Re: [PATCH 2/2] Add the of_find_i2c_device_by_node function, V4

["Jon Smirl" <jonsmirl@gmail.com>]

On 7/1/08, Jean Delvare <khali@linux-fr.org> wrote:
> On Tue, 1 Jul 2008 13:00:08 -0400, Jon Smirl wrote:
>  > On 7/1/08, Grant Likely <grant.likely@secretlab.ca> wrote:
>
> > > My preference is for things like of_spi and of_i2c to go with the
>  > >  related busses; I think it makes more sense to keep all the I2C stuff
>  > >  together, but I've already lost that battle once.
>  >
>  > This is a similar problem to adding aliases to the i2c driver drivers
>  > for the device tree names of the i2c devices. Instead we have code in
>  > drivers/of/of_i2c.c that tries to guess the translation from device
>  > tree to linux names. Adding aliases to the drivers would eliminate the
>  > need for of_find_i2c_driver().
>  >
>  > I've previously posted patches implementing device tree names in the
>  > drivers that used ifdef to only instantiate on powerpc builds. For
>  > example....
>  >
>  > diff --git a/drivers/i2c/chips/tps65010.c b/drivers/i2c/chips/tps65010.c
>  > index e07274d..9cd1770 100644
>  > --- a/drivers/i2c/chips/tps65010.c
>  > +++ b/drivers/i2c/chips/tps65010.c
>  > @@ -571,6 +571,10 @@ static const struct i2c_device_id tps65010_id[] = {
>  >         { "tps65011", TPS65011 },
>  >         { "tps65012", TPS65012 },
>  >         { "tps65013", TPS65013 },
>  > +       OF_ID("ti,tps65010", TPS65010)
>  > +       OF_ID("ti,tps65011", TPS65011)
>  > +       OF_ID("ti,tps65012", TPS65012)
>  > +       OF_ID("ti,tps65013", TPS65013)
>  >         { },
>  >  };
>  >  MODULE_DEVICE_TABLE(i2c, tps65010_id);
>
>
> Yeah, yeah, you've been asking for this for months already, but it's
>  just not going to happen, sorry. You want to abuse the standard Linux
>  alias mechanism for your personal (i.e. openfirmware) use, but that's
>  bad. Linux drivers shouldn't have to know whether they are used in
>  openfirmware trees and what device names are used there. And device
>  names as seen by user-space shouldn't vary depending on whether the
>  device comes from an openfirmware tree or not - otherwise all
>  user-space apps need to learn about both naming conversions.
>
>  Unsurprisingly, no other subsystem does what you propose.

Then what are all of the PCI aliases doing?

The only difference is that you are recognizing the PCI group as a
naming authority and not recognizing the PowerPC device tree group.
But on the PowerPC platform that is our naming authority. That's why I
proposed adding the names on ifdefs so that they disappear on non
PowerPC platforms.

PS - adding an alias to a driver does not change the name of the
driver. My PCI e1000 module has about 100 aliases but it is always
e1000.

-- 
Jon Smirl
jonsmirl@gmail.com