Re: [PATCH] i2c: mxs: Add PIO and mixed-DMA support

[Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>]

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On Thu, Nov 22, 2012 at 01:50:37AM +0100, Marek Vasut wrote:
> Dear Marek Vasut,
> 
> > Add support for the PIO mode and mixed PIO/DMA mode support. The mixed
> > PIO/DMA is the default mode of operation. This shall leverage overhead
> > that the driver creates due to setting up DMA descriptors even for very
> > short transfers.
> > 
> > The current boundary between PIO/DMA 8 bytes, transfers shorter than 8
> > bytes are transfered by PIO, longer transfers use DMA. The performance
> > of write transfers remains unchanged, while there is a minor improvement
> > of read performance. Reading 16KB EEPROM with DMA-only operations gives
> > a read speed of 39.5KB/s, while with then new mixed-mode the speed is
> > blazing 40.6KB/s.
> > 
> > Signed-off-by: Marek Vasut <marex-ynQEQJNshbs@public.gmane.org>
> > Cc: Fabio Estevam <fabio.estevam-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
> > Cc: Shawn Guo <shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> > Cc: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> [...]
> 
> btw. Wolfram, you might want to drop me some credit into the MX28 i2c driver, I 
> suspect most of the code in there is mine now anyway :-D

It's fine if you do this yourself.

-- 
Pengutronix e.K.                           | Wolfram Sang                |
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