[PATCH v3] media: tpg: Add function to return colors' order of test image

[Kaaira Gupta <kgupta@es.iitr.ac.in>]

Currently there is no method to know the correct order of the colors for
a test image generated by tpg. Write a function that returns a string of
colors' order given a tpg. It returns a NULL pointer in case of test
patterns which do not have a well defined colors' order. Hence add a
NULL check for text in tpg_gen_text().

Signed-off-by: Kaaira Gupta <kgupta@es.iitr.ac.in>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
---

Changes since v2:
	- Create a 'define' to prevent repetition of the common color
	  sequence string.
	- Use 'fallthrough' on case statement to prevent repetition of
	  code.

Changes since v1:
	- Returned NULL for patterns whose color order cannot be
          defined. (Reported-by: kernel test robot <lkp@intel.com>)
        - Made separate switch cases for separate test patterns
         (Reported-by: kernel test robot <lkp@intel.com>)

 drivers/media/common/v4l2-tpg/v4l2-tpg-core.c | 32 +++++++++++++++++--
 include/media/tpg/v4l2-tpg.h                  |  1 +
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/drivers/media/common/v4l2-tpg/v4l2-tpg-core.c b/drivers/media/common/v4l2-tpg/v4l2-tpg-core.c
index 50f1e0b28b25..c96204cef155 100644
--- a/drivers/media/common/v4l2-tpg/v4l2-tpg-core.c
+++ b/drivers/media/common/v4l2-tpg/v4l2-tpg-core.c
@@ -1959,12 +1959,14 @@ void tpg_gen_text(const struct tpg_data *tpg, u8 *basep[TPG_MAX_PLANES][2],
 	unsigned step = V4L2_FIELD_HAS_T_OR_B(tpg->field) ? 2 : 1;
 	unsigned div = step;
 	unsigned first = 0;
-	unsigned len = strlen(text);
+	unsigned len;
 	unsigned p;
 
-	if (font8x16 == NULL || basep == NULL)
+	if (font8x16 == NULL || basep == NULL || text == NULL)
 		return;
 
+	len = strlen(text);
+
 	/* Checks if it is possible to show string */
 	if (y + 16 >= tpg->compose.height || x + 8 >= tpg->compose.width)
 		return;
@@ -2006,6 +2008,32 @@ void tpg_gen_text(const struct tpg_data *tpg, u8 *basep[TPG_MAX_PLANES][2],
 }
 EXPORT_SYMBOL_GPL(tpg_gen_text);
 
+char *tpg_g_color_order(const struct tpg_data *tpg)
+{
+	#define COLORBAR(order) #order "white, yellow, cyan, green, magenta, red, blue, black"
+
+	switch (tpg->pattern) {
+	case TPG_PAT_75_COLORBAR:
+	case TPG_PAT_100_COLORBAR:
+	case TPG_PAT_CSC_COLORBAR:
+		return COLORBAR("Left to right:");
+	case TPG_PAT_100_HCOLORBAR:
+		return COLORBAR("Top to bottom:");
+	case TPG_PAT_BLACK:
+		return "Black";
+	case TPG_PAT_WHITE:
+		return "White";
+	case TPG_PAT_RED:
+		return "Red";
+	case TPG_PAT_GREEN:
+		return "Green";
+	case TPG_PAT_BLUE:
+		return "Blue";
+	default:
+		return NULL;
+	}
+}
+
 void tpg_update_mv_step(struct tpg_data *tpg)
 {
 	int factor = tpg->mv_hor_mode > TPG_MOVE_NONE ? -1 : 1;
diff --git a/include/media/tpg/v4l2-tpg.h b/include/media/tpg/v4l2-tpg.h
index eb191e85d363..4f79cac87b85 100644
--- a/include/media/tpg/v4l2-tpg.h
+++ b/include/media/tpg/v4l2-tpg.h
@@ -252,6 +252,7 @@ void tpg_fillbuffer(struct tpg_data *tpg, v4l2_std_id std,
 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);
+char *tpg_g_color_order(const struct tpg_data *tpg);
 
 static inline void tpg_s_pattern(struct tpg_data *tpg, enum tpg_pattern pattern)
 {
-- 
2.17.1