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Commit ba87a9be authored by Jouni Hogander's avatar Jouni Hogander Committed by Kevin Hilman
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OMAP: UART: Add sysfs interface for adjusting UART sleep timeout 



This patch makes it possible to change uart sleep timeout. New sysfs
entry is added (/sys/devices/platform/serial8250.<uart>/sleep_timeout)
Writing zero will disable the timeout feature and prevent UART clocks
from being disabled.

Also default timeout is increased to 5 second to make serial console
more usable.

Original patch was written by Tero Kristo.

Cc: Tero Kristo <Tero.Kristo@nokia.com>
Signed-off-by: default avatarJouni Hogander <jouni.hogander@nokia.com>
Signed-off-by: default avatarKevin Hilman <khilman@deeprootsystems.com>
parent 4af4016c

arch/arm/mach-omap2/serial.c

+51 −4
Original line number Diff line number Diff line
@@ -32,7 +32,7 @@ 


#define UART_OMAP_WER		0x17	/* Wake-up enable register */



#define DEFAULT_TIMEOUT (2 * HZ)

#define DEFAULT_TIMEOUT (5 * HZ)



struct omap_uart_state {

	int num;
@@ -235,7 +235,10 @@ static void omap_uart_block_sleep(struct omap_uart_state *uart) 


	omap_uart_smart_idle_enable(uart, 0);

	uart->can_sleep = 0;

	if (uart->timeout)

		mod_timer(&uart->timer, jiffies + uart->timeout);

	else

		del_timer(&uart->timer);

}



static void omap_uart_allow_sleep(struct omap_uart_state *uart)
@@ -340,6 +343,8 @@ static irqreturn_t omap_uart_interrupt(int irq, void *dev_id) 
	return IRQ_NONE;

}



static u32 sleep_timeout = DEFAULT_TIMEOUT;



static void omap_uart_idle_init(struct omap_uart_state *uart)

{

	u32 v;
@@ -347,7 +352,7 @@ static void omap_uart_idle_init(struct omap_uart_state *uart) 
	int ret;



	uart->can_sleep = 0;

	uart->timeout = DEFAULT_TIMEOUT;

	uart->timeout = sleep_timeout;

	setup_timer(&uart->timer, omap_uart_idle_timer,

		    (unsigned long) uart);

	mod_timer(&uart->timer, jiffies + uart->timeout);
@@ -427,6 +432,39 @@ static void omap_uart_idle_init(struct omap_uart_state *uart) 
	WARN_ON(ret);

}



static ssize_t sleep_timeout_show(struct kobject *kobj,

				  struct kobj_attribute *attr,

				  char *buf)

{

	return sprintf(buf, "%u\n", sleep_timeout / HZ);

}



static ssize_t sleep_timeout_store(struct kobject *kobj,

				   struct kobj_attribute *attr,

				   const char *buf, size_t n)

{

	struct omap_uart_state *uart;

	unsigned int value;



	if (sscanf(buf, "%u", &value) != 1) {

		printk(KERN_ERR "sleep_timeout_store: Invalid value\n");

		return -EINVAL;

	}

	sleep_timeout = value * HZ;

	list_for_each_entry(uart, &uart_list, node) {

		uart->timeout = sleep_timeout;

		if (uart->timeout)

			mod_timer(&uart->timer, jiffies + uart->timeout);

		else

			/* A zero value means disable timeout feature */

			omap_uart_block_sleep(uart);

	}

	return n;

}



static struct kobj_attribute sleep_timeout_attr =

	__ATTR(sleep_timeout, 0644, sleep_timeout_show, sleep_timeout_store);



#else

static inline void omap_uart_idle_init(struct omap_uart_state *uart) {}

#endif /* CONFIG_PM */
@@ -496,6 +534,15 @@ static struct platform_device serial_device = { 


static int __init omap_init(void)

{

	return platform_device_register(&serial_device);

	int ret;



	ret = platform_device_register(&serial_device);



#ifdef CONFIG_PM

	if (!ret)

		ret = sysfs_create_file(&serial_device.dev.kobj,

					&sleep_timeout_attr.attr);

#endif

	return ret;

}

arch_initcall(omap_init);