media: imx: imx7-mipi-csis: Align image width based on format

The total number of bits per line needs to be a multiple of 8, which
requires aligning the image width based on the format width. The
csis_pix_format structure contains a pix_width_alignment field that
serves this purpose, but the field is never set. Instead of fixing that,
calculate the alignment constraints based on the bus width for the
format, and drop the unneeded pix_width_alignment field.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Rui Miguel Silva <rmfrfs@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/imx/imx7-mipi-csis.c

@@ -258,7 +258,6 @@ struct csi_state {
 };
 
 struct csis_pix_format {
-	unsigned int pix_width_alignment;
 	u32 code;
 	u32 fmt_reg;
 	u8 width;
@@ -774,6 +773,7 @@ static int mipi_csis_set_fmt(struct v4l2_subdev *mipi_sd,
 	struct csi_state *state = mipi_sd_to_csis_state(mipi_sd);
 	struct csis_pix_format const *csis_fmt;
 	struct v4l2_mbus_framefmt *fmt;
+	unsigned int align;
 
 	/*
 	 * The CSIS can't transcode in any way, the source format can't be
@@ -798,8 +798,31 @@ static int mipi_csis_set_fmt(struct v4l2_subdev *mipi_sd,
 	fmt->width = sdformat->format.width;
 	fmt->height = sdformat->format.height;
 
-	v4l_bound_align_image(&fmt->width, 1, CSIS_MAX_PIX_WIDTH,
-			      csis_fmt->pix_width_alignment,
+	/*
+	 * The total number of bits per line must be a multiple of 8. We thus
+	 * need to align the width for formats that are not multiples of 8
+	 * bits.
+	 */
+	switch (csis_fmt->width % 8) {
+	case 0:
+		align = 1;
+		break;
+	case 4:
+		align = 2;
+		break;
+	case 2:
+	case 6:
+		align = 4;
+		break;
+	case 1:
+	case 3:
+	case 5:
+	case 7:
+		align = 8;
+		break;
+	}
+
+	v4l_bound_align_image(&fmt->width, 1, CSIS_MAX_PIX_WIDTH, align,
 			      &fmt->height, 1, CSIS_MAX_PIX_HEIGHT, 1, 0);
 
 	sdformat->format = *fmt;