From: Mark Brown <broonie@kernel.org>
To: Liguang Zhang <zhangliguang@linux.alibaba.com>
Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] spi: set right CS polarity depend on gpiolib
Date: Fri, 7 May 2021 16:30:09 +0100 [thread overview]
Message-ID: <20210507153009.GB6383@sirena.org.uk> (raw)
In-Reply-To: <20210507145117.43221-1-zhangliguang@linux.alibaba.com>
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On Fri, May 07, 2021 at 10:51:17PM +0800, Liguang Zhang wrote:
> After a kernel upgrade from 4.19 to 5.10, we found that tpm flow control
> always causes TIMEOUT which caused by wrong CS polarity setting depend
> on gpiolib.
> if (spi->cs_gpiod)
> /* polarity handled by gpiolib */
> - gpiod_set_value_cansleep(spi->cs_gpiod, activate);
> + gpiod_set_value_cansleep(spi->cs_gpiod, !enable);
Whatever is going on here it doesn't seem likely that this is a problem
in the SPI core given the widespread use of gpiod based chip selects -
can you provide more explanation of what you're seeing here, how is the
chip select configured, what is the hardware expectation and what
actually ends up happening?
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next prev parent reply other threads:[~2021-05-07 15:30 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-07 14:51 [PATCH] spi: set right CS polarity depend on gpiolib Liguang Zhang
2021-05-07 15:30 ` Mark Brown [this message]
2021-05-08 1:01 ` 乱石
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