pon., 30 gru 2019 o 14:38 Geert Uytterhoeven <geert+renesas@xxxxxxxxx> napisał(a): > > Hi all, > > As GPIO hogs are configured at GPIO controller initialization time, > adding/removing GPIO hogs in Device Tree overlays currently does not > work. Hence this patch series adds support for that, by registering an > of_reconfig notifier, as is already done for platform, i2c, and SPI > devices. > > Perhaps this would be better served through a pinctrl-gpio driver? > Pinctrl is already working fine with DT overlays, as the pinctrl-* > properties are part of the slave device node, and thus looked up at > slave device node attachment time, not at pin controller initialization > time. > > In my particular use case (talking to SPI devices connected to a PMOD > connector on the RSK+RZA1 development board), the GPIO performs board > level muxing of a.o. the SPI MOSI/MISO/SCK signals. Hence the hog > really needs to be active only while talking to the SPI device, so the > muxing could (in theory) be done upon demand. > But how to describe that in DT, and implement it (using Runtime PM?)? > I may be missing the whole picture, but from your description this sounds like a job for the mux framework. Maybe we could make runtime PM aware of muxing for this type of use-cases? Bart
