Re: [PATCH 2/3] i2c: Let bus drivers add SPD to their class

[David Brownell <david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>]

On Tuesday 03 June 2008, Jean Delvare wrote:

> > Few embedded platforms use discrete sticks of DRAM.
> > My two cents:  use the opposite default in those cases.
> 
> I wish I knew which of these bus drivers exactly are for embedded
> platforms.

To be strictly correct, "embedded" is an application issue
more than a hardware issue.  One can "embed" mainframes in
an Air Traffic Control system.

So the issue there is more whether such usage is common
or, in some cases, even practical.


> Would you be able to give me a list of all drivers under 
> drivers/i2c/busses that fall in this category? I would be able to update
> http://lists.lm-sensors.org/pipermail/i2c/2008-May/003713.html
> then.

Not really; sorry.


> Also, couldn't these platforms have other EEPROMs on these buses,
> either EDID EEPROMs or proprietary ones, for which people might be
> using the read-only eeprom driver at the moment? I don't want users to
> experience a regression by applying this patch set. I'd rather have
> them migrate their platform to the at24 driver once it is upstream and
> remove the I2C_CLASS_SPD flag when they do.

Unlikely.  At least in the cases I called out.

Oh, and parport.  DRAM sticks, or LCD displays, over parport
links would be strange.  ;)

- Dave



> > I'll highlight a few below, where I happen to have more
> > specific knowledge.
> > 
> > 
> > > So, bus driver maintainers and users 
> > > should feel free to remove the SPD class from drivers those buses never
> > > have SPD EEPROMs or they don't want the eeprom driver to bind to them.
> > > Likewise, feel free to add the SPD class to any bus driver I might have
> > > missed.
> > > 
> > > Signed-off-by: Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>
> > > ---
> > >  drivers/i2c/busses/i2c-ali1535.c       |    2 +-
> > >  drivers/i2c/busses/i2c-ali1563.c       |    2 +-
> > >  drivers/i2c/busses/i2c-ali15x3.c       |    2 +-
> > >  drivers/i2c/busses/i2c-amd756.c        |    2 +-
> > >  drivers/i2c/busses/i2c-amd8111.c       |    2 +-
> > >  drivers/i2c/busses/i2c-at91.c          |    2 +-
> > 
> > I've never heard of an AT91 board using DRAM sticks ...
> > 
> > >  drivers/i2c/busses/i2c-cpm.c           |    2 +-
> > >  drivers/i2c/busses/i2c-davinci.c       |    2 +-
> > 
> > ... or a DaVinci one ...
> > 
> > 
> > >  drivers/i2c/busses/i2c-elektor.c       |    2 +-
> > >  drivers/i2c/busses/i2c-gpio.c          |    2 +-
> > >  drivers/i2c/busses/i2c-i801.c          |    2 +-
> > >  drivers/i2c/busses/i2c-ibm_iic.c       |    4 ++--
> > >  drivers/i2c/busses/i2c-iop3xx.c        |    2 +-
> > >  drivers/i2c/busses/i2c-isch.c          |    2 +-
> > >  drivers/i2c/busses/i2c-mpc.c           |    2 +-
> > >  drivers/i2c/busses/i2c-mv64xxx.c       |    2 +-
> > >  drivers/i2c/busses/i2c-nforce2.c       |    2 +-
> > >  drivers/i2c/busses/i2c-ocores.c        |    2 +-
> > >  drivers/i2c/busses/i2c-omap.c          |    2 +-
> > 
> > ... or an OMAP one ...
> > 
> > >  drivers/i2c/busses/i2c-parport-light.c |    2 +-
> > >  drivers/i2c/busses/i2c-parport.c       |    2 +-
> > >  drivers/i2c/busses/i2c-pasemi.c        |    2 +-
> > >  drivers/i2c/busses/i2c-piix4.c         |    2 +-
> > >  drivers/i2c/busses/i2c-pmcmsp.c        |    2 +-
> > >  drivers/i2c/busses/i2c-s3c2410.c       |    2 +-
> > >  drivers/i2c/busses/i2c-sibyte.c        |    4 ++--
> > >  drivers/i2c/busses/i2c-sis5595.c       |    2 +-
> > >  drivers/i2c/busses/i2c-sis630.c        |    2 +-
> > >  drivers/i2c/busses/i2c-sis96x.c        |    2 +-
> > >  drivers/i2c/busses/i2c-stub.c          |    2 +-
> > >  drivers/i2c/busses/i2c-tiny-usb.c      |    2 +-
> > 
> > ... DRAM-over-USB would be bizarre too ...
> > 
> > >  drivers/i2c/busses/i2c-via.c           |    2 +-
> > >  drivers/i2c/busses/i2c-viapro.c        |    2 +-
> > >  drivers/i2c/busses/scx200_acb.c        |    2 +-
> > >  include/linux/i2c.h                    |    1 +
> > >  35 files changed, 37 insertions(+), 36 deletions(-)
> 
> OK, I'll revert the change for these 4 drivers.



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