linux-kernel - Re: [PATCH] regmap: Allow regmap_bulk_write() to work for "no-bus" regmaps

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Date:	Thu, 26 Dec 2013 11:34:16 -0800
From:	Stephen Boyd <sboyd@...eaurora.org>
To:	Mark Brown <broonie@...nel.org>
Cc:	Samuel Ortiz <sameo@...ux.intel.com>,
	Lee Jones <lee.jones@...aro.org>,
	Srinivas Ramana <sramana@...eaurora.org>,
	linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] regmap: Allow regmap_bulk_write() to work for "no-bus"
 regmaps

On 12/24, Mark Brown wrote:
> On Mon, Dec 23, 2013 at 12:05:53PM -0800, Stephen Boyd wrote:
> > On 12/18/13 10:45, Mark Brown wrote:
> 
> > > This doesn't quite work - val is an array of objects of the size of the
> > > size of a register not of unsigned integers so you're parsing extra data
> > > out there.  That possibly wasn't the best choice of API but we have
> > > quite a few users now so ick.
> 
> > Are you concerned that we'll read past the end of the val buffer? Do we
> > need to cast the pointer to be the appropriate size according to
> > val_bytes? Something like this?
> 
> That's one issue, the other is that if we try to read (say) and 8 bit
> value as an unsigned int we'll not just read the value we're looking
> for.

Ah right. My no-bus implementation was clearing out the upper 24
bits of the word so I could just send the u8 value. With this
approach that isn't necessary.

> 
> >                 for (i = 0; i < val_count; i++) {
> >                         unsigned int ival;
> > 
> >                         switch (val_bytes) {
> >                         case 1: 
> >                                 ival = *(u8 *)(val + (i * val_bytes));
> >                                 break;
> 
> I think we do sadly.  Or refactor the API to work in unsigned ints
> which would've been more sensible in the first place but that'd make it
> asymmetrical with the read API as it stands...

Ok it sounds like you're willing to go with this updated loop.
I'll resend a proper patch.

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