linux-kernel - Re: [PATCH 3/6] dma:imx-dma:Use devm_clk_get

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240823130700.00001d6d@Huawei.com>
Date: Fri, 23 Aug 2024 13:07:00 +0100
From: Jonathan Cameron <Jonathan.Cameron@...wei.com>
To: Liao Yuanhong <liaoyuanhong@...o.com>
CC: <vkoul@...nel.org>, <linux-arm-kernel@...ts.infradead.org>,
	<dmaengine@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/6] dma:imx-dma:Use devm_clk_get_enabled() helpers

On Fri, 23 Aug 2024 18:19:30 +0800
Liao Yuanhong <liaoyuanhong@...o.com> wrote:

> Use devm_clk_get_enabled() instead of clk functions in imx-dma.
> 
> Signed-off-by: Liao Yuanhong <liaoyuanhong@...o.com>
Straight forward case, but nice to combine this with
use of return dev_err_probe() in the paths where you now have
direct returns.  Other comments below.

 
> ---
>  drivers/dma/imx-dma.c | 38 +++++++++++++-------------------------
>  1 file changed, 13 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/dma/imx-dma.c b/drivers/dma/imx-dma.c
> index ebf7c115d553..1ef926304d0e 100644
> --- a/drivers/dma/imx-dma.c
> +++ b/drivers/dma/imx-dma.c
> @@ -1039,6 +1039,8 @@ static int __init imxdma_probe(struct platform_device *pdev)
>  	struct imxdma_engine *imxdma;
>  	int ret, i;
>  	int irq, irq_err;
> +	struct clk *dma_ahb;
> +	struct clk *dma_ipg;
	struct clk *dma_ahb, *dma_ipg;
should be fine.
>  
>  	imxdma = devm_kzalloc(&pdev->dev, sizeof(*imxdma), GFP_KERNEL);
>  	if (!imxdma)
> @@ -1055,20 +1057,13 @@ static int __init imxdma_probe(struct platform_device *pdev)
>  	if (irq < 0)
>  		return irq;
>  
> -	imxdma->dma_ipg = devm_clk_get(&pdev->dev, "ipg");
> -	if (IS_ERR(imxdma->dma_ipg))
> -		return PTR_ERR(imxdma->dma_ipg);
> +	dma_ipg = devm_clk_get_enabled(&pdev->dev, "ipg");
> +	if (IS_ERR(dma_ipg))
> +		return PTR_ERR(dma_ipg);
>  
> -	imxdma->dma_ahb = devm_clk_get(&pdev->dev, "ahb");
> -	if (IS_ERR(imxdma->dma_ahb))
> -		return PTR_ERR(imxdma->dma_ahb);
> -
> -	ret = clk_prepare_enable(imxdma->dma_ipg);
> -	if (ret)
> -		return ret;
> -	ret = clk_prepare_enable(imxdma->dma_ahb);
> -	if (ret)
> -		goto disable_dma_ipg_clk;
> +	dma_ahb = devm_clk_get_enabled(&pdev->dev, "ahb");
> +	if (IS_ERR(dma_ahb))
> +		return PTR_ERR(dma_ahb);
>  
>  	/* reset DMA module */
>  	imx_dmav1_writel(imxdma, DCR_DRST, DMA_DCR);
> @@ -1078,21 +1073,21 @@ static int __init imxdma_probe(struct platform_device *pdev)
>  				       dma_irq_handler, 0, "DMA", imxdma);
>  		if (ret) {
>  			dev_warn(imxdma->dev, "Can't register IRQ for DMA\n");
> -			goto disable_dma_ahb_clk;
> +			return ret;
Odd not to make that a dev_error given driver fails to probe as a result.
I'd switch to return dev_err_rpobe()
>  		}
>  		imxdma->irq = irq;
>  
>  		irq_err = platform_get_irq(pdev, 1);
>  		if (irq_err < 0) {
>  			ret = irq_err;
> -			goto disable_dma_ahb_clk;
> +			return ret;
>  		}
>  
>  		ret = devm_request_irq(&pdev->dev, irq_err,
>  				       imxdma_err_handler, 0, "DMA", imxdma);
>  		if (ret) {
>  			dev_warn(imxdma->dev, "Can't register ERRIRQ for DMA\n");
> -			goto disable_dma_ahb_clk;
> +			return ret;
Here as well.

>  		}
>  		imxdma->irq_err = irq_err;
>  	}
> @@ -1130,7 +1125,7 @@ static int __init imxdma_probe(struct platform_device *pdev)
>  				dev_warn(imxdma->dev, "Can't register IRQ %d "
>  					 "for DMA channel %d\n",
>  					 irq + i, i);
> -				goto disable_dma_ahb_clk;
> +				return ret;
and here.

>  			}
>  
>  			imxdmac->irq = irq + i;
> @@ -1174,7 +1169,7 @@ static int __init imxdma_probe(struct platform_device *pdev)
>  	ret = dma_async_device_register(&imxdma->dma_device);
>  	if (ret) {
>  		dev_err(&pdev->dev, "unable to register\n");
> -		goto disable_dma_ahb_clk;
> +		return ret;
and finaly here.

>  	}
>  
>  	if (pdev->dev.of_node) {
> @@ -1190,10 +1185,6 @@ static int __init imxdma_probe(struct platform_device *pdev)
>  
>  err_of_dma_controller:
>  	dma_async_device_unregister(&imxdma->dma_device);
Maybe use a local callback and 
devm_add_action_or_reset() to get automate handling of this call as well.

> -disable_dma_ahb_clk:
> -	clk_disable_unprepare(imxdma->dma_ahb);
> -disable_dma_ipg_clk:
> -	clk_disable_unprepare(imxdma->dma_ipg);
>  	return ret;
>  }
>  
> @@ -1226,9 +1217,6 @@ static void imxdma_remove(struct platform_device *pdev)
>  
>  	if (pdev->dev.of_node)
>  		of_dma_controller_free(pdev->dev.of_node);
The ordering of the two items above here looks suspicious as it doesn't
reverse order of probably. Maybe worth cleaning that up whilst here.

> -
> -	clk_disable_unprepare(imxdma->dma_ipg);
> -	clk_disable_unprepare(imxdma->dma_ahb);
>  }
>  
>  static struct platform_driver imxdma_driver = {