On 07/16/2015 04:29 AM, Joerg Roedel wrote:
> From: Joerg Roedel <jroe...@suse.de>
> 
> The XR17V35X UART needs the ECB bit set in its XR_EFR
> register to enable access to IER [7:5], ISR [5:4], FCR[5:4],
> MCR[7:5], and MSR [7:0].
> 
> Also reset the IER register to mask interrupts after access
> to all bits of this register has been enabled.
> 
> This makes my 8-port XR17V35X working with the in-kernel
> serial driver.

Reviewed-by: Peter Hurley <pe...@hurleysoftware.com>

Also, would you please find out what bits are set in the IER
that this fixes and let me know? I don't have this hardware.

Regards,
Peter Hurley

> Cc: Peter Hurley <pe...@hurleysoftware.com>
> Cc: Michael Welling <mwell...@ieee.org>
> Cc: Joe Schultz <jschu...@xes-inc.com>
> Signed-off-by: Joerg Roedel <jroe...@suse.de>
> ---
>  drivers/tty/serial/8250/8250_core.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/drivers/tty/serial/8250/8250_core.c 
> b/drivers/tty/serial/8250/8250_core.c
> index 37fff12..4124a91 100644
> --- a/drivers/tty/serial/8250/8250_core.c
> +++ b/drivers/tty/serial/8250/8250_core.c
> @@ -2164,6 +2164,21 @@ int serial8250_do_startup(struct uart_port *port)
>        */
>       enable_rsa(up);
>  #endif
> +
> +     if (port->type == PORT_XR17V35X) {
> +             /*
> +              * First enable access to IER [7:5], ISR [5:4], FCR [5:4],
> +              * MCR [7:5] and MSR [7:0]
> +              */
> +             serial_port_out(port, UART_XR_EFR, UART_EFR_ECB);
> +
> +             /*
> +              * Make sure all interrups are masked until initialization is
> +              * complete and the FIFOs are cleared
> +              */
> +             serial_port_out(port, UART_IER, 0);
> +     }
> +
>       /*
>        * Clear the FIFO buffers and disable them.
>        * (they will be reenabled in set_termios())
> 

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