, char *text)
+		  int y, int x, const char *text)
 {
 	unsigned step = V4L2_FIELD_HAS_T_OR_B(tpg->field) ? 2 : 1;
 	unsigned div = step;

include/media/tpg/v4l2-tpg.h

@@ -241,7 +241,7 @@ void tpg_log_status(struct tpg_data *tpg);
 
 void tpg_set_font(const u8 *f);
 void tpg_gen_text(const struct tpg_data *tpg,
-		u8 *basep[TPG_MAX_PLANES][2], int y, int x, char *text);
+		u8 *basep[TPG_MAX_PLANES][2], int y, int x, const char *text);
 void tpg_calc_text_basep(struct tpg_data *tpg,
 		u8 *basep[TPG_MAX_PLANES][2], unsigned p, u8 *vbuf);
 unsigned tpg_g_interleaved_plane(const struct tpg_data *tpg, unsigned buf_line);