linux-kernel - Re: [PATCH v2 01/15] serial: sc16is7xx: remove useless enable of enhanced features

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Message-ID: <2025100219-neon-litter-24c0@gregkh>
Date: Thu, 2 Oct 2025 17:43:52 +0200
From: Greg KH <gregkh@...uxfoundation.org>
To: Hugo Villeneuve <hugo@...ovil.com>
Cc: jirislaby@...nel.org, fvallee@...rea.fr, linux-kernel@...r.kernel.org,
	linux-serial@...r.kernel.org,
	Hugo Villeneuve <hvilleneuve@...onoff.com>, stable@...r.kernel.org
Subject: Re: [PATCH v2 01/15] serial: sc16is7xx: remove useless enable of
 enhanced features

On Thu, Oct 02, 2025 at 10:57:24AM -0400, Hugo Villeneuve wrote:
> From: Hugo Villeneuve <hvilleneuve@...onoff.com>
> 
> Commit 43c51bb573aa ("sc16is7xx: make sure device is in suspend once
> probed") permanently enabled access to the enhanced features in
> sc16is7xx_probe(), and it is never disabled after that.
> 
> Therefore, remove useless re-enable of enhanced features in
> sc16is7xx_set_baud().
> 
> Fixes: 43c51bb573aa ("sc16is7xx: make sure device is in suspend once probed")
> Cc: stable@...r.kernel.org
> Signed-off-by: Hugo Villeneuve <hvilleneuve@...onoff.com>
> ---
>  drivers/tty/serial/sc16is7xx.c | 7 -------
>  1 file changed, 7 deletions(-)
> 
> diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
> index 1a2c4c14f6aac..c7435595dce13 100644
> --- a/drivers/tty/serial/sc16is7xx.c
> +++ b/drivers/tty/serial/sc16is7xx.c
> @@ -588,13 +588,6 @@ static int sc16is7xx_set_baud(struct uart_port *port, int baud)
>  		div /= prescaler;
>  	}
>  
> -	/* Enable enhanced features */
> -	sc16is7xx_efr_lock(port);
> -	sc16is7xx_port_update(port, SC16IS7XX_EFR_REG,
> -			      SC16IS7XX_EFR_ENABLE_BIT,
> -			      SC16IS7XX_EFR_ENABLE_BIT);
> -	sc16is7xx_efr_unlock(port);
> -
>  	/* If bit MCR_CLKSEL is set, the divide by 4 prescaler is activated. */
>  	sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
>  			      SC16IS7XX_MCR_CLKSEL_BIT,
> -- 
> 2.39.5
> 
> 

Why is this needed for stable kernels?  It's useless, what is it
harming?

If so, please send it separately, not as a part of a larger series.

thanks,

greg k-h