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SubjectRe: [PATCH v3 1/4] of: adapt of_find_i2c_driver() to be usable by SPI also
On 7/25/08, Grant Likely <grant.likely@secretlab.ca> wrote:
> On Fri, Jul 25, 2008 at 11:40 AM, Jon Smirl <jonsmirl@gmail.com> wrote:
> > On 7/25/08, Grant Likely <grant.likely@secretlab.ca> wrote:
> >> From: Grant Likely <grant.likely@secretlab.ca>
> >>
>
> >> + * At the moment, a single table is used for all bus types because it is
> >> + * assumed that the data size is small and that the compatible values
> >> + * should already be distinct enough to differentiate between SPI, I2C
> >> + * and other devices.
> >
> > Maybe add a section recommending to update the alias list in the linux
> > device driver before adding entries here? This table should be a last
> > resort. I'm not even sure this table should exist, what would be a
> > case where we would need to make an entry here instead of fixing the
> > device driver by adding an alias name?
>
>
> In principle I agree. However, this patch is simply porting the i2c
> specific code to something that can be used by both SPI and I2C. I
> don't want to rework the actual mechanism in this particular patch. I
> can submit an additional patch to change this along with reworking
> some of the behavior that needs to be improved.
>
>
> >> + * First method is to lookup the compatible value in of_modalias_table.
> >> + * Second is to look for a "linux,<modalias>" entry in the compatible list
> >> + * and used that for modalias. Third is to strip off the manufacturer
> >> + * prefix from the first compatible entry and use the remainder as modalias
> >
> > I also think this is a problem. Embedding the name of Linux device
> > drivers into device firmware makes it almost impossible to rename the
> > device driver. Again, what is a case where generic part numbers can't
> > be listed in the alias section of the linux device driver?
> >
> > Even eeprom was just fixed to take generic part numbers (at24).
>
>
> Again, I agree, but this change is very much a stop gap measure to get
> things working in a sane way without having to create bad device tree
> bindings (device tree bindings are hard to change, code is not). I've
> been considering posting a patch to remove this clause from the
> functions, but that needs to be reviewed separately from this change.

Isn't putting "compatible="linux,modalias"" into your device tree a
really bad idea?

>
> Thanks,
>
> g.
>
> --
> Grant Likely, B.Sc., P.Eng.
> Secret Lab Technologies Ltd.
>


--
Jon Smirl
jonsmirl@gmail.com


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