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path: root/drivers/input/serio/i8042.c
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Diffstat (limited to 'drivers/input/serio/i8042.c')
-rw-r--r--drivers/input/serio/i8042.c41
1 files changed, 41 insertions, 0 deletions
diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index eb3ff94af58..bc56e52b945 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -87,8 +87,22 @@ static bool i8042_bypass_aux_irq_test;
#include "i8042.h"
+/*
+ * i8042_lock protects serialization between i8042_command and
+ * the interrupt handler.
+ */
static DEFINE_SPINLOCK(i8042_lock);
+/*
+ * Writers to AUX and KBD ports as well as users issuing i8042_command
+ * directly should acquire i8042_mutex (by means of calling
+ * i8042_lock_chip() and i8042_unlock_ship() helpers) to ensure that
+ * they do not disturb each other (unfortunately in many i8042
+ * implementations write to one of the ports will immediately abort
+ * command that is being processed by another port).
+ */
+static DEFINE_MUTEX(i8042_mutex);
+
struct i8042_port {
struct serio *serio;
int irq;
@@ -113,6 +127,18 @@ static struct platform_device *i8042_platform_device;
static irqreturn_t i8042_interrupt(int irq, void *dev_id);
+void i8042_lock_chip(void)
+{
+ mutex_lock(&i8042_mutex);
+}
+EXPORT_SYMBOL(i8042_lock_chip);
+
+void i8042_unlock_chip(void)
+{
+ mutex_unlock(&i8042_mutex);
+}
+EXPORT_SYMBOL(i8042_unlock_chip);
+
/*
* The i8042_wait_read() and i8042_wait_write functions wait for the i8042 to
* be ready for reading values from it / writing values to it.
@@ -1161,6 +1187,21 @@ static void __devexit i8042_unregister_ports(void)
}
}
+/*
+ * Checks whether port belongs to i8042 controller.
+ */
+bool i8042_check_port_owner(const struct serio *port)
+{
+ int i;
+
+ for (i = 0; i < I8042_NUM_PORTS; i++)
+ if (i8042_ports[i].serio == port)
+ return true;
+
+ return false;
+}
+EXPORT_SYMBOL(i8042_check_port_owner);
+
static void i8042_free_irqs(void)
{
if (i8042_aux_irq_registered)