Jacek On 09/15/2018 03:00 PM, Jacek Anaszewski wrote: > Hi Pavel. > > On 09/14/2018 11:42 PM, Pavel Machek wrote: >> Hi! >> >>>> You may want to learn more about device tree and/or talk to the device >>>> tree maintainers. This is an old article. https://lwn.net/Articles/561462/ >>> >>> The article title is "Device trees as ABI". A device tree is defined >>> in the "*.dts" file that is then compiled to a dtb blob, which >>> constitutes the ABI. And this ABI should be kept backwards compatible. >>> >>> What is discussed here is a documentation of bindings, i.e. according >>> to ePAPR: "requirements for how specific types and classes of devices >>> are represented in the device tree". >>> >>> >From the bindings documented in the >>> Documentation/devicetree/bindings/mfd/ti-lmu.txt only >>> ti,lm3532-backlight is used in the mainline dts file >>> (arch/arm/boot/dts/omap4-droid4-xt894.dts). >>> >>> Having the above it seems that there is no risk of breaking any >>> users. >> >> DTBs and bindings are supposed to be portable between operating >> systems. You are right there are no _mainline_ _Linux_ users. > > No mainline users means no users we should care of. > Other people also don't care - see patch [0]. > >>>> NAK on this patch. I see that this binding has problems, but >>>> introducing different binding for subset of devices is _not_ a fix. >>>> >>>>>> What about the multi function devices? They should have same binding. >>>>> >>>>> The MFD devices defined are not in contention here only the SFD. >>>> >>>> I'd like to see common solutions for SFD and MFD, as the hardware is >>>> similar, and that includes the code. Having code that is easier to >>>> maintain is important, and having many drivers are harder to maintain >>>> than one driver. >>>> >>>> Milo's code looks better than yours in that regard. I disagree about >>>> Milo's code being "nightmare" to modify, and care about "easy to >>>> maintain" more than "binary size". >>> >>> Easy to maintain will be a dedicated LED class driver. >> >> You mean, 3 dedicated LED class drivers and 3 MFD drivers with LED >> parts? We'll need complex driver anyway, and I'd really like to have >> just one. > > In the LED subsystem we can wrap common functionalities > into a library object. MFD driver will be able to reuse it then. I am currently working on that code now. I expect a RFC on this this week. Dan > > [0] > https://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap.git/commit/?h=droid4-pending-v4.19&id=d774c7e447ac911e73a1b3c775e6d89f0422218c > -- ------------------ Dan Murphy
