Linux SPI subsystem development
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From: Nathan Barrett-Morrison <nathan.morrison@timesys.com>
To: broonie@kernel.org
Cc: greg.malysa@timesys.com, linux-kernel@vger.kernel.org,
	linux-spi@vger.kernel.org, nathan.morrison@timesys.com
Subject: RE: [PATCH] spi: cadence-quadspi: Add upper limit safety check to baudrate divisor
Date: Thu, 24 Nov 2022 06:53:54 -0500	[thread overview]
Message-ID: <20221124115354.132832-1-nathan.morrison@timesys.com> (raw)
In-Reply-To: <Y39YJL02jFbkEMqw@sirena.org.uk>

Hi Mark & Dhruva,

Your understanding is correct.  This is just checking if the divisor field has exceed the bit field's full scale (0xF) in this case.  This was observed when we had a reference block of 500MHz and a max SPI clock of 10MHz setting.

500000000/2*10000000 = 25
25 > 0xF (15)

Would you like me to add a dev_err (or such) bailout error condition and resubmit?

Sincerely,
Nathan

  reply	other threads:[~2022-11-24 11:53 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-23 21:17 [PATCH] spi: cadence-quadspi: Add upper limit safety check to baudrate divisor Nathan Barrett-Morrison
2022-11-24  6:46 ` Dhruva Gole
2022-11-24 11:35   ` Mark Brown
2022-11-24 12:27     ` Dhruva Gole
2022-11-24 12:41       ` Mark Brown
2022-11-24 11:40 ` Mark Brown
2022-11-24 11:53   ` Nathan Barrett-Morrison [this message]
2022-11-24 12:02     ` Mark Brown

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