Re: [PATCH 2/5] gpio/xilinx: enable for MIPS

From: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
To: Lars-Peter Clausen <lars@metafoo.de>
Cc: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>,
	ralf@linux-mips.org, robh+dt@kernel.org,
	linus.walleij@linaro.org, linux-mips@linux-mips.org,
	linux-gpio@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/5] gpio/xilinx: enable for MIPS
Date: Wed, 14 Oct 2015 09:54:50 -0700	[thread overview]
Message-ID: <20151014165450.GS15287@xsjsorenbubuntu> (raw)
In-Reply-To: <561E7B65.3090704@metafoo.de>

On Wed, 2015-10-14 at 05:57PM +0200, Lars-Peter Clausen wrote:
> On 10/14/2015 05:18 PM, Sören Brinkmann wrote:
> > On Wed, 2015-10-14 at 01:51PM +0100, Zubair Lutfullah Kakakhel wrote:
> >> MIPSfpga uses the axi gpio controller. Enable the driver for MIPS.
> >>
> >> Signed-off-by: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
> >> ---
> >>  drivers/gpio/Kconfig | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> >> index 8949b3f..58e9afd 100644
> >> --- a/drivers/gpio/Kconfig
> >> +++ b/drivers/gpio/Kconfig
> >> @@ -508,7 +508,7 @@ config GPIO_XGENE_SB
> >>  
> >>  config GPIO_XILINX
> >>  	tristate "Xilinx GPIO support"
> >> -	depends on OF_GPIO && (PPC || MICROBLAZE || ARCH_ZYNQ || X86)
> >> +	depends on OF_GPIO && (PPC || MICROBLAZE || ARCH_ZYNQ || X86 || MIPS)
> > 
> > Hmm, in general, this driver is hopefully generic enough that it doesn't
> > have any real architecture dependencies. And I suspect, we want to
> > enable this driver for ARM64 for ZynqMP soon too. Should we probably
> > drop these arch dependencies completely? It seems to become quite a long list.
> 
> I've been thinking about this a while ago. This is certainly not the only
> driver affected by this problem. But the thing is people always complain if
> new symbols become visable in Kconfig that don't apply to their platform.
> 
> Maybe we should introduce a HAS_REPROGRAMABLE_LOGIC (or similar) feature
> Kconfig symbol and let platforms which have a FPGA select it and let drivers
> for FPGA peripherals depend on it.

Sounds like a good idea to me. But, does that work for all use-cases.
E.g. if you plug some PCIe card with an FPGA into an x86(_64) machine.
That would allow you to use those drivers, but I'm not sure how that
could pull in the new config symbol.

	Sören