Re: [PATCH v2 2/2] drm/ingenic: Fix driver not probing when IPU port is missing

[Paul Cercueil]

Le dim. 30 août 2020 à 21:21, Ezequiel Garcia 
<ezequiel@xxxxxxxxxxxxxxxxxxxx> a écrit :
> Hi Paul,
>
> On Thu, 27 Aug 2020 at 09:04, Paul Cercueil <paul@xxxxxxxxxxxxxxx> 
> wrote:
> >  Even if support for the IPU was compiled in, we may run on a device
> >  (e.g. the Qi LB60) where the IPU is not available, or simply with 
> > an old
> >  devicetree without the IPU node. In that case the ingenic-drm 
> > refused to
> >  probe.
> >
> >  Fix the driver so that it will probe even if the IPU node is not 
> > present
> >  in devicetree (but then IPU support is disabled of course).
> >
> >  v2: Take a different approach
> >
> >  Fixes: fc1acf317b01 ("drm/ingenic: Add support for the IPU")
> >  Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> >  ---
> >   drivers/gpu/drm/ingenic/ingenic-drm-drv.c | 19 +++++++++++--------
> >   1 file changed, 11 insertions(+), 8 deletions(-)
> >
> >  diff --git a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c 
> > b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> >  index c1bcb93aed2d..b7074161ccf0 100644
> >  --- a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> >  +++ b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> >  @@ -673,7 +673,7 @@ static void ingenic_drm_unbind_all(void *d)
> >          component_unbind_all(priv->dev, &priv->drm);
> >   }
> >
> >  -static int ingenic_drm_bind(struct device *dev)
> >  +static int ingenic_drm_bind(struct device *dev, bool 
> > has_components)
> >   {
> >          struct platform_device *pdev = to_platform_device(dev);
> >          const struct jz_soc_info *soc_info;
> >  @@ -808,7 +808,7 @@ static int ingenic_drm_bind(struct device *dev)
> >                          return ret;
> >                  }
> >
> >  -               if (IS_ENABLED(CONFIG_DRM_INGENIC_IPU)) {
> >  +               if (IS_ENABLED(CONFIG_DRM_INGENIC_IPU) && 
> > has_components) {
> >                          ret = component_bind_all(dev, drm);
> >                          if (ret) {
> >                                  if (ret != -EPROBE_DEFER)
> >  @@ -939,6 +939,11 @@ static int ingenic_drm_bind(struct device *dev)
> >          return ret;
> >   }
> >
> >  +static int ingenic_drm_bind_with_components(struct device *dev)
> >  +{
> >  +       return ingenic_drm_bind(dev, true);
> >  +}
> >  +
> >   static int compare_of(struct device *dev, void *data)
> >   {
> >          return dev->of_node == data;
> >  @@ -957,7 +962,7 @@ static void ingenic_drm_unbind(struct device 
> > *dev)
> >   }
> >
> >   static const struct component_master_ops ingenic_master_ops = {
> >  -       .bind = ingenic_drm_bind,
> >  +       .bind = ingenic_drm_bind_with_components,
> >          .unbind = ingenic_drm_unbind,
> >   };
> >
> >  @@ -968,14 +973,12 @@ static int ingenic_drm_probe(struct 
> > platform_device *pdev)
> >          struct device_node *np;
> >
> >          if (!IS_ENABLED(CONFIG_DRM_INGENIC_IPU))
> >  -               return ingenic_drm_bind(dev);
> >  +               return ingenic_drm_bind(dev, false);
> >
> >          /* IPU is at port address 8 */
> >          np = of_graph_get_remote_node(dev->of_node, 8, 0);
>
> How about we get rid of this (seems a bit odd to rely on port 
> address) ?
> Rockchip-drm driver has a nice approach, and I think we might need
> something like that going forward, to support dw-hdmi.

The rockchip-drm approach works because all the sub-drivers must probe. 
In the case of ingenic-drm, even if the ingenic-drm driver was compiled 
with the ipu and dw-hdmi sub-drivers, you can't rely on these probing, 
as they are not present on e.g. the JZ4740.

Cheers,
-Paul