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Date: Tue, 23 Jan 2024 13:53:46 +0000
From: Mark Brown <broonie@kernel.org>
To: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Herve Codina <herve.codina@bootlin.com>,
	Amit Kumar Mahapatra <amit.kumar-mahapatra@amd.com>,
	Guenter Roeck <linux@roeck-us.net>,
	"linux-spi@vger.kernel.org" <linux-spi@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Subject: Re: [PATCH] spi: Raise limit on number of chip selects
Message-ID: <49b52941-6205-48bd-b2ae-e334018ac5cd@sirena.org.uk>
References: <20240122-spi-multi-cs-max-v1-1-a7e98cd5f6c7@kernel.org>
 <20240123120430.75c7ace0@bootlin.com>
 <cefafa30-b78d-471b-83e0-b05060d806d4@sirena.org.uk>
 <93385fc2-7596-4f66-b0c1-07d7d5c9ed8d@csgroup.eu>
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On Tue, Jan 23, 2024 at 01:26:04PM +0000, Christophe Leroy wrote:
> Le 23/01/2024 =E0 14:18, Mark Brown a =E9crit=A0:
> > On Tue, Jan 23, 2024 at 12:04:30PM +0100, Herve Codina wrote:

> >> Moving the SPI_CS_CNT_MAX value from 4 to 8 is not enough to handle my=
 case.
> >> Tested moving SPI_CS_CNT_MAX to 16 and it was ok.

> > OK, I've also heard 12 as a number which this would cover.

> By the way the comment in include/linux/spi/spi.h is confusing. This=20
> SPI_CS_CNT_MAX is really not the max number of CS supported per SPI=20
> device but the max number of CS supported per SPI controller.

Well, it's a combination of the comment being confusing and the
implementation being a bit broken - we simply shouldn't be limiting the
number of chip selects per controller, the per device limit is much more
reasonable.  So ideally the code would be changed to reflect the
comment.

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