Messages in this thread | | | Date | Sun, 26 Jan 2014 13:47:09 -0800 | From | Guenter Roeck <> | Subject | Re: lm90 driver no longer working on PCs in 3.13 |
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On 01/26/2014 12:52 PM, Mark Brown wrote: > On Sun, Jan 26, 2014 at 12:44:38PM -0800, Guenter Roeck wrote: >> On 01/26/2014 12:13 PM, Jean Delvare wrote: > >>> Me, I really don't know. I seem to remember I tested Wei's patch set on >>> an emulated ADM1032 chip and it was working fine. So maybe it depends >>> on the kernel configuration, or something changed on the regulator side >>> meanwhile. > >> The regulator code changed with 3.13; the dummy regulator no longer exists, >> and the functionality it provided is supposed to be handled automatically. >> But that only really works on devicetree based systems and otherwise returns >> -EPROBE_DEFER as mentioned above. > > CONFIG_REGULATOR_DUMMY should never have been used in production, it was > a debug tool to help bringup but it broke things as often as it fixed > them particularly with init ordering which is why it generated a warning > when it was used. > > The dummy driver is still there, if you're doing bringup you can hack it > in still or if you genuniely used it then specify that full constraints > are provided like the changelog says (and as I've previously said). > >> Another possible fix would be to have the regulator core return -ENODEV >> instead of -EPROBE_DEFER on non-dt systems. No idea if this would be acceptable >> or even feasible. > > No, this would introduce breakage due to init ordering. >
You have a solution for that in dt configurations. I don't think you have one for non-dt systems - you simply assume that all regulators are there. For dt, you even have a constraint to tell the kernel if regulator configurations are fully specified, and you automatically return success if not and if a regulator does not exist. So you know that there is a problem. For non-DT configurations you simply assume and expect that regulators are all declared. I don't think that is a feasible approach for non-DT systems.
Guenter
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