From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Brad Bishop <bradleyb@fuzziesquirrel.com>,
Eddie James <eajames@linux.ibm.com>,
Joel Stanley <joel@jms.id.au>, Mark Brown <broonie@kernel.org>,
Sasha Levin <sashal@kernel.org>,
linux-spi@vger.kernel.org
Subject: [PATCH AUTOSEL 5.8 021/101] spi: fsi: Fix clock running too fast
Date: Sun, 18 Oct 2020 15:19:06 -0400 [thread overview]
Message-ID: <20201018192026.4053674-21-sashal@kernel.org> (raw)
In-Reply-To: <20201018192026.4053674-1-sashal@kernel.org>
From: Brad Bishop <bradleyb@fuzziesquirrel.com>
[ Upstream commit 0b546bbe9474ff23e6843916ad6d567f703b2396 ]
Use a clock divider tuned to a 200MHz FSI bus frequency (the maximum). Use
of the previous divider at 200MHz results in corrupt data from endpoint
devices. Ideally the clock divider would be calculated from the FSI clock,
but that would require some significant work on the FSI driver. With FSI
frequencies slower than 200MHz, the SPI clock will simply run slower, but
safely.
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20200909222857.28653-3-eajames@linux.ibm.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/spi/spi-fsi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/spi/spi-fsi.c b/drivers/spi/spi-fsi.c
index 37a3e0f8e7526..6e6b3c6437288 100644
--- a/drivers/spi/spi-fsi.c
+++ b/drivers/spi/spi-fsi.c
@@ -350,7 +350,7 @@ static int fsi_spi_transfer_init(struct fsi_spi *ctx)
u64 status = 0ULL;
u64 wanted_clock_cfg = SPI_FSI_CLOCK_CFG_ECC_DISABLE |
SPI_FSI_CLOCK_CFG_SCK_NO_DEL |
- FIELD_PREP(SPI_FSI_CLOCK_CFG_SCK_DIV, 4);
+ FIELD_PREP(SPI_FSI_CLOCK_CFG_SCK_DIV, 19);
end = jiffies + msecs_to_jiffies(SPI_FSI_INIT_TIMEOUT_MS);
do {
--
2.25.1
parent reply other threads:[~2020-10-18 19:53 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <20201018192026.4053674-1-sashal@kernel.org>]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201018192026.4053674-21-sashal@kernel.org \
--to=sashal@kernel.org \
--cc=bradleyb@fuzziesquirrel.com \
--cc=broonie@kernel.org \
--cc=eajames@linux.ibm.com \
--cc=joel@jms.id.au \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-spi@vger.kernel.org \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).