Input: i8042 - allow installing platform filters for incoming data
Some hardware (such as Dell laptops) signal a variety of events through
the i8042 controller, even if these don't map to keyboard events. Add
support for drivers to filter the i8042 event stream in order to respond
to these events and (if appropriate) block them from entering the input
stream.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index 634da68..d84a36e 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -126,6 +126,8 @@
static struct platform_device *i8042_platform_device;
static irqreturn_t i8042_interrupt(int irq, void *dev_id);
+static bool (*i8042_platform_filter)(unsigned char data, unsigned char str,
+ struct serio *serio);
void i8042_lock_chip(void)
{
@@ -139,6 +141,48 @@
}
EXPORT_SYMBOL(i8042_unlock_chip);
+int i8042_install_filter(bool (*filter)(unsigned char data, unsigned char str,
+ struct serio *serio))
+{
+ unsigned long flags;
+ int ret = 0;
+
+ spin_lock_irqsave(&i8042_lock, flags);
+
+ if (i8042_platform_filter) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ i8042_platform_filter = filter;
+
+out:
+ spin_unlock_irqrestore(&i8042_lock, flags);
+ return ret;
+}
+EXPORT_SYMBOL(i8042_install_filter);
+
+int i8042_remove_filter(bool (*filter)(unsigned char data, unsigned char str,
+ struct serio *port))
+{
+ unsigned long flags;
+ int ret = 0;
+
+ spin_lock_irqsave(&i8042_lock, flags);
+
+ if (i8042_platform_filter != filter) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ i8042_platform_filter = NULL;
+
+out:
+ spin_unlock_irqrestore(&i8042_lock, flags);
+ return ret;
+}
+EXPORT_SYMBOL(i8042_remove_filter);
+
/*
* 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.
@@ -373,7 +417,8 @@
* It is called from i8042_interrupt and thus is running with interrupts
* off and i8042_lock held.
*/
-static bool i8042_filter(unsigned char data, unsigned char str)
+static bool i8042_filter(unsigned char data, unsigned char str,
+ struct serio *serio)
{
if (unlikely(i8042_suppress_kbd_ack)) {
if ((~str & I8042_STR_AUXDATA) &&
@@ -384,6 +429,11 @@
}
}
+ if (i8042_platform_filter && i8042_platform_filter(data, str, serio)) {
+ dbg("Filtered out by platfrom filter\n");
+ return true;
+ }
+
return false;
}
@@ -396,6 +446,7 @@
static irqreturn_t i8042_interrupt(int irq, void *dev_id)
{
struct i8042_port *port;
+ struct serio *serio;
unsigned long flags;
unsigned char str, data;
unsigned int dfl;
@@ -462,18 +513,19 @@
}
port = &i8042_ports[port_no];
+ serio = port->exists ? port->serio : NULL;
dbg("%02x <- i8042 (interrupt, %d, %d%s%s)",
data, port_no, irq,
dfl & SERIO_PARITY ? ", bad parity" : "",
dfl & SERIO_TIMEOUT ? ", timeout" : "");
- filtered = i8042_filter(data, str);
+ filtered = i8042_filter(data, str, serio);
spin_unlock_irqrestore(&i8042_lock, flags);
if (likely(port->exists && !filtered))
- serio_interrupt(port->serio, data, dfl);
+ serio_interrupt(serio, data, dfl);
out:
return IRQ_RETVAL(ret);