From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Mark Brown <broonie@kernel.org>
Cc: "linuxppc-dev@ozlabs.org" <linuxppc-dev@ozlabs.org>,
Sven Van Asbroeck <thesven73@gmail.com>,
Linus Walleij <linus.walleij@linaro.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-spi <linux-spi@vger.kernel.org>
Subject: Re: SPI not working on 5.10 and 5.11, bisected to 766c6b63aa04 ("spi: fix client driver breakages when using GPIO descriptors")
Date: Thu, 14 Jan 2021 12:27:42 +0100 [thread overview]
Message-ID: <9400d900-f315-815f-a358-16ed4963da6c@csgroup.eu> (raw)
In-Reply-To: <20210113123345.GD4641@sirena.org.uk>
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
next prev parent reply other threads:[~2021-01-14 11:32 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-13 8:49 SPI not working on 5.10 and 5.11, bisected to 766c6b63aa04 ("spi: fix client driver breakages when using GPIO descriptors") Christophe Leroy
2021-01-13 12:33 ` Mark Brown
2021-01-14 11:27 ` Christophe Leroy [this message]
2021-01-14 11:59 ` Mark Brown
2021-01-14 12:33 ` Christophe Leroy
2021-01-14 13:22 ` Mark Brown
2021-01-14 13:42 ` Christophe Leroy
2021-01-14 13:59 ` Mark Brown
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