linux-kernel - Re: [PATCH 06/11] usb: dwc3: imx8mp: use scoped device node handling to simplify error paths

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Message-ID: <ZrzQvfSa7Q9MGdRp@lizhi-Precision-Tower-5810>
Date: Wed, 14 Aug 2024 11:43:57 -0400
From: Frank Li <Frank.li@....com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc: Patrice Chotard <patrice.chotard@...s.st.com>,
	Thinh Nguyen <Thinh.Nguyen@...opsys.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Shawn Guo <shawnguo@...nel.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Pengutronix Kernel Team <kernel@...gutronix.de>,
	Fabio Estevam <festevam@...il.com>,
	Michal Simek <michal.simek@....com>,
	linux-arm-kernel@...ts.infradead.org, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org, imx@...ts.linux.dev,
	linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH 06/11] usb: dwc3: imx8mp: use scoped device node handling
 to simplify error paths

On Wed, Aug 14, 2024 at 12:35:42PM +0200, Krzysztof Kozlowski wrote:
> Obtain the device node reference with scoped/cleanup.h to reduce error
> handling and make the code a bit simpler.  Scoped/cleanup.h coding style
> expects variable declaration with initialization, so the
> of_get_compatible_child() call has to be moved earlier, before any goto
> jumps happen.
>
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>

Reviewed-by: Frank Li <Frank.Li@....com>

> ---
>  drivers/usb/dwc3/dwc3-imx8mp.c | 20 ++++++++------------
>  1 file changed, 8 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/usb/dwc3/dwc3-imx8mp.c b/drivers/usb/dwc3/dwc3-imx8mp.c
> index 869b5e7c15ed..8b88649b569f 100644
> --- a/drivers/usb/dwc3/dwc3-imx8mp.c
> +++ b/drivers/usb/dwc3/dwc3-imx8mp.c
> @@ -5,6 +5,7 @@
>   * Copyright (c) 2020 NXP.
>   */
>
> +#include <linux/cleanup.h>
>  #include <linux/clk.h>
>  #include <linux/interrupt.h>
>  #include <linux/io.h>
> @@ -147,7 +148,7 @@ static irqreturn_t dwc3_imx8mp_interrupt(int irq, void *_dwc3_imx)
>  static int dwc3_imx8mp_probe(struct platform_device *pdev)
>  {
>  	struct device		*dev = &pdev->dev;
> -	struct device_node	*dwc3_np, *node = dev->of_node;
> +	struct device_node	*node = dev->of_node;
>  	struct dwc3_imx8mp	*dwc3_imx;
>  	struct resource		*res;
>  	int			err, irq;
> @@ -193,6 +194,11 @@ static int dwc3_imx8mp_probe(struct platform_device *pdev)
>  		return irq;
>  	dwc3_imx->irq = irq;
>
> +	struct device_node *dwc3_np __free(device_node) = of_get_compatible_child(node,
> +										  "snps,dwc3");
> +	if (!dwc3_np)
> +		return dev_err_probe(dev, -ENODEV, "failed to find dwc3 core child\n");
> +
>  	imx8mp_configure_glue(dwc3_imx);
>
>  	pm_runtime_set_active(dev);
> @@ -201,17 +207,10 @@ static int dwc3_imx8mp_probe(struct platform_device *pdev)
>  	if (err < 0)
>  		goto disable_rpm;
>
> -	dwc3_np = of_get_compatible_child(node, "snps,dwc3");
> -	if (!dwc3_np) {
> -		err = -ENODEV;
> -		dev_err(dev, "failed to find dwc3 core child\n");
> -		goto disable_rpm;
> -	}
> -
>  	err = of_platform_populate(node, NULL, NULL, dev);
>  	if (err) {
>  		dev_err(&pdev->dev, "failed to create dwc3 core\n");
> -		goto err_node_put;
> +		goto disable_rpm;
>  	}
>
>  	dwc3_imx->dwc3 = of_find_device_by_node(dwc3_np);
> @@ -220,7 +219,6 @@ static int dwc3_imx8mp_probe(struct platform_device *pdev)
>  		err = -ENODEV;
>  		goto depopulate;
>  	}
> -	of_node_put(dwc3_np);
>
>  	err = devm_request_threaded_irq(dev, irq, NULL, dwc3_imx8mp_interrupt,
>  					IRQF_ONESHOT, dev_name(dev), dwc3_imx);
> @@ -236,8 +234,6 @@ static int dwc3_imx8mp_probe(struct platform_device *pdev)
>
>  depopulate:
>  	of_platform_depopulate(dev);
> -err_node_put:
> -	of_node_put(dwc3_np);
>  disable_rpm:
>  	pm_runtime_disable(dev);
>  	pm_runtime_put_noidle(dev);
>
> --
> 2.43.0
>