Re: [PATCH v2] i2c: imx: support DMA defer probing
From: Marc Kleine-Budde
Date: Tue Nov 26 2024 - 05:26:09 EST
On 26.11.2024 10:15:27, Carlos Song wrote:
> > > static void i2c_imx_dma_callback(void *arg) @@ -1803,6 +1804,13 @@
> > > static int i2c_imx_probe(struct platform_device *pdev)
> > > if (ret == -EPROBE_DEFER)
> > > goto clk_notifier_unregister;
> > >
> > > + /* Init DMA config if supported */
> > > + ret = i2c_imx_dma_request(i2c_imx, phy_addr);
> > > + if (ret == -EPROBE_DEFER) {
> > > + dev_err(&pdev->dev, "DMA not ready, go defer probe!\n");
> > > + goto clk_notifier_unregister;
> > > + }
> >
> > Don't spam the logs if the driver defers probing, it's not a error. And it looks
> > strange to ignore all other errors here. Either add a comment here, something
> > like "continue without DMA", or let the function return
> > 0 in case the driver should continue and propagate the error if the caller should
> > take care of it.
> >
>
> Hi,
> Thank you for your suggestion! I agree with you.
> I will change to this logic:
> ret = i2c_imx_dma_request(i2c_imx, phy_addr);
> if (ret) {
> if (ret == -EPROBE_DEFER)
> goto clk_notifier_unregister;
> dev_info(&pdev->dev, "use pio mode\n");
> }
>
> Ret = 0 -----> enable DMA successfully -------> no print
> Ret!=0 -----> defer probe ---------> no print and try again
> Ret!=0 -----> fail to enable DMA ------> remind now is using pio mode
>
> Do you think the logic is acceptable?
Yes, the other option is to move the logic into i2c_imx_dma_request()
and let it return 0 in case of DMA or fallback to PIO, or an error in
case of probe defer or a fatal error.
This way the probe function will look like this:
ret = i2c_imx_dma_request(i2c_imx, phy_addr);
if (ret)
return dev_err_probe(&pdev->dev, ret, "Failed to setup DMA\n");
regards,
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
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