linux-kernel - Re: [RESEND] i2c: imx: defer probing on dma channel request

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Date:   Tue, 26 Mar 2019 10:24:03 +0000
From:   Peter Rosin <peda@...ntia.se>
To:     Steven Price <steven.price@....com>,
        "laurentiu.tudor@....com" <laurentiu.tudor@....com>,
        "linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
        "ying.zhang22455@....com" <ying.zhang22455@....com>
CC:     "upstream-release@...ux.nxdi.nxp.com" 
        <upstream-release@...ux.nxdi.nxp.com>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "leoyang.li@....com" <leoyang.li@....com>,
        "linux-imx@....com" <linux-imx@....com>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "festevam@...il.com" <festevam@...il.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [RESEND] i2c: imx: defer probing on dma channel request

On 2019-03-25 18:12, Steven Price wrote:
> On 25/03/2019 15:30, laurentiu.tudor@....com wrote:
>> From: Laurentiu Tudor <laurentiu.tudor@....com>
>>
>> If the dma controller is not yet probed, defer i2c probe.
>> The error path in probe was slightly modified (no functional change)

*snip*

>> @@ -1161,19 +1162,25 @@ static int i2c_imx_probe(struct platform_device *pdev)
>>  	pm_runtime_mark_last_busy(&pdev->dev);
>>  	pm_runtime_put_autosuspend(&pdev->dev);
>>  
>> +	/* Init DMA config if supported */
>> +	ret = i2c_imx_dma_request(i2c_imx, phy_addr);
>> +	if (ret) {
>> +		if (ret != -EPROBE_DEFER)
>> +			dev_info(&pdev->dev, "can't use DMA, using PIO instead.\n");
>> +		else
>> +			goto del_adapter;
>> +	}
>> +
> 
> This can be simplified by reversing the condition:
> 
> 	if (ret) {
> 		if (ret == -EPROBE_DEFER)
> 			goto del_adapter;
> 		dev_info();
> 	}
> 
> or even:
> 
> 	if (ret == -EPROBE_DEFER)
> 		goto del_adapter;
> 	else if (ret)
> 		dev_info();
> 

While we're looking for stuff to take out, zap the "else"...

	if (ret == -EPROBE_DEFER)
		goto del_adapter;
	if (ret)
		dev_info(...);

Cheers,
Peter