On Wed, 12 Sep 2018, Alexandre Belloni wrote: > 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. I care for the kernel in general, not just the areas I'm responsible for. I guess I'm just that kinda guy! ;) > > > > 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. Oh I see. My question was relating to whether the H/W is physically capable of changing modes on-the-fly, rather than how Linux would handle that. If this is something we'd wish to support, then it would have to be a single driver, which is why I was asking. By separating the drivers this way, we are blocking that as a possibility. Although I guess the OP has already thought about that and made the decision not to support it. > > 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. Other drivers already do this. -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog
