Re: SPI not working on 5.10 and 5.11, bisected to 766c6b63aa04 ("spi: fix client driver breakages when using GPIO descriptors")

[Christophe Leroy]

Le 13/01/2021 à 13:33, Mark Brown a écrit :
> On Wed, Jan 13, 2021 at 09:49:12AM +0100, Christophe Leroy wrote:
>
> > With commit 766c6b63aa04 ("spi: fix client driver breakages when using GPIO
> > descriptors") reverted, it is back to work:
>
> ...
>
> > What shall I do ?
>
> I would guess that there's an error with the chip select polarity
> configuration on your system that just happened to work previously, I'd
> suggest fixing this in the board configuration to bring it in line with
> everything else.

Not that easy.

Today I have in the DTS the CS GPIOs declared as ACTIVE_LOW.

If I declare them as ACTIVE_HIGH instead, then I also have to set spi-cs-high property, otherwise 
of_gpio_flags_quirks() is not happy and forces the GPIO ACTIVE LOW.

When I set spi-cs-high property, it sets the SPI_CS_HIGH bit in spi->mode.

In fsl_spi_chipselect(), we have

	bool pol = spi->mode & SPI_CS_HIGH

Then
	pdata->cs_control(spi, pol);

So changing the board config is compensated by the above, and at the end it still doesn't work.


Whereas reverting the above mentionned commit sets back SPI_CS_HIGH into spi->mode without changing 
the ACTIVE level of the GPIO, resulting in the correct polarity.


So, I'm a bit lost, where is the problem exactly ?

Thanks
Christophe