[media] cec: add proper support for CDC-Only CEC devices

CDC-Only CEC devices are CEC devices that can only handle CDC messages,
all other messages are ignored.

Add a flag to signal that this is a CDC-Only device and act accordingly.

Also add helper functions to identify if a CEC device is configured as a
CDC-Only device, a second TV, a switch or a processor, since these variations
cannot be determined by the logical address alone.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 52 insertions, 0 deletions

diff --git a/include/linux/cec.h b/include/linux/cec.h
index 3f2f076027b1..9c87711c0e1c 100644
--- a/include/linux/cec.h
+++ b/include/linux/cec.h
@@ -396,6 +396,8 @@ struct cec_log_addrs {
 #define CEC_LOG_ADDRS_FL_ALLOW_UNREG_FALLBACK	(1 << 0)
 /* Passthrough RC messages to the input subsystem */
 #define CEC_LOG_ADDRS_FL_ALLOW_RC_PASSTHRU	(1 << 1)
+/* CDC-Only device: supports only CDC messages */
+#define CEC_LOG_ADDRS_FL_CDC_ONLY		(1 << 2)
 
 /* Events */
 
@@ -1016,4 +1018,54 @@ struct cec_event {
 #define CEC_OP_HPD_ERROR_OTHER				3
 #define CEC_OP_HPD_ERROR_NONE_NO_VIDEO			4
 
+/* End of Messages */
+
+/* Helper functions to identify the 'special' CEC devices */
+
+static inline bool cec_is_2nd_tv(const struct cec_log_addrs *las)
+{
+	/*
+	 * It is a second TV if the logical address is 14 or 15 and the
+	 * primary device type is a TV.
+	 */
+	return las->num_log_addrs &&
+	       las->log_addr[0] >= CEC_LOG_ADDR_SPECIFIC &&
+	       las->primary_device_type[0] == CEC_OP_PRIM_DEVTYPE_TV;
+}
+
+static inline bool cec_is_processor(const struct cec_log_addrs *las)
+{
+	/*
+	 * It is a processor if the logical address is 12-15 and the
+	 * primary device type is a Processor.
+	 */
+	return las->num_log_addrs &&
+	       las->log_addr[0] >= CEC_LOG_ADDR_BACKUP_1 &&
+	       las->primary_device_type[0] == CEC_OP_PRIM_DEVTYPE_PROCESSOR;
+}
+
+static inline bool cec_is_switch(const struct cec_log_addrs *las)
+{
+	/*
+	 * It is a switch if the logical address is 15 and the
+	 * primary device type is a Switch and the CDC-Only flag is not set.
+	 */
+	return las->num_log_addrs == 1 &&
+	       las->log_addr[0] == CEC_LOG_ADDR_UNREGISTERED &&
+	       las->primary_device_type[0] == CEC_OP_PRIM_DEVTYPE_SWITCH &&
+	       !(las->flags & CEC_LOG_ADDRS_FL_CDC_ONLY);
+}
+
+static inline bool cec_is_cdc_only(const struct cec_log_addrs *las)
+{
+	/*
+	 * It is a CDC-only device if the logical address is 15 and the
+	 * primary device type is a Switch and the CDC-Only flag is set.
+	 */
+	return las->num_log_addrs == 1 &&
+	       las->log_addr[0] == CEC_LOG_ADDR_UNREGISTERED &&
+	       las->primary_device_type[0] == CEC_OP_PRIM_DEVTYPE_SWITCH &&
+	       (las->flags & CEC_LOG_ADDRS_FL_CDC_ONLY);
+}
+
 #endif