RE: [PATCH v2 0/2] Add a property in at24.c

["Mani, Rajmohan" <rajmohan.mani@intel.com>]

Hi Bartosz,

> -----Original Message-----
> From: Yeh, Andy
> Sent: Tuesday, June 26, 2018 9:21 AM
> To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>; Bartosz
> Golaszewski <brgl@bgdev.pl>
> Cc: Chiang, AlanX <alanx.chiang@intel.com>; linux-i2c <linux-
> i2c@vger.kernel.org>; Sakari Ailus <sakari.ailus@linux.intel.com>; Mani,
> Rajmohan <rajmohan.mani@intel.com>; Andy Shevchenko
> <andy.shevchenko@gmail.com>; Rob Herring <robh+dt@kernel.org>; Mark
> Rutland <mark.rutland@arm.com>; Arnd Bergmann <arnd@arndb.de>; Greg
> Kroah-Hartman <gregkh@linuxfoundation.org>; Linux Kernel Mailing List
> <linux-kernel@vger.kernel.org>
> Subject: RE: [PATCH v2 0/2] Add a property in at24.c
> 
> > -----Original Message-----
> > From: Andy Shevchenko [mailto:andriy.shevchenko@linux.intel.com]
> > Sent: Tuesday, June 26, 2018 11:48 PM
> > To: Bartosz Golaszewski <brgl@bgdev.pl>
> > Cc: Chiang, AlanX <alanx.chiang@intel.com>; linux-i2c <linux-
> > i2c@vger.kernel.org>; Yeh, Andy <andy.yeh@intel.com>; Sakari Ailus
> > <sakari.ailus@linux.intel.com>; Mani, Rajmohan
> > <rajmohan.mani@intel.com>; Andy Shevchenko
> > <andy.shevchenko@gmail.com>; Rob Herring <robh+dt@kernel.org>; Mark
> > Rutland <mark.rutland@arm.com>; Arnd Bergmann <arnd@arndb.de>; Greg
> > Kroah-Hartman <gregkh@linuxfoundation.org>; Linux Kernel Mailing List
> > <linux- kernel@vger.kernel.org>
> > Subject: Re: [PATCH v2 0/2] Add a property in at24.c
> >
> > On Tue, 2018-06-26 at 15:30 +0200, Bartosz Golaszewski wrote:
> > > 2018-06-26 15:23 GMT+02:00 Andy Shevchenko
> > <andriy.shevchenko@linux.in
> > > tel.com>:
> > > > On Tue, 2018-06-26 at 14:36 +0200, Bartosz Golaszewski wrote:
> > > > > 2018-06-26 14:14 GMT+02:00 Andy Shevchenko
> > > > > <andriy.shevchenko@linux.intel.com>:
> > > > > > On Tue, 2018-06-26 at 09:41 +0200, Bartosz Golaszewski wrote:
> > > > > > > What is your use case exactly? Do you have an EEPROM model
> > > > > > > that's not yet supported explicitly in the driver? Why would
> > > > > > > you need this option?
> > > > > >
> > > > > > The current at24 driver has no address width support,  thus,
> > > > > > reusing same
> > > > > > (allocated) IDs (non-DT case) is hard.
> > > >
> > > > ^^^^^
> > > >
> > > > > Every supported compatible has the width already specified in
> > > > > its corresponding chip data.
> > > >
> > > >
> > > > Please, read again carefully what I wrote before.
> > > >
> > >
> > > Ok makes sense in that case. Could you just point me towards an
> > > example model which has the address width different than the default
> > > for its type?
> >
> > AFAIK, it's a companion device inside the camera voice coil IC, i.e.
> > DONGWOON DW9714.
> >
> 
> Nope, actually it is DW9807 instead, which is used on a Samsung Chromebook.

M24C64S is one example, where reusing same id (non-DT case) is not possible,
since this model uses 16 bits as address width, as the driver supports only
8 bits address width as default.

Thanks
Raj