[PATCH 2/8] altera_uart: Add support for polling mode (IRQ-less)

Anton Vorontsov
2010-10-01T13:21:43Z

Some Altera UART implementations doesn't route the IRQ line, so we have
to work in polling mode.

Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
---
drivers/serial/altera_uart.c | 23 ++++++++++++++++++++++-
1 files changed, 22 insertions(+), 1 deletions(-)

diff --git a/drivers/serial/altera_uart.c b/drivers/serial/altera_uart.c
index f8d8a00..7dd58da 100644
--- a/drivers/serial/altera_uart.c
+++ b/drivers/serial/altera_uart.c
@@ -15,6 +15,7 @@

#include <linux/kernel.h>
#include <linux/init.h>
+#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/console.h>
@@ -76,6 +77,7 @@
*/
struct altera_uart {
struct uart_port port;
+ struct timer_list tmr;
unsigned int sigs; /* Local copy of line sigs */
unsigned short imr; /* Local IMR mirror */
};
@@ -168,6 +170,7 @@ static void altera_uart_set_termios(struct uart_port *port,
tty_termios_encode_baud_rate(termios, baud, baud);

spin_lock_irqsave(&port->lock, flags);
+ uart_update_timeout(port, termios->c_cflag, baud);
writel(baudclk, port->membase + ALTERA_UART_DIVISOR_REG);
spin_unlock_irqrestore(&port->lock, flags);
}
@@ -268,6 +271,15 @@ static irqreturn_t altera_uart_interrupt(int irq, void *data)
return IRQ_RETVAL(isr);
}

+static void altera_uart_timer(unsigned long data)
+{
+ struct uart_port *port = (void *)data;
+ struct altera_uart *pp = container_of(port, struct altera_uart, port);
+
+ altera_uart_interrupt(0, port);
+ mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
+}
+
static void altera_uart_config_port(struct uart_port *port, int flags)
{
port->type = PORT_ALTERA_UART;
@@ -284,6 +296,12 @@ static int altera_uart_startup(struct uart_port *port)
unsigned long flags;
int ret;

+ if (!port->irq) {
+ setup_timer(&pp->tmr, altera_uart_timer, (unsigned long)port);
+ mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
+ return 0;
+ }
+
ret = request_irq(port->irq, altera_uart_interrupt, IRQF_DISABLED,
DRV_NAME, port);
if (ret) {
@@ -316,7 +334,10 @@ static void altera_uart_shutdown(struct uart_port *port)

spin_unlock_irqrestore(&port->lock, flags);

- free_irq(port->irq, port);
+ if (port->irq)
+ free_irq(port->irq, port);
+ else
+ del_timer_sync(&pp->tmr);
}

static const char *altera_uart_type(struct uart_port *port)
--
1.7.0.5