Re: [PATCH v1 3/5] tty: serial: meson: apply ttyS devname instead of ttyAML for new SoCs

Conor Dooley
2023-07-04T16:57:25Z

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On Tue, Jul 04, 2023 at 04:59:34PM +0300, Dmitry Rokosov wrote:
> It is worth noting that the devname ttyS is a widely recognized tty name
> and is commonly used by many uart device drivers. Given the established
> usage and compatibility concerns, it may not be feasible to change the
> devname for older SoCs. However, for new definitions, it is acceptable
> and even recommended to use a new devname to help ensure clarity and
> avoid any potential conflicts on lower or upper software levels.

> In
> addition, modify the meson_uart_dt match data for g12a, a1, and s4 to
> their appropriate values to ensure proper devname values and
> functionality.

IMO, this is a separate change that should be in another patch, had to
go looking through a several of unrelated $subject patches to understand
how the binding patch was going to work.

Cheers,
Conor.

> For more information please refer to IRC discussion at [1].
>
> Links:
> [1]: https://libera.irclog.whitequark.org/linux-amlogic/2023-07-03
>
> Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
> ---
> drivers/tty/serial/meson_uart.c | 33 +++++++++++++++++++++++++++++++--
> 1 file changed, 31 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c
> index 87c0eb5f2dba..361f9326b527 100644
> --- a/drivers/tty/serial/meson_uart.c
> +++ b/drivers/tty/serial/meson_uart.c
> @@ -82,6 +82,7 @@ static struct uart_driver meson_uart_driver;
> static struct uart_port *meson_ports[AML_UART_PORT_NUM];
>
> struct meson_uart_data {
> + const char *dev_name;
> bool has_xtal_div2;
> };
>
> @@ -683,6 +684,7 @@ static int meson_uart_probe_clocks(struct platform_device *pdev,
>
> static int meson_uart_probe(struct platform_device *pdev)
> {
> + const struct meson_uart_data *priv_data;
> struct resource *res_mem;
> struct uart_port *port;
> u32 fifosize = 64; /* Default is 64, 128 for EE UART_0 */
> @@ -729,6 +731,18 @@ static int meson_uart_probe(struct platform_device *pdev)
> if (ret)
> return ret;
>
> + priv_data = device_get_match_data(&pdev->dev);
> +
> + if (priv_data) {
> + struct console *cons = meson_uart_driver.cons;
> +
> + meson_uart_driver.dev_name = priv_data->dev_name;
> +
> + if (cons)
> + strscpy(cons->name, priv_data->dev_name,
> + sizeof(cons->name));
> + }
> +
> if (!meson_uart_driver.state) {
> ret = uart_register_driver(&meson_uart_driver);
> if (ret)
> @@ -748,7 +762,7 @@ static int meson_uart_probe(struct platform_device *pdev)
> port->x_char = 0;
> port->ops = &meson_uart_ops;
> port->fifosize = fifosize;
> - port->private_data = (void *)device_get_match_data(&pdev->dev);
> + port->private_data = (void *)priv_data;
>
> meson_ports[pdev->id] = port;
> platform_set_drvdata(pdev, port);
> @@ -780,6 +794,17 @@ static int meson_uart_remove(struct platform_device *pdev)
> }
>
> static struct meson_uart_data meson_g12a_uart_data = {
> + .dev_name = "ttyAML",
> + .has_xtal_div2 = true,
> +};
> +
> +static struct meson_uart_data meson_a1_uart_data = {
> + .dev_name = "ttyS",
> + .has_xtal_div2 = false,
> +};
> +
> +static struct meson_uart_data meson_s4_uart_data = {
> + .dev_name = "ttyS",
> .has_xtal_div2 = true,
> };
>
> @@ -794,7 +819,11 @@ static const struct of_device_id meson_uart_dt_match[] = {
> },
> {
> .compatible = "amlogic,meson-s4-uart",
> - .data = (void *)&meson_g12a_uart_data,
> + .data = (void *)&meson_s4_uart_data,
> + },
> + {
> + .compatible = "amlogic,meson-a1-uart",
> + .data = (void *)&meson_a1_uart_data,
> },
> { /* sentinel */ },
> };
> --
> 2.36.0
>

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