Message-ID: <9a51b37b-d2c4-fb73-bd3f-447c94a66c82@canonical.com>
Date:   Mon, 29 Nov 2021 09:52:15 +0100
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.3.1
Subject: Re: [PATCH 5/8] tty: serial: samsung: Enable console as module
Content-Language: en-US
To:     Sam Protsenko <semen.protsenko@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Brown <broonie@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Jaewon Kim <jaewon02.kim@samsung.com>,
        Chanho Park <chanho61.park@samsung.com>,
        David Virag <virag.david003@gmail.com>,
        Youngmin Nam <youngmin.nam@samsung.com>,
        devicetree@vger.kernel.org, linux-spi@vger.kernel.org,
        linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
        linux-i2c@vger.kernel.org
References: <20211127223253.19098-1-semen.protsenko@linaro.org>
 <20211127223253.19098-6-semen.protsenko@linaro.org>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
In-Reply-To: <20211127223253.19098-6-semen.protsenko@linaro.org>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 27/11/2021 23:32, Sam Protsenko wrote:
> Enable serial driver to be built as a module. To do so, init the console
> support on driver/module load instead of using console_initcall().
> 
> This is needed for proper support of USIv2 driver (which can be built as
> a module, which in turn makes SERIAL_SAMSUNG be a module too). It also
> might be useful for Android GKI modularization efforts.
> 
> Inspired by commit 87a0b9f98ac5 ("tty: serial: meson: enable console as
> module").
> 
> Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
> ---
>  drivers/tty/serial/Kconfig       |  2 +-
>  drivers/tty/serial/samsung_tty.c | 21 +++++++++++++++++++--
>  2 files changed, 20 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> index fc543ac97c13..0e5ccb25bdb1 100644
> --- a/drivers/tty/serial/Kconfig
> +++ b/drivers/tty/serial/Kconfig
> @@ -263,7 +263,7 @@ config SERIAL_SAMSUNG_UARTS
>  
>  config SERIAL_SAMSUNG_CONSOLE
>  	bool "Support for console on Samsung SoC serial port"
> -	depends on SERIAL_SAMSUNG=y
> +	depends on SERIAL_SAMSUNG
>  	select SERIAL_CORE_CONSOLE
>  	select SERIAL_EARLYCON
>  	help
> diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
> index f986a9253dc8..92a63e9392ed 100644
> --- a/drivers/tty/serial/samsung_tty.c
> +++ b/drivers/tty/serial/samsung_tty.c
> @@ -1720,10 +1720,10 @@ static int __init s3c24xx_serial_console_init(void)
>  	register_console(&s3c24xx_serial_console);
>  	return 0;
>  }
> -console_initcall(s3c24xx_serial_console_init);
>  
>  #define S3C24XX_SERIAL_CONSOLE &s3c24xx_serial_console
>  #else
> +static inline int s3c24xx_serial_console_init(void) { return 0; }
>  #define S3C24XX_SERIAL_CONSOLE NULL
>  #endif
>  
> @@ -2898,7 +2898,24 @@ static struct platform_driver samsung_serial_driver = {
>  	},
>  };
>  
> -module_platform_driver(samsung_serial_driver);
> +static int __init samsung_serial_init(void)
> +{
> +	int ret;
> +
> +	ret = s3c24xx_serial_console_init();
> +	if (ret)
> +		return ret;

This will trigger warns on module re-loading, won't it? Either suppress
unbind or cleanup in module exit.

> +
> +	return platform_driver_register(&samsung_serial_driver);
> +}
> +
> +static void __exit samsung_serial_exit(void)
> +{
> +	platform_driver_unregister(&samsung_serial_driver);
> +}
> +
> +module_init(samsung_serial_init);
> +module_exit(samsung_serial_exit);
>  
>  #ifdef CONFIG_SERIAL_SAMSUNG_CONSOLE
>  /*
> 


Best regards,
Krzysztof