Hi, On Sat, Jan 21, 2023 at 1:19 PM Lukas Zeller <l...@plan44.ch> wrote: > > Hi, > > > On 21 Jan 2023, at 08:56, Sergio Paracuellos <sergio.paracuel...@gmail.com> > > wrote: > > > > [...] Yes, you have to claim the pin group as gpio on the device tree to > > make this work. > > This revals a underlying problem I tried to ask about back in June 2022 [1] - > what is the state of userland GPIO support in OpenWrt? > > Changing the DT is *not* something an user of an educational/experimental > device based on OpenWrt is able to do, as long as the DT is baked into the > firmware image, and not modifiable from user space. > > Allowing configfs loadable device tree overlays would make that possible, but > that path was decided against (so far) [2]. > > So while I understand that using only the DT mechanisms for configuring GPIO > modes, named gpios and libgpiod instead of /sys/class/gpio etc. is the way to > go, I must also state that without loadable DT overlays, this essentially > makes openwrt unsuitable for experimental/educational devices.
Configure the GPIO modes is not something that is expected to be done by a user since all of that belongs to the pinctrl driver space and AFAIK linux kernel people are not thinking in doing pinctrl driver user-space tools. The libgpiod is useful to detect and set to on and off different pins (among other pure GPIO operations) but from the already function GPIO set up in them. I am not doing the rules, I am just saying the things that are now in the kernel and user space as I think they are. As I have already said, I am not an expert in this topic at all but maybe if we want to do such complex things like configuring the mode of a pin from user space some kind of user space drivers need to be provided in some way... So, if openWRT is using linux kernel, at the end they have to also live with kernel people's decisions in some way... > > I could also understand if this was an intentional decision, after all > OpenWrt is a router OS. > > But *is* it intentional? I find OpenWrt highly useful as a base OS for small > networked devices that are not routers, to cover the mostly empty space > between Arduino and RaspberryPi. Useful Linux in 16M flash rather than 32GB, > with no flash wear problems by design... > > [1] http://lists.openwrt.org/pipermail/openwrt-devel/2022-June/038912.html > [2] http://lists.openwrt.org/pipermail/openwrt-devel/2021-November/037139.html > > Lukas Best regards, Sergio Paracuellos _______________________________________________ openwrt-devel mailing list openwrt-devel@lists.openwrt.org https://lists.openwrt.org/mailman/listinfo/openwrt-devel
