MIPS: JZ4740: Add serial support

The JZ4740 UART interface is almost 16550 compatible.
The UART module needs to be enabled by setting a bit in the FCR register
and it has support for receive timeout interrupts.  Instead of adding yet
another machine specific quirk to the 8250 serial driver we provide a
serial_out implementation which sets the required additional flags.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1403/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Lars-Peter Clausen 2010-06-19 04:08:16 +00:00 committed by Ralf Baechle
parent eda0347bf8
commit c3b9566de8
2 changed files with 53 additions and 0 deletions

33
arch/mips/jz4740/serial.c Normal file
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/*
* Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
* JZ4740 serial support
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <linux/io.h>
#include <linux/serial_core.h>
#include <linux/serial_reg.h>
void jz4740_serial_out(struct uart_port *p, int offset, int value)
{
switch (offset) {
case UART_FCR:
value |= 0x10; /* Enable uart module */
break;
case UART_IER:
value |= (value & 0x4) << 2;
break;
default:
break;
}
writeb(value, p->membase + (offset << p->regshift));
}

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arch/mips/jz4740/serial.h Normal file
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/*
* Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
* JZ4740 serial support
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#ifndef __MIPS_JZ4740_SERIAL_H__
void jz4740_serial_out(struct uart_port *p, int offset, int value);
#endif