Re: [PATCH v3 2/2] usb: typec: tcpci: set ALERT_MASK register after devm_request_threaded_irq()

[Francesco Dolcini <francesco@dolcini.it>]

On Tue, Dec 17, 2024 at 05:41:17PM +0800, Xu Yang wrote:
> On Tue, Dec 17, 2024 at 10:29:05AM +0100, Francesco Dolcini wrote:
> > On Tue, Dec 17, 2024 at 05:12:08PM +0800, Xu Yang wrote:
> > > With edge irq support, the ALERT event may be missed currently. The reason
> > > is that ALERT_MASK register is written before devm_request_threaded_irq().
> > > If ALERT event happens in this time gap, it will be missed and ALERT line
> > > will not recover to high level. However, we don't meet this issue with
> > > level irq. To avoid the issue, this will set ALERT_MASK register after
> > > devm_request_threaded_irq() return.
> > > 
> > > Fixes: 77e85107a771 ("usb: typec: tcpci: support edge irq")
> > > Cc: stable@vger.kernel.org
> > > Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
> > > 
> > > ---
> > > Changes in v3:
> > >  - remove set_alert_mask flag
> > > Changes in v2:
> > >  - new patch
> > > ---
> > >  drivers/usb/typec/tcpm/tcpci.c | 17 ++++++++++++-----
> > >  1 file changed, 12 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
> > > index db42f4bf3632..48762508cc86 100644
> > > --- a/drivers/usb/typec/tcpm/tcpci.c
> > > +++ b/drivers/usb/typec/tcpm/tcpci.c
> > > @@ -700,7 +700,7 @@ static int tcpci_init(struct tcpc_dev *tcpc)
> > >  
> > >  	tcpci->alert_mask = reg;
> > >  
> > > -	return tcpci_write16(tcpci, TCPC_ALERT_MASK, reg);
> > > +	return 0;
> > 
> > Should we set the alert mask to 0 at the beginning of tcpci_init() ?
> > 
> > Just wondering if some bind/unbind or module reload use case would need
> > it.
> 
> Maybe not needed.
> 
> tcpci = devm_kzalloc(dev, sizeof(*tcpci), GFP_KERNEL);
> 
> tcpci will be reset to all 0 when allocate the memory. So alert_mask is 0
> by default.

I meant

  tcpci_write16(tcpci, TCPC_ALERT_MASK, 0);

in tcpci_init().