On 12/09/2018 12:43:52+0100, Lee Jones wrote: > > > But ... we can't have it both ways. *Either* it's a true MFD, in > > > which case it can/should have 2 separate compatible strings which can > > > be specified directly from the DT. *Or* it's not an MFD. In the > > > latter case, which I think we're all agreeing on (else we'd have 2 > > > compatible strings), MFD is not the place to handle this (my original > > > point). > > > > > > > If that is what bothers you, then let's move it out of mfd. > > As I've already mentioned. I don't just want it moved out of MFD and > shoved somewhere else. My aim is to fix this properly. > If it is out of MFD, then I'm not sure why you would care too much about it as you won't be maintaining that code. And I still this what was done was correct but I'm open to test what you suggest. > > > So ... this is a USART device which can do SPI, right? > > > > > > My current thinking is that; as this is a USART device first & > > > foremost, the USART should be probed in the first instance regardless, > > > then if SPI mode is specified it (the USART driver) registers the SPI > > > platform driver (as MFD does currently) and exits gracefully, allowing > > > the SPI driver to take over. > > > > > > Spanner in the works: is it physically possible to change the mode at > > > run-time? :s > > > > Yes it is possible but on Linux that will not happen without probing > > the drivers again. > > Not sure I understand what you mean. > I was just commenting on changing the mode at runtime. > I'm suggesting that you use the same platform_* interfaces MFD uses to > register the SPI driver if SPI mode has been selected. Only do so > from the appropriate driver i.e. USART. > Yeah, I understood that but I didn't comment because I'm not sure this will work yet. -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com