[RFC PATCH 11/11] drm/bridge: ti-sn65dsi86: Support hotplug detection

[Stephen Boyd]

Quoting Laurent Pinchart (2021-03-21 20:01:28)
> When the SN65DSI86 is used in DisplayPort mode, its output is likely
> routed to a DisplayPort connector, which can benefit from hotplug
> detection. Support it in such cases, with polling mode only for now.
> 
> The implementation is limited to the bridge operations, as the connector
> operations are legacy and new users should use
> DRM_BRIDGE_ATTACH_NO_CONNECTOR.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
> ---

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

>  drivers/gpu/drm/bridge/ti-sn65dsi86.c | 46 +++++++++++++++++++--------
>  1 file changed, 33 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> index f792227142a7..72f6362adf44 100644
> --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> @@ -890,6 +897,15 @@ static void ti_sn_bridge_post_disable(struct drm_bridge *bridge)
>         pm_runtime_put_sync(pdata->dev);
>  }
>  
> +static enum drm_connector_status ti_sn_bridge_detect(struct drm_bridge *bridge)
> +{
> +       struct ti_sn_bridge *pdata = bridge_to_ti_sn_bridge(bridge);
> +       int val;
> +
> +       regmap_read(pdata->regmap, SN_HPD_DISABLE_REG, &val);
> +       return val ? connector_status_connected : connector_status_disconnected;
> +}
> +
>  static struct edid *ti_sn_bridge_get_edid(struct drm_bridge *bridge,
>                                           struct drm_connector *connector)
>  {
> @@ -904,6 +920,7 @@ static const struct drm_bridge_funcs ti_sn_bridge_funcs = {
>         .enable = ti_sn_bridge_enable,
>         .disable = ti_sn_bridge_disable,
>         .post_disable = ti_sn_bridge_post_disable,
> +       .detect = ti_sn_bridge_detect,
>         .get_edid = ti_sn_bridge_get_edid,
>  };
>  
> @@ -1327,6 +1344,8 @@ static int ti_sn_bridge_probe(struct i2c_client *client,
>                 return ret;
>         }
>  
> +       pdata->no_hpd = of_property_read_bool(pdata->dev->of_node, "no-hpd");

I see that we missed adding this property to the DTS file but skated by
because it was the default in the driver. I don't think it's a big deal
just something we should fix in sc7180-trogdor.dtsi before this patch is
merged.

> +
>         ti_sn_bridge_parse_lanes(pdata, client->dev.of_node);
>  
>         ret = ti_sn_bridge_parse_regulators(pdata);