Date:   Wed, 22 Dec 2021 07:10:44 +0100
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Cc:     linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Prabhakar <prabhakar.csengg@gmail.com>
Subject: Re: [PATCH] usb: renesas_usbhs: Fix unused variable warning
Message-ID: <YcLBZBwIZkhhKxGD@kroah.com>
References: <20211221171532.29881-1-prabhakar.mahadev-lad.rj@bp.renesas.com>
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On Tue, Dec 21, 2021 at 05:15:32PM +0000, Lad Prabhakar wrote:
> This patch fixes the below warning:
> 
> drivers/usb/renesas_usbhs/mod.c: In function 'usbhs_status_get_each_irq':
> drivers/usb/renesas_usbhs/mod.c:195:13: warning: variable 'intenb0'
> set but not used [-Wunused-but-set-variable]
>   195 |         u16 intenb0, intenb1;
>       |
> 
> Fixes: 33e4245ee919 ("usb: renesas_usbhs: Use platform_get_irq() to get the interrupt")
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
>  drivers/usb/renesas_usbhs/mod.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/renesas_usbhs/mod.c b/drivers/usb/renesas_usbhs/mod.c
> index f2ea3e1412d2..3919e350b487 100644
> --- a/drivers/usb/renesas_usbhs/mod.c
> +++ b/drivers/usb/renesas_usbhs/mod.c
> @@ -192,13 +192,12 @@ static int usbhs_status_get_each_irq(struct usbhs_priv *priv,
>  				     struct usbhs_irq_state *state)
>  {
>  	struct usbhs_mod *mod = usbhs_mod_get_current(priv);
> -	u16 intenb0, intenb1;
>  	unsigned long flags;
> +	u16 intenb1;
>  
>  	/********************  spin lock ********************/
>  	usbhs_lock(priv, flags);
>  	state->intsts0 = usbhs_read(priv, INTSTS0);
> -	intenb0 = usbhs_read(priv, INTENB0);

Did you just break the hardware?  Reading is often times needed and
clang has no idea about hardware issues.  We need proof in the changlog
that this really is safe to do.

How did you test your change?

thanks,

greg k-h