linux-kernel - Re: [PATCH 3/9] memory: samsung: exynos5422-dmc: use scoped device node handling to simplify error paths

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Message-ID: <20240814174246.00007e4e@Huawei.com>
Date: Wed, 14 Aug 2024 17:42:46 +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 3/9] memory: samsung: exynos5422-dmc: use scoped device
 node handling to simplify error paths

On Mon, 12 Aug 2024 15:33:57 +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>
Trivial comments inline
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>

> ---
>  drivers/memory/samsung/exynos5422-dmc.c | 31 +++++++++++--------------------
>  1 file changed, 11 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/memory/samsung/exynos5422-dmc.c b/drivers/memory/samsung/exynos5422-dmc.c
> index da7ecd921c72..d3ae4d95a3ba 100644
> --- a/drivers/memory/samsung/exynos5422-dmc.c
> +++ b/drivers/memory/samsung/exynos5422-dmc.c
> @@ -4,6 +4,7 @@
>   * Author: Lukasz Luba <l.luba@...tner.samsung.com>
>   */
>  
> +#include <linux/cleanup.h>
>  #include <linux/clk.h>
>  #include <linux/devfreq.h>
>  #include <linux/devfreq-event.h>
> @@ -1176,10 +1177,10 @@ static int of_get_dram_timings(struct exynos5_dmc *dmc)
>  {
>  	int ret = 0;
>  	int idx;
> -	struct device_node *np_ddr;

This would definitely benefit from a
struct device *dev = dmc->dev;

>  	u32 freq_mhz, clk_period_ps;
>  
> -	np_ddr = of_parse_phandle(dmc->dev->of_node, "device-handle", 0);
> +	struct device_node *np_ddr __free(device_node) = of_parse_phandle(dmc->dev->of_node,
> +									  "device-handle", 0);
Trivial. Maybe consider the wrap suggested in patch 1.
> +	struct device_node *np_ddr __free(device_node) =
		of_parse_phandle(dmc->dev->of_node, "device-handle", 0);

>  	if (!np_ddr) {
>  		dev_warn(dmc->dev, "could not find 'device-handle' in DT\n");
>  		return -EINVAL;
> @@ -1187,39 +1188,31 @@ static int of_get_dram_timings(struct exynos5_dmc *dmc)
>  
>  	dmc->timing_row = devm_kmalloc_array(dmc->dev, TIMING_COUNT,
>  					     sizeof(u32), GFP_KERNEL);
> -	if (!dmc->timing_row) {
> -		ret = -ENOMEM;
> -		goto put_node;
> -	}
> +	if (!dmc->timing_row)
> +		return -ENOMEM;
>  
>  	dmc->timing_data = devm_kmalloc_array(dmc->dev, TIMING_COUNT,
>  					      sizeof(u32), GFP_KERNEL);
> -	if (!dmc->timing_data) {
> -		ret = -ENOMEM;
> -		goto put_node;
> -	}
> +	if (!dmc->timing_data)
> +		return -ENOMEM;
>  
>  	dmc->timing_power = devm_kmalloc_array(dmc->dev, TIMING_COUNT,
>  					       sizeof(u32), GFP_KERNEL);
> -	if (!dmc->timing_power) {
> -		ret = -ENOMEM;
> -		goto put_node;
> -	}
> +	if (!dmc->timing_power)
> +		return -ENOMEM;
>  
>  	dmc->timings = of_lpddr3_get_ddr_timings(np_ddr, dmc->dev,
>  						 DDR_TYPE_LPDDR3,
>  						 &dmc->timings_arr_size);
>  	if (!dmc->timings) {
>  		dev_warn(dmc->dev, "could not get timings from DT\n");
> -		ret = -EINVAL;
> -		goto put_node;
> +		return -EINVAL;
>  	}
>  
>  	dmc->min_tck = of_lpddr3_get_min_tck(np_ddr, dmc->dev);
>  	if (!dmc->min_tck) {
>  		dev_warn(dmc->dev, "could not get tck from DT\n");
> -		ret = -EINVAL;
> -		goto put_node;
> +		return -EINVAL;
>  	}
>  
>  	/* Sorted array of OPPs with frequency ascending */
> @@ -1239,8 +1232,6 @@ static int of_get_dram_timings(struct exynos5_dmc *dmc)
>  	dmc->bypass_timing_data = dmc->timing_data[idx - 1];
>  	dmc->bypass_timing_power = dmc->timing_power[idx - 1];
>  
> -put_node:
> -	of_node_put(np_ddr);
>  	return ret;
>  }
>  
>