On Wed, Mar 14, 2018 at 2:36 AM, Daniel Kurtz <djkurtz@xxxxxxxxxxxx> wrote:
> AMD Carrizo / Stoneyridge use a DesignWare 8250 UART that uses a 48 MHz
> input clock.
>
> Allow these platforms to set up this clock by specifying a kernel command
> line like:
> earlycon=amdcz,mmio32,0xfedc6000,115200
>
Thanks, this is what I meant.
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Suggested-by: ?
> Signed-off-by: Daniel Kurtz <djkurtz@xxxxxxxxxxxx>
> ---
> drivers/tty/serial/8250/8250_early.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
> index ae6a256524d8..c6bf971a6038 100644
> --- a/drivers/tty/serial/8250/8250_early.c
> +++ b/drivers/tty/serial/8250/8250_early.c
> @@ -195,3 +195,18 @@ static int __init early_au_setup(struct earlycon_device *dev, const char *opt)
> OF_EARLYCON_DECLARE(palmchip, "ralink,rt2880-uart", early_au_setup);
>
> #endif
> +
> +#ifdef CONFIG_SERIAL_8250_DW
> +static int __init early_amdcz_setup(struct earlycon_device *dev,
> + const char *opt)
> +{
> + struct uart_port *port = &dev->port;
> +
> + port->uartclk = 48000000;
> +
> + return early_serial8250_setup(dev, opt);
> +}
> +
> +EARLYCON_DECLARE(amdcz, early_amdcz_setup);
> +
> +#endif
> --
> 2.16.2.804.g6dcf76e118-goog
>
--
With Best Regards,
Andy Shevchenko
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