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From: Mark Brown <broonie@kernel.org>
To: Kevin Mehall <km@kevinmehall.net>
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 v2 1/2] spi: sun6i: Honor CS setup delay on the first transfer with native CS
Date: Thu, 23 Apr 2026 19:50:05 +0100	[thread overview]
Message-ID: <5ccd1ed2-b4b3-4f94-8c32-89bb27d4066f@sirena.org.uk> (raw)
In-Reply-To: <53c2d366-2d76-4a6d-a72b-99544026ee27@app.fastmail.com>

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On Thu, Apr 23, 2026 at 12:40:34PM -0600, Kevin Mehall wrote:
> I realized this is incorrect. With a GPIO chip select, sun6i_spi_set_cs() is not called,
> thus CS_MANUAL would not be set, and the hardware would then automatically
> assert native CS 0 during the transfer. My testing was with native CS 1 and a second GPIO chip select,
> so I didn't see this because native CS 0 is not used on the Orange Pi Zero 3.

> Therefore, I think the best place to set CS_MANUAL is in sun6i_spi_prepare_message
> as I had in my original patch [1], unless you think it should be duplicated in both places
> or have a better suggestion of where to set it. sun6i_spi_prepare_message() is still called
> before set_cs(), so it still fixes the skipped delay.

That sounds about right, the other option would be
SPI_CONTROLLER_GPIO_SS but I don't think this controller needs it.

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  reply	other threads:[~2026-04-23 18:50 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-04-23 17:39 [PATCH v2 0/2] spi: sun6i: Fix chip select handling around autosuspend Kevin Mehall
2026-04-23 17:40 ` [PATCH v2 1/2] spi: sun6i: Honor CS setup delay on the first transfer with native CS Kevin Mehall
2026-04-23 18:40   ` Kevin Mehall
2026-04-23 18:50     ` Mark Brown [this message]
2026-04-23 17:40 ` [PATCH v2 2/2] spi: sun6i: Set SPI mode in prepare_message Kevin Mehall

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