Re: [PATCH 4/4] drm/bridge: ti-sn65dsi86: Add NO_CONNECTOR support

From: Doug Anderson <dianders@chromium.org>
To: Rob Clark <robdclark@gmail.com>
Cc: dri-devel <dri-devel@lists.freedesktop.org>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	freedreno <freedreno@lists.freedesktop.org>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Stephen Boyd <swboyd@chromium.org>,
	Rob Clark <robdclark@chromium.org>,
	Andrzej Hajda <a.hajda@samsung.com>,
	Neil Armstrong <narmstrong@baylibre.com>,
	Robert Foss <robert.foss@linaro.org>,
	Jonas Karlman <jonas@kwiboo.se>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4/4] drm/bridge: ti-sn65dsi86: Add NO_CONNECTOR support
Date: Thu, 12 Aug 2021 10:22:15 -0700	[thread overview]
Message-ID: <CAD=FV=V_bE0MfHDZn=u98UZ1eDw7vQXMpG=btwW6XGGqCF4brw@mail.gmail.com> (raw)
In-Reply-To: <20210811235253.924867-5-robdclark@gmail.com>

Hi,

On Wed, Aug 11, 2021 at 4:51 PM Rob Clark <robdclark@gmail.com> wrote:
>
> From: Rob Clark <robdclark@chromium.org>
>
> Slightly awkward to fish out the display_info when we aren't creating
> own connector.  But I don't see an obvious better way.
>
> Signed-off-by: Rob Clark <robdclark@chromium.org>
> ---
>  drivers/gpu/drm/bridge/ti-sn65dsi86.c | 34 +++++++++++++++++++++++----
>  1 file changed, 29 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> index 38dcc49eccaf..dc8112bab3d3 100644
> --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> @@ -693,9 +693,11 @@ static int ti_sn_bridge_attach(struct drm_bridge *bridge,
>                 return ret;
>         }
>
> -       ret = ti_sn_bridge_connector_init(pdata);
> -       if (ret < 0)
> -               goto err_conn_init;
> +       if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)) {
> +               ret = ti_sn_bridge_connector_init(pdata);
> +               if (ret < 0)
> +                       goto err_conn_init;
> +       }
>
>         /*
>          * TODO: ideally finding host resource and dsi dev registration needs
> @@ -757,7 +759,8 @@ static int ti_sn_bridge_attach(struct drm_bridge *bridge,
>  err_dsi_attach:
>         mipi_dsi_device_unregister(dsi);
>  err_dsi_host:
> -       drm_connector_cleanup(&pdata->connector);
> +       if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR))
> +               drm_connector_cleanup(&pdata->connector);
>  err_conn_init:
>         drm_dp_aux_unregister(&pdata->aux);
>         return ret;
> @@ -806,9 +809,30 @@ static void ti_sn_bridge_set_dsi_rate(struct ti_sn65dsi86 *pdata)
>         regmap_write(pdata->regmap, SN_DSIA_CLK_FREQ_REG, val);
>  }
>
> +/*
> + * Find the connector and fish out the bpc from display_info.  It would
> + * be nice if we could get this instead from drm_bridge_state, but that
> + * doesn't yet appear to be the case.
> + */
>  static unsigned int ti_sn_bridge_get_bpp(struct ti_sn65dsi86 *pdata)
>  {
> -       if (pdata->connector.display_info.bpc <= 6)
> +       struct drm_bridge *bridge = &pdata->bridge;
> +       struct drm_connector_list_iter conn_iter;
> +       struct drm_connector *connector;
> +       unsigned bpc = 0;
> +
> +       drm_connector_list_iter_begin(bridge->dev, &conn_iter);
> +       drm_for_each_connector_iter(connector, &conn_iter) {
> +               if (drm_connector_has_possible_encoder(connector, bridge->encoder)) {
> +                       bpc = connector->display_info.bpc;
> +                       break;
> +               }
> +       }
> +       drm_connector_list_iter_end(&conn_iter);

This looks reasonable to me. I'll plan to apply it to drm-misc-next
sometime next week to give Laurent a chance to comment on whether this
causes any problems with his planned support for full DP using this
bridge chip. IIUC that means it'll hit mainline 1 rev later, but as
per IRC comments this should be fine.

Reviewed-by: Douglas Anderson <dianders@chromium.org>

-Doug