media: bcm2835-unicam: Fix RGB format / mbus code association

The Unicam driver is a MIPI-CSI2 Receiver, that can capture RGB 4:4:4,
YCbCr 4:2:2, and raw formats.

RGB 4:4:4 is converted to the MIPI-CSI2 RGB888 video format, and
associated to the MEDIA_BUS_FMT_RGB888_1X24 media bus code.

However, V4L2_PIX_FMT_RGB24 is defined as having its color components in
the R, G and B order, from left to right. MIPI-CSI2 however defines the
RGB888 format with blue first, and that's what MEDIA_BUS_FMT_RGB888_1X24
defines too.

This essentially means that the R and B will be swapped compared to what
V4L2_PIX_FMT_RGB24 defines. The same situation occurs with
V4L2_PIX_FMT_BGR24 being associated to MEDIA_BUS_FMT_BGR888_1X24.

In order to fix the swapped components, we need to change the
association of V4L2_PIX_FMT_BGR24 to MEDIA_BUS_FMT_RGB888_1X24, and of
V4L2_PIX_FMT_RGB24 to MEDIA_BUS_FMT_BGR888_1X24.

Since the media bus code is exposed to userspace, and validated by
unicam's link_validate implementation, we need to explicitly accept (and
warn) the old association still to preserve backward compatibility.

Signed-off-by: Maxime Ripard <mripard@redhat.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>

diff --git a/drivers/media/platform/broadcom/bcm2835-unicam.c b/drivers/media/platform/broadcom/bcm2835-unicam.c
index f0a41f147dfeba4e4a8e9704f68efeaaf0d7fd8e..8d28ba0b59a39972f9885861216ae9d771d3f006 100644 (file)
--- a/drivers/media/platform/broadcom/bcm2835-unicam.c
+++ b/drivers/media/platform/broadcom/bcm2835-unicam.c
@@ -338,12 +338,12 @@ static const struct unicam_format_info unicam_image_formats[] = {
                .csi_dt         = MIPI_CSI2_DT_RGB565,
        }, {
                .fourcc         = V4L2_PIX_FMT_RGB24, /* rgb */
-               .code           = MEDIA_BUS_FMT_RGB888_1X24,
+               .code           = MEDIA_BUS_FMT_BGR888_1X24,
                .depth          = 24,
                .csi_dt         = MIPI_CSI2_DT_RGB888,
        }, {
                .fourcc         = V4L2_PIX_FMT_BGR24, /* bgr */
-               .code           = MEDIA_BUS_FMT_BGR888_1X24,
+               .code           = MEDIA_BUS_FMT_RGB888_1X24,
                .depth          = 24,
                .csi_dt         = MIPI_CSI2_DT_RGB888,
        }, {
@@ -2144,22 +2144,45 @@ static int unicam_video_link_validate(struct media_link *link)
                const struct v4l2_pix_format *fmt = &node->fmt.fmt.pix;
                const struct unicam_format_info *fmtinfo;
 
-               fmtinfo = unicam_find_format_by_fourcc(fmt->pixelformat,
-                                                      UNICAM_SD_PAD_SOURCE_IMAGE);
+               fmtinfo = unicam_find_format_by_code(format->code,
+                                                    UNICAM_SD_PAD_SOURCE_IMAGE);
                if (WARN_ON(!fmtinfo)) {
                        ret = -EPIPE;
                        goto out;
                }
 
-               if (fmtinfo->code != format->code ||
-                   fmt->height != format->height ||
+               /*
+                * Unicam initially associated BGR24 to BGR888_1X24 and RGB24 to
+                * RGB888_1X24.
+                *
+                * In order to allow the applications using the old behaviour to
+                * run, let's accept the old combination, but warn about it.
+                */
+               if (fmtinfo->fourcc != fmt->pixelformat) {
+                       if ((fmt->pixelformat == V4L2_PIX_FMT_BGR24 &&
+                            format->code == MEDIA_BUS_FMT_BGR888_1X24) ||
+                           (fmt->pixelformat == V4L2_PIX_FMT_RGB24 &&
+                            format->code == MEDIA_BUS_FMT_RGB888_1X24)) {
+                               dev_warn_once(node->dev->dev,
+                                             "Incorrect pixel format %p4cc for 0x%04x. Fix your application to use %p4cc.\n",
+                                             &fmt->pixelformat, format->code, &fmtinfo->fourcc);
+                       } else {
+                               dev_dbg(node->dev->dev,
+                                       "image: format mismatch: 0x%04x <=> %p4cc\n",
+                                       format->code, &fmt->pixelformat);
+                               ret = -EPIPE;
+                               goto out;
+                       }
+               }
+
+               if (fmt->height != format->height ||
                    fmt->width != format->width ||
                    fmt->field != format->field) {
                        dev_dbg(node->dev->dev,
-                               "image: (%u x %u) 0x%08x %s != (%u x %u) 0x%08x %s\n",
-                               fmt->width, fmt->height, fmtinfo->code,
+                               "image: (%u x %u) %s != (%u x %u) %s\n",
+                               fmt->width, fmt->height,
                                v4l2_field_names[fmt->field],
-                               format->width, format->height, format->code,
+                               format->width, format->height,
                                v4l2_field_names[format->field]);
                        ret = -EPIPE;
                }