[PATCH v3] drm/bridge: sn65dsi86: defer if there is no dsi host

[PATCH v3] drm/bridge: sn65dsi86: defer if there is no dsi host

[Rob Clark]

From: Rob Clark <robdclark@chromium.org>

Otherwise we don't get another shot at it if the bridge probes before
the dsi host is registered.  It seems like this is what *most* (but not
all) of the other bridges do.

It looks like this was missed in the conversion to attach dsi host at
probe time.

Fixes: c3b75d4734cb ("drm/bridge: sn65dsi86: Register and attach our DSI device at probe")
Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Doug Anderson <dianders@chromium.org>
---
v2: Drop DRM_ERROR() in favor of drm_err_probe() and shift around the
    spot where we report the error
v3: Add \n and cull error msgs a bit further

 drivers/gpu/drm/bridge/ti-sn65dsi86.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index 02b490671f8f..c2928a6409b1 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -714,16 +714,12 @@ static int ti_sn_attach_host(struct ti_sn65dsi86 *pdata)
 	};
 
 	host = of_find_mipi_dsi_host_by_node(pdata->host_node);
-	if (!host) {
-		DRM_ERROR("failed to find dsi host\n");
-		return -ENODEV;
-	}
+	if (!host)
+		return -EPROBE_DEFER;
 
 	dsi = devm_mipi_dsi_device_register_full(dev, host, &info);
-	if (IS_ERR(dsi)) {
-		DRM_ERROR("failed to create dsi device\n");
+	if (IS_ERR(dsi))
 		return PTR_ERR(dsi);
-	}
 
 	/* TODO: setting to 4 MIPI lanes always for now */
 	dsi->lanes = 4;
@@ -740,10 +736,8 @@ static int ti_sn_attach_host(struct ti_sn65dsi86 *pdata)
 	pdata->dsi = dsi;
 
 	ret = devm_mipi_dsi_attach(dev, dsi);
-	if (ret < 0) {
-		DRM_ERROR("failed to attach dsi to host\n");
+	if (ret < 0)
 		return ret;
-	}
 
 	return 0;
 }
@@ -1267,8 +1261,10 @@ static int ti_sn_bridge_probe(struct auxiliary_device *adev,
 	drm_bridge_add(&pdata->bridge);
 
 	ret = ti_sn_attach_host(pdata);
-	if (ret)
+	if (ret) {
+		dev_err_probe(pdata->dev, ret, "failed to attach dsi host\n");
 		goto err_remove_bridge;
+	}
 
 	return 0;
 
-- 
2.33.1

Re: [PATCH v3] drm/bridge: sn65dsi86: defer if there is no dsi host

[Doug Anderson]

Hi,

On Tue, Dec 7, 2021 at 1:52 PM Rob Clark <robdclark@gmail.com> wrote:
>
> From: Rob Clark <robdclark@chromium.org>
>
> Otherwise we don't get another shot at it if the bridge probes before
> the dsi host is registered.  It seems like this is what *most* (but not
> all) of the other bridges do.
>
> It looks like this was missed in the conversion to attach dsi host at
> probe time.
>
> Fixes: c3b75d4734cb ("drm/bridge: sn65dsi86: Register and attach our DSI device at probe")
> Signed-off-by: Rob Clark <robdclark@chromium.org>
> Reviewed-by: Doug Anderson <dianders@chromium.org>
> ---
> v2: Drop DRM_ERROR() in favor of drm_err_probe() and shift around the
>     spot where we report the error
> v3: Add \n and cull error msgs a bit further
>
>  drivers/gpu/drm/bridge/ti-sn65dsi86.c | 18 +++++++-----------
>  1 file changed, 7 insertions(+), 11 deletions(-)

I can add a further:

Tested-by: Doug Anderson <dianders@chromium.org>

Since it's pretty straightforward and I don't expect it to be
controversial, I'll plan to land it tomorrow in drm-misc-next unless I
hear otherwise.

-Doug

Re: [PATCH v3] drm/bridge: sn65dsi86: defer if there is no dsi host

[Stephen Boyd]

Quoting Rob Clark (2021-12-07 13:57:52)
> From: Rob Clark <robdclark@chromium.org>
>
> Otherwise we don't get another shot at it if the bridge probes before
> the dsi host is registered.  It seems like this is what *most* (but not
> all) of the other bridges do.
>
> It looks like this was missed in the conversion to attach dsi host at
> probe time.
>
> Fixes: c3b75d4734cb ("drm/bridge: sn65dsi86: Register and attach our DSI device at probe")
> Signed-off-by: Rob Clark <robdclark@chromium.org>
> Reviewed-by: Doug Anderson <dianders@chromium.org>
> ---

Reviewed-by: Stephen Boyd <swboyd@chromium.org>

One more nit below

> v2: Drop DRM_ERROR() in favor of drm_err_probe() and shift around the
>     spot where we report the error
> v3: Add \n and cull error msgs a bit further
>
>  drivers/gpu/drm/bridge/ti-sn65dsi86.c | 18 +++++++-----------
>  1 file changed, 7 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> index 02b490671f8f..c2928a6409b1 100644
> --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> @@ -740,10 +736,8 @@ static int ti_sn_attach_host(struct ti_sn65dsi86 *pdata)
>         pdata->dsi = dsi;
>
>         ret = devm_mipi_dsi_attach(dev, dsi);
> -       if (ret < 0) {
> -               DRM_ERROR("failed to attach dsi to host\n");
> +       if (ret < 0)
>                 return ret;
> -       }
>
>         return 0;

This can be simplified further to

	return devm_mipi_dsi_attach(dev, dsi);

Re: [PATCH v3] drm/bridge: sn65dsi86: defer if there is no dsi host

[Doug Anderson]

Hi,

On Tue, Dec 7, 2021 at 8:44 PM Stephen Boyd <swboyd@chromium.org> wrote:
>
> Quoting Rob Clark (2021-12-07 13:57:52)
> > From: Rob Clark <robdclark@chromium.org>
> >
> > Otherwise we don't get another shot at it if the bridge probes before
> > the dsi host is registered.  It seems like this is what *most* (but not
> > all) of the other bridges do.
> >
> > It looks like this was missed in the conversion to attach dsi host at
> > probe time.
> >
> > Fixes: c3b75d4734cb ("drm/bridge: sn65dsi86: Register and attach our DSI device at probe")
> > Signed-off-by: Rob Clark <robdclark@chromium.org>
> > Reviewed-by: Doug Anderson <dianders@chromium.org>
> > ---
>
> Reviewed-by: Stephen Boyd <swboyd@chromium.org>
>
> One more nit below
>
> > v2: Drop DRM_ERROR() in favor of drm_err_probe() and shift around the
> >     spot where we report the error
> > v3: Add \n and cull error msgs a bit further
> >
> >  drivers/gpu/drm/bridge/ti-sn65dsi86.c | 18 +++++++-----------
> >  1 file changed, 7 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> > index 02b490671f8f..c2928a6409b1 100644
> > --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> > +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> > @@ -740,10 +736,8 @@ static int ti_sn_attach_host(struct ti_sn65dsi86 *pdata)
> >         pdata->dsi = dsi;
> >
> >         ret = devm_mipi_dsi_attach(dev, dsi);
> > -       if (ret < 0) {
> > -               DRM_ERROR("failed to attach dsi to host\n");
> > +       if (ret < 0)
> >                 return ret;
> > -       }
> >
> >         return 0;
>
> This can be simplified further to
>
>         return devm_mipi_dsi_attach(dev, dsi);

Squahsed in Stephen's fix and pushed. Had to also remove "ret" which
was no longer used in this function after Stephen's change.

03848335b5b1 drm/bridge: sn65dsi86: defer if there is no dsi host

-Doug