On Fri, May 3, 2024 at 6:22 PM Sean Anderson <sean.anderson@xxxxxxxxx> wrote: > This series adds support for muxing individual pins, instead of > requiring groups to be muxed together. See [1] for additional > discussion. > > [1] https://lore.kernel.org/linux-arm-kernel/5bb0dc7e-4c89-4f3d-abc6-41ae9ded5ae9@xxxxxxxxx/ The way I usually would recommend to solve this would be to define new subgroups, so e.g. for a UARTS: uart0_grp = pin_rx, pin_tx, pin_cts, pin_dts, pin_dcd; And today this would be used like that: mux0: function = "uart0"; groups = "uart0_grp"; Then we realize that not everyone need all the modem control signals provided. What to do. Well this: uart0_rxtx_grp = pin_rx, pin_tx: uart0_modem_grp = pin_cts, pin_dts, pin_dcd; mux0: function = "uart0"; groups = "uart0_rxtx_grp"; Now the CTS, DTS, DCD pins can be reused for something else such as GPIO. I *know* that this breaks ABI: the driver group definitions change and the device tree needs to be changed too. This only matters if the users have a habit of distributing the kernel and DTB separately so a new kernel needs to support and old DTB. This varies in how much control we have but I think for Xilinx systems the kernel and DTB are always updated in lockstep, so it really does not matter? Yours, Linus Walleij
