From: "Kevin Mehall" <km@kevinmehall.net>
To: "Mark Brown" <broonie@kernel.org>
Cc: "Chen-Yu Tsai" <wens@kernel.org>,
"Jernej Skrabec" <jernej.skrabec@gmail.com>,
"Samuel Holland" <samuel@sholland.org>,
"Mirko Vogt" <mirko-dev|linux@nanl.de>,
"Ralf Schlatterbeck" <rsc@runtux.com>,
linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] spi: sun6i: Set SPI mode in prepare_message
Date: Thu, 23 Apr 2026 11:46:28 -0600 [thread overview]
Message-ID: <9987fdee-7146-4dfd-a34b-d475a96685eb@app.fastmail.com> (raw)
In-Reply-To: <f93e1bc6-608b-4c75-8b1a-80f701ff37ce@sirena.org.uk>
I tested with `spi-cs-setup-delay-ns = <1000000>;` and a hardware CS in the
device tree, and confirmed the suspected second bug: without this patch, the
first transfer after autosuspend ignores the setup delay.
> I do see that the driver uses a reset controller over suspend, are you
> sure that setup() will be called again on resume?
SUN6I_TFR_CTL_REG is indeed being reset after autosuspend because the above bug
reoccurs after a few seconds of inactivity. I am not sure if setup() is running on
resume because the datasheet reset value of SUN6I_TFR_CTL_CS_LEVEL is the same
as what would be written. Either way, it's moot if we set all CS-related bits in
the same register write.
I've moved the line that sets SUN6I_TFR_CTL_CS_MANUAL into sun6i_spi_set_cs()
rather than into sun6i_spi_prepare_message() as a separated commit in a new patch
series:
https://lore.kernel.org/linux-spi/20260423174001.2797797-1-km@kevinmehall.net/
prev parent reply other threads:[~2026-04-23 17:47 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-20 16:46 [PATCH] spi: sun6i: Set SPI mode in prepare_message Kevin Mehall
2026-04-22 14:57 ` Mark Brown
2026-04-22 19:01 ` Kevin Mehall
2026-04-22 19:50 ` Mark Brown
2026-04-23 17:46 ` Kevin Mehall [this message]
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