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From: Peter Ujfalusi <peter.ujfalusi@ti.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Vinod Koul <vkoul@kernel.org>,
	dmaengine <dmaengine@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Dan Williams <dan.j.williams@intel.com>
Subject: Re: [PATCH 0/3] dmaengine: Stear users towards dma_request_slave_chan()
Date: Mon, 3 Feb 2020 12:59:13 +0200	[thread overview]
Message-ID: <e47927aa-8d40-aa71-aef4-5f9c4cbbc03a@ti.com> (raw)
In-Reply-To: <CAHp75Vf__isc59YBS9=O+9ApSV62XuZ2nBAWKKD_K7i72P-yFg@mail.gmail.com>

Hi Andy,

On 03/02/2020 12.37, Andy Shevchenko wrote:
> On Mon, Feb 3, 2020 at 12:32 PM Peter Ujfalusi <peter.ujfalusi@ti.com> wrote:
> 
>> dma_request_slave_channel_reason() no longer have user in mainline, it
>> can be removed.
>>
>> Advise users of dma_request_slave_channel() and
>> dma_request_slave_channel_compat() to move to dma_request_slave_chan()
> 
> How? There are legacy ARM boards you have to care / remove before.
> DMAengine subsystem makes a p*s off decisions

The dma_slave_map support is added few years back for the legacy ARM
boards, because we do care.
daVinci, OMAP1, pxa, s3cx4xx and even m68k/coldfire moved over.

Imho it is confusing to have 4+ APIs to do the same thing, but in a
slightly different way.

> without taking care of
> (I'm talking now about dma release callback, for example) end users.

I have been converting users in the background, but the _compat() is a
bit more problematic as I need to maintainers of those legacy platforms
to craft the map. If they care.

Obviously the APIs are not going to be removed if we have a single user
and if there is clearly a need for something the _compat() was doing and
it can not be done via the dma_slave_map, then rest assured there will
be a clean API to achieve just that.

> They will be scary for no reason.

There is a reason: to clean up the API to make it non confusing for the
users.
New drivers should not use the old API i new code and developers tend to
pick the API they use after a quick 'git grep dma_request_' and see what
the majority is using.

- Péter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

  reply	other threads:[~2020-02-03 10:59 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-03 10:18 [PATCH 0/3] dmaengine: Stear users towards dma_request_slave_chan() Peter Ujfalusi
2020-02-03 10:18 ` [PATCH 1/3] dmaengine: Remove unused define for dma_request_slave_channel_reason() Peter Ujfalusi
2020-02-03 13:35   ` Geert Uytterhoeven
2020-02-03 10:18 ` [PATCH 2/3] dmaengine: Mark dma_request_slave_channel() deprecated Peter Ujfalusi
2020-02-03 10:18 ` [PATCH 3/3] dmaengine: Encourage dma_request_slave_channel_compat() users to migrate Peter Ujfalusi
2020-02-03 10:35   ` Andy Shevchenko
2020-02-03 10:37 ` [PATCH 0/3] dmaengine: Stear users towards dma_request_slave_chan() Andy Shevchenko
2020-02-03 10:59   ` Peter Ujfalusi [this message]
2020-02-03 11:16     ` Andy Shevchenko
2020-02-03 12:09       ` Peter Ujfalusi
2020-02-03 12:48         ` Andy Shevchenko
2020-02-03 13:32         ` Geert Uytterhoeven
2020-02-03 20:21           ` John Paul Adrian Glaubitz
2020-02-03 20:34             ` Geert Uytterhoeven
2020-02-03 21:26               ` John Paul Adrian Glaubitz
2020-02-04  8:13                 ` Geert Uytterhoeven
2020-02-04  6:52               ` Peter Ujfalusi
2020-02-04  8:01                 ` Geert Uytterhoeven
2020-02-04  8:15                   ` Peter Ujfalusi
2020-02-04  8:21                     ` Peter Ujfalusi
2020-02-04  9:16                   ` Rob Landley
2020-02-04  9:27                     ` Geert Uytterhoeven
2020-02-04 10:18                       ` Rob Landley
2020-02-04  6:21   ` Vinod Koul
2020-02-04 11:21     ` Andy Shevchenko
2020-02-05  4:43       ` Vinod Koul
2020-02-05  8:10         ` Peter Ujfalusi
2020-02-05 11:31           ` Vinod Koul
2020-02-05 11:56             ` Peter Ujfalusi
2020-02-05 11:59               ` Vinod Koul

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