Re: [PATCH 3/5] Input: s3c2410_ts: Use devm_platform_ioremap_resource()

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Mukesh Ojha <mojha@codeaurora.org>
Cc: shawnguo@kernel.org, s.hauer@pengutronix.de, linux-imx@nxp.com,
	linux-input@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/5] Input: s3c2410_ts: Use devm_platform_ioremap_resource()
Date: Tue, 16 Jul 2019 09:39:35 +0200	[thread overview]
Message-ID: <20190716073935.GE1182@penguin> (raw)
In-Reply-To: <1554362243-2888-4-git-send-email-mojha@codeaurora.org>

Hi Mukesh,

On Thu, Apr 04, 2019 at 12:47:21PM +0530, Mukesh Ojha wrote:
> devm_platform_ioremap_resource() internally have platform_get_resource()
> and devm_ioremap_resource() in it. So instead of calling them separately
> use devm_platform_ioremap_resource() directly.
> 
> Signed-off-by: Mukesh Ojha <mojha@codeaurora.org>
> ---
>  drivers/input/touchscreen/s3c2410_ts.c | 10 +---------
>  1 file changed, 1 insertion(+), 9 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/s3c2410_ts.c b/drivers/input/touchscreen/s3c2410_ts.c
> index 1173890..e11cdae 100644
> --- a/drivers/input/touchscreen/s3c2410_ts.c
> +++ b/drivers/input/touchscreen/s3c2410_ts.c
> @@ -242,7 +242,6 @@ static int s3c2410ts_probe(struct platform_device *pdev)
>  	struct s3c2410_ts_mach_info *info;
>  	struct device *dev = &pdev->dev;
>  	struct input_dev *input_dev;
> -	struct resource *res;
>  	int ret = -EINVAL;
>  
>  	/* Initialise input stuff */
> @@ -277,14 +276,7 @@ static int s3c2410ts_probe(struct platform_device *pdev)
>  		goto err_clk;
>  	}
>  
> -	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> -	if (!res) {
> -		dev_err(dev, "no resource for registers\n");
> -		ret = -ENOENT;
> -		goto err_clk;
> -	}
> -
> -	ts.io = ioremap(res->start, resource_size(res));
> +	ts.io = devm_platform_ioremap_resource(pdev, 0);

This is not an equivalent transformation: the original code (rightly or
wrongly) did not request the memory regions described by 'res' while new
variant does.

Also you can't simply slap a single devm resource in a driver that does
not use managed resources as it messes up the release order.

-- 
Dmitry