Re: [PATCH 7/8] staging: wilc1000: replace udelay with usleep_range

[Ajay Singh <ajay.kathat@microchip.com>]

Hi Greg,

On Sun, 5 Aug 2018 16:11:17 +0200
Greg KH <gregkh@linuxfoundation.org> wrote:

> On Fri, Aug 03, 2018 at 01:58:51PM +0530, Ajay Singh wrote:
> > Hi Greg,
> > 
> > On Thu, 2 Aug 2018 09:34:15 +0200
> > Greg KH <gregkh@linuxfoundation.org> wrote:
> >   
> > > On Sun, Jul 29, 2018 at 11:36:56AM +0530, Ajay Singh wrote:  
> > > > Cleanup patch to avoid the below checkpatch reported issue.
> > > > 
> > > > "usleep_range is preferred over udelay; see
> > > > Documentation/timers/timers-howto.txt".
> > > > 
> > > > Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
> > > > ---
> > > >  drivers/staging/wilc1000/wilc_wlan.c | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > 
> > > > diff --git a/drivers/staging/wilc1000/wilc_wlan.c
> > > > b/drivers/staging/wilc1000/wilc_wlan.c index 6bac3f7..655952a
> > > > 100644 --- a/drivers/staging/wilc1000/wilc_wlan.c
> > > > +++ b/drivers/staging/wilc1000/wilc_wlan.c
> > > > @@ -425,7 +425,7 @@ void chip_wakeup(struct wilc *wilc)
> > > >  		} while (wilc_get_chipid(wilc, true) == 0);
> > > >  	} else if ((wilc->io_type & 0x1) == HIF_SDIO) {
> > > >  		wilc->hif_func->hif_write_reg(wilc, 0xfa, 1);
> > > > -		udelay(200);
> > > > +		usleep_range(200, 201);    
> > > 
> > > Hah, that's funny.
> > > 
> > > No, do it right, don't try to game checkpatch here.  
> > 
> > The delay of 200us was added to have a short wait between HW
> > register write and read operation. The short delay of 200us was
> > enough for this but the duration range is not available. So to
> > replace udelay() of 200us with usleep_range(), I have used used
> > range from 200, 201.  
> 
> What do you mean that "the duration range is not available"?  You know
> what is allowed here, please provide that range.  You do know the
> reason for this suggestion from checkpatch, right?  By doing what you
> did here, you are totally subverting the real goal here, you are not
> solving anything.


Actually, we need a delay of 200us but there is no upper limit for it.
usleep_range() also expects upper limit, so added '1us' to the
lower limit (200us) to use for upper limit value.

I will rework on this and resubmit the patch.

Thank you.

Regards,
Ajay