V4L/DVB (8625): saa7134: Add NEC prococol IR decoding capability
This patch adds the capability of decoding NEC protocol, received via GPIO18 line.
This GPIO port can trigger saa7134 IRQ.
A future improvement would be to make it a little more generic to work also
with GPIO16 line.
A pure IRQ code didn't work, since some delays were introduced on the tests we
did.
A possible approach would be to use polling at a rate of 2.5 ms or less. If a
new code were taken, a code similar to nec_task() could be used. However, this
would add an extra overhead to kernel, and will consume more power.
Due to that, we took an hybrid approach: an IRQ upper half to trigger when a
new key is received and a bottom half to convert pulse-distance into a keycode.
The bottom half is polling based, to improve performance. During the bottom
half proccess, GPIO18 IRQ line is disabled, preventing IRQ reentrancy and
improving performance a little bit.
Thanks to Sistema Fenix (http://www.sistemafenix.com.br/) for sponsoring this
development.
Signed-off-by: Gilberto <gilberto@sistemafenix.com.br>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/include/media/ir-common.h b/include/media/ir-common.h
index b8e8aa9..f5566d4 100644
--- a/include/media/ir-common.h
+++ b/include/media/ir-common.h
@@ -25,6 +25,7 @@
#include <linux/input.h>
#include <linux/workqueue.h>
+#include <linux/interrupt.h>
#define IR_TYPE_RC5 1
#define IR_TYPE_PD 2 /* Pulse distance encoded IR */
@@ -85,6 +86,10 @@
u32 code; /* raw code under construction */
struct timeval base_time; /* time of last seen code */
int active; /* building raw code */
+
+ /* NEC decoding */
+ u32 nec_gpio;
+ struct tasklet_struct tlet;
};
void ir_input_init(struct input_dev *dev, struct ir_input_state *ir,