lkml.org 
[lkml]   [2021]   [Mar]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v3 3/4] drm/bridge: ti-sn65dsi86: Read EDID blob over DDC
Hi Stephen,

Reviving a bit of an old thread, for a question.

On Mon, Nov 02, 2020 at 10:11:43AM -0800, Stephen Boyd wrote:
> Use the DDC connection to read the EDID from the eDP panel instead of
> relying on the panel to tell us the modes.
>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
> Reviewed-by: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
> Cc: Jonas Karlman <jonas@kwiboo.se>
> Cc: Jernej Skrabec <jernej.skrabec@siol.net>
> Cc: Sean Paul <seanpaul@chromium.org>
> Acked-by: Sam Ravnborg <sam@ravnborg.org>
> Signed-off-by: Stephen Boyd <swboyd@chromium.org>
> ---
> drivers/gpu/drm/bridge/ti-sn65dsi86.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> index 8276fa50138f..6b6e98ca2881 100644
> --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> @@ -119,6 +119,7 @@
> * @debugfs: Used for managing our debugfs.
> * @host_node: Remote DSI node.
> * @dsi: Our MIPI DSI source.
> + * @edid: Detected EDID of eDP panel.
> * @refclk: Our reference clock.
> * @panel: Our panel.
> * @enable_gpio: The GPIO we toggle to enable the bridge.
> @@ -144,6 +145,7 @@ struct ti_sn_bridge {
> struct drm_bridge bridge;
> struct drm_connector connector;
> struct dentry *debugfs;
> + struct edid *edid;
> struct device_node *host_node;
> struct mipi_dsi_device *dsi;
> struct clk *refclk;
> @@ -265,6 +267,23 @@ connector_to_ti_sn_bridge(struct drm_connector *connector)
> static int ti_sn_bridge_connector_get_modes(struct drm_connector *connector)
> {
> struct ti_sn_bridge *pdata = connector_to_ti_sn_bridge(connector);
> + struct edid *edid = pdata->edid;
> + int num, ret;
> +
> + if (!edid) {
> + pm_runtime_get_sync(pdata->dev);
> + edid = pdata->edid = drm_get_edid(connector, &pdata->aux.ddc);
> + pm_runtime_put(pdata->dev);

Is there any specific reason to use the indirect access method, compared
to the direct method that translates access to an I2C ancillary address
to an I2C-over-AUX transaction (see page 20 of SLLSEH2B) ? The direct
method seems it would be more efficient.

> + }
> +
> + if (edid && drm_edid_is_valid(edid)) {
> + ret = drm_connector_update_edid_property(connector, edid);
> + if (!ret) {
> + num = drm_add_edid_modes(connector, edid);
> + if (num)
> + return num;
> + }
> + }
>
> return drm_panel_get_modes(pdata->panel, connector);
> }
> @@ -1245,6 +1264,7 @@ static int ti_sn_bridge_remove(struct i2c_client *client)
> if (!pdata)
> return -EINVAL;
>
> + kfree(pdata->edid);
> ti_sn_debugfs_remove(pdata);
>
> of_node_put(pdata->host_node);

--
Regards,

Laurent Pinchart

\
 
 \ /
  Last update: 2021-03-18 01:22    [W:0.085 / U:1.852 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site