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From: Arnd Bergmann <arnd@arndb.de>
To: "Heiko Stübner" <heiko@sntech.de>
Cc: linux-arm-kernel@lists.infradead.org,
	Romain Perier <romain.perier@gmail.com>,
	linux-rockchip@lists.infradead.org, devicetree@vger.kernel.org,
	netdev@vger.kernel.org
Subject: Re: [PATCH v4 1/4] ethernet: arc: Add support for Rockchip SoC layer device tree bindings
Date: Wed, 03 Sep 2014 14:50:22 +0200	[thread overview]
Message-ID: <3545574.7Z5WmaTlg0@wuerfel> (raw)
In-Reply-To: <12261801.xhz3LcucGs@diego>

On Wednesday 03 September 2014 14:20:50 Heiko Stübner wrote:
> > 
> > One last question: is this the location given as .grf_offset the
> > only thing in grf that is potentially of concern to this driver?
> > 
> > If it is, you can change the binding to include the register number
> > in the syscon reference, like
> > 
> >       rockchip,grf = <&grf 0x154>;
> > 
> > and then read it from there, to simplify the code needed to get the
> > number from the device id.
> 
> I would disagree here 
> 
> Specific to the emac, there also exists a second register in the grf (0xa8 for 
> the rk3188) that contains a field 
> 
> ----
> emac_newrcv_en - the selection of RMII receive selection
> 0: don't support the data package without header
> 1: support the data package without header
> ----
> 
> which we don't handle currently but somebody might want to in the future.
> [There also is no documentation of this at all]

Ok, fair enough. If there is a chance that there would be more of these
fields that we may want to support in the future, the table approach
seems reasonable.

The main advantage of putting the register number into the syscon
reference is to support future models without driver changes, but
it's not clear if that's worth it.

	Arnd

WARNING: multiple messages have this Message-ID (diff)
From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v4 1/4] ethernet: arc: Add support for Rockchip SoC layer device tree bindings
Date: Wed, 03 Sep 2014 14:50:22 +0200	[thread overview]
Message-ID: <3545574.7Z5WmaTlg0@wuerfel> (raw)
In-Reply-To: <12261801.xhz3LcucGs@diego>

On Wednesday 03 September 2014 14:20:50 Heiko St?bner wrote:
> > 
> > One last question: is this the location given as .grf_offset the
> > only thing in grf that is potentially of concern to this driver?
> > 
> > If it is, you can change the binding to include the register number
> > in the syscon reference, like
> > 
> >       rockchip,grf = <&grf 0x154>;
> > 
> > and then read it from there, to simplify the code needed to get the
> > number from the device id.
> 
> I would disagree here 
> 
> Specific to the emac, there also exists a second register in the grf (0xa8 for 
> the rk3188) that contains a field 
> 
> ----
> emac_newrcv_en - the selection of RMII receive selection
> 0: don't support the data package without header
> 1: support the data package without header
> ----
> 
> which we don't handle currently but somebody might want to in the future.
> [There also is no documentation of this at all]

Ok, fair enough. If there is a chance that there would be more of these
fields that we may want to support in the future, the table approach
seems reasonable.

The main advantage of putting the register number into the syscon
reference is to support future models without driver changes, but
it's not clear if that's worth it.

	Arnd

  reply	other threads:[~2014-09-03 12:51 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-03 10:27 [PATCH v4 1/4] ethernet: arc: Add support for Rockchip SoC layer device tree bindings Romain Perier
2014-09-03 10:27 ` Romain Perier
2014-09-03 10:27 ` [PATCH 2/4] dt-bindings: Document EMAC Rockchip Romain Perier
2014-09-03 10:27   ` Romain Perier
2014-09-03 14:26   ` Heiko Stübner
2014-09-03 14:26     ` Heiko Stübner
2014-09-03 10:27 ` [PATCH 3/4] ARM: dts: Add emac nodes to the rk3188 device tree Romain Perier
2014-09-03 10:27   ` Romain Perier
2014-09-03 10:27 ` [PATCH 4/4] ARM: dts: Enable emac node on the rk3188-radxarock boards Romain Perier
2014-09-03 10:27   ` Romain Perier
2014-09-03 15:29   ` Naoki FUKAUMI
2014-09-03 15:29     ` Naoki FUKAUMI
2014-09-03 16:37     ` PERIER Romain
2014-09-03 16:37       ` PERIER Romain
2014-09-03 17:45       ` Arnd Bergmann
2014-09-03 17:45         ` Arnd Bergmann
2014-09-03 10:42 ` [PATCH v4 1/4] ethernet: arc: Add support for Rockchip SoC layer device tree bindings Varka Bhadram
2014-09-03 10:42   ` Varka Bhadram
2014-09-03 11:14 ` Arnd Bergmann
2014-09-03 11:14   ` Arnd Bergmann
2014-09-03 12:20   ` Heiko Stübner
2014-09-03 12:20     ` Heiko Stübner
2014-09-03 12:50     ` Arnd Bergmann [this message]
2014-09-03 12:50       ` Arnd Bergmann

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