On 04/07/2023 15:59, Dmitry Rokosov wrote:
Actually, the meson_uart module is already a platform_driver, but it is
currently registered manually and the uart core registration is run
outside the probe() scope, which results in some restrictions. For
instance, it is not possible to communicate with the OF subsystem
because it requires an initialized device object.
To address this issue, apply module_platform_driver() instead of direct
module init/exit routines. Additionally, move uart_register_driver() to
the driver probe(), and destroy manual console registration because it's
already run in the uart_register_driver() flow.
Signed-off-by: Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxx>
---
drivers/tty/serial/meson_uart.c | 46 +++++++--------------------------
1 file changed, 10 insertions(+), 36 deletions(-)
diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c
index 169f028956ae..87c0eb5f2dba 100644
--- a/drivers/tty/serial/meson_uart.c
+++ b/drivers/tty/serial/meson_uart.c
@@ -621,12 +621,6 @@ static struct console meson_serial_console = {
.data = &meson_uart_driver,
};
-static int __init meson_serial_console_init(void)
-{
- register_console(&meson_serial_console);
- return 0;
-}
-
static void meson_serial_early_console_write(struct console *co,
const char *s,
u_int count)
@@ -652,9 +646,6 @@ OF_EARLYCON_DECLARE(meson, "amlogic,meson-ao-uart",
#define MESON_SERIAL_CONSOLE (&meson_serial_console)
#else
-static int __init meson_serial_console_init(void) {
- return 0;
-}
#define MESON_SERIAL_CONSOLE NULL
#endif
@@ -738,6 +729,13 @@ static int meson_uart_probe(struct platform_device *pdev)
if (ret)
return ret;
+ if (!meson_uart_driver.state) {
+ ret = uart_register_driver(&meson_uart_driver);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret,
+ "failed to register meson-uart driver\n");
+ }
PL010 protects this in a mutex, and I think you should do the same otherwise
if multiple uart probes at the same it will do weird stuff.
+
port->iotype = UPIO_MEM;
port->mapbase = res_mem->start;
port->mapsize = resource_size(res_mem);
@@ -776,6 +774,8 @@ static int meson_uart_remove(struct platform_device *pdev)
uart_remove_one_port(&meson_uart_driver, port);
meson_ports[pdev->id] = NULL;
+ uart_unregister_driver(&meson_uart_driver);
+
This is dangerous, it will remove the driver even if some uart are still attached to it.
You should probably do like in pl010_remove() and remove only if the last one is removed.
return 0;
}
@@ -809,33 +809,7 @@ static struct platform_driver meson_uart_platform_driver = {
},
};
-static int __init meson_uart_init(void)
-{
- int ret;
-
- ret = meson_serial_console_init();
- if (ret)
- return ret;
-
- ret = uart_register_driver(&meson_uart_driver);
- if (ret)
- return ret;
-
- ret = platform_driver_register(&meson_uart_platform_driver);
- if (ret)
- uart_unregister_driver(&meson_uart_driver);
-
- return ret;
-}
-
-static void __exit meson_uart_exit(void)
-{
- platform_driver_unregister(&meson_uart_platform_driver);
- uart_unregister_driver(&meson_uart_driver);
-}
-
-module_init(meson_uart_init);
-module_exit(meson_uart_exit);
+module_platform_driver(meson_uart_platform_driver);
Only pl010 uses this scheme, and I don't know why... if it works then it's ok for me.
Thanks,
Neil
MODULE_AUTHOR("Carlo Caione <carlo@xxxxxxxxxx>");
MODULE_DESCRIPTION("Amlogic Meson serial port driver");
