linux-kernel - Re: [PATCH 2/2] Input: pxa27x_keypad: Handle return value of clk_prepare

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Date:   Thu, 31 Aug 2017 11:50:54 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Arvind Yadav <arvind.yadav.cs@...il.com>
Cc:     linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] Input: pxa27x_keypad: Handle return value of
 clk_prepare_enable.

On Tue, Aug 01, 2017 at 03:34:10PM +0530, Arvind Yadav wrote:
> clk_prepare_enable() can fail here and we must check its return value.
> 
> Signed-off-by: Arvind Yadav <arvind.yadav.cs@...il.com>
> ---
>  drivers/input/keyboard/pxa27x_keypad.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/input/keyboard/pxa27x_keypad.c b/drivers/input/keyboard/pxa27x_keypad.c
> index 3841fa3..a3396a7 100644
> --- a/drivers/input/keyboard/pxa27x_keypad.c
> +++ b/drivers/input/keyboard/pxa27x_keypad.c
> @@ -644,9 +644,12 @@ static void pxa27x_keypad_config(struct pxa27x_keypad *keypad)
>  static int pxa27x_keypad_open(struct input_dev *dev)
>  {
>  	struct pxa27x_keypad *keypad = input_get_drvdata(dev);
> -
> +	int ret;
>  	/* Enable unit clock */
> -	clk_prepare_enable(keypad->clk);
> +	ret = clk_prepare_enable(keypad->clk);
> +	if (ret)
> +		return ret;
> +
>  	pxa27x_keypad_config(keypad);
>  
>  	return 0;
> @@ -683,6 +686,7 @@ static int pxa27x_keypad_resume(struct device *dev)
>  	struct platform_device *pdev = to_platform_device(dev);
>  	struct pxa27x_keypad *keypad = platform_get_drvdata(pdev);
>  	struct input_dev *input_dev = keypad->input_dev;
> +	int ret;
>  
>  	/*
>  	 * If the keypad is used as wake up source, the clock is not turned
> @@ -695,7 +699,11 @@ static int pxa27x_keypad_resume(struct device *dev)
>  
>  		if (input_dev->users) {
>  			/* Enable unit clock */
> -			clk_prepare_enable(keypad->clk);
> +			ret = clk_prepare_enable(keypad->clk);
> +			if (ret) {
> +				mutex_unlock(&input_dev->mutex);
> +				return ret;
> +			}
>  			pxa27x_keypad_config(keypad);
>  		}

Rewrote as

	int ret = 0;

	...

		mutex_lock(&input_dev->mutex);

		if (input_dev->users) {
			/* Enable unit clock */
			ret = clk_prepare_enable(keypad->clk);
			if (!ret)
				pxa27x_keypad_config(keypad);
		}

		mutex_unlock(&input_dev->mutex);

	...
	return ret;

to avoid unlocking mutex in 2 places and applied, thanks.

-- 
Dmitry