linux-kernel - Re: [PATCH 3/3] mfd: arizona: Use regmap_read_poll

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Date:   Fri, 6 Jan 2017 09:28:44 +0000
From:   Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
To:     Lee Jones <lee.jones@...aro.org>
CC:     <patches@...nsource.wolfsonmicro.com>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] mfd: arizona: Use regmap_read_poll_timeout instead
 of hard coding it

On Thu, Jan 05, 2017 at 02:48:22PM +0000, Lee Jones wrote:
> On Thu, 05 Jan 2017, Charles Keepax wrote:
> 
> > On Thu, Jan 05, 2017 at 08:07:01AM +0000, Lee Jones wrote:
> > > On Wed, 04 Jan 2017, Charles Keepax wrote:
> > > 
> > > > arizona_poll_reg essentially hard-codes regmap_read_poll_timeout, this
> > > > patch updates the implementation to use regmap_read_poll_timeout. We
> > > > still keep arizona_poll_reg around as regmap_read_poll_timeout is a
> > > > macro so rather than expand this for each caller keep it wrapped in
> > > > arizona_poll_reg.
> > > > 
> > > > Signed-off-by: Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
> > > > ---
> > > >  drivers/mfd/arizona-core.c | 28 +++++++++++-----------------
> > > >  1 file changed, 11 insertions(+), 17 deletions(-)
> > > > 
> > > > diff --git a/drivers/mfd/arizona-core.c b/drivers/mfd/arizona-core.c
> > > > index 4cb34c3..e6fae3c 100644
> > > > --- a/drivers/mfd/arizona-core.c
> > > > +++ b/drivers/mfd/arizona-core.c
> > > > @@ -236,28 +236,22 @@ static irqreturn_t arizona_overclocked(int irq, void *data)
> > > >  }
> > > >  
> > > >  static int arizona_poll_reg(struct arizona *arizona,
> > > > -			    int timeout, unsigned int reg,
> > > > +			    int npolls, unsigned int reg,
> > > >  			    unsigned int mask, unsigned int target)
> > > >  {
> > > > +	const int poll_us = 7500;
> > > 
> > > Get rid of this and replace its usage with a nice #define describing
> > > exactly what the timeout is for i.e what timed out.
> > > 
> > 
> > I can replace this with a define if you prefer although since the
> > value is only used locally I generally prefer a const variable as
> > it keeps all the relevant code together.
> 
> I'd prefer a DEFINE, then you can rid the requirement for a variable
> altogether.
> 

Fair enough I will respin.

> > that. As for the number passed into the function that depends on
> > how long that particular register should be polled for, this is a
> > function that is used in several places for polling for a
> > particular register state.
> 
> I would have thought a consumer would be more likely to know how long
> it would poll for, rather than how many times to poll.  Knowledge of
> time-between-polls in only known locally.  Do you see where I'm going
> with this?

Yeah that's a fair point I will switch it around so the user
specifies the total time out and npolls is worked out internally.

Thanks,
Charles