linux-kernel - Re: [PATCH] drivers/applicom:Removed the unused variable byte_reset

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Message-ID: <2024100808-antarctic-matching-9be0@gregkh>
Date: Tue, 8 Oct 2024 09:47:55 +0200
From: Greg KH <gregkh@...uxfoundation.org>
To: Zhu Jun <zhujun2@...s.chinamobile.com>
Cc: arnd@...db.de, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drivers/applicom:Removed the unused variable
 byte_reset_it

On Tue, Oct 08, 2024 at 12:28:25AM -0700, Zhu Jun wrote:
> Remove unused variable and redundant readb in ac_register_board
> 
> Signed-off-by: Zhu Jun <zhujun2@...s.chinamobile.com>
> ---
>  drivers/char/applicom.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/drivers/char/applicom.c b/drivers/char/applicom.c
> index 9fed9706d9cd..ea25caf35346 100644
> --- a/drivers/char/applicom.c
> +++ b/drivers/char/applicom.c
> @@ -127,8 +127,6 @@ static int dummy;	/* dev_id for request_irq() */
>  static int ac_register_board(unsigned long physloc, void __iomem *loc, 
>  		      unsigned char boardno)
>  {
> -	volatile unsigned char byte_reset_it;
> -
>  	if((readb(loc + CONF_END_TEST)     != 0x00) ||
>  	   (readb(loc + CONF_END_TEST + 1) != 0x55) ||
>  	   (readb(loc + CONF_END_TEST + 2) != 0xAA) ||
> @@ -156,7 +154,6 @@ static int ac_register_board(unsigned long physloc, void __iomem *loc,
>  	apbs[boardno].RamIO = loc;
>  	init_waitqueue_head(&apbs[boardno].FlagSleepSend);
>  	spin_lock_init(&apbs[boardno].mutex);
> -	byte_reset_it = readb(loc + RAM_IT_TO_PC);

As Arnd said, this is doing something, please be more familiar with
hardware types (i.e. reads are required to ensure a write happens),
before removing lines that feel they are not needed, unless you can test
the driver change yourself.

thanks,

greg k-h