8250_keystone.c
1.64 KB
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/*
* TI Keystone 16550 UART "driver"
*
* This isn't a full driver; it just provides for special initialization
* that keystone UARTs need. Everything else is just using the standard
* 8250 support.
*
* Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/
*
* 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 version 2.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <linux/of_platform.h>
#include <linux/serial_8250.h>
#include <linux/serial_reg.h>
#include "8250.h"
/*
* Texas Instruments Keystone registers
*/
#define UART_KEYSTONE_PWREMU 0x0c /* Power and Emulation */
/*
* Keystone PWREMU register definitions
*/
#define UART_KEYSTONE_PWREMU_FREE (1 << 0) /* Free-running enable */
#define UART_KEYSTONE_PWREMU_URRST (1 << 13) /* Receiver reset and enable */
#define UART_KEYSTONE_PWREMU_UTRST (1 << 14) /* Transmitter reset and enable */
int keystone_serial8250_init(struct uart_port *port)
{
unsigned long flags;
if (!of_device_is_compatible(port->dev->of_node, "ti,keystone-uart"))
return 0;
spin_lock_irqsave(&port->lock, flags);
serial_port_out(port, UART_KEYSTONE_PWREMU,
UART_KEYSTONE_PWREMU_FREE |
UART_KEYSTONE_PWREMU_URRST |
UART_KEYSTONE_PWREMU_UTRST);
spin_unlock_irqrestore(&port->lock, flags);
return 0;
}
EXPORT_SYMBOL(keystone_serial8250_init);