Re: [PATCH] platform/chrome: cros_ec_typec: Skip Type-C mux handling in EC-driven devices

[Andrei Kuchynski <akuchynski@chromium.org>]

Hi Diogo,

On Thu, Feb 5, 2026 at 11:04 AM Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt> wrote:
>
> Currently the code assumes that the EC firmware will leave Type-C mux
> handling logic to the AP, exposing an interface to query and change the
> mux state via a request from the AP. However, in devices such as Smaug
> the EC automatically takes care of mux configuration and only USB role
> switching needs to be handled by the AP. In fact, in such devices this
> interface is not exposed by the EC making the whole process fail,
> including role switching.
>
> Fix this by first separating Type-C mux handling and USB role switching,
> explicitly querying the behaviour of the EC and execute each part
> conditionally according to what the EC reported.
>
> Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
> ---
>  drivers/platform/chrome/cros_ec_typec.c | 49 +++++++++++++++++++++++----------
>  drivers/platform/chrome/cros_ec_typec.h |  2 +-
>  2 files changed, 35 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
> index b712bcff6fb2..bd7e6c365cab 100644
> --- a/drivers/platform/chrome/cros_ec_typec.c
> +++ b/drivers/platform/chrome/cros_ec_typec.c
> @@ -751,11 +751,10 @@ static int cros_typec_configure_mux(struct cros_typec_data *typec, int port_num,
>         }
>
>         /* No change needs to be made, let's exit early. */
> -       if (port->mux_flags == resp.flags && port->role == pd_ctrl->role)
> +       if (port->mux_flags == resp.flags)
>                 return 0;
>
>         port->mux_flags = resp.flags;
> -       port->role = pd_ctrl->role;
>
>         if (port->mux_flags == USB_PD_MUX_NONE) {
>                 ret = cros_typec_usb_disconnect_state(port);
> @@ -771,12 +770,6 @@ static int cros_typec_configure_mux(struct cros_typec_data *typec, int port_num,
>         if (ret)
>                 return ret;
>
> -       ret = usb_role_switch_set_role(typec->ports[port_num]->role_sw,
> -                                       pd_ctrl->role & PD_CTRL_RESP_ROLE_DATA
> -                                       ? USB_ROLE_HOST : USB_ROLE_DEVICE);
> -       if (ret)
> -               return ret;
> -
>         if (port->mux_flags & USB_PD_MUX_USB4_ENABLED) {
>                 ret = cros_typec_enable_usb4(typec, port_num, pd_ctrl);
>         } else if (port->mux_flags & USB_PD_MUX_TBT_COMPAT_ENABLED) {
> @@ -822,6 +815,25 @@ static int cros_typec_configure_mux(struct cros_typec_data *typec, int port_num,
>         return ret;
>  }
>
> +static int cros_typec_set_role(struct cros_typec_data *typec, int port_num,
> +                              struct ec_response_usb_pd_control_v1 *resp)
> +{
> +       enum usb_role cur_role = usb_role_switch_get_role(typec->ports[port_num]->role_sw);
> +       enum usb_role role = resp->role & PD_CTRL_RESP_ROLE_DATA ? USB_ROLE_HOST :
> +                                                                  USB_ROLE_DEVICE;
> +       bool connected = resp->enabled & PD_CTRL_RESP_ENABLED_CONNECTED;
> +       int ret;
> +
> +       if (!connected || cur_role == role)
> +               return 0;
> +
> +       ret = usb_role_switch_set_role(typec->ports[port_num]->role_sw, role);
> +       if (ret)
> +               dev_err(typec->dev, "Failed USB role switch, err = %d\n", ret);

While testing on Brya, I've got a role switch failure:
cros-ec-typec GOOG0014:00: Failed USB role switch, err = -22
cros-ec-typec GOOG0014:00: Update failed for port: 1

Steps to reproduce: deactivate any alt-mode.
Verified on the Brya platform.

This may be attributed to the altered sequence of mux and switch settings.


Thanks,
Andrei