media: rp1: csi2: Fix csi2_pad_set_fmt()

The CSI-2 subdev's set_fmt currently allows setting the source and sink
pad formats quite freely. This is not right, as the CSI-2 block can only
do one of the following when processing the stream: 1) pass through as
is, 2) expand to 16-bits, 3) compress.

The csi2_pad_set_fmt() should take this into account, and only allow
changing the source side mbus code, compared to the sink side format.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>

diff --git a/drivers/media/platform/raspberrypi/rp1_cfe/csi2.c b/drivers/media/platform/raspberrypi/rp1_cfe/csi2.c
index 898a35e..a801af6 100644 (file)
--- a/drivers/media/platform/raspberrypi/rp1_cfe/csi2.c
+++ b/drivers/media/platform/raspberrypi/rp1_cfe/csi2.c
@@ -438,25 +438,60 @@ static int csi2_pad_set_fmt(struct v4l2_subdev *sd,
                            struct v4l2_subdev_state *state,
                            struct v4l2_subdev_format *format)
 {
-       struct v4l2_mbus_framefmt *fmt;
-       const struct cfe_fmt *cfe_fmt;
-
-       /* TODO: format validation */
+       if (format->pad < CSI2_NUM_CHANNELS) {
+               /*
+                * Store the sink pad format and propagate it to the source pad.
+                */
 
-       cfe_fmt = find_format_by_code(format->format.code);
-       if (!cfe_fmt)
-               cfe_fmt = find_format_by_code(MEDIA_BUS_FMT_SBGGR10_1X10);
+               struct v4l2_mbus_framefmt *fmt;
 
-       format->format.code = cfe_fmt->code;
+               fmt = v4l2_subdev_get_pad_format(sd, state, format->pad);
+               if (!fmt)
+                       return -EINVAL;
 
-       fmt = v4l2_subdev_get_pad_format(sd, state, format->pad);
-       *fmt = format->format;
+               *fmt = format->format;
 
-       if (format->pad < CSI2_NUM_CHANNELS) {
-               /* Propagate to the source pad */
                fmt = v4l2_subdev_get_pad_format(sd, state,
-                                                format->pad + CSI2_NUM_CHANNELS);
+                       format->pad + CSI2_NUM_CHANNELS);
+               if (!fmt)
+                       return -EINVAL;
+
+               format->format.field = V4L2_FIELD_NONE;
+
                *fmt = format->format;
+       } else {
+               /*
+                * Only allow changing the source pad mbus code.
+                */
+
+               struct v4l2_mbus_framefmt *sink_fmt, *source_fmt;
+               u32 sink_code;
+               u32 code;
+
+               sink_fmt = v4l2_subdev_get_pad_format(sd, state,
+                       format->pad - CSI2_NUM_CHANNELS);
+               if (!sink_fmt)
+                       return -EINVAL;
+
+               source_fmt = v4l2_subdev_get_pad_format(sd, state, format->pad);
+               if (!source_fmt)
+                       return -EINVAL;
+
+               sink_code = sink_fmt->code;
+               code = format->format.code;
+
+               /*
+                * If the source code from the user does not match the code in
+                * the sink pad, check that the source code matches either the
+                * 16-bit version or the compressed version of the sink code.
+                */
+
+               if (code != sink_code &&
+                   (code == cfe_find_16bit_code(sink_code) ||
+                    code == cfe_find_compressed_code(sink_code)))
+                       source_fmt->code = code;
+
+               format->format.code = source_fmt->code;
        }
 
        return 0;