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authorJouni Hogander <jouni.hogander@nokia.com>2008-12-09 13:36:50 +0200
committerKevin Hilman <khilman@deeprootsystems.com>2009-05-28 10:59:07 -0700
commitba87a9beae8b39894f55761f4aff5ae2ca624f81 (patch)
tree58947da1a5ea2f46212c3460700f0175441b2be0 /arch
parent4af4016c53f52b26461b8030211f8427a58fa5ed (diff)
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: Jouni Hogander <jouni.hogander@nokia.com> Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/mach-omap2/serial.c55
1 files changed, 51 insertions, 4 deletions
diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index 53cbe0620286..a0a280377a8c 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -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;
- 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)
@@ -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);