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. [0] https://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap.git/commit/?h=droid4-pending-v4.19&id=d774c7e447ac911e73a1b3c775e6d89f0422218c -- Best regards, Jacek Anaszewski
