[U-Boot] [PATCH v3 0/3] i2c: sunxi: Support every i2c controller on each supported platform

[Paul Kocialkowski]

Le dimanche 05 avril 2015 à 22:59 +0200, Paul Kocialkowski a écrit :
> Hi Hans,
> 
> Le dimanche 05 avril 2015 à 10:44 +0200, Hans de Goede a écrit :
> > Hi,
 
[snip]

> > Thanks for your work on this, may I request one more change ? For sunxi I would
> > like to also see a CONFIG_I2C0_ENABLE, the reason for this is that on sun6i / sun8i
> > we do not really use i2c0 as we use p2wi resp. rsb to talk to the axp pmic there.
> > 
> > This way we will not end up messing with the muxing of the PH14/15 (sun6i) resp.
> > PH2/3 (sun8i) which may be used in some other fashion.
> > 
> > This also means making a small change to the first patch to also make registering
> > of twsi0 #ifdef CONFIG_I2C_MVTWSI_BASE0 .
> > 
> > Can you please make the default for CONFIG_I2C0_ENABLE y on sun4i / sun5i / sun7i and n
> > on others?
> 
> Ack that, it makes sense to me.

Implementing this leads to build errors:
drivers/i2c/mvtwsi.c:319:13: attention : ‘twsi_i2c_init’ defined but not
used [-Wunused-function]
drivers/i2c/mvtwsi.c:362:12: attention : ‘twsi_i2c_probe’ defined but
not used [-Wunused-function]
drivers/i2c/mvtwsi.c:388:12: attention : ‘twsi_i2c_read’ defined but not
used [-Wunused-function]
drivers/i2c/mvtwsi.c:424:12: attention : ‘twsi_i2c_write’ defined but
not used [-Wunused-function]

Ways to get rid of those include:
* not building the driver at all when no controller 0 base is defined,
which involves moving moving SYS_I2C_MVTWSI to Kconfig and selecting it
when at least one i2c controller is selected in the sunxi Kconfig
* having twsi0 enabled on all sunxi devices, as it was before

What do you prefer?

> > Also I'm not entirely convinced that patch 3/3 is a good idea, on the olimex boards
> > which have a i2c eeprom enabling the attached i2c controller makes sense, but on the
> > other boards the i2c pins are really just gpio pins, any daughter board can be connected
> > including one which uses them differently. I believe that in the defconfig the i2c
> > controllers should thus be left off. It is after all a default config, users with
> > a daughter board which they want to use in u-boot can easily change the config after
> > running make foo_defconfig.
> 
> I think the right bargain here would be to enable i2c lines that already
> have something useful for U-Boot attached (e.g. not an accelerometer
> sensor). I concur to your point otherwise.
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