linux-kernel - Re: [PATCH 3/7] Input: ep93xx_keypad: Prepare clock before using it

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Message-ID: <YMfQR8iM9be5Qg8+@google.com>
Date:   Mon, 14 Jun 2021 14:55:19 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Alexander Sverdlin <alexander.sverdlin@...il.com>
Cc:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        Nikita Shubin <nikita.shubin@...uefel.me>,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/7] Input: ep93xx_keypad: Prepare clock before using it

Hi Alexander,

On Mon, Jun 14, 2021 at 01:30:37AM +0200, Alexander Sverdlin wrote:
> Use clk_prepare_enable()/clk_disable_unprepare() in preparation for switch
> to Common Clock Framework.

Can this be merged standalone?

> 
> Signed-off-by: Alexander Sverdlin <alexander.sverdlin@...il.com>
> ---
>  drivers/input/keyboard/ep93xx_keypad.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/input/keyboard/ep93xx_keypad.c b/drivers/input/keyboard/ep93xx_keypad.c
> index c8194333d612..e0e931e796fa 100644
> --- a/drivers/input/keyboard/ep93xx_keypad.c
> +++ b/drivers/input/keyboard/ep93xx_keypad.c
> @@ -157,7 +157,7 @@ static int ep93xx_keypad_open(struct input_dev *pdev)
>  
>  	if (!keypad->enabled) {
>  		ep93xx_keypad_config(keypad);
> -		clk_enable(keypad->clk);
> +		clk_prepare_enable(keypad->clk);
>  		keypad->enabled = true;
>  	}
>  
> @@ -169,7 +169,7 @@ static void ep93xx_keypad_close(struct input_dev *pdev)
>  	struct ep93xx_keypad *keypad = input_get_drvdata(pdev);
>  
>  	if (keypad->enabled) {
> -		clk_disable(keypad->clk);
> +		clk_disable_unprepare(keypad->clk);
>  		keypad->enabled = false;

While we are at it, I wonder about handling suspend/resume. I see that
we disable the clock even if keyboard is configured as a wakeup source.
Is it really capable of waking up the system when clock is off?

Thanks.

-- 
Dmitry