media: cec: add core support for low-level CEC pin monitoring

Add support for the new MONITOR_PIN mode.

Add the cec_pin_event function that the CEC pin code will call to queue pin
change events.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/cec/cec-adap.c

@@ -153,6 +153,22 @@ static void cec_queue_event(struct cec_adapter *adap,
 	mutex_unlock(&adap->devnode.lock);
 }
 
+/* Notify userspace that the CEC pin changed state at the given time. */
+void cec_queue_pin_event(struct cec_adapter *adap, bool is_high, ktime_t ts)
+{
+	struct cec_event ev = {
+		.event = is_high ? CEC_EVENT_PIN_HIGH : CEC_EVENT_PIN_LOW,
+	};
+	struct cec_fh *fh;
+
+	mutex_lock(&adap->devnode.lock);
+	list_for_each_entry(fh, &adap->devnode.fhs, list)
+		if (fh->mode_follower == CEC_MODE_MONITOR_PIN)
+			cec_queue_event_fh(fh, &ev, ktime_to_ns(ts));
+	mutex_unlock(&adap->devnode.lock);
+}
+EXPORT_SYMBOL_GPL(cec_queue_pin_event);
+
 /*
  * Queue a new message for this filehandle.
  *

drivers/media/cec/cec-api.c

@@ -370,6 +370,10 @@ static long cec_s_mode(struct cec_adapter *adap, struct cec_fh *fh,
 	    !(adap->capabilities & CEC_CAP_MONITOR_ALL))
 		return -EINVAL;
 
+	if (mode_follower == CEC_MODE_MONITOR_PIN &&
+	    !(adap->capabilities & CEC_CAP_MONITOR_PIN))
+		return -EINVAL;
+
 	/* Follower modes should always be able to send CEC messages */
 	if ((mode_initiator == CEC_MODE_NO_INITIATOR ||
 	     !(adap->capabilities & CEC_CAP_TRANSMIT)) &&
@@ -378,11 +382,11 @@ static long cec_s_mode(struct cec_adapter *adap, struct cec_fh *fh,
 		return -EINVAL;
 
 	/* Monitor modes require CEC_MODE_NO_INITIATOR */
-	if (mode_initiator && mode_follower >= CEC_MODE_MONITOR)
+	if (mode_initiator && mode_follower >= CEC_MODE_MONITOR_PIN)
 		return -EINVAL;
 
 	/* Monitor modes require CAP_NET_ADMIN */
-	if (mode_follower >= CEC_MODE_MONITOR && !capable(CAP_NET_ADMIN))
+	if (mode_follower >= CEC_MODE_MONITOR_PIN && !capable(CAP_NET_ADMIN))
 		return -EPERM;
 
 	mutex_lock(&adap->lock);
@@ -421,8 +425,13 @@ static long cec_s_mode(struct cec_adapter *adap, struct cec_fh *fh,
 
 	if (fh->mode_follower == CEC_MODE_FOLLOWER)
 		adap->follower_cnt--;
+	if (fh->mode_follower == CEC_MODE_MONITOR_PIN)
+		adap->monitor_pin_cnt--;
 	if (mode_follower == CEC_MODE_FOLLOWER)
 		adap->follower_cnt++;
+	if (mode_follower == CEC_MODE_MONITOR_PIN) {
+		adap->monitor_pin_cnt++;
+	}
 	if (mode_follower == CEC_MODE_EXCL_FOLLOWER ||
 	    mode_follower == CEC_MODE_EXCL_FOLLOWER_PASSTHRU) {
 		adap->passthrough =
@@ -566,6 +575,8 @@ static int cec_release(struct inode *inode, struct file *filp)
 	}
 	if (fh->mode_follower == CEC_MODE_FOLLOWER)
 		adap->follower_cnt--;
+	if (fh->mode_follower == CEC_MODE_MONITOR_PIN)
+		adap->monitor_pin_cnt--;
 	if (fh->mode_follower == CEC_MODE_MONITOR_ALL)
 		cec_monitor_all_cnt_dec(adap);
 	mutex_unlock(&adap->lock);

include/media/cec.h

@@ -177,6 +177,7 @@ struct cec_adapter {
 	bool is_configuring;
 	bool is_configured;
 	u32 monitor_all_cnt;
+	u32 monitor_pin_cnt;
 	u32 follower_cnt;
 	struct cec_fh *cec_follower;
 	struct cec_fh *cec_initiator;
@@ -271,6 +272,16 @@ static inline void cec_received_msg(struct cec_adapter *adap,
 	cec_received_msg_ts(adap, msg, ktime_get());
 }
 
+/**
+ * cec_queue_pin_event() - queue a pin event with a given timestamp.
+ *
+ * @adap:	pointer to the cec adapter
+ * @is_high:	when true the pin is high, otherwise it is low
+ * @ts:		the timestamp for this event
+ *
+ */
+void cec_queue_pin_event(struct cec_adapter *adap, bool is_high, ktime_t ts);
+
 /**
  * cec_get_edid_phys_addr() - find and return the physical address
  *