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Message-ID: <60927fc6-2819-a01a-6ea8-f1af301b1bad@linaro.org>
Date: Thu, 6 Jul 2023 08:59:54 +0200
From: neil.armstrong@...aro.org
To: Dmitry Rokosov <ddrokosov@...rdevices.ru>,
gregkh@...uxfoundation.org, robh+dt@...nel.org,
krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
jbrunet@...libre.com, jirislaby@...nel.org, khilman@...libre.com,
martin.blumenstingl@...glemail.com
Cc: kelvin.zhang@...ogic.com, xianwei.zhao@...ogic.com,
kernel@...rdevices.ru, rockosov@...il.com,
linux-amlogic@...ts.infradead.org, linux-serial@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 2/7] tty: serial: meson: redesign the module to
platform_driver
On 05/07/2023 20:18, 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@...rdevices.ru>
> ---
> drivers/tty/serial/meson_uart.c | 51 ++++++++++-----------------------
> 1 file changed, 15 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c
> index bca54f3d92a1..dcf994a11a21 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,
> + "can't register uart driver\n");
> + }
> +
> port->iotype = UPIO_MEM;
> port->mapbase = res_mem->start;
> port->mapsize = resource_size(res_mem);
> @@ -776,6 +774,13 @@ static int meson_uart_remove(struct platform_device *pdev)
> uart_remove_one_port(&meson_uart_driver, port);
> meson_ports[pdev->id] = NULL;
>
> + for (int id = 0; id < AML_UART_PORT_NUM; id++)
> + if (meson_ports[id])
> + return 0;
> +
> + /* No more available uart ports, unregister uart driver */
> + uart_unregister_driver(&meson_uart_driver);
> +
> return 0;
> }
>
> @@ -809,33 +814,7 @@ 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);
>
> MODULE_AUTHOR("Carlo Caione <carlo@...one.org>");
> MODULE_DESCRIPTION("Amlogic Meson serial port driver");
Reviewed-by: Neil Armstrong <neil.armstrong@...aro.org>
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