Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: [PATCH] usb: typec: don't disable sink or source on initialization | From | Guenter Roeck <> | Date | Sun, 9 Sep 2018 07:43:44 -0700 |
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On 09/09/2018 07:36 AM, Angus Ainslie wrote: > On 2018-09-09 08:20, Guenter Roeck wrote: >> On 09/09/2018 07:08 AM, Angus Ainslie wrote: >>> Hi Guenter >>> >>> On 2018-09-07 06:55, Guenter Roeck wrote: >>>> On 09/07/2018 03:34 AM, Heikki Krogerus wrote: >>>>> +Guenter >>>>> >>>>> On Thu, Sep 06, 2018 at 01:26:44PM -0600, Angus Ainslie (Purism) wrote: >>>>>> If the board is being powered by USB disabling the source and sink >>>>>> can remove power from the board. Default to source and sink enabled. >>>>>> >>>> >>>> Seems to me that might violate the specification, and cause trouble for systems >>>> where vbus has to be off initially. It may be better to provide this kind of >>>> information as configuration parameter instead of imposing it on everyone. >>>> >>> >>> It felt like it would not be the correct thing to do either. I've tried re-arranging the code in tcpci.c to enable the sink before disabling the source but the only way I found to not disable the power was by setting both of those to true. >>> >>> What about adding some device tree entries for the initial vbus state and default to false if they are not present ? >>> >>> init-vbus-source and init-vbus-charge ? >>> >> >> Yes, I think we should do something along that line. Another question is >> if we could or should optionally pull the current state from the low level >> driver, but that may be secondary. >> > > I thought of trying to do that but from reading the "PTN5110N PD PHY application programming guide" there didn't seem to be a direct way to read those parameters. >
Let's put that on the backburner (maybe it works for some other chips) and go with the devicetree property for now.
Guenter
>> Thanks, >> Guenter >> >>> Angus >>> >>>> Guenter >>>> >>>>>> Signed-off-by: Angus Ainslie (Purism) <angus@akkea.ca> >>>>>> --- >>>>>> drivers/usb/typec/tcpm.c | 8 +++++--- >>>>>> 1 file changed, 5 insertions(+), 3 deletions(-) >>>>>> >>>>>> diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c >>>>>> index ca7bedb46f7f..a1b819cf31da 100644 >>>>>> --- a/drivers/usb/typec/tcpm.c >>>>>> +++ b/drivers/usb/typec/tcpm.c >>>>>> @@ -2462,9 +2462,11 @@ static int tcpm_init_vbus(struct tcpm_port *port) >>>>>> { >>>>>> int ret; >>>>>> - ret = port->tcpc->set_vbus(port->tcpc, false, false); >>>>>> - port->vbus_source = false; >>>>>> - port->vbus_charge = false; >>>>>> + /* default to source and sink enabled in case USB is our only power >>>>>> + * source */ >>>> >>>> I am personally in favor of standard multi-line comments. >>>> >>>>>> + ret = port->tcpc->set_vbus(port->tcpc, true, true); >>>>>> + port->vbus_source = true; >>>>>> + port->vbus_charge = true; >>>>>> return ret; >>>>>> } >>>>> >>> >>> > >
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