linux-kernel - Re: [PATCH V3 2/2] serial: uartlite: Use dynamic allocation for major number when uart ports

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Message-Id: <20231116053502.a66a6da2a82db94f4cbdb350@hugovil.com>
Date:   Thu, 16 Nov 2023 05:35:02 -0500
From:   Hugo Villeneuve <hugo@...ovil.com>
To:     Manikanta Guntupalli <manikanta.guntupalli@....com>
Cc:     <git@....com>, <michal.simek@....com>, <jacmet@...site.dk>,
        <gregkh@...uxfoundation.org>, <jirislaby@...nel.org>,
        <linux-serial@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <corbet@....net>, <christophe.leroy@...roup.eu>,
        <rdunlap@...radead.org>, <airlied@...hat.com>,
        <ogabbay@...nel.org>, <linux-doc@...r.kernel.org>,
        <radhey.shyam.pandey@....com>, <srinivas.goud@....com>,
        <shubhrajyoti.datta@....com>, <manion05gk@...il.com>
Subject: Re: [PATCH V3 2/2] serial: uartlite: Use dynamic allocation for
 major number when uart ports > 4

On Thu, 16 Nov 2023 12:59:15 +0530
Manikanta Guntupalli <manikanta.guntupalli@....com> wrote:

Hi,

> Device number 204 has a range of minors on major number.
> uart_register_driver is failing due to lack of minor numbers
> when more number of uart ports used. So, to avoid minor number
> limitation on 204 major number use dynamic major allocation
> when more than 4 uart ports used otherwise use static major
> allocation.
> 
> https://docs.kernel.org/arch/arm/sa1100/serial_uart.html
> 
> Signed-off-by: Manikanta Guntupalli <manikanta.guntupalli@....com>
> ---
> Changes for V2:
> Update logic to use either static or dynamic major allocation.
> Update commit description.
> Update description of SERIAL_UARTLITE_NR_UARTS in Kconfig.
> Changes for V3:
> Fix typo.
> Remove parentheses.
> ---
>  drivers/tty/serial/Kconfig    | 2 ++
>  drivers/tty/serial/uartlite.c | 5 +++++
>  2 files changed, 7 insertions(+)
> 
> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> index 732c893c8d16..c3c82b740078 100644
> --- a/drivers/tty/serial/Kconfig
> +++ b/drivers/tty/serial/Kconfig
> @@ -532,6 +532,8 @@ config SERIAL_UARTLITE_NR_UARTS
>  	help
>  	  Set this to the number of uartlites in your system, or the number
>  	  you think you might implement.
> +	  If maximum number of uartlite serial ports are more than 4, then driver uses

"are more" -> "is more"

"then driver" -> "the driver" (or "then the driver")

Hugo.

> +	  dynamic allocation instead of static allocation for major number.
>  
>  config SERIAL_SUNCORE
>  	bool
> diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
> index 404c14acafa5..66d751edcf45 100644
> --- a/drivers/tty/serial/uartlite.c
> +++ b/drivers/tty/serial/uartlite.c
> @@ -24,8 +24,13 @@
>  #include <linux/pm_runtime.h>
>  
>  #define ULITE_NAME		"ttyUL"
> +#if CONFIG_SERIAL_UARTLITE_NR_UARTS > 4
> +#define ULITE_MAJOR             0       /* use dynamic node allocation */
> +#define ULITE_MINOR             0
> +#else
>  #define ULITE_MAJOR		204
>  #define ULITE_MINOR		187
> +#endif
>  #define ULITE_NR_UARTS		CONFIG_SERIAL_UARTLITE_NR_UARTS
>  
>  /* ---------------------------------------------------------------------
> -- 
> 2.25.1
> 


-- 
Hugo Villeneuve <hugo@...ovil.com>