usb: typec: fusb302: add DRM DP HPD bridge support

[PATCH] usb: typec: fusb302: add DRM DP HPD bridge support

Posted by Sebastian Reichel 4 weeks ago

Add support to use fusb302 based USB-C connectors with the DP altmode
helper code on devicetree based platforms. To get this working there
must be a DRM bridge chain from the DisplayPort controller to the USB-C
connector. E.g. on Rockchip RK3576:

root@rk3576 # cat /sys/kernel/debug/dri/0/encoder-0/bridges
bridge[0]: dw_dp_bridge_funcs
	refcount: 7
	type: [10] DP
	OF: /soc/dp@27e40000:rockchip,rk3576-dp
	ops: [0x47] detect edid hpd
bridge[1]: drm_aux_bridge_funcs
	refcount: 4
	type: [0] Unknown
	OF: /soc/phy@2b010000:rockchip,rk3576-usbdp-phy
	ops: [0x0]
bridge[2]: drm_aux_hpd_bridge_funcs
	refcount: 5
	type: [10] DP
	OF: /soc/i2c@2ac50000/typec-portc@22/connector:usb-c-connector
	ops: [0x4] hpd

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
To make this usable on Rockchip RK3588 and RK3576 platforms as shown in
the commit message, the Designware DP driver and the USBDP PHY driver
also need changes. Those are being send separately as the fusb302 patch
can be merged completley independently.
---
 drivers/usb/typec/tcpm/Kconfig   |  2 ++
 drivers/usb/typec/tcpm/fusb302.c | 13 +++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/drivers/usb/typec/tcpm/Kconfig b/drivers/usb/typec/tcpm/Kconfig
index 8cdd84ca5d6f..00baa7503d45 100644
--- a/drivers/usb/typec/tcpm/Kconfig
+++ b/drivers/usb/typec/tcpm/Kconfig
@@ -58,6 +58,8 @@ config TYPEC_FUSB302
 	tristate "Fairchild FUSB302 Type-C chip driver"
 	depends on I2C
 	depends on EXTCON || !EXTCON
+	depends on DRM || DRM=n
+	select DRM_AUX_HPD_BRIDGE if DRM_BRIDGE && OF
 	help
 	  The Fairchild FUSB302 Type-C chip driver that works with
 	  Type-C Port Controller Manager to provide USB PD and USB
diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
index 19ff8217818e..ce7069fb4be6 100644
--- a/drivers/usb/typec/tcpm/fusb302.c
+++ b/drivers/usb/typec/tcpm/fusb302.c
@@ -5,6 +5,7 @@
  * Fairchild FUSB302 Type-C Chip Driver
  */
 
+#include <drm/bridge/aux-bridge.h>
 #include <linux/debugfs.h>
 #include <linux/delay.h>
 #include <linux/errno.h>
@@ -1689,6 +1690,7 @@ static int fusb302_probe(struct i2c_client *client)
 {
 	struct fusb302_chip *chip;
 	struct i2c_adapter *adapter = client->adapter;
+	struct auxiliary_device *bridge_dev;
 	struct device *dev = &client->dev;
 	const char *name;
 	int ret = 0;
@@ -1747,6 +1749,13 @@ static int fusb302_probe(struct i2c_client *client)
 		goto destroy_workqueue;
 	}
 
+	bridge_dev = devm_drm_dp_hpd_bridge_alloc(chip->dev, to_of_node(chip->tcpc_dev.fwnode));
+	if (IS_ERR(bridge_dev)) {
+		ret = PTR_ERR(bridge_dev);
+		dev_err_probe(chip->dev, ret, "failed to alloc bridge\n");
+		goto destroy_workqueue;
+	}
+
 	chip->tcpm_port = tcpm_register_port(&client->dev, &chip->tcpc_dev);
 	if (IS_ERR(chip->tcpm_port)) {
 		fwnode_handle_put(chip->tcpc_dev.fwnode);
@@ -1764,6 +1773,10 @@ static int fusb302_probe(struct i2c_client *client)
 	enable_irq_wake(chip->gpio_int_n_irq);
 	i2c_set_clientdata(client, chip);
 
+	ret = devm_drm_dp_hpd_bridge_add(chip->dev, bridge_dev);
+	if (ret)
+		return ret;
+
 	return ret;
 
 tcpm_unregister_port:

---
base-commit: 6de23f81a5e08be8fbf5e8d7e9febc72a5b5f27f
change-id: 20260310-fusb302-drm-dp-hpd-bridge-00f6c9aec3ab

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

Re: [PATCH] usb: typec: fusb302: add DRM DP HPD bridge support

Posted by Alexey Charkov 3 weeks, 4 days ago

Hi Sebastian,

On Tue, Mar 10, 2026 at 9:17 PM Sebastian Reichel
<sebastian.reichel@collabora.com> wrote:
>
> Add support to use fusb302 based USB-C connectors with the DP altmode
> helper code on devicetree based platforms. To get this working there
> must be a DRM bridge chain from the DisplayPort controller to the USB-C
> connector. E.g. on Rockchip RK3576:
>
> root@rk3576 # cat /sys/kernel/debug/dri/0/encoder-0/bridges
> bridge[0]: dw_dp_bridge_funcs
>         refcount: 7
>         type: [10] DP
>         OF: /soc/dp@27e40000:rockchip,rk3576-dp
>         ops: [0x47] detect edid hpd
> bridge[1]: drm_aux_bridge_funcs
>         refcount: 4
>         type: [0] Unknown
>         OF: /soc/phy@2b010000:rockchip,rk3576-usbdp-phy
>         ops: [0x0]
> bridge[2]: drm_aux_hpd_bridge_funcs
>         refcount: 5
>         type: [10] DP
>         OF: /soc/i2c@2ac50000/typec-portc@22/connector:usb-c-connector
>         ops: [0x4] hpd
>
> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> ---
> To make this usable on Rockchip RK3588 and RK3576 platforms as shown in
> the commit message, the Designware DP driver and the USBDP PHY driver
> also need changes. Those are being send separately as the fusb302 patch
> can be merged completley independently.
> ---
>  drivers/usb/typec/tcpm/Kconfig   |  2 ++
>  drivers/usb/typec/tcpm/fusb302.c | 13 +++++++++++++
>  2 files changed, 15 insertions(+)
>
> diff --git a/drivers/usb/typec/tcpm/Kconfig b/drivers/usb/typec/tcpm/Kconfig
> index 8cdd84ca5d6f..00baa7503d45 100644
> --- a/drivers/usb/typec/tcpm/Kconfig
> +++ b/drivers/usb/typec/tcpm/Kconfig
> @@ -58,6 +58,8 @@ config TYPEC_FUSB302
>         tristate "Fairchild FUSB302 Type-C chip driver"
>         depends on I2C
>         depends on EXTCON || !EXTCON
> +       depends on DRM || DRM=n
> +       select DRM_AUX_HPD_BRIDGE if DRM_BRIDGE && OF
>         help
>           The Fairchild FUSB302 Type-C chip driver that works with
>           Type-C Port Controller Manager to provide USB PD and USB
> diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
> index 19ff8217818e..ce7069fb4be6 100644
> --- a/drivers/usb/typec/tcpm/fusb302.c
> +++ b/drivers/usb/typec/tcpm/fusb302.c
> @@ -5,6 +5,7 @@
>   * Fairchild FUSB302 Type-C Chip Driver
>   */
>
> +#include <drm/bridge/aux-bridge.h>
>  #include <linux/debugfs.h>
>  #include <linux/delay.h>
>  #include <linux/errno.h>
> @@ -1689,6 +1690,7 @@ static int fusb302_probe(struct i2c_client *client)
>  {
>         struct fusb302_chip *chip;
>         struct i2c_adapter *adapter = client->adapter;
> +       struct auxiliary_device *bridge_dev;
>         struct device *dev = &client->dev;
>         const char *name;
>         int ret = 0;
> @@ -1747,6 +1749,13 @@ static int fusb302_probe(struct i2c_client *client)
>                 goto destroy_workqueue;
>         }
>
> +       bridge_dev = devm_drm_dp_hpd_bridge_alloc(chip->dev, to_of_node(chip->tcpc_dev.fwnode));
> +       if (IS_ERR(bridge_dev)) {
> +               ret = PTR_ERR(bridge_dev);
> +               dev_err_probe(chip->dev, ret, "failed to alloc bridge\n");
> +               goto destroy_workqueue;
> +       }
> +
>         chip->tcpm_port = tcpm_register_port(&client->dev, &chip->tcpc_dev);
>         if (IS_ERR(chip->tcpm_port)) {
>                 fwnode_handle_put(chip->tcpc_dev.fwnode);
> @@ -1764,6 +1773,10 @@ static int fusb302_probe(struct i2c_client *client)
>         enable_irq_wake(chip->gpio_int_n_irq);
>         i2c_set_clientdata(client, chip);
>
> +       ret = devm_drm_dp_hpd_bridge_add(chip->dev, bridge_dev);
> +       if (ret)
> +               return ret;
> +
>         return ret;

Nit: how about

return devm_drm_dp_hpd_bridge_add(chip->dev, bridge_dev);

Saves three lines :)

Thanks a lot,
Alexey

Re: [PATCH] usb: typec: fusb302: add DRM DP HPD bridge support

Posted by Sebastian Reichel 3 weeks, 4 days ago

Hi,

On Fri, Mar 13, 2026 at 12:15:08PM +0400, Alexey Charkov wrote:
> [...]
> > +       ret = devm_drm_dp_hpd_bridge_add(chip->dev, bridge_dev);
> > +       if (ret)
> > +               return ret;
> > +
> >         return ret;
> 
> Nit: how about
> 
> return devm_drm_dp_hpd_bridge_add(chip->dev, bridge_dev);
> 
> Saves three lines :)

The patch got queued already. I can provide a follow-up patch if
that is something people want to see. Generally this is a style
decision handled differently between subsystems. Your suggestion
saves three lines and is more efficient (but compiler will optimize
to that anyways). Meanwhile the version I provided results in
smaller diff when more code is appended in the probe function or
the order has to be changed for some reason.

FWIW I would like to see this driver be more converted towards
device managed resource and then use drm_dp_hpd_bridge_register()
instead of doing the allocation and add step separetely. But I
would wait with the cleanup until the 7.2 cycle as
devm_alloc_ordered_workqueue() will land in 7.1.

Greetings,

-- Sebastian

Re: [PATCH] usb: typec: fusb302: add DRM DP HPD bridge support

Posted by Dmitry Baryshkov 3 weeks, 4 days ago

On Fri, 13 Mar 2026 at 17:23, Sebastian Reichel
<sebastian.reichel@collabora.com> wrote:
>
> Hi,
>
> On Fri, Mar 13, 2026 at 12:15:08PM +0400, Alexey Charkov wrote:
> > [...]
> > > +       ret = devm_drm_dp_hpd_bridge_add(chip->dev, bridge_dev);
> > > +       if (ret)
> > > +               return ret;
> > > +
> > >         return ret;
> >
> > Nit: how about
> >
> > return devm_drm_dp_hpd_bridge_add(chip->dev, bridge_dev);
> >
> > Saves three lines :)
>
> The patch got queued already. I can provide a follow-up patch if
> that is something people want to see. Generally this is a style
> decision handled differently between subsystems. Your suggestion
> saves three lines and is more efficient (but compiler will optimize
> to that anyways). Meanwhile the version I provided results in
> smaller diff when more code is appended in the probe function or
> the order has to be changed for some reason.
>
> FWIW I would like to see this driver be more converted towards
> device managed resource and then use drm_dp_hpd_bridge_register()

This API is more fragile. Using it can result in various side effects,
starting from EPROBE_DEFER loops if it is used in a wrong place.
Other bridges might also get the pointed to the bridge and then
witness its disappearance.
I think in the long term we should remove that API completely.

> instead of doing the allocation and add step separetely. But I
> would wait with the cleanup until the 7.2 cycle as
> devm_alloc_ordered_workqueue() will land in 7.1.
>
> Greetings,
>
> -- Sebastian



-- 
With best wishes
Dmitry

Re: [PATCH] usb: typec: fusb302: add DRM DP HPD bridge support

Posted by Heikki Krogerus 3 weeks, 6 days ago

Tue, Mar 10, 2026 at 06:17:34PM +0100, Sebastian Reichel kirjoitti:
> Add support to use fusb302 based USB-C connectors with the DP altmode
> helper code on devicetree based platforms. To get this working there
> must be a DRM bridge chain from the DisplayPort controller to the USB-C
> connector. E.g. on Rockchip RK3576:
> 
> root@rk3576 # cat /sys/kernel/debug/dri/0/encoder-0/bridges
> bridge[0]: dw_dp_bridge_funcs
> 	refcount: 7
> 	type: [10] DP
> 	OF: /soc/dp@27e40000:rockchip,rk3576-dp
> 	ops: [0x47] detect edid hpd
> bridge[1]: drm_aux_bridge_funcs
> 	refcount: 4
> 	type: [0] Unknown
> 	OF: /soc/phy@2b010000:rockchip,rk3576-usbdp-phy
> 	ops: [0x0]
> bridge[2]: drm_aux_hpd_bridge_funcs
> 	refcount: 5
> 	type: [10] DP
> 	OF: /soc/i2c@2ac50000/typec-portc@22/connector:usb-c-connector
> 	ops: [0x4] hpd
> 
> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
> To make this usable on Rockchip RK3588 and RK3576 platforms as shown in
> the commit message, the Designware DP driver and the USBDP PHY driver
> also need changes. Those are being send separately as the fusb302 patch
> can be merged completley independently.
> ---
>  drivers/usb/typec/tcpm/Kconfig   |  2 ++
>  drivers/usb/typec/tcpm/fusb302.c | 13 +++++++++++++
>  2 files changed, 15 insertions(+)
> 
> diff --git a/drivers/usb/typec/tcpm/Kconfig b/drivers/usb/typec/tcpm/Kconfig
> index 8cdd84ca5d6f..00baa7503d45 100644
> --- a/drivers/usb/typec/tcpm/Kconfig
> +++ b/drivers/usb/typec/tcpm/Kconfig
> @@ -58,6 +58,8 @@ config TYPEC_FUSB302
>  	tristate "Fairchild FUSB302 Type-C chip driver"
>  	depends on I2C
>  	depends on EXTCON || !EXTCON
> +	depends on DRM || DRM=n
> +	select DRM_AUX_HPD_BRIDGE if DRM_BRIDGE && OF
>  	help
>  	  The Fairchild FUSB302 Type-C chip driver that works with
>  	  Type-C Port Controller Manager to provide USB PD and USB
> diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
> index 19ff8217818e..ce7069fb4be6 100644
> --- a/drivers/usb/typec/tcpm/fusb302.c
> +++ b/drivers/usb/typec/tcpm/fusb302.c
> @@ -5,6 +5,7 @@
>   * Fairchild FUSB302 Type-C Chip Driver
>   */
>  
> +#include <drm/bridge/aux-bridge.h>
>  #include <linux/debugfs.h>
>  #include <linux/delay.h>
>  #include <linux/errno.h>
> @@ -1689,6 +1690,7 @@ static int fusb302_probe(struct i2c_client *client)
>  {
>  	struct fusb302_chip *chip;
>  	struct i2c_adapter *adapter = client->adapter;
> +	struct auxiliary_device *bridge_dev;
>  	struct device *dev = &client->dev;
>  	const char *name;
>  	int ret = 0;
> @@ -1747,6 +1749,13 @@ static int fusb302_probe(struct i2c_client *client)
>  		goto destroy_workqueue;
>  	}
>  
> +	bridge_dev = devm_drm_dp_hpd_bridge_alloc(chip->dev, to_of_node(chip->tcpc_dev.fwnode));
> +	if (IS_ERR(bridge_dev)) {
> +		ret = PTR_ERR(bridge_dev);
> +		dev_err_probe(chip->dev, ret, "failed to alloc bridge\n");
> +		goto destroy_workqueue;
> +	}
> +
>  	chip->tcpm_port = tcpm_register_port(&client->dev, &chip->tcpc_dev);
>  	if (IS_ERR(chip->tcpm_port)) {
>  		fwnode_handle_put(chip->tcpc_dev.fwnode);
> @@ -1764,6 +1773,10 @@ static int fusb302_probe(struct i2c_client *client)
>  	enable_irq_wake(chip->gpio_int_n_irq);
>  	i2c_set_clientdata(client, chip);
>  
> +	ret = devm_drm_dp_hpd_bridge_add(chip->dev, bridge_dev);
> +	if (ret)
> +		return ret;
> +
>  	return ret;
>  
>  tcpm_unregister_port:
> 
> ---
> base-commit: 6de23f81a5e08be8fbf5e8d7e9febc72a5b5f27f
> change-id: 20260310-fusb302-drm-dp-hpd-bridge-00f6c9aec3ab
> 
> Best regards,
> -- 
> Sebastian Reichel <sebastian.reichel@collabora.com>

-- 
heikki