From: Jouni Hogander <jouni.hogander@xxxxxxxxx>
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@xxxxxxxxx>
Signed-off-by: Jouni Hogander <jouni.hogander@xxxxxxxxx>
Signed-off-by: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/mach-omap2/serial.c | 55 ++++++++++++++++++++++++++++++++++++++---
1 files changed, 51 insertions(+), 4 deletions(-)
diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index 50bff3d..854ac94 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -30,7 +30,7 @@
#include "pm.h"
#include "prm-regbits-34xx.h"
-#define DEFAULT_TIMEOUT (2 * HZ)
+#define DEFAULT_TIMEOUT (5 * HZ)
struct omap_uart_state {
int num;
@@ -233,7 +233,10 @@ static void omap_uart_block_sleep(struct omap_uart_state *uart)
omap_uart_smart_idle_enable(uart, 0);
uart->can_sleep = 0;
- mod_timer(&uart->timer, jiffies + uart->timeout);
+ 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)
@@ -338,6 +341,8 @@ 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;
@@ -345,7 +350,7 @@ 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);
@@ -425,6 +430,39 @@ 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 */
@@ -494,6 +532,15 @@ 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);
--
1.6.2.2
--
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