linux-kernel - Re: [PATCH 0/3] 8250: Split Fintek PCIE to UART to independent file

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Message-ID: <1454092514.32507.3.camel@linux.intel.com>
Date:	Fri, 29 Jan 2016 20:35:14 +0200
From:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:	Sudip Mukherjee <sudipm.mukherjee@...il.com>,
	Andy Shevchenko <andy.shevchenko@...il.com>
Cc:	Peter Hung <hpeter@...il.com>, Rob Groner <rgroner@....com>,
	One Thousand Gnomes <gnomes@...rguk.ukuu.org.uk>,
	Paul Gortmaker <paul.gortmaker@...driver.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jslaby@...e.com>,
	"Krogerus, Heikki" <heikki.krogerus@...ux.intel.com>,
	Peter Hurley <peter@...leysoftware.com>,
	soeren.grunewald@...y.de, Wang YanQing <udknight@...il.com>,
	adam.lee@...onical.com, Arnd Bergmann <arnd@...db.de>,
	Masahiro Yamada <yamada.masahiro@...ionext.com>,
	Måns Rullgård <mans@...sr.com>,
	scottwood@...escale.com, Paul Burton <paul.burton@...tec.com>,
	Matthias Brugger <matthias.bgg@...il.com>,
	Joachim Eastwood <manabian@...il.com>,
	Peter Ujfalusi <peter.ujfalusi@...com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-serial@...r.kernel.org" <linux-serial@...r.kernel.org>,
	Peter H <peter_hong@...tek.com.tw>,
	Peter Hung <hpeter+linux_kernel@...il.com>
Subject: Re: [PATCH 0/3] 8250: Split Fintek PCIE to UART to independent file

On Fri, 2016-01-29 at 23:08 +0530, Sudip Mukherjee wrote:
> On Fri, Jan 22, 2016 at 03:44:16PM +0200, Andy Shevchenko wrote:
> > On Fri, Jan 22, 2016 at 12:53 PM, Sudip Mukherjee
> > <sudipm.mukherjee@...il.com> wrote:
> > > On Wed, Jan 20, 2016 at 04:24:36PM +0800, Peter Hung wrote:
> > > > Hi Sudip,
> > > > 
> > > > Sudip Mukherjee 於 2016/1/20 下午 02:22 寫道:
> > > > > On Wed, Jan 20, 2016 at 10:59:28AM +0800, Peter Hung wrote:
> > > > 
> > > > > But my personal opinion, if we move out the serial port
> > > > > related code
> > > > > into a new driver (a new Kconfig symbol) userspace of many
> > > > > system will
> > > > > break if this new symbol is not enabled by the distributions.
> > > > > But in the
> > > > > way I have done the new symbol needs to be enabled only if
> > > > > the user
> > > > > wants to use the GPIO capability. If that is not enabled GPIO
> > > > > cannot be
> > > > > used but it will never break the serial port related code for
> > > > > them.
> > > > > I think we should give a thought to that before splitting out
> > > > > the codes
> > > > > from 8250_pci.
> > > > 
> > > > I agree with your opinion. I'm trying to implement GPIO with 2
> > > > ways,
> > > > One is like yours, add platform_device with in 8250_pci.c and
> > > > implement
> > > > GPIOLIB platform driver with in 'driver/gpio", and the other is
> > > > trying
> > > > split out from 8250_pci.c to MFD.
> > > > 
> > > > In my personal opinion, the first method is less impact with
> > > > compatible
> > > > old system.
> > > 
> > > Looks like no one else is in support of our opinion. Fair enough,
> > > I will
> > > split out the related code from 8250_pci and create the MFD
> > > driver this
> > > weekend for my hardware.
> > 
> > Yeah, MFD looks preferable.
> > 
> > Btw, don't forget to backlist your devices in 8250_pci since they
> > quite possible provide a PCI class which is used by 8250_pci driver
> > for default enumeration.
> 
> One doubt. If I have understood correctly the main reason you have
> asked
> me to split the code out of 8250_pci so that the size reduces. But
> pci_xr17v35x_setup() is also used by another card which has
> PCI_VENDOR_ID_COMMTECH. So even if I create a separate file for exar
> cards,
> almost identical function will still remain in 8250_pci.

For me looks like re-branded Exar chip (Exar is a real chip vendor,
right?). Even names fall in different pattern.


Also,
        {       PCI_VENDOR_ID_COMMTECH,
PCI_DEVICE_ID_COMMTECH_4222PCIE,
                PCI_ANY_ID, PCI_ANY_ID,
                0,
                0, pbn_exar_XR17V352 },
^^^^!


Move those IDs to your driver as well.

-- 
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Intel Finland Oy