Messages in this thread | | | Subject | Re: [BUG] SPI broken for SPI based panel drivers | From | "H. Nikolaus Schaller" <> | Date | Tue, 1 Dec 2020 18:10:17 +0100 |
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Hi Sven,
> Am 01.12.2020 um 17:53 schrieb Sven Van Asbroeck <thesven73@gmail.com>: > > Hi Nikolaus, > > On Tue, Dec 1, 2020 at 11:43 AM H. Nikolaus Schaller <hns@goldelico.com> wrote: >> >> You are right. It is active low. >> > > In that case, we have a very simple solution, just remove the spi-cs-high, > and things will work.
We originally had it that way and because there was a change in gpiolib we had to introduce it.
See: f1f028ff89cb0d3
where we were forced to introduce it although I had preferred to not change DT.
I am not sure if DT maintainers accept that we revert a DT change just to handle some change in a driver. Usually they insist on fixing a driver and live with the DT. DT is carved in stone or could be ROM...
So you could try to submit a revert of f1f028ff89cb0d3 with a description why it is needed. And please make sure that it is also applied where your patch is backported to stable. So it should have some
Fixes: 766c6b63aa04 ("spi: fix client driver breakages when using GPIO descriptors")
> > In case of SPI CS gpios, the current kernel ignores all > GPIO_ACTIVE_HIGH/LOW > flags, and uses the presence/absence of spi-cs-high instead, to > determine active high / active low.
So you mean you are just restoring the behaviour before
6953c57ab172
was introduced?
The alternative is that you restore the cs-gpios + spi-cs-high semantics as defined by 6953c57ab172 and everything is fine without touching (our) DTS (again).
BR and thanks, Nikolaus
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