Re: [PATCH] usb: dwc3: gadget: fix writing NYET threshold

[Thinh Nguyen <Thinh.Nguyen@synopsys.com>]

On Fri, Dec 06, 2024, Thinh Nguyen wrote:
> On Fri, Dec 06, 2024, André Draszik wrote:
> > Before writing a new value to the register, the old value needs to be
> > masked out for the new value to be programmed as intended.
> > 
> > At the moment, the dwc3 core initialises the threshold to the maximum
> > value (0xf), with the option to override it via a DT. No upstream DTs
> > seem to override it, therefore this commit doesn't change behaviour for
> > any upstream platform. Nevertheless, the code should be fixed to have
> > the desired outcome.
> > 
> > Do so.
> > 
> > Signed-off-by: André Draszik <andre.draszik@linaro.org>
> > ---
> >  drivers/usb/dwc3/core.h   | 1 +
> >  drivers/usb/dwc3/gadget.c | 4 +++-
> >  2 files changed, 4 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> > index ee73789326bc..9335fd095968 100644
> > --- a/drivers/usb/dwc3/core.h
> > +++ b/drivers/usb/dwc3/core.h
> > @@ -465,6 +465,7 @@
> >  
> >  /* These apply for core versions 1.94a and later */
> >  #define DWC3_DCTL_NYET_THRES(n)		(((n) & 0xf) << 20)
> > +#define DWC3_DCTL_NYET_THRES_MASK	DWC3_DCTL_NYET_THRES(0xf)
> 
> If you're going to define a mask macro this way, do this:
> DWC3_DCTL_NYET_THRES(~0)
> 

Actually, let's keep it consistent as how the other masks are defined,
don't use DWC3_DCTL_NYET_THRES(n) to define the mask.

Use GENMASK or do something like this:
#define DWC3_DCTL_NYET_THRES_MASK	(0xf << 20)

BR,
Thinh