From mboxrd@z Thu Jan  1 00:00:00 1970
From: l.stach@pengutronix.de (Lucas Stach)
Date: Wed, 18 Nov 2015 12:36:16 +0100
Subject: [PATCH 2/2] ARM: dts: imx6q: add Novena board
In-Reply-To: <201511181232.42446.marex@denx.de>
References: <1447840120-8513-1-git-send-email-marex@denx.de>
 <201511181135.40171.marex@denx.de>
 <1447845958.3144.61.camel@pengutronix.de>
 <201511181232.42446.marex@denx.de>
Message-ID: <1447846576.3144.63.camel@pengutronix.de>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Am Mittwoch, den 18.11.2015, 12:32 +0100 schrieb Marek Vasut:
> On Wednesday, November 18, 2015 at 12:25:58 PM, Lucas Stach wrote:
> > Am Mittwoch, den 18.11.2015, 11:35 +0100 schrieb Marek Vasut:
> > > On Wednesday, November 18, 2015 at 11:10:12 AM, Lucas Stach wrote:
> > > > Hi Marek,
[...]
> > > [...]
> > > 
> > > > > +&ecspi3 {
> > > > > +	pinctrl-names = "default";
> > > > > +	pinctrl-0 = <&pinctrl_ecspi3_novena>;
> > > > > +	fsl,spi-num-chipselects = <3>;
> > > > > +	status = "okay";
> > > > > +
> > > > > +	spidev at 0 {
> > > > > +		compatible = "spidev";
> > > > 
> > > > This will explode on a new kernel. Specifying spidev without using a
> > > > more specific compatible will trigger a WARN_ON(), as it's considered
> > > > bad style.
> > > 
> > > Oh, looks like imx_v6_v7_defconfig didn't have SPIDEV active, which is
> > > why I didn't catch it during my last test, dang.
> > > 
> > > This SPI interface is routed into the FPGA, so what do you suggest I put
> > > in the compatible string? There is no other sensible driver for the
> > > peripheral, since the peripheral can be anything.
> > 
> > I'm not really the right person to ask for that, but I would guess that
> > inventing a "novena,fpga-spi" compatible or something like that and
> > adding it to the spidev driver would be the right thing to do.
> 
> So what's the rationale behind generic "spidev" being bad ? In my mind, it
> is much better to use generic driver and generic compatible prop "spidev"
> than to generate many one-off compatible props and have a driver with a list
> of all of those.
> 
>>From the commit log:

"Since spidev is a detail of how Linux controls a device rather than a
description of the hardware in the system we should never have a node
described as "spidev" in DT, any SPI device could be a spidev so this is
just not a useful description."

If you want to know about the details you would have to discuss this
with Mark Brown.

Regards,
Lucas

-- 
Pengutronix e.K.             | Lucas Stach                 |
Industrial Linux Solutions   | http://www.pengutronix.de/  |