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

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Message-ID: <CAAEAJfD9q-iB9iCgCBWdA0_77=T1zsk9DFh-qvVtLHWqEnOWbQ@mail.gmail.com>
Date:   Sun, 30 Aug 2020 21:21:00 -0300
From:   Ezequiel Garcia <ezequiel@...guardiasur.com.ar>
To:     Paul Cercueil <paul@...pouillou.net>
Cc:     David Airlie <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>,
        Sam Ravnborg <sam@...nborg.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        od@...c.me
Subject: Re: [PATCH v2 2/2] drm/ingenic: Fix driver not probing when IPU port
 is missing

Hi Paul,

On Thu, 27 Aug 2020 at 09:04, Paul Cercueil <paul@...pouillou.net> 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@...pouillou.net>
> ---
>  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.

Thanks,
Ezequiel