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Re: [PATCH v3 03/11] dmaengine: dw: set polarity of handshake interface

Started by"Maarten Brock" <m.brock@vanmierlo.com>
First post2016-05-06 13:30 +0200
Last post2016-05-06 13:40 +0200
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  Re: [PATCH v3 03/11] dmaengine: dw: set polarity of handshake  interface "Maarten Brock" <m.brock@vanmierlo.com> - 2016-05-06 13:30 +0200
    Re: [PATCH v3 03/11] dmaengine: dw: set polarity of handshake interface Andy Shevchenko <andy.shevchenko@gmail.com> - 2016-05-06 13:40 +0200

#1395782 — Re: [PATCH v3 03/11] dmaengine: dw: set polarity of handshake interface

From"Maarten Brock" <m.brock@vanmierlo.com>
Date2016-05-06 13:30 +0200
SubjectRe: [PATCH v3 03/11] dmaengine: dw: set polarity of handshake interface
Message-ID<rvM7f-3YW-7@gated-at.bofh.it>
----- Original Message -----
From: Andy Shevchenko [mailto:andriy.shevchenko@linux.intel.com]
To: Bryan O'Donoghue [mailto:pure.logic@nexus-software.ie], Peter Hurley [mailto:peter@hurleysoftware.com], linux-serial@vger.kernel.org, Vinod Koul [mailto:vinod.koul@intel.com], linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, Greg Kroah-Hartman [mailto:gregkh@linuxfoundation.org], ismo.puustinen@intel.com, Heikki Krogerus [mailto:heikki.krogerus@linux.intel.com]
Sent: Fri, 06 May 2016 12:42:00 +0200
Subject: Re: [PATCH v3 03/11] dmaengine: dw: set polarity of handshake interface


> On Thu, 2016-05-05 at 18:54 +0100, Bryan O'Donoghue wrote:
> > On Wed, 2016-04-27 at 16:48 +0300, Andy Shevchenko wrote:
> > > 
> > > +       bool                    polarity;
> > So this variable is not very intuitively named.
> 
> There is a help above. This is a property of the Synopsys DesignWare DMA
> engine. Anyone familiar with datasheet easily understands this.
> 
> > 
> > You end up setting somepointer->polarity = true; in a later patch. 
> > 
> > Since you're respining a V4 I'd suggest a name that describes a little
> > bit better than polarity. Setting polarity = true is a little bit
> > liked being asked "you you like ice-cream or apple pie" and then
> > saying "yes please".
> 
> It's about handshake interface polarity, so, what about hs_polarity?

So it means: handshake has polarity (true) or handshake has no polarity
(omnidirectional?) (false), right?

Maarten

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#1395787 — Re: [PATCH v3 03/11] dmaengine: dw: set polarity of handshake interface

FromAndy Shevchenko <andy.shevchenko@gmail.com>
Date2016-05-06 13:40 +0200
SubjectRe: [PATCH v3 03/11] dmaengine: dw: set polarity of handshake interface
Message-ID<rvMgW-466-3@gated-at.bofh.it>
In reply to#1395782
On Fri, May 6, 2016 at 2:20 PM, Maarten Brock <m.brock@vanmierlo.com> wrote:
>> > >
>> > > +       bool                    polarity;
>> > So this variable is not very intuitively named.
>>
>> There is a help above. This is a property of the Synopsys DesignWare DMA
>> engine. Anyone familiar with datasheet easily understands this.
>>
>> >
>> > You end up setting somepointer->polarity = true; in a later patch.
>> >
>> > Since you're respining a V4 I'd suggest a name that describes a little
>> > bit better than polarity. Setting polarity = true is a little bit
>> > liked being asked "you you like ice-cream or apple pie" and then
>> > saying "yes please".
>>
>> It's about handshake interface polarity, so, what about hs_polarity?
>
> So it means: handshake has polarity (true) or handshake has no polarity
> (omnidirectional?) (false), right?

It means that handshake polarity _signal_ is inverted (true) or
default (false) in terms of hardware gates.

-- 
With Best Regards,
Andy Shevchenko

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