On Tue, Feb 25, 2025 at 12:24:09PM +0000, Maud Spierings | GOcontroll wrote: > From: Krzysztof Kozlowski <krzk@xxxxxxxxxx> > Sent: Tuesday, February 25, 2025 12:52 PM > > >On Tue, Feb 25, 2025 at 07:39:52AM +0000, Maud Spierings | GOcontroll wrote: > >> From: Rob Herring <robh@xxxxxxxxxx> > >> Sent: Monday, February 24, 2025 9:44 PM > >> > >> >On Mon, Feb 24, 2025 at 02:50:55PM +0100, Maud Spierings wrote: > >> >> The main point of the Moduline series of embedded controllers is its > >> >> ecosystem of IO modules, these currently are operated through the spidev > >> >> interface. Ideally there will be a full dedicated driver in the future. > >> >> > >> >> Add the gocontroll moduline-module-slot device to enable the required > >> >> spidev interface. > >> >> > >> >> Signed-off-by: Maud Spierings <maudspierings@xxxxxxxxxxxxxx> > >> >> --- > >> >> Documentation/devicetree/bindings/trivial-devices.yaml | 2 ++ > >> >> 1 file changed, 2 insertions(+) > >> >> > >> >> diff --git a/Documentation/devicetree/bindings/trivial-devices.yaml b/Documentation/devicetree/bindings/trivial-devices.yaml > >> >> index 8255bb590c0cc619d15b27dcbfd3aa85389c0a54..24ba810f91b73efdc615c7fb46f771a300926f05 100644 > >> >> --- a/Documentation/devicetree/bindings/trivial-devices.yaml > >> >> +++ b/Documentation/devicetree/bindings/trivial-devices.yaml > >> >> @@ -107,6 +107,8 @@ properties: > >> >> - fsl,mpl3115 > >> >> # MPR121: Proximity Capacitive Touch Sensor Controller > >> >> - fsl,mpr121 > >> >> + # GOcontroll Moduline module slot for spi based IO modules > >> > > >> >I couldn't find anything about SPI for GOcontroll Moduline. Can you > >> >point me to what this hardware looks like. Based on what I did find, > >> >this seems incomplete and not likely a trivial device. > >> > >> I'll give some more details, if there is a v2 of this patch I will also > >> add more information in the commit message. > >> > >> The module slots have a number of pins, a lot of them currently unused as > >> they have not found a function yet, this is very much still a developing > >> product. The currently used interfaces to the SoC are: > >> 1. SPI bus as a spidev to ease developing new modules and quickly > >> integrate them. This is the main communication interface for control and > >> firmware updates. > >> 2. A reset pin, this is/was driven with the gpio-led driver but I doubt > >> that would get accepted upstream so I intend to switch to the much better > >> suited libgpio. > > > >reset-gpios is not in trivial devices, so that's already a hint you > >cannot use this binding. > > > >> 3. An interrupt pin, this is currently only used in the firmware update > >> utility [2] to speed up the update process. Other communication is done at > >> a regular interval. > >> > >> What is unused: > >> 1. A potentially multi-master i2c bus between all the module slots and > >> the SoC > >> 2. An SMBus alert line is shared between the modules, but not the SoC. > >> 3. A shared line designated as a clock line, intended to in the future > >> aid with synchronizing modules to each other for time critical control. > >> > >> current software that is used to work with the modules can be found at > >> [2] and [3], one of them is a Node-RED module the other is a blockset for > >> Matlab/Simulink generated code. > >> > >> If you know a better way I could describe this in the devicetree then I > > > >You need dedicated binding where you describe entire device, entire > >hardware, not what your driver supports in current release. > > I see now that I also forgot the patch that adds this compatible to the > spidev driver. Didn't check for the spidevs in testing I guess. > > Could I write bindings for this device, and then add the compatible to the > spidev driver for now? So it probes that driver, and then later when there > is a driver remove the compatible there and keep it only in the purpose > built driver? > > So I'll write gocontroll,moduline-module-slot.yaml, don't quite know where > that would go. Define all these attributes in there and then add the > compatible to drivers/spi/spidev.c > > Is that okay? Yes. Bindings are forever, but drivers change. ;) Perhaps put it in connector/ as this looks a bit like a connector. Do you envision DT overlays for the IO modules? Or modules don't have sub-devices you need to describe? There's some effort to on connector bindings (for mikrobus in particular) in order to de-couple host buses/signals from the modules (i.e. so a DT overlay can be applied to any DT defining the connector). Rob
