Re: [PATCH v5 7/8] platform/chrome: cros_ec_typec: Thunderbolt support

[Dzmitry Sankouski]

On 12/14/24 2:35 AM, Abhishek Pandit-Subedi wrote:
> Add support for entering and exiting Thunderbolt alt-mode using AP
> driven alt-mode.
>
> Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
> ---
(...)

> diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
> index 1bcaa7269395..1ac5798d887f 100644
> --- a/drivers/platform/chrome/cros_ec_typec.c
> +++ b/drivers/platform/chrome/cros_ec_typec.c
> @@ -303,18 +303,19 @@ static int cros_typec_register_port_altmodes(struct cros_typec_data *typec,
>   
>   	/*
>   	 * Register TBT compatibility alt mode. The EC will not enter the mode
> -	 * if it doesn't support it, so it's safe to register it unconditionally
> -	 * here for now.
> +	 * if it doesn't support it and it will not enter automatically by
> +	 * design so we can use the |ap_driven_altmode| feature to check if we
> +	 * should register it.
>   	 */
> -	memset(&desc, 0, sizeof(desc));
> -	desc.svid = USB_TYPEC_TBT_SID;
> -	desc.mode = TYPEC_ANY_MODE;
> -	amode = typec_port_register_altmode(port->port, &desc);
> -	if (IS_ERR(amode))
> -		return PTR_ERR(amode);
> -	port->port_altmode[CROS_EC_ALTMODE_TBT] = amode;
> -	typec_altmode_set_drvdata(amode, port);
> -	amode->ops = &port_amode_ops;

The last usage of port_amode_ops is deleted here. Is this a mistake?
AFAIU from kernel docs, port_amode_ops needed for alternate mode driver 
to send vdm messages to partner. Now, when it's unused, how does 
alternate modes work in this driver?

> +	if (typec->ap_driven_altmode) {
> +		memset(&desc, 0, sizeof(desc));
> +		desc.svid = USB_TYPEC_TBT_SID;
> +		desc.mode = TBT_MODE;
> +		amode = cros_typec_register_thunderbolt(port, &desc);
> +		if (IS_ERR(amode))
> +			return PTR_ERR(amode);
> +		port->port_altmode[CROS_EC_ALTMODE_TBT] = amode;
> +	}
>   
>   	port->state.alt = NULL;
>   	port->state.mode = TYPEC_STATE_USB;