From: Marc Dietrich <marvin24@gmx.de>
To: SIMRAN SINGHAL <singhalsimran0@gmail.com>, linux-tegra@vger.kernel.org
Cc: outreachy-kernel <outreachy-kernel@googlegroups.com>,
        gregkh@linuxfoundation.org, devel@driverdev.osuosl.org,
        linux-kernel@vger.kernel.org
Subject: Re: [Outreachy kernel] [PATCH] staging: nvec: cleanup USLEEP_RANGEcheckpatch checks
Date: Thu, 02 Mar 2017 15:57:01 +0100
Message-ID: <1935856.5rv8sDmiv7@fb07-iapwap2>
In-Reply-To: <b90bc602-cf06-4abb-bea2-6386d4976864@googlegroups.com>
References: <20170302142418.GA16773@singhal-Inspiron-5558> <alpine.DEB.2.20.1703021535500.3414@hadrien> <b90bc602-cf06-4abb-bea2-6386d4976864@googlegroups.com>
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Hi Simran,

Am Donnerstag, 2. M=E4rz 2017, 15:48:13 CET schrieb SIMRAN SINGHAL:
> On Thursday, March 2, 2017 at 8:06:40 PM UTC+5:30, Julia Lawall wrote:
> > On Thu, 2 Mar 2017, simran singhal wrote:
> > > Resolve strict checkpatch USLEEP_RANGE checks by converting delays and
> > > sleeps as described in ./Documentation/timers/timers-howto.txt.
> > >=20
> > > CHECK: usleep_range is preferred over udelay; see Documentation/
> > > timers/timers-howto.txt
> > >=20
> > > Signed-off-by: simran singhal <singhal...@gmail.com <javascript:>>

I prefer not to change this. The whole interrupt routine is very wonky, and=
=20
changing some delays might break the communication with the i2c master. Als=
o=20
this is in interrupt context, so a change to usleep_range may not by=20
justified.

Marc


> > > ---
> > >=20
> > >  drivers/staging/nvec/nvec.c | 4 ++--
> > >  1 file changed, 2 insertions(+), 2 deletions(-)
> > >=20
> > > diff --git a/drivers/staging/nvec/nvec.c b/drivers/staging/nvec/nvec.c
> > > index c1feccf..cd35e64 100644
> > > --- a/drivers/staging/nvec/nvec.c
> > > +++ b/drivers/staging/nvec/nvec.c
> > > @@ -631,7 +631,7 @@ static irqreturn_t nvec_interrupt(int irq, void
> >=20
> > *dev)
> >=20
> > >                  break;
> > >         =20
> > >          case 2:                /* first byte after command */
> > >         =20
> > >                  if (status =3D=3D (I2C_SL_IRQ | RNW | RCVD)) {
> > >=20
> > > -                        udelay(33);
> > > +                        usleep_range(33, 100);
> >=20
> > How did you choose the upper limit.
> >=20
> > I believe that Greg previously suggested not to make these changes if y=
ou
> > have no way to test them.
> >=20
> > Julia, After going through the reply given by Nicholas Mc Guire
>=20
> https://www.mail-archive.com/kernelnewbies@kernelnewbies.org/msg16464.html
> in this reply he has mentioned that even the range of 10 microsecond is
> enough,
> so I prefer to take 100 as upper limit.
>=20
> Simran
>=20
> julia
>=20
> > >                          if (nvec->rx->data[0] !=3D 0x01) {
> > >                         =20
> > >                                  dev_err(nvec->dev,
> > >                                 =20
> > >                                          "Read without prior read
> >=20
> > command\n");
> >=20
> > > @@ -718,7 +718,7 @@ static irqreturn_t nvec_interrupt(int irq, void
> >=20
> > *dev)
> >=20
> > >           * We experience less incomplete messages with this delay th=
an
> >=20
> > without
> >=20
> > >           * it, but we don't know why. Help is appreciated.
> > >           */
> > >=20
> > > -        udelay(100);
> > > +        usleep_range(100, 200);
> > >=20
> > >          return IRQ_HANDLED;
> > > =20
> > >  }
> >=20
> > Groups "outreachy-kernel" group.
> >=20
> > > To unsubscribe from this group and stop receiving emails from it, send
> >=20
> > an email to outreachy-kern...@googlegroups.com <javascript:>.
> >=20
> > > To post to this group, send email to outreach...@googlegroups.com
> >=20
> > <javascript:>.
> >=20
> > > To view this discussion on the web visit
> >=20
> > https://groups.google.com/d/msgid/outreachy-kernel/20170302142418.GA167=
73%
> > 40singhal-Inspiron-5558.>=20
> > > For more options, visit https://groups.google.com/d/optout.


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