linux-kernel - Re: [PATCH 1/9] memory: atmel-ebi: use scoped device node handling to simplify error paths

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Message-ID: <20240814173834.000002c8@Huawei.com>
Date: Wed, 14 Aug 2024 17:38:34 +0100
From: Jonathan Cameron <Jonathan.Cameron@...wei.com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
CC: Krzysztof Kozlowski <krzk@...nel.org>, Nicolas Ferre
	<nicolas.ferre@...rochip.com>, Alexandre Belloni
	<alexandre.belloni@...tlin.com>, Claudiu Beznea <claudiu.beznea@...on.dev>,
	Lukasz Luba <lukasz.luba@....com>, Alim Akhtar <alim.akhtar@...sung.com>,
	Maxime Coquelin <mcoquelin.stm32@...il.com>, Alexandre Torgue
	<alexandre.torgue@...s.st.com>, Thierry Reding <thierry.reding@...il.com>,
	Jonathan Hunter <jonathanh@...dia.com>, Santosh Shilimkar
	<ssantosh@...nel.org>, <linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-pm@...r.kernel.org>,
	<linux-samsung-soc@...r.kernel.org>,
	<linux-stm32@...md-mailman.stormreply.com>, <linux-tegra@...r.kernel.org>
Subject: Re: [PATCH 1/9] memory: atmel-ebi: use scoped device node handling
 to simplify error paths

On Mon, 12 Aug 2024 15:33:55 +0200
Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org> wrote:

> Obtain the device node reference with scoped/cleanup.h to reduce error
> handling and make the code a bit simpler.
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>

Hi,

Comments inline.
> ---
>  drivers/memory/atmel-ebi.c | 29 ++++++++++-------------------
>  1 file changed, 10 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/memory/atmel-ebi.c b/drivers/memory/atmel-ebi.c
> index e8bb5f37f5cb..fcbfc2655d8d 100644
> --- a/drivers/memory/atmel-ebi.c
> +++ b/drivers/memory/atmel-ebi.c
> @@ -6,6 +6,7 @@
>   * Copyright (C) 2013 Jean-Jacques Hiblot <jjhiblot@...phandler.com>
>   */
>  
> +#include <linux/cleanup.h>
>  #include <linux/clk.h>
>  #include <linux/io.h>
>  #include <linux/mfd/syscon.h>
> @@ -517,7 +518,7 @@ static int atmel_ebi_dev_disable(struct atmel_ebi *ebi, struct device_node *np)
>  static int atmel_ebi_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> -	struct device_node *child, *np = dev->of_node, *smc_np;
> +	struct device_node *child, *np = dev->of_node;
>  	struct atmel_ebi *ebi;
>  	int ret, reg_cells;
>  	struct clk *clk;
> @@ -541,30 +542,24 @@ static int atmel_ebi_probe(struct platform_device *pdev)
>  
>  	ebi->clk = clk;
>  
> -	smc_np = of_parse_phandle(dev->of_node, "atmel,smc", 0);
> +	struct device_node *smc_np __free(device_node) = of_parse_phandle(dev->of_node,
> +									  "atmel,smc", 0);
Trivial:
I'd line break this as
> +	struct device_node *smc_np __free(device_node) =
		of_parse_phandle(dev->of_node, "atmel,smc", 0);

>  
>  	ebi->smc.regmap = syscon_node_to_regmap(smc_np);
> -	if (IS_ERR(ebi->smc.regmap)) {
> -		ret = PTR_ERR(ebi->smc.regmap);
> -		goto put_node;
> -	}
> +	if (IS_ERR(ebi->smc.regmap))
> +		return PTR_ERR(ebi->smc.regmap);
>  
>  	ebi->smc.layout = atmel_hsmc_get_reg_layout(smc_np);
> -	if (IS_ERR(ebi->smc.layout)) {
> -		ret = PTR_ERR(ebi->smc.layout);
> -		goto put_node;
> -	}
> +	if (IS_ERR(ebi->smc.layout))
> +		return PTR_ERR(ebi->smc.layout);
>  
>  	ebi->smc.clk = of_clk_get(smc_np, 0);
>  	if (IS_ERR(ebi->smc.clk)) {
> -		if (PTR_ERR(ebi->smc.clk) != -ENOENT) {
> -			ret = PTR_ERR(ebi->smc.clk);
> -			goto put_node;
> -		}
> +		if (PTR_ERR(ebi->smc.clk) != -ENOENT)
> +			return PTR_ERR(ebi->smc.clk);
>  
>  		ebi->smc.clk = NULL;
>  	}
> -	of_node_put(smc_np);

The large change in scope is a bit inelegant as it now hangs on to
the smc_np much longer than before.

Maybe it's worth pulling out the modified code as a 
atem_eb_probe_smc(struct device_node *smc_np, struct atmel_ebi_smc *smc )

or something like with a struct_group to define the atmel_ebi_smc

That would keep the tight scope for the data and generally simplify it
a bit.

>  	ret = clk_prepare_enable(ebi->smc.clk);
>  	if (ret)
>  		return ret;
> @@ -615,10 +610,6 @@ static int atmel_ebi_probe(struct platform_device *pdev)
>  	}
>  
>  	return of_platform_populate(np, NULL, NULL, dev);
> -
> -put_node:
> -	of_node_put(smc_np);
> -	return ret;
>  }
>  
>  static __maybe_unused int atmel_ebi_resume(struct device *dev)
>