From f902c1e95d5dfe5102f8467d69dc51d505f832ee Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hans.verkuil@cisco.com>
Date: Wed, 7 Jun 2017 11:46:12 -0300
Subject: [media] cec: add CEC_CAP_NEEDS_HPD
Git-commit: f902c1e95d5dfe5102f8467d69dc51d505f832ee
Patch-mainline: v4.13-rc1
References: FATE#326289

Add a new capability CEC_CAP_NEEDS_HPD. If this capability is set
then the hardware can only use CEC if the HDMI Hotplug Detect pin
is high. Such hardware cannot handle the corner case in the CEC specification
where it is possible to transmit messages even if no hotplug signal is
present (needed for some displays that turn off the HPD when in standby,
but still have CEC enabled).

Typically hardware that needs this capability have the HPD wired to the CEC
block, often to a 'power' or 'active' pin.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/media/cec/cec-adap.c |   20 ++++++++++++++------
 drivers/media/cec/cec-api.c  |    5 ++++-
 drivers/media/cec/cec-core.c |    1 +
 include/media/cec.h          |    1 +
 include/uapi/linux/cec.h     |    2 ++
 5 files changed, 22 insertions(+), 7 deletions(-)

--- a/drivers/media/cec/cec-adap.c
+++ b/drivers/media/cec/cec-adap.c
@@ -368,6 +368,8 @@ int cec_thread_func(void *_adap)
 			 * transmit should be canceled.
 			 */
 			err = wait_event_interruptible_timeout(adap->kthread_waitq,
+				(adap->needs_hpd &&
+				 (!adap->is_configured && !adap->is_configuring)) ||
 				kthread_should_stop() ||
 				(!adap->transmitting &&
 				 !list_empty(&adap->transmit_queue)),
@@ -383,7 +385,9 @@ int cec_thread_func(void *_adap)
 
 		mutex_lock(&adap->lock);
 
-		if (kthread_should_stop()) {
+		if ((adap->needs_hpd &&
+		     (!adap->is_configured && !adap->is_configuring)) ||
+		    kthread_should_stop()) {
 			cec_flush(adap);
 			goto unlock;
 		}
@@ -649,7 +653,7 @@ int cec_transmit_msg_fh(struct cec_adapt
 		return -EINVAL;
 	}
 	if (!adap->is_configured && !adap->is_configuring) {
-		if (msg->msg[0] != 0xf0) {
+		if (adap->needs_hpd || msg->msg[0] != 0xf0) {
 			dprintk(1, "%s: adapter is unconfigured\n", __func__);
 			return -ENONET;
 		}
@@ -1128,7 +1132,9 @@ static int cec_config_log_addr(struct ce
  */
 static void cec_adap_unconfigure(struct cec_adapter *adap)
 {
-	WARN_ON(adap->ops->adap_log_addr(adap, CEC_LOG_ADDR_INVALID));
+	if (!adap->needs_hpd ||
+	    adap->phys_addr != CEC_PHYS_ADDR_INVALID)
+		WARN_ON(adap->ops->adap_log_addr(adap, CEC_LOG_ADDR_INVALID));
 	adap->log_addrs.log_addr_mask = 0;
 	adap->is_configuring = false;
 	adap->is_configured = false;
@@ -1357,6 +1363,8 @@ void __cec_s_phys_addr(struct cec_adapte
 	if (phys_addr == adap->phys_addr || adap->devnode.unregistered)
 		return;
 
+	dprintk(1, "new physical address %x.%x.%x.%x\n",
+		cec_phys_addr_exp(phys_addr));
 	if (phys_addr == CEC_PHYS_ADDR_INVALID ||
 	    adap->phys_addr != CEC_PHYS_ADDR_INVALID) {
 		adap->phys_addr = CEC_PHYS_ADDR_INVALID;
@@ -1366,7 +1374,7 @@ void __cec_s_phys_addr(struct cec_adapte
 		if (adap->monitor_all_cnt)
 			WARN_ON(call_op(adap, adap_monitor_all_enable, false));
 		mutex_lock(&adap->devnode.lock);
-		if (list_empty(&adap->devnode.fhs))
+		if (adap->needs_hpd || list_empty(&adap->devnode.fhs))
 			WARN_ON(adap->ops->adap_enable(adap, false));
 		mutex_unlock(&adap->devnode.lock);
 		if (phys_addr == CEC_PHYS_ADDR_INVALID)
@@ -1374,7 +1382,7 @@ void __cec_s_phys_addr(struct cec_adapte
 	}
 
 	mutex_lock(&adap->devnode.lock);
-	if (list_empty(&adap->devnode.fhs) &&
+	if ((adap->needs_hpd || list_empty(&adap->devnode.fhs)) &&
 	    adap->ops->adap_enable(adap, true)) {
 		mutex_unlock(&adap->devnode.lock);
 		return;
@@ -1382,7 +1390,7 @@ void __cec_s_phys_addr(struct cec_adapte
 
 	if (adap->monitor_all_cnt &&
 	    call_op(adap, adap_monitor_all_enable, true)) {
-		if (list_empty(&adap->devnode.fhs))
+		if (adap->needs_hpd || list_empty(&adap->devnode.fhs))
 			WARN_ON(adap->ops->adap_enable(adap, false));
 		mutex_unlock(&adap->devnode.lock);
 		return;
--- a/drivers/media/cec/cec-api.c
+++ b/drivers/media/cec/cec-api.c
@@ -202,7 +202,8 @@ static long cec_transmit(struct cec_adap
 		err = -EPERM;
 	else if (adap->is_configuring)
 		err = -ENONET;
-	else if (!adap->is_configured && msg.msg[0] != 0xf0)
+	else if (!adap->is_configured &&
+		 (adap->needs_hpd || msg.msg[0] != 0xf0))
 		err = -ENONET;
 	else if (cec_is_busy(adap, fh))
 		err = -EBUSY;
@@ -515,6 +516,7 @@ static int cec_open(struct inode *inode,
 
 	mutex_lock(&devnode->lock);
 	if (list_empty(&devnode->fhs) &&
+	    !adap->needs_hpd &&
 	    adap->phys_addr == CEC_PHYS_ADDR_INVALID) {
 		err = adap->ops->adap_enable(adap, true);
 		if (err) {
@@ -559,6 +561,7 @@ static int cec_release(struct inode *ino
 	mutex_lock(&devnode->lock);
 	list_del(&fh->list);
 	if (list_empty(&devnode->fhs) &&
+	    !adap->needs_hpd &&
 	    adap->phys_addr == CEC_PHYS_ADDR_INVALID) {
 		WARN_ON(adap->ops->adap_enable(adap, false));
 	}
--- a/drivers/media/cec/cec-core.c
+++ b/drivers/media/cec/cec-core.c
@@ -230,6 +230,7 @@ struct cec_adapter *cec_allocate_adapter
 	adap->log_addrs.cec_version = CEC_OP_CEC_VERSION_2_0;
 	adap->log_addrs.vendor_id = CEC_VENDOR_ID_NONE;
 	adap->capabilities = caps;
+	adap->needs_hpd = caps & CEC_CAP_NEEDS_HPD;
 	adap->available_log_addrs = available_las;
 	adap->sequence = 0;
 	adap->ops = ops;
--- a/include/media/cec.h
+++ b/include/media/cec.h
@@ -164,6 +164,7 @@ struct cec_adapter {
 	u8 available_log_addrs;
 
 	u16 phys_addr;
+	bool needs_hpd;
 	bool is_configuring;
 	bool is_configured;
 	u32 monitor_all_cnt;
--- a/include/uapi/linux/cec.h
+++ b/include/uapi/linux/cec.h
@@ -336,6 +336,8 @@ static inline int cec_is_unconfigured(__
 #define CEC_CAP_RC		(1 << 4)
 /* Hardware can monitor all messages, not just directed and broadcast. */
 #define CEC_CAP_MONITOR_ALL	(1 << 5)
+/* Hardware can use CEC only if the HDMI HPD pin is high. */
+#define CEC_CAP_NEEDS_HPD	(1 << 6)
 
 /**
  * struct cec_caps - CEC capabilities structure.