Linus, On Thu, 15 Nov 2012 15:03:40 +0100, Linus Walleij wrote:
> > I have to say that I agree with this, notifiers seem to make life more > > complicated for limited gain. Otherwise I guess we could enhance > > notifiers so that they're able to trigger deferrals? > > OK I'll have to come up with a patch to the device core > instead... it'll be much simpler anyway and if both of you guys > can back it I guess Greg might be OK with it too. At ELCE, I've discussed with one person having an interesting use case: they are using the same pin for two different purposes during the system operation. At boot time, this pin is muxed as a SPI pin and is used to program the bitstream of a FPGA. This is done in Linux, through a userspace application. Then, once it is done, this pin is remuxed as a UART pin, and used to communicate with another device on the board. If the pinctrl configuration is done at probe() time inside the driver core, then how can this kind of use case be supported? If each driver does its own muxing, we could think of letting the SPI and UART driver only do their muxing when the device is opened, and remove their muxing when the device is closed, so that such sharing of pins for two separate functions could be supported. Is this something we want to support? Best regards, Thomas -- Thomas Petazzoni, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
