2020-12-12 05:59:23

by Badhri Jagan Sridharan

Subject: [PATCH v1] usb: typec: tcpm: Update vbus_vsafe0v on init

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 <[email protected]>
---
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)
--
2.29.2.576.ga3fc446d84-goog

2020-12-12 09:56:39

by Heikki Krogerus

Subject: Re: [PATCH v1] usb: typec: tcpm: Update vbus_vsafe0v on init

On Thu, Dec 10, 2020 at 11:19:11PM -0800, 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 <[email protected]>

One nitpick bellow, but it's so minor that you can ignore it if you
like. FWIW:

Reviewed-by: Heikki Krogerus <[email protected]>

> ---
> 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);

Couldn't that be the other way around?

...
else if (port->tcpc->is_vbus_vsafe0v)
port->vbus_vsafe0v = port->tcpc->is_vbus_vsafe0v(port->tcpc);
else
port->vbus_vsafe0v = true;
...

> tcpm_set_state(port, tcpm_default_state(port), 0);
>
> if (port->tcpc->get_cc(port->tcpc, &cc1, &cc2) == 0)
> --
> 2.29.2.576.ga3fc446d84-goog

thanks,

--
heikki