Re: [PATCH v2 6/8] platform/chrome: cros_ec_typec: Use Thunderbolt 3 cable discover mode VDO in USB4 mode

Heikki Krogerus
2020-11-17T12:11:05Z

On Fri, Nov 13, 2020 at 12:25:01PM -0800, Utkarsh Patel wrote:
> Configure Thunderbolt3/USB4 cable generation value by filing Thunderbolt 3
> cable discover mode VDO to support rounded and non-rounded Thunderbolt3/
> USB4 cables.
> While we are here use Thunderbolt 3 cable discover mode VDO to fill active
> cable plug link training value.
>
> Suggested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> Signed-off-by: Utkarsh Patel <utkarsh.h.patel@intel.com>

FWIW:

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

> --
> Changes in v2:
> - No change.
> --
> ---
> drivers/platform/chrome/cros_ec_typec.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
> index 8111ed1fc574..b7416e82c3b3 100644
> --- a/drivers/platform/chrome/cros_ec_typec.c
> +++ b/drivers/platform/chrome/cros_ec_typec.c
> @@ -514,8 +514,18 @@ static int cros_typec_enable_usb4(struct cros_typec_data *typec,
> else if (pd_ctrl->control_flags & USB_PD_CTRL_ACTIVE_CABLE)
> data.eudo |= EUDO_CABLE_TYPE_RE_TIMER << EUDO_CABLE_TYPE_SHIFT;
>
> - data.active_link_training = !!(pd_ctrl->control_flags &
> - USB_PD_CTRL_ACTIVE_LINK_UNIDIR);
> + /*
> + * This driver does not have access to the identity information or
> + * capabilities of the cable, so we don't know is it a real USB4 or
> + * TBT3 cable. Therefore pretending that it's always TBT3 cable by
> + * filling the TBT3 Cable VDO.
> + */
> + data.tbt_cable_vdo = TBT_MODE;
> +
> + if (pd_ctrl->control_flags & USB_PD_CTRL_ACTIVE_LINK_UNIDIR)
> + data.tbt_cable_vdo |= TBT_CABLE_LINK_TRAINING;
> +
> + data.tbt_cable_vdo |= TBT_SET_CABLE_ROUNDED(pd_ctrl->cable_gen);
>
> port->state.alt = NULL;
> port->state.data = &data;
> --
> 2.17.1

--
heikki