Re: spi-imx: add support for single burst mode (8,16,32)

[Vladimir Zapolskiy <vladimir_zapolskiy@xxxxxxxxxx>]

On 31.05.2016 12:40, Chris Ruehl wrote:
> Hi,
> 
> as imx6 using multiple burst to send data to spi slaves and drop the chipselect 
> between the words by default my sensor NXP MPL115A1 wasn't working.
> The hint comes from a discussion in the Freescale forum from 2013 where Jeff 
> Coffman posted his solution for a 3.x kernel.
> I'd pick-up the idea behind and develop something which works "so far" with
> 4.6 and linux-next
> 
> Up front - I'm not happy using the xfer->cs_change to get set the single burst
> I more likely want add a new xfer bit which allow to dedicated set a single burst.
> To replace todays:
>          xfer[0].cs_change = 0;
> with a
> 	xfer[0].singleburst = 1;
> 
> An other issue with is not yet solved; when I have a odd number of bytes (8 bpw) 
> in a transfer, its result in 3 bytes eaten on the start and 0x00 added on the 
> tail -

Do you use PIO or DMA transfer mode? The problem description resembles
a known issue within SDMA firmware (referenced as TKT238285 or ERR008517)
and you should not be able to face it, if SPI controller operates in PIO
mode.

--
With best wishes,
Vladimir
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