Alt Mode drivers are responsible for sending Enter Mode through the TCPM,
but only a DFP is allowed to send Enter Mode. typec_get_data_role gets
the port's data role, which can then be used in altmode drivers via
typec_altmode_get_data_role to know if Enter Mode should be sent.

Signed-off-by: RD Babiera <rdbabiera@google.com>
---
Changes from v1:
* changed typec_altmode_get_data_role documentation format
---
 drivers/usb/typec/class.c         | 13 +++++++++++++
 include/linux/usb/typec.h         |  1 +
 include/linux/usb/typec_altmode.h | 13 +++++++++++++
 3 files changed, 27 insertions(+)

diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 67a533e35150..9b2647cb199b 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -2120,6 +2120,19 @@ void typec_set_data_role(struct typec_port *port, enum typec_data_role role)
 }
 EXPORT_SYMBOL_GPL(typec_set_data_role);
 
+/**
+ * typec_get_data_role - Get port data role
+ * @port: The USB Type-C Port to query
+ *
+ * This routine is used by the altmode drivers to determine if the port is the
+ * DFP before issuing Enter Mode
+ */
+enum typec_data_role typec_get_data_role(struct typec_port *port)
+{
+	return port->data_role;
+}
+EXPORT_SYMBOL_GPL(typec_get_data_role);
+
 /**
  * typec_set_pwr_role - Report power role change
  * @port: The USB Type-C Port where the role was changed
diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h
index 252af3f77039..309251572e2e 100644
--- a/include/linux/usb/typec.h
+++ b/include/linux/usb/typec.h
@@ -337,6 +337,7 @@ struct typec_plug *typec_register_plug(struct typec_cable *cable,
 void typec_unregister_plug(struct typec_plug *plug);
 
 void typec_set_data_role(struct typec_port *port, enum typec_data_role role);
+enum typec_data_role typec_get_data_role(struct typec_port *port);
 void typec_set_pwr_role(struct typec_port *port, enum typec_role role);
 void typec_set_vconn_role(struct typec_port *port, enum typec_role role);
 void typec_set_pwr_opmode(struct typec_port *port, enum typec_pwr_opmode mode);
diff --git a/include/linux/usb/typec_altmode.h b/include/linux/usb/typec_altmode.h
index b3c0866ea70f..f7db3bd4c90e 100644
--- a/include/linux/usb/typec_altmode.h
+++ b/include/linux/usb/typec_altmode.h
@@ -172,6 +172,19 @@ typec_altmode_get_svdm_version(struct typec_altmode *altmode)
 	return typec_get_negotiated_svdm_version(typec_altmode2port(altmode));
 }
 
+/**
+ * typec_altmode_get_data_role - Get port data role
+ * @altmode: Handle to the alternate mode
+ *
+ * Alt Mode drivers should only issue Enter Mode through the port if they are
+ * the DFP.
+ */
+static inline enum typec_data_role
+typec_altmode_get_data_role(struct typec_altmode *altmode)
+{
+	return typec_get_data_role(typec_altmode2port(altmode));
+}
+
 /**
  * struct typec_altmode_driver - USB Type-C alternate mode device driver
  * @id_table: Null terminated array of SVIDs
-- 
2.51.0.534.gc79095c0ca-goog

On Tue, Sep 23, 2025 at 06:16:07PM +0000, RD Babiera wrote:
> Alt Mode drivers are responsible for sending Enter Mode through the TCPM,
> but only a DFP is allowed to send Enter Mode. typec_get_data_role gets
> the port's data role, which can then be used in altmode drivers via
> typec_altmode_get_data_role to know if Enter Mode should be sent.
> 
> Signed-off-by: RD Babiera <rdbabiera@google.com>

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

> ---
> Changes from v1:
> * changed typec_altmode_get_data_role documentation format
> ---
>  drivers/usb/typec/class.c         | 13 +++++++++++++
>  include/linux/usb/typec.h         |  1 +
>  include/linux/usb/typec_altmode.h | 13 +++++++++++++
>  3 files changed, 27 insertions(+)
> 
> diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
> index 67a533e35150..9b2647cb199b 100644
> --- a/drivers/usb/typec/class.c
> +++ b/drivers/usb/typec/class.c
> @@ -2120,6 +2120,19 @@ void typec_set_data_role(struct typec_port *port, enum typec_data_role role)
>  }
>  EXPORT_SYMBOL_GPL(typec_set_data_role);
>  
> +/**
> + * typec_get_data_role - Get port data role
> + * @port: The USB Type-C Port to query
> + *
> + * This routine is used by the altmode drivers to determine if the port is the
> + * DFP before issuing Enter Mode
> + */
> +enum typec_data_role typec_get_data_role(struct typec_port *port)
> +{
> +	return port->data_role;
> +}
> +EXPORT_SYMBOL_GPL(typec_get_data_role);
> +
>  /**
>   * typec_set_pwr_role - Report power role change
>   * @port: The USB Type-C Port where the role was changed
> diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h
> index 252af3f77039..309251572e2e 100644
> --- a/include/linux/usb/typec.h
> +++ b/include/linux/usb/typec.h
> @@ -337,6 +337,7 @@ struct typec_plug *typec_register_plug(struct typec_cable *cable,
>  void typec_unregister_plug(struct typec_plug *plug);
>  
>  void typec_set_data_role(struct typec_port *port, enum typec_data_role role);
> +enum typec_data_role typec_get_data_role(struct typec_port *port);
>  void typec_set_pwr_role(struct typec_port *port, enum typec_role role);
>  void typec_set_vconn_role(struct typec_port *port, enum typec_role role);
>  void typec_set_pwr_opmode(struct typec_port *port, enum typec_pwr_opmode mode);
> diff --git a/include/linux/usb/typec_altmode.h b/include/linux/usb/typec_altmode.h
> index b3c0866ea70f..f7db3bd4c90e 100644
> --- a/include/linux/usb/typec_altmode.h
> +++ b/include/linux/usb/typec_altmode.h
> @@ -172,6 +172,19 @@ typec_altmode_get_svdm_version(struct typec_altmode *altmode)
>  	return typec_get_negotiated_svdm_version(typec_altmode2port(altmode));
>  }
>  
> +/**
> + * typec_altmode_get_data_role - Get port data role
> + * @altmode: Handle to the alternate mode
> + *
> + * Alt Mode drivers should only issue Enter Mode through the port if they are
> + * the DFP.
> + */
> +static inline enum typec_data_role
> +typec_altmode_get_data_role(struct typec_altmode *altmode)
> +{
> +	return typec_get_data_role(typec_altmode2port(altmode));
> +}
> +
>  /**
>   * struct typec_altmode_driver - USB Type-C alternate mode device driver
>   * @id_table: Null terminated array of SVIDs
> -- 
> 2.51.0.534.gc79095c0ca-goog

-- 
heikki