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Message-ID: <f6196a7e-0953-d458-a7d7-75e30446b407@roeck-us.net>
Date: Fri, 11 Dec 2020 07:15:26 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Badhri Jagan Sridharan <badhri@...gle.com>,
Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] usb: typec: tcpm: Update vbus_vsafe0v on init
On 12/10/20 11:19 PM, Badhri Jagan Sridharan wrote:
> During init, vbus_vsafe0v does not get updated till the first
> connect as a sink. This causes TCPM to be stuck in SRC_ATTACH_WAIT
> state while booting with a sink (For instance: a headset) connected.
>
> [ 1.429168] Start toggling
> [ 1.439907] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
> [ 1.445242] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
> [ 53.358528] CC1: 0 -> 0, CC2: 0 -> 2 [state TOGGLING, polarity 0, connected]
> [ 53.358564] state change TOGGLING -> SRC_ATTACH_WAIT [rev1 NONE_AMS]
>
> Fix this by updating vbus_vsafe0v based on vbus_present status
> on boot.
>
> Signed-off-by: Badhri Jagan Sridharan <badhri@...gle.com>
Reviewed-by: Guenter Roeck <linux@...ck-us.net>
> ---
> drivers/usb/typec/tcpm/tcpm.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index cedc6cf82d61..58a6302c549f 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -4794,6 +4794,24 @@ static void tcpm_init(struct tcpm_port *port)
> if (port->vbus_present)
> port->vbus_never_low = true;
>
> + /*
> + * 1. When vbus_present is true, voltage on VBUS is already at VSAFE5V.
> + * So implicitly vbus_vsafe0v = false.
> + *
> + * 2. When vbus_present is false and TCPC does NOT support querying
> + * vsafe0v status, then, it's best to assume vbus is at VSAFE0V i.e.
> + * vbus_vsafe0v is true.
> + *
> + * 3. When vbus_present is false and TCPC does support querying vsafe0v,
> + * then, query tcpc for vsafe0v status.
> + */
> + if (port->vbus_present)
> + port->vbus_vsafe0v = false;
> + else if (!port->tcpc->is_vbus_vsafe0v)
> + port->vbus_vsafe0v = true;
> + else
> + port->vbus_vsafe0v = port->tcpc->is_vbus_vsafe0v(port->tcpc);
> +
> tcpm_set_state(port, tcpm_default_state(port), 0);
>
> if (port->tcpc->get_cc(port->tcpc, &cc1, &cc2) == 0)
>
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