diff mbox series

[v13,05/10] drm/bridge: anx7625: Check for Type-C during panel registration

Message ID 20230303143350.815623-6-treapking@chromium.org (mailing list archive)
State New, archived
Headers show
Series Register Type-C mode-switch in DP bridge endpoints | expand

Commit Message

Pin-yen Lin March 3, 2023, 2:33 p.m. UTC
The output port endpoints can be connected to USB-C connectors.
Running drm_of_find_panel_or_bridge() with such endpoints leads to
a continuous return value of -EPROBE_DEFER, even though there is
no panel present.

To avoid this, check for the existence of a "mode-switch" property in
the port endpoint, and skip panel registration completely if so.

Signed-off-by: Pin-yen Lin <treapking@chromium.org>

---

Changes in v13:
- Use the new typec_mode_switch_node_count helper

Changes in v12:
- Updated to use fwnode_for_each_typec_mode_switch macro
- Dropped collected tags

Changes in v10:
- Collected Reviewed-by and Tested-by tags

Changes in v6:
- New in v6

 drivers/gpu/drm/bridge/analogix/anx7625.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

Comments

Andy Shevchenko March 6, 2023, 11:51 a.m. UTC | #1
On Fri, Mar 03, 2023 at 10:33:45PM +0800, Pin-yen Lin wrote:
> The output port endpoints can be connected to USB-C connectors.
> Running drm_of_find_panel_or_bridge() with such endpoints leads to
> a continuous return value of -EPROBE_DEFER, even though there is
> no panel present.
> 
> To avoid this, check for the existence of a "mode-switch" property in
> the port endpoint, and skip panel registration completely if so.

...

> +	port_node = of_graph_get_port_by_id(np, 1);
> +	count = typec_mode_switch_node_count(&port_node->fwnode);

Do you need to drop reference count here?
(I don't know myself, so, please check this)

If no, patch LGTM.

> +	if (count)
> +		return 0;
Pin-yen Lin March 8, 2023, 10:25 a.m. UTC | #2
HI Andy,

On Mon, Mar 6, 2023 at 7:52 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Fri, Mar 03, 2023 at 10:33:45PM +0800, Pin-yen Lin wrote:
> > The output port endpoints can be connected to USB-C connectors.
> > Running drm_of_find_panel_or_bridge() with such endpoints leads to
> > a continuous return value of -EPROBE_DEFER, even though there is
> > no panel present.
> >
> > To avoid this, check for the existence of a "mode-switch" property in
> > the port endpoint, and skip panel registration completely if so.
>
> ...
>
> > +     port_node = of_graph_get_port_by_id(np, 1);
> > +     count = typec_mode_switch_node_count(&port_node->fwnode);
>
> Do you need to drop reference count here?
> (I don't know myself, so, please check this)
>
> If no, patch LGTM.

The helper completes the for-loop of fwnode_for_each_child_node, which
drops the reference count whenever the next node is get. So we don't
need drop the reference count here.
>
> > +     if (count)
> > +             return 0;
>
> --
> With Best Regards,
> Andy Shevchenko
>
>
Best regards,
Pin-yen
diff mbox series

Patch

diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index 6846199a2ee1..3f6bf7674d32 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.c
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
@@ -1648,7 +1648,8 @@  static int anx7625_get_swing_setting(struct device *dev,
 static int anx7625_parse_dt(struct device *dev,
 			    struct anx7625_platform_data *pdata)
 {
-	struct device_node *np = dev->of_node, *ep0;
+	struct device_node *np = dev->of_node, *ep0, *port_node;
+	unsigned int count;
 	int bus_type, mipi_lanes;
 
 	anx7625_get_swing_setting(dev, pdata);
@@ -1687,6 +1688,15 @@  static int anx7625_parse_dt(struct device *dev,
 	if (of_property_read_bool(np, "analogix,audio-enable"))
 		pdata->audio_en = 1;
 
+	/*
+	 * Don't bother finding a panel if a Type-C `mode-switch` property is
+	 * present in one of the endpoints in the output port.
+	 */
+	port_node = of_graph_get_port_by_id(np, 1);
+	count = typec_mode_switch_node_count(&port_node->fwnode);
+	if (count)
+		return 0;
+
 	pdata->panel_bridge = devm_drm_of_get_bridge(dev, np, 1, 0);
 	if (IS_ERR(pdata->panel_bridge)) {
 		if (PTR_ERR(pdata->panel_bridge) == -ENODEV) {