linux-kernel - Re: [RFC 12/32] iio: adc: Kconfig: add HAS

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Message-ID: <20220130150510.66ea7cd4@jic23-huawei>
Date:   Sun, 30 Jan 2022 15:05:10 +0000
From:   Jonathan Cameron <jic23@...nel.org>
To:     Niklas Schnelle <schnelle@...ux.ibm.com>
Cc:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        Arnd Bergmann <arnd@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        John Garry <john.garry@...wei.com>,
        Nick Hu <nickhu@...estech.com>,
        Greentime Hu <green.hu@...il.com>,
        Vincent Chen <deanbo422@...il.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>, Guo Ren <guoren@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux-Arch <linux-arch@...r.kernel.org>,
        linux-pci <linux-pci@...r.kernel.org>,
        linux-riscv <linux-riscv@...ts.infradead.org>,
        linux-csky@...r.kernel.org, linux-iio@...r.kernel.org,
        Michael Hennerich <Michael.Hennerich@...log.com>
Subject: Re: [RFC 12/32] iio: adc: Kconfig: add HAS_IOPORT dependencies

On Tue, 28 Dec 2021 17:01:25 +0000
Jonathan Cameron <jic23@...23.retrosnub.co.uk> wrote:

> On Tue, 28 Dec 2021 13:50:20 +0100
> Niklas Schnelle <schnelle@...ux.ibm.com> wrote:
> 
> > On Tue, 2021-12-28 at 11:32 +0100, Geert Uytterhoeven wrote:  
> > > Hi Niklas,
> > > 
> > > On Mon, Dec 27, 2021 at 5:53 PM Niklas Schnelle <schnelle@...ux.ibm.com> wrote:    
> > > > In a future patch HAS_IOPORT=n will result in inb()/outb() and friends
> > > > not being declared. We thus need to add HAS_IOPORT as dependency for
> > > > those drivers using them.
> > > > 
> > > > Co-developed-by: Arnd Bergmann <arnd@...nel.org>
> > > > Signed-off-by: Arnd Bergmann <arnd@...nel.org>
> > > > Signed-off-by: Niklas Schnelle <schnelle@...ux.ibm.com>    
> 
> As a side note, whilst it doesn't always happen and I regularly forget
> to fix it up whilst applying, it's really helpful to make sure the driver
> name is somewhere in the patch title.
> 
> e.g. iio: adc: ad7606: add HAS_IOPORT dependencies.
> 
> > > 
> > > Thanks for your patch!
> > >     
> > > > --- a/drivers/iio/adc/Kconfig
> > > > +++ b/drivers/iio/adc/Kconfig
> > > > @@ -119,7 +119,7 @@ config AD7606
> > > > 
> > > >  config AD7606_IFACE_PARALLEL
> > > >         tristate "Analog Devices AD7606 ADC driver with parallel interface support"
> > > > -       depends on HAS_IOMEM
> > > > +       depends on HAS_IOPORT    
> > > 
> > > While this driver uses ins[bw](), this seems unrelated to legacy
> > > I/O space, as the driver maps a MMIO region.  Probably different
> > > accessors should be used instead.    
> > 
> > You're right on first glance it looks like a misuse of the ins[bw]()
> > accessors. I do wonder how that even works, if PCI_IOBASE is 0 it would
> > result in readsw()/readsb() with presumably the correct address but no
> > idea how this interacts witth x86's special I/O instructions.
> >   
> > > 
> > > Note that this driver has no in-tree users. Same for the SPI variant,
> > > but at least that one has modern json-schema DT bindings ;-)    
> > 
> > Can't find any mention in the MAINTAINERS file either.  
> 
> It falls under the Analog devices catch all.
> We don't list them all individually because there are a lot of them and
> it would just be noise in many case.
> 
> Added Michael to CC. You already have Lars.
> 
> ANALOG DEVICES INC IIO DRIVERS
> M:	Lars-Peter Clausen <lars@...afoo.de>
> M:	Michael Hennerich <Michael.Hennerich@...log.com>
> S:	Supported
> W:	http://wiki.analog.com/
> W:	http://ez.analog.com/community/linux-device-drivers
> F:	Documentation/ABI/testing/sysfs-bus-iio-frequency-ad9523
> F:	Documentation/ABI/testing/sysfs-bus-iio-frequency-adf4350
> F:	Documentation/devicetree/bindings/iio/*/adi,*
> F:	Documentation/devicetree/bindings/iio/dac/adi,ad5758.yaml
> F:	drivers/iio/*/ad*
> F:	drivers/iio/adc/ltc249*
> F:	drivers/iio/amplifiers/hmc425a.c
> F:	drivers/staging/iio/*/ad*
> X:	drivers/iio/*/adjd*
> 
> https://wiki.analog.com/resources/tools-software/linux-drivers/iio-adc/ad7606
> includes some details.
> 
> I'll leave it to the Lars or Michael to confirm what is going on here.

Can someone (probably at Analog Devices) take a look at this?

Thanks,

Jonathan

> 
> Jonathan
> 
> >   
> > >     
> > > >         select AD7606
> > > >         help
> > > >           Say yes here to build parallel interface support for Analog Devices:    
> > > 
> > > Gr{oetje,eeting}s,
> > > 
> > >                         Geert
> > > 
> > > --
> > > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org
> > > 
> > > In personal conversations with technical people, I call myself a hacker. But
> > > when I'm talking to journalists I just say "programmer" or something like that.
> > >                                 -- Linus Torvalds    
> >   
>