Re: [PATCH v2 2/2] drm/bridge: parade-ps8640: Populate devices on aux-bus

From: Stephen Boyd
Date: Mon Oct 25 2021 - 16:23:27 EST


Quoting Philip Chen (2021-10-21 14:06:00)
> diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
> index 220ca3b03d24..f99a2e0808b7 100644
> --- a/drivers/gpu/drm/bridge/parade-ps8640.c
> +++ b/drivers/gpu/drm/bridge/parade-ps8640.c
> @@ -149,6 +150,23 @@ static inline struct ps8640 *aux_to_ps8640(struct drm_dp_aux *aux)
> return container_of(aux, struct ps8640, aux);
> }
>
> +static bool ps8640_of_panel_on_aux_bus(struct device *dev)
> +{
> + struct device_node *bus, *panel;
> +
> + bus = of_get_child_by_name(dev->of_node, "aux-bus");
> + if (!bus)
> + return false;
> + of_node_put(bus);

This should come after the next line...

> +
> + panel = of_get_child_by_name(bus, "panel");

here, so that 'bus' can't go away before getting children nodes. It
doesn't actually matter in this case because 'device' holds the aux-bus,
but we shouldn't add anti-patterns to the code lest someone copies it
where it actually matters.

> + if (!panel)
> + return false;
> + of_node_put(panel);
> +
> + return true;
> +}
> +
> static void ps8640_ensure_hpd(struct ps8640 *ps_bridge)
> {
> struct regmap *map = ps_bridge->regmap[PAGE2_TOP_CNTL];

Otherwise

Reviewed-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>