Re: [PATCH] spi: imx: Don't expect DMA for i.MX{25,35,50,51,53} cspi devices

[Martin Kaiser <martin@xxxxxxxxx>]

Hi Uwe,

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

> 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