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SubjectRe: [PATCH] spi: imx: fix the burst length at DMA mode and CPU mode
Date
> -----Original Message-----
> From: Marc Kleine-Budde <mkl@pengutronix.de>
> Sent: Wednesday, January 31, 2024 4:08 PM
> To: Carlos Song <carlos.song@nxp.com>
> Cc: broonie@kernel.org; shawnguo@kernel.org; s.hauer@pengutronix.de;
> kernel@pengutronix.de; dl-linux-imx <linux-imx@nxp.com>; benjamin@bigler.one;
> stefanmoring@gmail.com; linux-kernel@vger.kernel.org;
> linux-arm-kernel@lists.infradead.org; linux-spi@vger.kernel.org
> Subject: [EXT] Re: [PATCH] spi: imx: fix the burst length at DMA mode and CPU
> mode
>
> On 31.01.2024 10:46:23, carlos.song@nxp.com wrote:
> > From: Carlos Song <carlos.song@nxp.com>
> >
> > For DMA mode, the bus width of the DMA is equal to the size of data
> > word, so burst length should be configured as bits per word.
> >
> > For CPU mode, because of the spi transfer len is in byte, so burst
> > length should be configured as bits per byte * spi_imx->count.
> >
> > Signed-off-by: Carlos Song <carlos.song@nxp.com>
> > Reviewed-by: Clark Wang <xiaoning.wang@nxp.com>
> > Fixes: e9b220aeacf1 ("spi: spi-imx: correctly configure burst length
> > when using dma")
> > Fixes: 5f66db08cbd3 ("spi: imx: Take in account bits per word instead
> > of assuming 8-bits")
> > ---
> > drivers/spi/spi-imx.c | 9 ++++-----
> > 1 file changed, 4 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c index
> > 546cdce525fc..b4ade2d53fef 100644
> > --- a/drivers/spi/spi-imx.c
> > +++ b/drivers/spi/spi-imx.c
> > @@ -54,7 +54,7 @@ MODULE_PARM_DESC(polling_limit_us,
> > #define MX51_ECSPI_CTRL_MAX_BURST 512
> > /* The maximum bytes that IMX53_ECSPI can transfer in target mode.*/
> > #define MX53_MAX_TRANSFER_BYTES 512
> > -
> > +#define BITS_PER_BYTE 8
>

It will be removed and I will send patch V2.
Thank you!

BR
Carlos

> That's already defined in linux/bits.h
>
> regards,
> Marc
>
> --
> Pengutronix e.K. | Marc Kleine-Budde |
> Embedded Linux | https://www.pengutronix.de |
> Vertretung Nürnberg | Phone: +49-5121-206917-129 |
> Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-9 |
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