Re: [PATCH v2 3/4] usb: typec: tcpci: clear the fault status bit

[Guenter Roeck]

On 5/4/23 07:27, Marco Felsch wrote:
> On 23-05-04, Guenter Roeck wrote:
> > On 5/4/23 06:46, Marco Felsch wrote:
> > > According the "USB Type-C Port Controller Interface Specification v2.0"
> > > the TCPC sets the fault status register bit-7
> > > (AllRegistersResetToDefault) once the registers have been reseted to
> >
> > cleared ? set ?
>
> Sry. I don't get this.

instead of "reseted" which isn't really a word.

> > > their default values.
> > >
> > > This triggers an alert(-irq) on PTN5110 devices albeit we do mask the
> > > fault-irq. Fix this gernally by writing a one to the correspondig
> >
> > generically ?
>
> Sure, thanks.
>
> > corresponding
>
> Of course!
>
> > > bit-7.
> > >
> > > Signed-off-by: Marco Felsch <m.felsch@xxxxxxxxxxxxxx>
> > > ---
> > >    drivers/usb/typec/tcpm/tcpci.c | 5 +++++
> > >    include/linux/usb/tcpci.h      | 1 +
> > >    2 files changed, 6 insertions(+)
> > >
> > > diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
> > > index 8da23240afbe..15632d023e4c 100644
> > > --- a/drivers/usb/typec/tcpm/tcpci.c
> > > +++ b/drivers/usb/typec/tcpm/tcpci.c
> > > @@ -602,6 +602,11 @@ static int tcpci_init(struct tcpc_dev *tcpc)
> > >    	if (time_after(jiffies, timeout))
> > >    		return -ETIMEDOUT;
> > > +	regmap_read(tcpci->regmap, TCPC_FAULT_STATUS, &reg);
> >
> > Needs error check.
>
> I will add this.
>
> > Also, I am not sure if this is the correct place for this code. The alert
> > status is cleared after vendor initialization. Should the same be done
> > here ?
>
> According the spec the bit must be cleared before the TCPC_ALERT is
> cleared. Of course the vendor-init can (re-)trigger the bit, therefore
> we should move behind the vendor init and right before the TCPC_ALERT
> clear.
>
> > Also, why not just write the bit unconditionally, similar
> > to TCPC_ALERT ?
>
> Thought about this too.. I will change it in the v3.
>
> Thanks for the feedback,
>    Marco
>
> > Thanks,
> > Guenter
> >
> > > +	if (reg & TCPC_FAULT_STATUS_ALL_REG_RST_TO_DEFAULT)
> > > +		tcpci_write16(tcpci, TCPC_FAULT_STATUS,
> > > +			      TCPC_FAULT_STATUS_ALL_REG_RST_TO_DEFAULT);
> > > +
> > >    	/* Handle vendor init */
> > >    	if (tcpci->data->init) {
> > >    		ret = tcpci->data->init(tcpci, tcpci->data);
> > > diff --git a/include/linux/usb/tcpci.h b/include/linux/usb/tcpci.h
> > > index 85e95a3251d3..83376473ac76 100644
> > > --- a/include/linux/usb/tcpci.h
> > > +++ b/include/linux/usb/tcpci.h
> > > @@ -103,6 +103,7 @@
> > >    #define TCPC_POWER_STATUS_SINKING_VBUS	BIT(0)
> > >    #define TCPC_FAULT_STATUS		0x1f
> > > +#define TCPC_FAULT_STATUS_ALL_REG_RST_TO_DEFAULT BIT(7)
> > >    #define TCPC_ALERT_EXTENDED		0x21