[EXT] Re: [PATCH v2] i2c: imx-lpi2c: change to PIO mode in system-wide suspend/resume progress

[Carlos Song]

> -----Original Message-----
> From: Daniel Baluta <daniel.baluta at gmail.com>
> Sent: Thursday, November 20, 2025 9:56 PM
> To: Carlos Song <carlos.song at nxp.com>
> Cc: Aisheng Dong <aisheng.dong at nxp.com>; andi.shyti at kernel.org;
> shawnguo at kernel.org; s.hauer at pengutronix.de; kernel at pengutronix.de;
> Frank Li <frank.li at nxp.com>; linux-i2c at vger.kernel.org; imx at lists.linux.dev;
> linux-arm-kernel at lists.infradead.org; linux-kernel at vger.kernel.org
> Subject: [EXT] Re: [PATCH v2] i2c: imx-lpi2c: change to PIO mode in system-wide
> suspend/resume progress
> 
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> 
> On Thu, Nov 20, 2025 at 12:31 PM Carlos Song <carlos.song at nxp.com> wrote:
> >
> > EDMA resume is in early stage and suspend is in late stage, but LPI2C
> > resume and suspend are in NOIRQ stage. So LPI2C resource become ready
> > earlier than EDMA. When IRQ enabled, immediately slave will trigger
> > LPI2C to read data and the length meets the requirements for DMA
> > usage, the DMA will be needed at this time. Within a very small time
> > window, EDMA is still not resumed.
> >
> > If a system-wide suspend or resume transition is in progress. LPI2C
> > should use PIO to transfer data not DMA to avoid issue caused by not
> > ready DMA HW resource.
> >
> > Fixes: a09c8b3f9047 ("i2c: imx-lpi2c: add eDMA mode support for
> > LPI2C")
> > Signed-off-by: Carlos Song <carlos.song at nxp.com>
> > ---
> 
Thank you very much. I miss it. I will do this then.

> For future patches please add here a small description of what changed since v1:
> e.g
> 
> Changes since v1:
> * updated commit message as per discussion with Frank.