[U-Boot] [RFC] Make i2c probe opt-outable?

[Tom Rini <trini@ti.com>]

Hey all,

I'd like to propose making 'i2c probe' be a command that is
opt-out'able.  In the Linux Kernel the notion of probing for devices was
abandoned a while ago due to, in short, devices misbehaving when
randomly poked at.  Over in omap24xx_i2c land we changed our probe
method a while ago from an attempted read to an attempted write as some
i2c devices would NAK the read.  But now with the am33xx SoM family we
have a new issue which is that attempting to write to an address doesn't
immediately issue a NAK so probe sees all addresses as valid and in turn
leaves the bus upset.  I've worked around this for now by making
i2c_probe use the read method instead, only on am33xx (so most devices
would be spotted, but the ones that caused the initial change would not
show up).  But a possibly better solution is to just make the i2c probe
command not implemented for am33xx (as you don't have to run i2c probe
to try and use your device).

Thoughts?  Thanks!

-- 
Tom