[EXT] Re: [PATCH v3] i2c: imx: support DMA defer probing

Carlos Song carlos.song at nxp.com
Wed Nov 27 00:18:19 PST 2024



> -----Original Message-----
> From: Marc Kleine-Budde <mkl at pengutronix.de>
> Sent: Wednesday, November 27, 2024 3:59 PM
> To: Carlos Song <carlos.song at nxp.com>
> Cc: Frank Li <frank.li at nxp.com>; o.rempel at pengutronix.de; 
> kernel at pengutronix.de; andi.shyti at kernel.org; shawnguo at kernel.org; 
> s.hauer at pengutronix.de; festevam at gmail.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: Re: RE: [EXT] Re: [PATCH v3] i2c: imx: support DMA defer 
> probing
> 
> On 27.11.2024 07:48:13, Carlos Song wrote:
> > > >  static void i2c_imx_dma_callback(void *arg) @@ -1803,6 +1804,23 
> > > > @@ static int i2c_imx_probe(struct platform_device *pdev)
> > > >  	if (ret == -EPROBE_DEFER)
> > > >  		goto clk_notifier_unregister;
> > > >
> > > > +	/*
> > > > +	 * Init DMA config if supported, -ENODEV means DMA not enabled at
> > > > +	 * this platform, that is not a real error, so just remind "only
> > > > +	 * PIO mode is used". If DMA is enabled, but meet error when
> request
> > > > +	 * DMA channel, error should be showed in probe error log. PIO mode
> > > > +	 * should be available regardless of DMA.
> > > > +	 */
> > > > +	ret = i2c_imx_dma_request(i2c_imx, phy_addr);
> > > > +	if (ret) {
> > > > +		if (ret == -EPROBE_DEFER)
> > > > +			goto clk_notifier_unregister;
> > > > +		else if (ret == -ENODEV)
> > > > +			dev_info(&pdev->dev, "Only use PIO mode\n");
> > >
> > > On a system without DMA configured, with this patch we now get 
> > > this info message that wasn't there before. I think this might 
> > > annoy some people, so you should remove it.
> > >
> >
> > :-) hhh, get it.
> 
> Some things look reasonable when discussing the patch, but when you 
> see the new, cleaned-up version, you immediately realize that this is 
> going to annoy people :)
> 

Such valuable experience~ Thank you very much, Marc! This is definitely what I haven't thought about before.
I'll pay more attention in the future. :)

> > How about change to dev_dbg?
> 
> Good idea.
> 
Will fix it at V4.

> regards,
> Marc
> 
> --
> Pengutronix e.K.                 | Marc Kleine-Budde          |
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