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/*
* linux/drivers/serial/pxa.c
*
* Based on drivers/serial/8250.c by Russell King.
*
* Author: Nicolas Pitre
* Created: Feb 20, 2003
* Copyright: (C) 2003 Monta Vista Software, Inc.
*
* 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.
*
* Note 1: This driver is made separate from the already too overloaded
* 8250.c because it needs some kirks of its own and that'll make it
* easier to add DMA support.
*
* Note 2: I'm too sick of device allocation policies for serial ports.
* If someone else wants to request an "official" allocation of major/minor
* for this driver please be my guest. And don't forget that new hardware
* to come from Intel might have more than 3 or 4 of those UARTs. Let's
* hope for a better port registration and dynamic device allocation scheme
* with the serial core maintainer satisfaction to appear soon.
*/
#if defined(CONFIG_SERIAL_PXA_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/serial_reg.h>
#include <linux/circ_buf.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <asm/io.h>
#include <asm/hardware.h>
#include <asm/irq.h>
#include <asm/arch/pxa-regs.h>
struct uart_pxa_port {
struct uart_port port;
unsigned char ier;
unsigned char lcr;
unsigned char mcr;
unsigned int lsr_break_flag;
unsigned int cken;
char *name;
};
static inline unsigned int serial_in(struct uart_pxa_port *up, int offset)
{
offset <<= 2;
return readl(up->port.membase + offset);
}
static inline void serial_out(struct uart_pxa_port *up, int offset, int value)
{
offset <<= 2;
writel(value, up->port.membase + offset);
}
static void serial_pxa_enable_ms(struct uart_port *port)
{
struct uart_pxa_port *up = (struct uart_pxa_port *)port;
up->ier |= UART_IER_MSI;
serial_out(up, UART_IER, up->ier);
}
static void serial_pxa_stop_tx(struct uart_port *port)
{
struct uart_pxa_port *up = (struct uart_pxa_port *)port;
if (up->ier & UART_IER_THRI) {
up->ier &= ~UART_IER_THRI;
serial_out(up, UART_IER, up->ier);
}
}
static void serial_pxa_stop_rx(struct uart_port *port)
{
struct uart_pxa_port *up = (struct uart_pxa_port *)port;
up->ier &= ~UART_IER_RLSI;
up->port.read_status_mask &= ~UART_LSR_DR;
serial_out(up, UART_IER, up->ier);
}
static inline void
receive_chars(struct uart_pxa_port *up, int *status, struct pt_regs *regs)
{
struct tty_struct *tty = up->port.info->tty;
unsigned int ch, flag;
int max_count = 256;
do {
ch = serial_in(up, UART_RX);
flag = TTY_NORMAL;
up->port.icount.rx++;
if (unlikely(*status & (UART_LSR_BI | UART_LSR_PE |
UART_LSR_FE | UART_LSR_OE))) {
/*
* For statistics only
*/
if (*status & UART_LSR_BI) {
*status &= ~(UART_LSR_FE | UART_LSR_PE);
up->port.icount.brk++;
/*
* We do the SysRQ and SAK checking
* here because otherwise the break
* may get masked by ignore_status_mask
* or read_status_mask.
*/
if (uart_handle_break(&up->port))
goto ignore_char;
} else if (*status & UART_LSR_PE)
up->port.icount.parity++;
else if (*status & UART_LSR_FE)
up->port.icount.frame++;
if (*status & UART_LSR_OE)
up->port.icount.overrun++;
/*
* Mask off conditions which should be ignored.
*/
*status &= up->port.read_status_mask;
#ifdef CONFIG_SERIAL_PXA_CONSOLE
if (up->port.line == up->port.cons->index) {
/* Recover the break flag from console xmit */
*status |= up->lsr_break_flag;
up->lsr_break_flag = 0;
}
#endif
if (*status & UART_LSR_BI) {
flag = TTY_BREAK;
} else if (*status & UART_LSR_PE)
flag = TTY_PARITY;
else if (*status & UART_LSR_FE)
flag = TTY_FRAME;
}
if (uart_handle_sysrq_char(&up->port, ch, regs))
goto ignore_char;
uart_insert_char(&up->port, *status, UART_LSR_OE, ch, flag);
ignore_char:
*status = serial_in(up, UART_LSR);
} while ((*status & UART_LSR_DR) && (max_count-- > 0));
tty_flip_buffer_push(tty);
}
static void transmit_chars(struct uart_pxa_port *up)
{
struct circ_buf *xmit = &up->port.info->xmit;
int count;
if (up->port.x_char) {
serial_out(up, UART_TX, up->port.x_char);
up->port.icount.tx++;
up->port.x_char = 0;
return;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) {
serial_pxa_stop_tx(&up->port);
return;
}
count = up->port.fifosize / 2;
do {
serial_out(up, UART_TX, xmit->buf[xmit->tail]);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
up->port.icount.tx++;
if (uart_circ_empty(xmit))
break;
} while (--count > 0);
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&up->port);
if (uart_circ_empty(xmit))
serial_pxa_stop_tx(&up->port);
}
static void serial_pxa_start_tx(struct uart_port *port)
{
struct uart_pxa_port *up = (struct uart_pxa_port *)port;
if (!(up->ier & UART_IER_THRI)) {
up->ier |= UART_IER_THRI;
serial_out(up, UART_IER, up->ier);
}
}
static inline void check_modem_status(struct uart_pxa_port *up)
{
int status;
status = serial_in(up, UART_MSR);
if ((status & UART_MSR_ANY_DELTA) == 0)
return;
if (status & UART_MSR_TERI)
up->port.icount.rng++;
if (status & UART_MSR_DDSR)
up->port.icount.dsr++;
if (status & UART_MSR_DDCD)
uart_handle_dcd_change(&up->port, status & UART_MSR_DCD);
if (status & UART_MSR_DCTS)
uart_handle_cts_change(&up->port, status & UART_MSR_CTS);
wake_up_interruptible(&up->port.info->delta_msr_wait);
}
/*
* This handles the interrupt from one port.
*/
static inline irqreturn_t
serial_pxa_irq(int irq, void *dev_id, struct pt_regs *regs)
{
struct uart_pxa_port *up = (struct uart_pxa_port *)dev_id;
unsigned int iir, lsr;
iir = serial_in(up, UART_IIR);
if (iir & UART_IIR_NO_INT)
return IRQ_NONE;
lsr = serial_in(up, UART_LSR);
if (lsr & UART_LSR_DR)
receive_chars(up, &lsr, regs);
check_modem_status(up);
if (lsr & UART_LSR_THRE)
transmit_chars(up);
return IRQ_HANDLED;
}
static unsigned int serial_pxa_tx_empty(struct uart_port *port)
{
struct uart_pxa_port *up = (struct uart_pxa_port *)port;
unsigned long flags;
unsigned int ret;
spin_lock_irqsave(&up->port.lock, flags);
ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
spin_unlock_irqrestore(&up->port.lock, flags);
return ret;
}
static unsigned int serial_pxa_get_mctrl(struct uart_port *port)
{
struct uart_pxa_port *up = (struct uart_pxa_port *)port;
unsigned char status;
unsigned int ret;
status = serial_in(up, UART_MSR);
ret = 0;
if (status & UART_MSR_DCD)
ret |= TIOCM_CAR;
if (status & UART_MSR_RI)
ret |= TIOCM_RNG;
if (status & UART_MSR_DSR)
ret |= TIOCM_DSR;
if (status & UART_MSR_CTS)
ret |= TIOCM_CTS;
return ret;
}
static void serial_pxa_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
struct uart_pxa_port *up = (struct uart_pxa_port *)port;
unsigned char mcr = 0;
if (mctrl & TIOCM_RTS)
mcr |= UART_MCR_RTS;
if (mctrl & TIOCM_DTR)
mcr |= UART_MCR_DTR;
if (mctrl & TIOCM_OUT1)
mcr |= UART_MCR_OUT1;
if (mctrl & TIOCM_OUT2)
mcr |= UART_MCR_OUT2;
if (mctrl & TIOCM_LOOP)
mcr |= UART_MCR_LOOP;
mcr |= up->mcr;
serial_out(up, UART_MCR, mcr);
}
static void serial_pxa_break_ctl(struct uart_port *port, int break_state)
{
struct uart_pxa_port *up = (struct uart_pxa_port *)port;
unsigned long flags;
spin_lock_irqsave(&up->port.lock, flags);
if (break_state == -1)
up->lcr |= UART_LCR_SBC;
else
up->lcr &= ~UART_LCR_SBC;
serial_out(up, UART_LCR, up->lcr);
spin_unlock_irqrestore(&up->port.lock, flags);
}
#if 0
static void serial_pxa_dma_init(struct pxa_uart *up)
{
up->rxdma =
pxa_request_dma(up->name, DMA_PRIO_LOW, pxa_receive_dma, up);
if (up->rxdma < 0)
goto out;
up->txdma =
pxa_request_dma(up->name, DMA_PRIO_LOW, pxa_transmit_dma, up);
if (up->txdma < 0)
goto err_txdma;
up->dmadesc = kmalloc(4 * sizeof(pxa_dma_desc), GFP_KERNEL);
if (!up->dmadesc)
goto err_alloc;
/* ... */
err_alloc:
pxa_free_dma(up->txdma);
err_rxdma:
pxa_free_dma(up->rxdma);
out:
return;
}
#endif
static int serial_pxa_startup(struct uart_port *port)
{
struct uart_pxa_port *up = (struct uart_pxa_port *)port;
unsigned long flags;
int retval;
if (port->line == 3) /* HWUART */
up->mcr |= UART_MCR_AFE;
else
up->mcr = 0;
/*
* Allocate the IRQ
*/
retval = request_irq(up->port.irq, serial_pxa_irq, 0, up->name, up);
if (retval)
return retval;
/*
* Clear the FIFO buffers and disable them.
* (they will be reenabled in set_termios())
*/
serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
serial_out(up, UART_FCR, 0);
/*
* Clear the interrupt registers.
*/
(void) serial_in(up, UART_LSR);
(void) serial_in(up, UART_RX);
(void) serial_in(up, UART_IIR);
(void) serial_in(up, UART_MSR);
/*
* Now, initialize the UART
*/
serial_out(up, UART_LCR, UART_LCR_WLEN8);
spin_lock_irqsave(&up->port.lock, flags);
up->port.mctrl |= TIOCM_OUT2;
serial_pxa_set_mctrl(&up->port, up->port.mctrl);
spin_unlock_irqrestore(&up->port.lock, flags);
/*
* Finally, enable interrupts. Note: Modem status interrupts
* are set via set_termios(), which will be occurring imminently
* anyway, so we don't enable them here.
*/
up->ier = UART_IER_RLSI | UART_IER_RDI | UART_IER_RTOIE | UART_IER_UUE;
serial_out(up, UART_IER, up->ier);
/*
* And clear the interrupt registers again for luck.
*/
(void) serial_in(up, UART_LSR);
(void) serial_in(up, UART_RX);
(void) serial_in(up, UART_IIR);
(void) serial_in(up, UART_MSR);
return 0;
}
static void serial_pxa_shutdown(struct uart_port *port)
{
struct uart_pxa_port *up = (struct uart_pxa_port *)port;
unsigned long flags;
free_irq(up->port.irq, up);
/*
* Disable interrupts from this port
*/
up->ier = 0;
serial_out(up, UART_IER, 0);
spin_lock_irqsave(&up->port.lock, flags);
up->port.mctrl &= ~TIOCM_OUT2;
serial_pxa_set_mctrl(&up->port, up->port.mctrl);
spin_unlock_irqrestore(&up->port.lock, flags);
/*
* Disable break condition and FIFOs
*/
serial_out(up, UART_LCR, serial_in(up, UART_LCR) & ~UART_LCR_SBC);
serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
UART_FCR_CLEAR_RCVR |
UART_FCR_CLEAR_XMIT);
serial_out(up, UART_FCR, 0);
}
static void
serial_pxa_set_termios(struct uart_port *port, struct termios *termios,
struct termios *old)
{
struct uart_pxa_port *up = (struct uart_pxa_port *)port;
unsigned char cval, fcr = 0;
unsigned long flags;
unsigned int baud, quot;
switch (termios->c_cflag & CSIZE) {
case CS5:
cval = UART_LCR_WLEN5;
break;
case CS6:
cval = UART_LCR_WLEN6;
break;
case CS7:
cval = UART_LCR_WLEN7;
break;
default:
case CS8:
cval = UART_LCR_WLEN8;
break;
}
if (termios->c_cflag & CSTOPB)
cval |= UART_LCR_STOP;
if (termios->c_cflag & PARENB)
cval |= UART_LCR_PARITY;
if (!(termios->c_cflag & PARODD))
cval |= UART_LCR_EPAR;
/*
* Ask the core to calculate the divisor for us.
*/
baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
quot = uart_get_divisor(port, baud);
if ((up->port.uartclk / quot) < (2400 * 16))
fcr = UART_FCR_ENABLE_FIFO | UART_FCR_PXAR1;
else if ((up->port.uartclk / quot) < (230400 * 16))
fcr = UART_FCR_ENABLE_FIFO | UART_FCR_PXAR8;
else
fcr = UART_FCR_ENABLE_FIFO | UART_FCR_PXAR32;
/*
* Ok, we're now changing the port state. Do it with
* interrupts disabled.
*/
spin_lock_irqsave(&up->port.lock, flags);
/*
* Ensure the port will be enabled.
* This is required especially for serial console.
*/
up->ier |= IER_UUE;
/*
* Update the per-port timeout.
*/
uart_update_timeout(port, termios->c_cflag, baud);
up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
if (termios->c_iflag & INPCK)
up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
if (termios->c_iflag & (BRKINT | PARMRK))
up->port.read_status_mask |= UART_LSR_BI;
/*
* Characters to ignore
*/
up->port.ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
if (termios->c_iflag & IGNBRK) {
up->port.ignore_status_mask |= UART_LSR_BI;
/*
* If we're ignoring parity and break indicators,
* ignore overruns too (for real raw support).
*/
if (termios->c_iflag & IGNPAR)
up->port.ignore_status_mask |= UART_LSR_OE;
}
/*
* ignore all characters if CREAD is not set
*/
if ((termios->c_cflag & CREAD) == 0)
up->port.ignore_status_mask |= UART_LSR_DR;
/*
* CTS flow control flag and modem status interrupts
*/
up->ier &= ~UART_IER_MSI;
if (UART_ENABLE_MS(&up->port, termios->c_cflag))
up->ier |= UART_IER_MSI;
serial_out(up, UART_IER, up->ier);
serial_out(up, UART_LCR, cval | UART_LCR_DLAB);/* set DLAB */
serial_out(up, UART_DLL, quot & 0xff); /* LS of divisor */
serial_out(up, UART_DLM, quot >> 8); /* MS of divisor */
serial_out(up, UART_LCR, cval); /* reset DLAB */
up->lcr = cval; /* Save LCR */
serial_pxa_set_mctrl(&up->port, up->port.mctrl);
serial_out(up, UART_FCR, fcr);
spin_unlock_irqrestore(&up->port.lock, flags);
}
static void
serial_pxa_pm(struct uart_port *port, unsigned int state,
unsigned int oldstate)
{
struct uart_pxa_port *up = (struct uart_pxa_port *)port;
pxa_set_cken(up->cken, !state);
if (!state)
udelay(1);
}
static void serial_pxa_release_port(struct uart_port *port)
{
}
static int serial_pxa_request_port(struct uart_port *port)
{
return 0;
}
static void serial_pxa_config_port(struct uart_port *port, int flags)
{
struct uart_pxa_port *up = (struct uart_pxa_port *)port;
up->port.type = PORT_PXA;
}
static int
serial_pxa_verify_port(struct uart_port *port, struct serial_struct *ser)
{
/* we don't want the core code to modify any port params */
return -EINVAL;
}
static const char *
serial_pxa_type(struct uart_port *port)
{
struct uart_pxa_port *up = (struct uart_pxa_port *)port;
return up->name;
}
#ifdef CONFIG_SERIAL_PXA_CONSOLE
static struct uart_pxa_port serial_pxa_ports[];
static struct uart_driver serial_pxa_reg;
#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
/*
* Wait for transmitter & holding register to empty
*/
static inline void wait_for_xmitr(struct uart_pxa_port *up)
{
unsigned int status, tmout = 10000;
/* Wait up to 10ms for the character(s) to be sent. */
do {
status = serial_in(up, UART_LSR);
if (status & UART_LSR_BI)
up->lsr_break_flag = UART_LSR_BI;
if (--tmout == 0)
break;
udelay(1);
} while ((status & BOTH_EMPTY) != BOTH_EMPTY);
/* Wait up to 1s for flow control if necessary */
if (up->port.flags & UPF_CONS_FLOW) {
tmout = 1000000;
while (--tmout &&
((serial_in(up, UART_MSR) & UART_MSR_CTS) == 0))
udelay(1);
}
}
static void serial_pxa_console_putchar(struct uart_port *port, int ch)
{
struct uart_pxa_port *up = (struct uart_pxa_port *)port;
wait_for_xmitr(up);
serial_out(up, UART_TX, ch);
}
/*
* Print a string to the serial port trying not to disturb
* any possible real use of the port...
*
* The console_lock must be held when we get here.
*/
static void
serial_pxa_console_write(struct console *co, const char *s, unsigned int count)
{
struct uart_pxa_port *up = &serial_pxa_ports[co->index];
unsigned int ier;
/*
* First save the IER then disable the interrupts
*/
ier = serial_in(up, UART_IER);
serial_out(up, UART_IER, UART_IER_UUE);
uart_console_write(&up->port, s, count, serial_pxa_console_putchar);
/*
* Finally, wait for transmitter to become empty
* and restore the IER
*/
wait_for_xmitr(up);
serial_out(up, UART_IER, ier);
}
static int __init
serial_pxa_console_setup(struct console *co, char *options)
{
struct uart_pxa_port *up;
int baud = 9600;
int bits = 8;
int parity = 'n';
int flow = 'n';
if (co->index == -1 || co->index >= serial_pxa_reg.nr)
co->index = 0;
up = &serial_pxa_ports[co->index];
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(&up->port, co, baud, parity, bits, flow);
}
static struct console serial_pxa_console = {
.name = "ttyS",
.write = serial_pxa_console_write,
.device = uart_console_device,
.setup = serial_pxa_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &serial_pxa_reg,
};
static int __init
serial_pxa_console_init(void)
{
register_console(&serial_pxa_console);
return 0;
}
console_initcall(serial_pxa_console_init);
#define PXA_CONSOLE &serial_pxa_console
#else
#define PXA_CONSOLE NULL
#endif
struct uart_ops serial_pxa_pops = {
.tx_empty = serial_pxa_tx_empty,
.set_mctrl = serial_pxa_set_mctrl,
.get_mctrl = serial_pxa_get_mctrl,
.stop_tx = serial_pxa_stop_tx,
.start_tx = serial_pxa_start_tx,
.stop_rx = serial_pxa_stop_rx,
.enable_ms = serial_pxa_enable_ms,
.break_ctl = serial_pxa_break_ctl,
.startup = serial_pxa_startup,
.shutdown = serial_pxa_shutdown,
.set_termios = serial_pxa_set_termios,
.pm = serial_pxa_pm,
.type = serial_pxa_type,
.release_port = serial_pxa_release_port,
.request_port = serial_pxa_request_port,
.config_port = serial_pxa_config_port,
.verify_port = serial_pxa_verify_port,
};
static struct uart_pxa_port serial_pxa_ports[] = {
{ /* FFUART */
.name = "FFUART",
.cken = CKEN6_FFUART,
.port = {
.type = PORT_PXA,
.iotype = UPIO_MEM,
.membase = (void *)&FFUART,
.mapbase = __PREG(FFUART),
.irq = IRQ_FFUART,
.uartclk = 921600 * 16,
.fifosize = 64,
.ops = &serial_pxa_pops,
.line = 0,
},
}, { /* BTUART */
.name = "BTUART",
.cken = CKEN7_BTUART,
.port = {
.type = PORT_PXA,
.iotype = UPIO_MEM,
.membase = (void *)&BTUART,
.mapbase = __PREG(BTUART),
.irq = IRQ_BTUART,
.uartclk = 921600 * 16,
.fifosize = 64,
.ops = &serial_pxa_pops,
.line = 1,
},
}, { /* STUART */
.name = "STUART",
.cken = CKEN5_STUART,
.port = {
.type = PORT_PXA,
.iotype = UPIO_MEM,
.membase = (void *)&STUART,
.mapbase = __PREG(STUART),
.irq = IRQ_STUART,
.uartclk = 921600 * 16,
.fifosize = 64,
.ops = &serial_pxa_pops,
.line = 2,
},
}, { /* HWUART */
.name = "HWUART",
.cken = CKEN4_HWUART,
.port = {
.type = PORT_PXA,
.iotype = UPIO_MEM,
.membase = (void *)&HWUART,
.mapbase = __PREG(HWUART),
.irq = IRQ_HWUART,
.uartclk = 921600 * 16,
.fifosize = 64,
.ops = &serial_pxa_pops,
.line = 3,
},
}
};
static struct uart_driver serial_pxa_reg = {
.owner = THIS_MODULE,
.driver_name = "PXA serial",
.dev_name = "ttyS",
.major = TTY_MAJOR,
.minor = 64,
.nr = ARRAY_SIZE(serial_pxa_ports),
.cons = PXA_CONSOLE,
};
static int serial_pxa_suspend(struct platform_device *dev, pm_message_t state)
{
struct uart_pxa_port *sport = platform_get_drvdata(dev);
if (sport)
uart_suspend_port(&serial_pxa_reg, &sport->port);
return 0;
}
static int serial_pxa_resume(struct platform_device *dev)
{
struct uart_pxa_port *sport = platform_get_drvdata(dev);
if (sport)
uart_resume_port(&serial_pxa_reg, &sport->port);
return 0;
}
static int serial_pxa_probe(struct platform_device *dev)
{
serial_pxa_ports[dev->id].port.dev = &dev->dev;
uart_add_one_port(&serial_pxa_reg, &serial_pxa_ports[dev->id].port);
platform_set_drvdata(dev, &serial_pxa_ports[dev->id]);
return 0;
}
static int serial_pxa_remove(struct platform_device *dev)
{
struct uart_pxa_port *sport = platform_get_drvdata(dev);
platform_set_drvdata(dev, NULL);
if (sport)
uart_remove_one_port(&serial_pxa_reg, &sport->port);
return 0;
}
static struct platform_driver serial_pxa_driver = {
.probe = serial_pxa_probe,
.remove = serial_pxa_remove,
.suspend = serial_pxa_suspend,
.resume = serial_pxa_resume,
.driver = {
.name = "pxa2xx-uart",
},
};
int __init serial_pxa_init(void)
{
int ret;
ret = uart_register_driver(&serial_pxa_reg);
if (ret != 0)
return ret;
ret = platform_driver_register(&serial_pxa_driver);
if (ret != 0)
uart_unregister_driver(&serial_pxa_reg);
return ret;
}
void __exit serial_pxa_exit(void)
{
platform_driver_unregister(&serial_pxa_driver);
uart_unregister_driver(&serial_pxa_reg);
}
module_init(serial_pxa_init);
module_exit(serial_pxa_exit);
MODULE_LICENSE("GPL");