[media] rc: rc-loopback: Add loopback of filter scancodes

Add the s_wakeup_filter callback to the rc-loopback driver, which instead of
setting the filter just feeds the scancode back through the input device
so that it can be verified.

Signed-off-by: James Hogan <[e-mail]>
Signed-off-by: Antti Seppälä <[e-mail]>
Cc: David Härdeman <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/rc/rc-loopback.c

···
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/sched.h>
+#include <linux/slab.h>
 #include <media/rc-core.h>
 
 #define DRIVER_NAME	"rc-loopback"
···
 	return 0;
 }
 
+static int loop_set_wakeup_filter(struct rc_dev *dev,
+				  struct rc_scancode_filter *sc_filter)
+{
+	static const unsigned int max = 512;
+	struct ir_raw_event *raw;
+	int ret;
+	int i;
+
+	/* fine to disable filter */
+	if (!sc_filter->mask)
+		return 0;
+
+	/* encode the specified filter and loop it back */
+	raw = kmalloc_array(max, sizeof(*raw), GFP_KERNEL);
+	ret = ir_raw_encode_scancode(dev->enabled_wakeup_protocols, sc_filter,
+				     raw, max);
+	/* still loop back the partial raw IR even if it's incomplete */
+	if (ret == -ENOBUFS)
+		ret = max;
+	if (ret >= 0) {
+		/* do the loopback */
+		for (i = 0; i < ret; ++i)
+			ir_raw_event_store(dev, &raw[i]);
+		ir_raw_event_handle(dev);
+
+		ret = 0;
+	}
+
+	kfree(raw);
+
+	return ret;
+}
+
 static int __init loop_init(void)
 {
 	struct rc_dev *rc;
···
 	rc->map_name		= RC_MAP_EMPTY;
 	rc->priv		= &loopdev;
 	rc->driver_type		= RC_DRIVER_IR_RAW;
+	rc->encode_wakeup	= true;
 	rc->allowed_protocols	= RC_BIT_ALL;
 	rc->timeout		= 100 * 1000 * 1000; /* 100 ms */
 	rc->min_timeout		= 1;
···
 	rc->s_idle		= loop_set_idle;
 	rc->s_learning_mode	= loop_set_learning_mode;
 	rc->s_carrier_report	= loop_set_carrier_report;
+	rc->s_wakeup_filter	= loop_set_wakeup_filter;
 
 	loopdev.txmask		= RXMASK_REGULAR;
 	loopdev.txcarrier	= 36000;