On Thu, Feb 18, 2016 at 05:53:13PM +0200, Daniel Baluta wrote:
> From: Adriana Reus <adriana.reus@intel.com>
> 
> Add a check in i2c_mux_master_xfer before calling the select callback.
> This is necessary so that NULL callbacks can be safely registered.
> 
> Signed-off-by: Adriana Reus <adriana.reus@intel.com>
> Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>

Hmm, rather than supporting that in the core, I'd prefer to have the
driver pass an empty function instead. Then, in the driver, we can have
a comment explaining the special situation.