Linux kernel and device drivers for NXP i.MX platforms
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From: Martin Kaiser <martin@kaiser.cx>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Mark Brown <broonie@kernel.org>, Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>,
	Alexander Stein <alexander.stein@ew.tq-group.com>,
	Francesco Dolcini <francesco.dolcini@toradex.com>,
	linux-spi@vger.kernel.org, imx@lists.linux.dev,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] spi: imx: Don't expect DMA for i.MX{25,35,50,51,53} cspi devices
Date: Wed, 8 May 2024 15:44:53 +0200	[thread overview]
Message-ID: <ZjuB1Rjyu1ooYvDi@akranes.kaiser.cx> (raw)
In-Reply-To: <20240508095610.2146640-2-u.kleine-koenig@pengutronix.de>

Hi Uwe,

Thus wrote Uwe Kleine-König (u.kleine-koenig@pengutronix.de):

> While in commit 2dd33f9cec90 ("spi: imx: support DMA for imx35") it was
> claimed that DMA works on i.MX25, i.MX31 and i.MX35 the respective
> device trees don't add DMA channels. The Reference manuals of i.MX31 and
> i.MX25 also don't mention the CSPI core being DMA capable. (I didn't
> check the others.)

If I'm not mistaken, the imx25 reference manual

https://www.nxp.com/docs/en/reference-manual/IMX25RM.pdf

does say that CSPI has DMA support. Section 18.1.1 (Features) lists DMA as one
of the features. There's also DMA events (section 3) for CSPI-1/2/3 RX, TX.

I'd have to dig up the hardware to test again if this is actually working...

   Martin

  reply	other threads:[~2024-05-08 14:01 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-08  9:56 [PATCH] spi: imx: Don't expect DMA for i.MX{25,35,50,51,53} cspi devices Uwe Kleine-König
2024-05-08 13:44 ` Martin Kaiser [this message]
2024-05-10 12:32   ` [PATCH] spi: imx: Don't expect DMA for i.MX{25, 35, 50, 51, 53} " Uwe Kleine-König
2024-05-10 13:40     ` Uwe Kleine-König
2024-05-12 16:14       ` Martin Kaiser
2024-05-15 19:26         ` Martin Kaiser
2024-06-12 16:52           ` Marc Kleine-Budde
2024-06-13 16:11             ` Martin Kaiser
2024-06-23 12:07 ` [PATCH] spi: imx: Don't expect DMA for i.MX{25,35,50,51,53} " Mark Brown

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