[PATCH v2 4/5] tty: serial: samsung: Enable console as module

From: Sam Protsenko
Date: Mon Nov 29 2021 - 21:27:55 EST


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 USI 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@xxxxxxxxxx>
---
Changes in v2:
- Added error path handling in samsung_serial_init()
- Added console unregister in samsung_serial_exit()

drivers/tty/serial/Kconfig | 2 +-
drivers/tty/serial/samsung_tty.c | 36 ++++++++++++++++++++++++++++----
2 files changed, 33 insertions(+), 5 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..61ccb359620a 100644
--- a/drivers/tty/serial/samsung_tty.c
+++ b/drivers/tty/serial/samsung_tty.c
@@ -1715,15 +1715,21 @@ s3c24xx_serial_verify_port(struct uart_port *port, struct serial_struct *ser)

static struct console s3c24xx_serial_console;

-static int __init s3c24xx_serial_console_init(void)
+static void __init s3c24xx_serial_register_console(void)
{
register_console(&s3c24xx_serial_console);
- return 0;
}
-console_initcall(s3c24xx_serial_console_init);
+
+static void s3c24xx_serial_unregister_console(void)
+{
+ if (s3c24xx_serial_console.flags & CON_ENABLED)
+ unregister_console(&s3c24xx_serial_console);
+}

#define S3C24XX_SERIAL_CONSOLE &s3c24xx_serial_console
#else
+static inline void s3c24xx_serial_register_console(void) { }
+static inline void s3c24xx_serial_unregister_console(void) { }
#define S3C24XX_SERIAL_CONSOLE NULL
#endif

@@ -2898,7 +2904,29 @@ static struct platform_driver samsung_serial_driver = {
},
};

-module_platform_driver(samsung_serial_driver);
+static int __init samsung_serial_init(void)
+{
+ int ret;
+
+ s3c24xx_serial_register_console();
+
+ ret = platform_driver_register(&samsung_serial_driver);
+ if (ret) {
+ s3c24xx_serial_unregister_console();
+ return ret;
+ }
+
+ return 0;
+}
+
+static void __exit samsung_serial_exit(void)
+{
+ platform_driver_unregister(&samsung_serial_driver);
+ s3c24xx_serial_unregister_console();
+}
+
+module_init(samsung_serial_init);
+module_exit(samsung_serial_exit);

#ifdef CONFIG_SERIAL_SAMSUNG_CONSOLE
/*
--
2.30.2