pca954x devices sharing reset-gpios

pca954x devices sharing reset-gpios

[Chris Packham]

Hi All,

I've run into a problem trying to accurately model some hardware.

In this particular design there are a bunch of pca9548 i2c muxes and 
some of them share the same reset pins coming out of a custom FPGA 
(we've written a gpio driver to represent that part of the FPGA). 
Initially we had this working by using a gpio-hog for the reset lines 
and pretty much forgetting they were there.

If I start building the fpga-gpio driver as a module I run into a 
situation where there is an implicit dependency between the fpga-gpio 
driver and the pca954x i2c muxes. Because it's implicit the 
pca954x_probe runs early and fails for these devices. I can make that 
dependency explicit by using the reset-gpios property which correctly 
defers the probe until the fpga-gpio driver is loaded. But as some of 
these pca9548 share reset lines they ones that get probed second get 
-EBUSY when they request the GPIO.

Is there any way I can represent these pca9548 devices as a group with a 
single reset-gpio property for the group?

Thanks,
Chris