[media] media: rc: add sysfs scancode filtering interface

Add and document a generic sysfs based scancode filtering interface for
making use of IR data matching hardware to filter out uninteresting
scancodes. Two filters exist, one for normal operation and one for
filtering scancodes which are permitted to wake the system from suspend.

The following files are added to /sys/class/rc/rc?/:
 - filter: normal scancode filter value
 - filter_mask: normal scancode filter mask
 - wakeup_filter: wakeup scancode filter value
 - wakeup_filter_mask: wakeup scancode filter mask

A new s_filter() driver callback is added which must arrange for the
specified filter to be applied at the right time. Drivers can convert
the scancode filter into a raw IR data filter, which can be applied
immediately or later (for wake up filters).

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: linux-media@vger.kernel.org
Cc: Rob Landley <rob@landley.net>
Cc: linux-doc@vger.kernel.org
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/include/media/rc-core.h b/include/media/rc-core.h
index 2f6f1f78d95..4a72176e04f 100644
--- a/include/media/rc-core.h
+++ b/include/media/rc-core.h
@@ -35,6 +35,29 @@ enum rc_driver_type {
 };
 
 /**
+ * struct rc_scancode_filter - Filter scan codes.
+ * @data:	Scancode data to match.
+ * @mask:	Mask of bits of scancode to compare.
+ */
+struct rc_scancode_filter {
+	u32 data;
+	u32 mask;
+};
+
+/**
+ * enum rc_filter_type - Filter type constants.
+ * @RC_FILTER_NORMAL:	Filter for normal operation.
+ * @RC_FILTER_WAKEUP:	Filter for waking from suspend.
+ * @RC_FILTER_MAX:	Number of filter types.
+ */
+enum rc_filter_type {
+	RC_FILTER_NORMAL = 0,
+	RC_FILTER_WAKEUP,
+
+	RC_FILTER_MAX
+};
+
+/**
  * struct rc_dev - represents a remote control device
  * @dev: driver model's view of this device
  * @input_name: name of the input child device
@@ -70,6 +93,7 @@ enum rc_driver_type {
  * @max_timeout: maximum timeout supported by device
  * @rx_resolution : resolution (in ns) of input sampler
  * @tx_resolution: resolution (in ns) of output sampler
+ * @scancode_filters: scancode filters (indexed by enum rc_filter_type)
  * @change_protocol: allow changing the protocol used on hardware decoders
  * @open: callback to allow drivers to enable polling/irq when IR input device
  *	is opened.
@@ -84,6 +108,7 @@ enum rc_driver_type {
  *	device doesn't interrupt host until it sees IR pulses
  * @s_learning_mode: enable wide band receiver used for learning
  * @s_carrier_report: enable carrier reports
+ * @s_filter: set the scancode filter of a given type
  */
 struct rc_dev {
 	struct device			dev;
@@ -116,6 +141,7 @@ struct rc_dev {
 	u32				max_timeout;
 	u32				rx_resolution;
 	u32				tx_resolution;
+	struct rc_scancode_filter	scancode_filters[RC_FILTER_MAX];
 	int				(*change_protocol)(struct rc_dev *dev, u64 *rc_type);
 	int				(*open)(struct rc_dev *dev);
 	void				(*close)(struct rc_dev *dev);
@@ -127,6 +153,9 @@ struct rc_dev {
 	void				(*s_idle)(struct rc_dev *dev, bool enable);
 	int				(*s_learning_mode)(struct rc_dev *dev, int enable);
 	int				(*s_carrier_report) (struct rc_dev *dev, int enable);
+	int				(*s_filter)(struct rc_dev *dev,
+						    enum rc_filter_type type,
+						    struct rc_scancode_filter *filter);
 };
 
 #define to_rc_dev(d) container_of(d, struct rc_dev, dev)