[PATCH] omapdrm: Make fixed resolution panels work

[Rob Clark]

On Thu, Feb 14, 2013 at 6:52 AM, Archit Taneja <archit at ti.com> wrote:
> The omapdrm driver requires omapdss panel drivers to expose ops like detect,
> set_timings and check_timings. These can be NULL for fixed panel DPI, DBI, DSI
> and SDI drivers. At some places, there are no checks to see if the panel driver
> has these ops or not, and that leads to a crash.
>
> The following things are done to make fixed panels work:
>
> - The omap_connector's detect function is modified such that it considers panel
>   types which are generally fixed panels as always connected(provided the panel
>   driver doesn't have a detect op). Hence, the connector corresponding to these
>   panels is always in a 'connected' state.
>
> - If a panel driver doesn't have a check_timings op, assume that it supports the
>   mode passed to omap_connector_mode_valid(the 'mode_valid' drm helper function)
>
> - The function omap_encoder_update shouldn't really do anything for fixed
>   resolution panels, make sure that it calls set_timings only if the panel
>   driver has one.
>
> I tested this with picodlp on a OMAP4 sdp board. I couldn't get any other
> working boards with fixed DPI panels. I could try the DSI video mode panel
> on an OMAP5 sevm, but that will require me to patch a lot of things to get
> omap5 dss work with DT. I can try if needed.
>
> Signed-off-by: Archit Taneja <archit at ti.com>
> ---
>  drivers/staging/omapdrm/omap_connector.c |   10 ++++++++--
>  drivers/staging/omapdrm/omap_encoder.c   |    6 ++++--
>  2 files changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/staging/omapdrm/omap_connector.c b/drivers/staging/omapdrm/omap_connector.c
> index 4cc9ee7..839c6e4 100644
> --- a/drivers/staging/omapdrm/omap_connector.c
> +++ b/drivers/staging/omapdrm/omap_connector.c
> @@ -110,6 +110,11 @@ static enum drm_connector_status omap_connector_detect(
>                         ret = connector_status_connected;
>                 else
>                         ret = connector_status_disconnected;
> +       } else if (dssdev->type == OMAP_DISPLAY_TYPE_DPI ||
> +                       dssdev->type == OMAP_DISPLAY_TYPE_DBI ||
> +                       dssdev->type == OMAP_DISPLAY_TYPE_SDI ||
> +                       dssdev->type == OMAP_DISPLAY_TYPE_DSI) {
> +               ret = connector_status_connected;

hmm, why not just have a default detect fxn for panel drivers which
always returns true?  Seems a bit cleaner.. otherwise, I guess we
could just change omap_connector so that if dssdev->detect is null,
assume always connected.  Seems maybe a slightly better way since
currently omap_connector doesn't really know too much about different
sorts of panels.  But I'm not too picky if that is a big pain because
we probably end up changing all this as CFP starts coming into
existence.

Same goes for check_timings/set_timings..  it seems a bit cleaner just
to have default fxns in the panel drivers that do-the-right-thing,
although I suppose it might be a bit more convenient for out-of-tree
panel drivers to just assume fixed panel if these fxns are null.

BR,
-R

>         } else {
>                 ret = connector_status_unknown;
>         }
> @@ -189,12 +194,13 @@ static int omap_connector_mode_valid(struct drm_connector *connector,
>         struct omap_video_timings timings = {0};
>         struct drm_device *dev = connector->dev;
>         struct drm_display_mode *new_mode;
> -       int ret = MODE_BAD;
> +       int r, ret = MODE_BAD;
>
>         copy_timings_drm_to_omap(&timings, mode);
>         mode->vrefresh = drm_mode_vrefresh(mode);
>
> -       if (!dssdrv->check_timings(dssdev, &timings)) {
> +       r = dssdrv->check_timings ? dssdrv->check_timings(dssdev, &timings) : 0;
> +       if (!r) {
>                 /* check if vrefresh is still valid */
>                 new_mode = drm_mode_duplicate(dev, mode);
>                 new_mode->clock = timings.pixel_clock;
> diff --git a/drivers/staging/omapdrm/omap_encoder.c b/drivers/staging/omapdrm/omap_encoder.c
> index e053160..871af12e 100644
> --- a/drivers/staging/omapdrm/omap_encoder.c
> +++ b/drivers/staging/omapdrm/omap_encoder.c
> @@ -128,13 +128,15 @@ int omap_encoder_update(struct drm_encoder *encoder,
>
>         dssdev->output->manager = mgr;
>
> -       ret = dssdrv->check_timings(dssdev, timings);
> +       ret = dssdrv->check_timings ?
> +               dssdrv->check_timings(dssdev, timings) : 0;
>         if (ret) {
>                 dev_err(dev->dev, "could not set timings: %d\n", ret);
>                 return ret;
>         }
>
> -       dssdrv->set_timings(dssdev, timings);
> +       if (dssdrv->set_timings)
> +               dssdrv->set_timings(dssdev, timings);
>
>         return 0;
>  }
> --
> 1.7.9.5
>