linux-kernel - Re: [PATCH v6 09/10] power: supply: Support ROHM bd99954 charger

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Date:   Wed, 25 Mar 2020 09:47:50 +0000
From:   "Vaittinen, Matti" <Matti.Vaittinen@...rohmeurope.com>
To:     "andriy.shevchenko@...ux.intel.com" 
        <andriy.shevchenko@...ux.intel.com>
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Subject: Re: [PATCH v6 09/10] power: supply: Support ROHM bd99954 charger


On Tue, 2020-03-24 at 12:53 +0200, Matti Vaittinen wrote:
> Hello Andy,
> 
> I do agree with most of the things you pointed out. I didn't comment
> them.
> 
> On Tue, 2020-03-24 at 11:50 +0200, Andy Shevchenko wrote:
> > On Tue, Mar 24, 2020 at 10:32:19AM +0200, Matti Vaittinen wrote:
> > > The ROHM BD99954 is a Battery Management LSI for 1-4 cell
> > > Lithium-
> > > Ion
> > > secondary battery intended to be used in space-constraint
> > > equipment
> > > such
> > > as Low profile Notebook PC, Tablets and other applications.
> > > BD99954
> > > provides a Dual-source Battery Charger, two port BC1.2 detection
> > > and a
> > > Battery Monitor.
> > 
> > > +	do {
> > > +		ret = regmap_field_read(bd-
> > > >rmap_fields[F_OTPLD_STATE], 
> > > &state);
> > > +		if (ret)
> > > +			return ret;
> > > +
> > > +		msleep(10);
> > > +	} while (state == 0 && --rst_check_counter);
> > 
> > regmap_read_poll_timeout() exists, but I see you use it for field.
> > Perhaps it's
> > a time to introduce similar helper for field polling.
> This series is again getting lengthy... I'll see if I add such an API
> in this series. I've learned that adding changes will increase the
> time
> it takes to push the series through. It might be more reviewer
> friendly
> to add it in own patch with limited review audience (as would be the
> patch 10/10 in this series). But I think your point is valid.

I took a peek at regmap_read_poll_timeout(). Nice API - and if we were
to create similar for fields, we should probably make behaviour
identical to regmap_read_poll_timeout(). I see
regmap_read_poll_timeout() is using hrtimers for timeout - which is
overkill for the BD99954 needs. I'd rather keep the msleep here.

Br,
	Matti