Date:   Sun, 28 Nov 2021 15:27:00 +0100
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Sam Protsenko <semen.protsenko@linaro.org>
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Brown <broonie@kernel.org>,
        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
Subject: Re: [PATCH 6/8] tty: serial: Make SERIAL_SAMSUNG=y impossible when
 EXYNOS_USI_V2=m
Message-ID: <YaORtBO4b9AyFYyd@kroah.com>
References: <20211127223253.19098-1-semen.protsenko@linaro.org>
 <20211127223253.19098-7-semen.protsenko@linaro.org>
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In-Reply-To: <20211127223253.19098-7-semen.protsenko@linaro.org>
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On Sun, Nov 28, 2021 at 12:32:51AM +0200, Sam Protsenko wrote:
> When UART is encapsulated in USIv2 block (e.g. in Exynos850), USIv2
> driver must be loaded first, as it's preparing USI hardware for
> particular protocol use. Make it impossible for Samsung serial driver to
> be built-in when USIv2 driver is built as a module, to prevent incorrect
> booting order for those drivers.
> 
> Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
> ---
>  drivers/tty/serial/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> index 0e5ccb25bdb1..47bc24e74041 100644
> --- a/drivers/tty/serial/Kconfig
> +++ b/drivers/tty/serial/Kconfig
> @@ -237,6 +237,7 @@ config SERIAL_CLPS711X_CONSOLE
>  config SERIAL_SAMSUNG
>  	tristate "Samsung SoC serial support"
>  	depends on PLAT_SAMSUNG || ARCH_S5PV210 || ARCH_EXYNOS || ARCH_APPLE || COMPILE_TEST
> +	depends on EXYNOS_USI_V2 || !EXYNOS_USI_V2

That's odd, and is not going to help if everything is built as a module
and loaded that way.

This needs to be done properly in code to handle the issues if the
"wrong" code is loaded first.  Please trigger off of the hardware type
correctly so you don't have to worry about this at all.

thanks,

greg k-h