linux-kernel - Re: [PATCH 1/4] usb: typec: tcpm: fix cc role at port reset

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Message-ID: <ZBA8Y/dbozOk2df7@kuha.fi.intel.com>
Date:   Tue, 14 Mar 2023 11:20:35 +0200
From:   Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To:     Frank Wang <frank.wang@...k-chips.com>
Cc:     linux@...ck-us.net, gregkh@...uxfoundation.org, heiko@...ech.de,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-rockchip@...ts.infradead.org, huangtao@...k-chips.com,
        william.wu@...k-chips.com, jianwei.zheng@...k-chips.com,
        yubing.zhang@...k-chips.com, wmc@...k-chips.com
Subject: Re: [PATCH 1/4] usb: typec: tcpm: fix cc role at port reset

On Mon, Mar 13, 2023 at 10:58:40AM +0800, Frank Wang wrote:
> In the current implementation, the tcpm set CC1/CC2 role to open when
> it do port reset would cause the VBUS removed by the Type-C partner.
> 
> The Figure 4-20 in the TCPCI 2.0 specification show that the CC1/CC2
> role should set to 01b (Rp) or 10b (Rd) at Power On or Reset stage
> in DRP initialization and connection detection.
> 
> So set CC1/CC2 to Rd to fix it.
> 
> Signed-off-by: Frank Wang <frank.wang@...k-chips.com>
> ---
>  drivers/usb/typec/tcpm/tcpm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index a0d943d785800..66de02a56f512 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -4851,7 +4851,7 @@ static void run_state_machine(struct tcpm_port *port)
>  		break;
>  	case PORT_RESET:
>  		tcpm_reset_port(port);
> -		tcpm_set_cc(port, TYPEC_CC_OPEN);
> +		tcpm_set_cc(port, TYPEC_CC_RD);
>  		tcpm_set_state(port, PORT_RESET_WAIT_OFF,
>  			       PD_T_ERROR_RECOVERY);
>  		break;

Will this work if the port is for example source only?

thanks,

-- 
heikki