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

[Christophe Leroy]

Le 14/01/2021 à 12:59, Mark Brown a écrit :
> On Thu, Jan 14, 2021 at 12:27:42PM +0100, Christophe Leroy wrote:
> 
>> 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.
> 
> OK, so it sounds like you want SPI_CS_HIGH and that is being set
> correctly?
> 
>> 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.
> 
> This is a driver bug, the driver set_cs() operation should not be
> modifying the value it is told to set.
> 

A driver bug ? Or maybe a change forgotten in commit  766c6b63aa04 ("spi: fix client driver 
breakages when using GPIO descriptors") ?

I'm almost sure it was not a bug, it is in line which what is said in the comment removed by the 
above mentionned commit.

I'll send a fix.

Christophe