[PATCH v2 01/13] drm/sun4i: backend: Simplify the get_id logic

[Chen-Yu Tsai]

On Fri, Mar 15, 2019 at 4:16 AM Maxime Ripard <maxime.ripard at bootlin.com> wrote:
>
> Using the new helpers introduced since we wrote that code, we can simplify
> the code to retrieve the backend ID significantly.
>
> The new code will also allow us to deal nicely with endpoints that don't
> have a reg property, as expected in the case where there's a single
> endpoint for a given port.
>
> Signed-off-by: Maxime Ripard <maxime.ripard at bootlin.com>
> ---
>  drivers/gpu/drm/sun4i/sun4i_backend.c | 34 +++++++++-------------------
>  1 file changed, 11 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c
> index 4c0d51f73237..02ef8e455db8 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_backend.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_backend.c
> @@ -720,33 +720,21 @@ static int sun4i_backend_free_sat(struct device *dev) {
>   */
>  static int sun4i_backend_of_get_id(struct device_node *node)
>  {
> -       struct device_node *port, *ep;
> -       int ret = -EINVAL;
> +       struct device_node *ep, *remote;
> +       struct of_endpoint of_ep;
>
> -       /* input is port 0 */
> -       port = of_graph_get_port_by_id(node, 0);
> -       if (!port)
> +       /* Input port is 0, and we want the first endpoint. */
> +       ep = of_graph_get_endpoint_by_regs(node, 0, -1);
> +       if (!ep)
>                 return -EINVAL;
>
> -       /* try finding an upstream endpoint */
> -       for_each_available_child_of_node(port, ep) {
> -               struct device_node *remote;
> -               u32 reg;
> -
> -               remote = of_graph_get_remote_endpoint(ep);
> -               if (!remote)
> -                       continue;
> -
> -               ret = of_property_read_u32(remote, "reg", &reg);
> -               if (ret)
> -                       continue;
> -
> -               ret = reg;
> -       }
> -
> -       of_node_put(port);
> +       remote = of_graph_get_remote_endpoint(ep);

I believe you also need to call of_node_put for ep?

Otherwise,

Reviewed-by: Chen-Yu Tsai <wens at csie.org>

> +       if (!remote)
> +               return -EINVAL;
>
> -       return ret;
> +       of_graph_parse_endpoint(remote, &of_ep);
> +       of_node_put(remote);
> +       return of_ep.id;
>  }
>
>  /* TODO: This needs to take multiple pipelines into account */
> --
> git-series 0.9.1