Headphone amp driver doesn't work for inputs without a decimal point

[tvannoy]

When writing to the volume register, values without a decimal point do not get parsed correctly. For example, writing -20 to the volume register results in

[  914.313055] Maximum attenuation exceeded.
[  914.313062] Setting attenuation to -100 dB.

being printed to the kernel log.

In light of this, perhaps all of our drivers should use shared (and tested) string parsing/conversion functions.

[fe-wickham]

This would be stemming from a bug in the set_fixed_num function, correct? As you are seeing, it looks like the function just doesn't handle there not being a decimal point.

[tvannoy]

Yes, that should be the case. set_fixed_num in custom_functions.h should have a working implementation. I'd vote for including that header in this driver to avoid duplicating code.