media: hi556: correct the test pattern configuration

Hynix hi556 support 8 test pattern modes:
hi556_test_pattern_menu[] = {
{
	"Disabled",
	"Solid Colour",
	"100% Colour Bars",
	"Fade To Grey Colour Bars",
	"PN9",
	"Gradient Horizontal",
	"Gradient Vertical",
	"Check Board",
	"Slant Pattern",
}

The test pattern is set by a 8-bit register according to the
specification.
+--------+-------------------------------+
| BIT[0] |  Solid color                  |
+--------+-------------------------------+
| BIT[1] |  Color bar                    |
+--------+-------------------------------+
| BIT[2] |  Fade to grey color bar       |
+--------+-------------------------------+
| BIT[3] |  PN9                          |
+--------+-------------------------------+
| BIT[4] |  Gradient horizontal          |
+--------+-------------------------------+
| BIT[5] |  Gradient vertical            |
+--------+-------------------------------+
| BIT[6] |  Check board                  |
+--------+-------------------------------+
| BIT[7] |  Slant pattern                |
+--------+-------------------------------+
Based on function above, current test pattern programming is wrong.
This patch fixes it by 'BIT(pattern - 1)'. If pattern is 0, driver
will disable the test pattern generation and set the pattern to 0.

Fixes: e621384 ("media: hi556: Add support for Hi-556 sensor")
Cc: [email protected]
Signed-off-by: Bingbu Cao <[email protected]>
Signed-off-by: Sakari Ailus <[email protected]>
Signed-off-by: Hans Verkuil <[email protected]>

Author: bingbucao

drivers/media/i2c/hi556.c

@@ -762,21 +762,23 @@ static int hi556_test_pattern(struct hi556 *hi556, u32 pattern)
 	int ret;
 	u32 val;
 
-	if (pattern) {
-		ret = hi556_read_reg(hi556, HI556_REG_ISP,
-				     HI556_REG_VALUE_08BIT, &val);
-		if (ret)
-			return ret;
+	ret = hi556_read_reg(hi556, HI556_REG_ISP,
+			     HI556_REG_VALUE_08BIT, &val);
+	if (ret)
+		return ret;
 
-		ret = hi556_write_reg(hi556, HI556_REG_ISP,
-				      HI556_REG_VALUE_08BIT,
-				      val | HI556_REG_ISP_TPG_EN);
-		if (ret)
-			return ret;
-	}
+	val = pattern ? (val | HI556_REG_ISP_TPG_EN) :
+		(val & ~HI556_REG_ISP_TPG_EN);
+
+	ret = hi556_write_reg(hi556, HI556_REG_ISP,
+			      HI556_REG_VALUE_08BIT, val);
+	if (ret)
+		return ret;
+
+	val = pattern ? BIT(pattern - 1) : 0;
 
 	return hi556_write_reg(hi556, HI556_REG_TEST_PATTERN,
-			       HI556_REG_VALUE_08BIT, pattern);
+			       HI556_REG_VALUE_08BIT, val);
 }
 
 static int hi556_set_ctrl(struct v4l2_ctrl *ctrl)