On Wed, 2019-08-21 at 19:42 +0200, Guido Günther wrote: > Hi, > On Tue, Aug 13, 2019 at 01:07:52PM +0200, Arnd Bergmann wrote: > > On Tue, Aug 13, 2019 at 12:10 PM Guido Günther <agx@xxxxxxxxxxx> wrote: > > > On Tue, Aug 13, 2019 at 10:08:44AM +0200, Arnd Bergmann wrote: > > > > On Fri, Aug 9, 2019 at 6:24 PM Guido Günther <agx@xxxxxxxxxxx> wrote: > > > > > > > > > > This adds all the gpr registers and the define needed for selecting > > > > > the input source in the imx-nwl drm bridge. > > > > > > > > > > Signed-off-by: Guido Günther <agx@xxxxxxxxxxx> > > > > > + > > > > > +#define IOMUXC_GPR0 0x00 > > > > > +#define IOMUXC_GPR1 0x04 > > > > > +#define IOMUXC_GPR2 0x08 > > > > > +#define IOMUXC_GPR3 0x0c > > > > > +#define IOMUXC_GPR4 0x10 > > > > > +#define IOMUXC_GPR5 0x14 > > > > > +#define IOMUXC_GPR6 0x18 > > > > > +#define IOMUXC_GPR7 0x1c > > > > > > > > (more of the same) > > > > > > > > huh? > > > > > > These are the names from the imx8MQ reference manual (general purpose > > > registers, they lump together all sorts of things), it's the same on > > > imx6/imx7): > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/mfd/syscon/imx6q-iomuxc-gpr.h > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/mfd/syscon/imx7-iomuxc-gpr.h > > > > > > > > +/* i.MX8Mq iomux gpr register field defines */ > > > > > +#define IMX8MQ_GPR13_MIPI_MUX_SEL BIT(2) > > > > > > > > I think this define should probably be local to the pinctrl driver, to > > > > ensure that no other drivers fiddle with the registers manually. > > > > > > The purpose of these bits is for a driver to fiddle with them to select > > > the input source. Similar on imx7 it's already used for e.g. the phy > > > refclk in the pci controller: > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/pci/controller/dwc/pci-imx6.c#n638 > > > > That one should likely use either the clk interface or the phy > > interface instead. > > > > > The GPRs are not about pad configuration but gather all sorts of things > > > (section 8.2.4 of the imx8mq reference manual): pcie setup, dsi related > > > bits so I don't think this should be done via a pinctrl > > > driver. Should we handle that differently than on imx6/7? > > > > It would be nice to fix the existing code as well, but for the moment, > > I only think we should not add more of that. > > > > Generally speaking, we can use syscon to do random things that don't > > have a subsystem of their own, but we should not use it to do things > > that have an existing driver framework like pinctrl, clock, reset, phy > > etc. > > Since it's not an external pin i opted to use MUX_MMIO instead which > seems like a good fit here. Does that make sense? Yes, I agree. The i.MX6 display subsystem predates the mux framework, otherwise I would have used it for the LVDS and HDMI muxes in the first place. We should probably switch imx-drm over as well, in a backwards compatible fashion. The &mux definitions are already there in arch/arm/boot/dts/imx6q.dtsi. regards Philipp
