linux-kernel - Re: [PATCH v2 1/5] dmaengine: qcom: bam

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Date:   Wed, 14 Feb 2018 18:19:54 +0000
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     vinod.koul@...el.com, andy.gross@...aro.org,
        dmaengine@...r.kernel.org, robh+dt@...nel.org,
        mark.rutland@....com, david.brown@...aro.org,
        dan.j.williams@...el.com, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-soc@...r.kernel.org, yanhe@...cinc.com,
        ramkri@....qualcomm.com, sdharia@...cinc.com
Subject: Re: [PATCH v2 1/5] dmaengine: qcom: bam_dma: make bam clk optional

Thanks for the Review,

On 14/02/18 15:41, Bjorn Andersson wrote:
>>   
>>   	bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk");
>> -	if (IS_ERR(bdev->bamclk))
>> -		return PTR_ERR(bdev->bamclk);
>> -
>> -	ret = clk_prepare_enable(bdev->bamclk);
>> -	if (ret) {
>> -		dev_err(bdev->dev, "failed to prepare/enable clock\n");
>> -		return ret;
>> +	if (IS_ERR(bdev->bamclk)) {
> In the case of !bdev->controlled_remotely I think this should still be
> an error.
> 
Yep makes sense,

You mean something like this?

------------------------->cut<------------------------
         bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk");
         if (IS_ERR(bdev->bamclk)) {
                 if (!bdev->controlled_remotely);
                         return PTR_ERR(bdev->bamclk);

                 bdev->bamclk = NULL;
         }

         ret = clk_prepare_enable(bdev->bamclk);
         if (ret) {
                 dev_err(bdev->dev, "failed to prepare/enable clock\n");
                 return ret;
         }

------------------------->cut<------------------------


>> +		bdev->bamclk = NULL;
>> +	} else {
>> +		ret = clk_prepare_enable(bdev->bamclk);
>> +		if (ret) {
>> +			dev_err(bdev->dev, "failed to prepare/enable clock\n");
>> +			return ret;
>> +		}
> The rest of the driver will keep operating the bamclk (which is okay),
> so for symmetry purposes I think you should just keep the
> clk_prepare_enable() block unmodified.
> 
Yep, with above change, this block should be unchanged.


--srini
> Regards,
> Bjorn