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Commit 0ab84da2 authored by Aaron Sierra's avatar Aaron Sierra Committed by Greg Kroah-Hartman
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serial: 8250: Preserve DLD[7:4] for PORT_XR17V35X 



The upper four bits of the XR17V35x fractional divisor register (DLD)
control general chip function (RS-485 direction pin polarity, multidrop
mode, XON/XOFF parity check, and fast IR mode). Don't allow these bits
to be clobbered when setting the baudrate.

Signed-off-by: default avatarAaron Sierra <asierra@xes-inc.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 8ffb8209

drivers/tty/serial/8250/8250_port.c

+4 −1
Original line number Original line Diff line number Diff line
@@ -2586,9 +2586,12 @@ static void serial8250_set_divisor(struct uart_port *port, unsigned int baud, 
	serial_dl_write(up, quot);

	serial_dl_write(up, quot);





	/* XR17V35x UARTs have an extra fractional divisor register (DLD) */

	/* XR17V35x UARTs have an extra fractional divisor register (DLD) */

	if (up->port.type == PORT_XR17V35X)

	if (up->port.type == PORT_XR17V35X) {

		/* Preserve bits not related to baudrate; DLD[7:4]. */

		quot_frac |= serial_port_in(port, 0x2) & 0xf0;

		serial_port_out(port, 0x2, quot_frac);

		serial_port_out(port, 0x2, quot_frac);

	}

	}

}





static unsigned int serial8250_get_baud_rate(struct uart_port *port,

static unsigned int serial8250_get_baud_rate(struct uart_port *port,

					     struct ktermios *termios,

					     struct ktermios *termios,