* Jon Hunter <jon-hunter@xxxxxx> [130204 11:37]: > > On 02/04/2013 01:15 PM, Tony Lindgren wrote: > > * Jon Hunter <jon-hunter@xxxxxx> [130204 10:49]: > >> On 02/04/2013 11:45 AM, Tony Lindgren wrote: > >>> > >>> AFAIK SYSBOOT_n values reflect the boot time values of the actual SYSBOOT > >>> pins, so using generic pinconf there makes sense. But this of course should > >>> be checked. > >> > >> Not sure I am a fan of that idea. It is possible the pins could be > >> re-used as GPIOs after reset. Given that the state at reset is latched > >> in a register, it is best just to read the register directly. > > > > Yes the physical SYSBOOT pins can be reused as GPIO, but that's are already > > handled by the padconf and GPIO registers. This is a different register > > showing the boot time pin values for some pins. So it makes sense to use > > generic pinconf to make the pin values available to the client drivers > > as needed. > > > > The advantage doing it this way is that we don't need to export any omap > > custom functions to the drivers from the SCM driver. This way we need zero > > platform glue code, and can deal with it directly in the drivers in a > > generic way. And all we need to do is just need to map the SoC specific > > SYSBOOT pin register in the .dts files. > > I see what you are saying exporting the state in control_status register > via the pinconf. That could work. > > > It may also make sense to export DEVICETYPE this way. At least early omaps > > had the GP vs HS mode configured by pulls on some pins during the boot time. > > So those bits too may reflect actual physical pins during the boot time > > configured by the efuse settings? > > I *believe* that was only omap1. Yeah but maybe the efuses just configure some pulls for selected pins for later omaps? > >>>>> Regarding omap_device, we should find a way to keep the dependencies > >>>>> between drivers and the bus code down to minimum. So ideally things > >>>>> like this would be only done using just the compatible flag. But the > >>>>> pdata we cannot remove quite yet. > >>>> > >>>> Agree. However, there are several drivers today (gpio, dmtimer, mmc, > >>>> serial, dss, etc), that make use of a function pointer to > >>>> omap_pm_get_dev_context_loss_count() to determine when the peripheral's > >>>> state has been lost. When booting with DT this function pointer is not > >>>> populated and so with DT we currently have no way to determine this. I > >>>> see this as a blocker to migrating completely to DT. Ideally we would > >>>> find a way for RPM to handle this and remove the function pointer. > >>>> However, right now we still need a generic way to pass this type of > >>>> platform data to drivers. > >>> > >>> Yeah pinconf generic won't help us with the legacy boot. > >> > >> Right. I view all this sort of thing as system-level device information > >> that some drivers may need. It does not seem that we have a good way to > >> handle that at the moment. Any ideas? > > > > I suggest just passing it in in pdata for now for the legacy boot. Then > > I suggest we make what we can generic with pinconf in the long run. > > I don't see why we would want to export a function pointer to > omap_pm_get_dev_context_loss_count() with pinconf. Have we got our wires > crossed here? Yes sorry, too many muxes here. I got this topic mixed up with the sysboot pin topic :) We really need to find a Linux generic API to query this. Sounds like it should be part of runtime PM? Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
