Messages in this thread | | | Date | Mon, 16 Nov 2020 21:06:32 +0000 | From | Mark Brown <> | Subject | Re: [PATCH v1] spi: fix client driver breakages when using GPIO descriptors |
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On Wed, Nov 11, 2020 at 02:36:07PM +0100, Linus Walleij wrote: > On Wed, Nov 11, 2020 at 1:33 PM Mark Brown <broonie@kernel.org> wrote: > > On Wed, Nov 11, 2020 at 02:05:19AM +0100, Linus Walleij wrote:
> > This is not clear to me, most of these settings are things that are > > constant for the device so it's not clear that they should be being set > > by the device tree in the first place.
> This was added initially with some two properties > in drivers/of/of_spi.c in 2008: > commit 284b01897340974000bcc84de87a4e1becc8a83d > "spi: Add OF binding support for SPI busses"
> This was around the time ARM was first starting to migrate > to device tree, so I suppose it made sense to them/us back > then.
That's from PowerPC days, not ARM, and frankly a lot of DT conversions were just fairly mechanical conversions of what was in platform data to DT so they may not have been especially considered.
> compatible-string. It was later that especially Rob pointed out that > random properties on device nodes was overused and that simply > knowing the compatible is often enough.
I've been pushing this since forever as well, as far as I remember it's been a thing since we started doing this.
> I don't know if we ever formalized it, there is nowadays a rule akin to
> "if a property can be determined from the compatible-string, and if the > compatible-string is identifying the variant of the electronic component, > then do not add this property to the device tree description. Just > deduce it from the compatible-string, assign it with code to the device > model of the operating system and handle it inside the operating system."
> I think this, while clear and intuitive, wasn't at all clear and intuitive in > the recent past.
I think the main push in the other direction has always been people who want to not have to write a driver at all and put absolutely everything into DT which has scaling issues :/ [unhandled content-type:application/pgp-signature] | |