linux-kernel - Re: [PATCH v6] i2c: imx: support DMA defer probing

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Message-ID: <gfjir4qyyptxjizkc2k5r2elwn74fndia644evv6acwyuj3fr5@3pl3xt7rqntw>
Date: Tue, 24 Dec 2024 00:13:52 +0100
From: Andi Shyti <andi.shyti@...nel.org>
To: Carlos Song <carlos.song@....com>
Cc: o.rempel@...gutronix.de, kernel@...gutronix.de, shawnguo@...nel.org, 
	s.hauer@...gutronix.de, festevam@...il.com, linux-i2c@...r.kernel.org, 
	imx@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, Clark Wang <xiaoning.wang@....com>, 
	Ahmad Fatoum <a.fatoum@...gutronix.de>
Subject: Re: [PATCH v6] i2c: imx: support DMA defer probing

Hi Carlos,

...

> @@ -1802,6 +1803,18 @@ static int i2c_imx_probe(struct platform_device *pdev)
>  	if (ret == -EPROBE_DEFER)
>  		goto clk_notifier_unregister;
>  
> +	/* As we can always fall back to PIO, let's ignore the error setting up 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_dbg(&pdev->dev, "Only use PIO mode\n");
> +		else
> +			dev_err(&pdev->dev, "Failed to setup DMA (%pe), only use PIO mode\n",
> +				ERR_PTR(ret));

My question here is not just about the use of dev_err vs
dev_err_probe, but why don't we exit the probe if we get an
error.

We should use PIO only in case of ENODEV, in all the other cases
I think we should just leave. E.g. why don't we exit if we meet
ret == -ENOMEM?

Andi