[PATCH 0/2] usb: typec: mux: avoid duplicated mux switches

[PATCH 0/2] usb: typec: mux: avoid duplicated mux switches

[Sebastian Reichel]

Recent Rockchip SoCs (e.g. RK3588, RK3576) have a PHY, which
handles USB3 and DisplayPort as well as orientation and lane
muxing. By setting up the DT graph from the USB-C connector
for the Superspeed and DP lanes to the PHY all mux/orientation
operations are applied twice.

I did not add any Fixes tag, since applying the settings twice
is not breaking anything. But it's confusing when debugging
USB-C issues and obviously wastes some CPU cycles.

Also I'm not super happy with the implementation I came up with
to do the actual duplicate elimination. In the end I figured
it does not matter to much considering the array size is 3 and
is not expected to become much bigger as the amount of muxes
on a single USB-C connector should be quite low :)

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
Sebastian Reichel (2):
      usb: typec: mux: avoid duplicated orientation switches
      usb: typec: mux: avoid duplicated mux switches

 drivers/usb/typec/mux.c | 28 ++++++++++++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)
---
base-commit: 05f7e89ab9731565d8a62e3b5d1ec206485eeb0b
change-id: 20260213-typec-mux-duplication-fix-ba5e58f6576a

Best regards,
-- 
Sebastian Reichel <sebastian.reichel@collabora.com>

[PATCH 1/2] usb: typec: mux: avoid duplicated orientation switches

[Sebastian Reichel]

Some devices use combo PHYs (i.e. USB3 + DisplayPort), which also
handle the orientation mux. These PHYs are referenced twice from
the USB-C connector (USB super-speed lines and SBU/AUX lines)
resulting in the switch being configured twice. Avoid this by
dropping duplicates.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 drivers/usb/typec/mux.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/typec/mux.c b/drivers/usb/typec/mux.c
index 182c902c42f6..db35b7398343 100644
--- a/drivers/usb/typec/mux.c
+++ b/drivers/usb/typec/mux.c
@@ -72,9 +72,9 @@ struct typec_switch *fwnode_typec_switch_get(struct fwnode_handle *fwnode)
 {
 	struct typec_switch_dev *sw_devs[TYPEC_MUX_MAX_DEVS];
 	struct typec_switch *sw;
+	int i, j, k;
 	int count;
 	int err;
-	int i;
 
 	sw = kzalloc(sizeof(*sw), GFP_KERNEL);
 	if (!sw)
@@ -96,6 +96,18 @@ struct typec_switch *fwnode_typec_switch_get(struct fwnode_handle *fwnode)
 		}
 	}
 
+	/* eliminate duplicates */
+	for (i = 0; i < count; i++) {
+		for (j = i + 1; j < count; j++) {
+			if (sw_devs[j] == sw_devs[i]) {
+				put_device(&sw_devs[j]->dev);
+				for (k = j; k < count; k++)
+					sw_devs[k] = sw_devs[k+1];
+				count--;
+			}
+		}
+	}
+
 	for (i = 0; i < count; i++) {
 		WARN_ON(!try_module_get(sw_devs[i]->dev.parent->driver->owner));
 		sw->sw_devs[i] = sw_devs[i];

-- 
2.51.0

[PATCH 2/2] usb: typec: mux: avoid duplicated mux switches

[Sebastian Reichel]

Some devices use combo PHYs (i.e. USB3 + DisplayPort), which also
handle the lane muxing. These PHYs are referenced twice from
the USB-C connector (USB super-speed lines and SBU/AUX lines)
resulting in the mux being configured twice. Avoid this by
dropping duplicates.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 drivers/usb/typec/mux.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/typec/mux.c b/drivers/usb/typec/mux.c
index db35b7398343..6a394326f236 100644
--- a/drivers/usb/typec/mux.c
+++ b/drivers/usb/typec/mux.c
@@ -309,9 +309,9 @@ struct typec_mux *fwnode_typec_mux_get(struct fwnode_handle *fwnode)
 {
 	struct typec_mux_dev *mux_devs[TYPEC_MUX_MAX_DEVS];
 	struct typec_mux *mux;
+	int i, j, k;
 	int count;
 	int err;
-	int i;
 
 	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
 	if (!mux)
@@ -333,6 +333,18 @@ struct typec_mux *fwnode_typec_mux_get(struct fwnode_handle *fwnode)
 		}
 	}
 
+	/* eliminate duplicates */
+	for (i = 0; i < count; i++) {
+		for (j = i + 1; j < count; j++) {
+			if (mux_devs[j] == mux_devs[i]) {
+				put_device(&mux_devs[j]->dev);
+				for (k = j; k < count; k++)
+					mux_devs[k] = mux_devs[k+1];
+				count--;
+			}
+		}
+	}
+
 	for (i = 0; i < count; i++) {
 		WARN_ON(!try_module_get(mux_devs[i]->dev.parent->driver->owner));
 		mux->mux_devs[i] = mux_devs[i];

-- 
2.51.0

Re: [PATCH 1/2] usb: typec: mux: avoid duplicated orientation switches

[Heikki Krogerus]

Hi Sebastian,

Fri, Feb 13, 2026 at 08:23:28PM +0100, Sebastian Reichel wrote:
> Some devices use combo PHYs (i.e. USB3 + DisplayPort), which also
> handle the orientation mux. These PHYs are referenced twice from
> the USB-C connector (USB super-speed lines and SBU/AUX lines)
> resulting in the switch being configured twice. Avoid this by
> dropping duplicates.
> 
> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> ---
>  drivers/usb/typec/mux.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/mux.c b/drivers/usb/typec/mux.c
> index 182c902c42f6..db35b7398343 100644
> --- a/drivers/usb/typec/mux.c
> +++ b/drivers/usb/typec/mux.c
> @@ -72,9 +72,9 @@ struct typec_switch *fwnode_typec_switch_get(struct fwnode_handle *fwnode)
>  {
>  	struct typec_switch_dev *sw_devs[TYPEC_MUX_MAX_DEVS];
>  	struct typec_switch *sw;
> +	int i, j, k;
>  	int count;
>  	int err;
> -	int i;
>  
>  	sw = kzalloc(sizeof(*sw), GFP_KERNEL);
>  	if (!sw)
> @@ -96,6 +96,18 @@ struct typec_switch *fwnode_typec_switch_get(struct fwnode_handle *fwnode)
>  		}
>  	}
>  
> +	/* eliminate duplicates */
> +	for (i = 0; i < count; i++) {
> +		for (j = i + 1; j < count; j++) {
> +			if (sw_devs[j] == sw_devs[i]) {
> +				put_device(&sw_devs[j]->dev);
> +				for (k = j; k < count; k++)
> +					sw_devs[k] = sw_devs[k+1];
> +				count--;
> +			}
> +		}
> +	}

I think that check could be done in typec_switch_match(). Just pass
that sw_devs to it as "data":

        -        count = fwnode_connection_find_matches(fwnode, "orientation-switch", NULL,
        +        count = fwnode_connection_find_matches(fwnode, "orientation-switch", sw_devs,

And then in typec_switch_match(), probable as the second last step:

         static void *typec_switch_match(const struct fwnode_handle *fwnode,
                                         const char *id, void *data)
         {
        +       struct typec_switch_dev *sw_devs = data;
        +       int i;
                ...
                dev = class_find_device(&typec_mux_class, NULL, fwnode,
                                        switch_fwnode_match);

        +	/* Skip duplicates */
        +       for (i = 0; i < TYPEC_MUX_MAX_DEVS; i++)
        +               if (to_typec_switch_dev(dev) == sw_devs[i]) {
        +                       put_device(dev);
        +                       return NULL;
        +               }

                return dev ? to_typec_switch_dev(dev) : ERR_PTR(-EPROBE_DEFER);
         }

thanks,

-- 
heikki

Re: [PATCH 2/2] usb: typec: mux: avoid duplicated mux switches

[Heikki Krogerus]

Fri, Feb 13, 2026 at 08:23:29PM +0100, Sebastian Reichel wrote:
> Some devices use combo PHYs (i.e. USB3 + DisplayPort), which also
> handle the lane muxing. These PHYs are referenced twice from
> the USB-C connector (USB super-speed lines and SBU/AUX lines)
> resulting in the mux being configured twice. Avoid this by
> dropping duplicates.
> 
> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> ---
>  drivers/usb/typec/mux.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/mux.c b/drivers/usb/typec/mux.c
> index db35b7398343..6a394326f236 100644
> --- a/drivers/usb/typec/mux.c
> +++ b/drivers/usb/typec/mux.c
> @@ -309,9 +309,9 @@ struct typec_mux *fwnode_typec_mux_get(struct fwnode_handle *fwnode)
>  {
>  	struct typec_mux_dev *mux_devs[TYPEC_MUX_MAX_DEVS];
>  	struct typec_mux *mux;
> +	int i, j, k;
>  	int count;
>  	int err;
> -	int i;
>  
>  	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
>  	if (!mux)
> @@ -333,6 +333,18 @@ struct typec_mux *fwnode_typec_mux_get(struct fwnode_handle *fwnode)
>  		}
>  	}
>  
> +	/* eliminate duplicates */
> +	for (i = 0; i < count; i++) {
> +		for (j = i + 1; j < count; j++) {
> +			if (mux_devs[j] == mux_devs[i]) {
> +				put_device(&mux_devs[j]->dev);
> +				for (k = j; k < count; k++)
> +					mux_devs[k] = mux_devs[k+1];
> +				count--;
> +			}
> +		}
> +	}

The same should work here. My code snippets probable has to be
modified, but the idea should work. The check should be more simple to
do in typec_switch_match().

Br,

-- 
heikki