Re: [PATCH v2] b43: Replace mdelay with usleep_range in b43_radio_2057_init_post

[Arend van Spriel]

On 1/9/2018 10:47 AM, Jia-Ju Bai wrote:
> On 2018/1/9 17:07, Arend van Spriel wrote:
> > On 1/9/2018 9:39 AM, Jia-Ju Bai wrote:
> > > On 2018/1/9 16:35, Greg KH wrote:
> > > > On Tue, Jan 09, 2018 at 09:40:06AM +0800, Jia-Ju Bai wrote:
> > > > > b43_radio_2057_init_post is not called in an interrupt handler
> > > > > nor holding a spinlock.
> > > > > The function mdelay in it can be replaced with usleep_range,
> > > > > to reduce busy wait.
> > > > >
> > > > > Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
> > > > > ---
> > > > > v2:
> > > > > * Replace mdelay with usleep_range, instead of msleep in v1.
> > > > >    Thank Larry for good advice.
> > > > > ---
> > > > >   drivers/net/wireless/broadcom/b43/phy_n.c |    2 +-
> > > > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/drivers/net/wireless/broadcom/b43/phy_n.c
> > > > > b/drivers/net/wireless/broadcom/b43/phy_n.c
> > > > > index a5557d7..f2a2f41 100644
> > > > > --- a/drivers/net/wireless/broadcom/b43/phy_n.c
> > > > > +++ b/drivers/net/wireless/broadcom/b43/phy_n.c
> > > > > @@ -1031,7 +1031,7 @@ static void b43_radio_2057_init_post(struct
> > > > > b43_wldev *dev)
> > > > >       b43_radio_set(dev, R2057_RFPLL_MISC_CAL_RESETN, 0x78);
> > > > >       b43_radio_set(dev, R2057_XTAL_CONFIG2, 0x80);
> > > > > -    mdelay(2);
> > > > > +    usleep_range(2000, 3000);
> > > > Where did 3000 come from?  Are you sure about that?
> > >
> > > I am not very sure, and I use it according to Larry's message:
> >
> > Hi Jia-Ju Bai,
> >
> > The duration here is for settling the registers so hardware can pick
> > it up. Right after this they are written again. Now this is during
> > initialization of the radio so not time critical, but probably
> > anything in the range of 2000..3000 would also have been fine.
>
> Hi Arend,
>
> Thanks for your detailed explanation :)
> So I think usleep_range(2000, 3000) is okay.

Sure.

Regards,
Arend