[RFC v2 4/6] video: rmk's HDMI notification prototype

[Philipp Zabel <p.zabel@pengutronix.de>]

This is extracted from Russell's food for thought HDMI notification
prototype [1]. I've put it into drivers/video for the time being because
my kernels don't have drivers/cec yet.

The current use case for the notifications on MediaTek MT8173 is to
let the (dis)connection notifications control an ALSA jack object.

No Signed-off-by yet since this is not my code, and up for discussion.

[1] https://patchwork.kernel.org/patch/7339011/
---
 drivers/video/Makefile   |  2 +-
 drivers/video/hdmi-not.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/hdmi-not.h | 39 +++++++++++++++++++++++++++++++
 3 files changed, 101 insertions(+), 1 deletion(-)
 create mode 100644 drivers/video/hdmi-not.c
 create mode 100644 include/linux/hdmi-not.h

diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index 9ad3c17..bf25760 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -1,5 +1,5 @@
 obj-$(CONFIG_VGASTATE)            += vgastate.o
-obj-$(CONFIG_HDMI)                += hdmi.o
+obj-$(CONFIG_HDMI)                += hdmi.o hdmi-not.o
 
 obj-$(CONFIG_VT)		  += console/
 obj-$(CONFIG_LOGO)		  += logo/
diff --git a/drivers/video/hdmi-not.c b/drivers/video/hdmi-not.c
new file mode 100644
index 0000000..ba3be8a
--- /dev/null
+++ b/drivers/video/hdmi-not.c
@@ -0,0 +1,61 @@
+#include <linux/export.h>
+#include <linux/hdmi-not.h>
+#include <linux/notifier.h>
+#include <linux/string.h>
+
+static BLOCKING_NOTIFIER_HEAD(hdmi_notifier);
+
+int hdmi_register_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&hdmi_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(hdmi_register_notifier);
+
+int hdmi_unregister_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&hdmi_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(hdmi_unregister_notifier);
+
+void hdmi_event_connect(struct device *dev)
+{
+	struct hdmi_event_base base;
+
+	base.source = dev;
+
+	blocking_notifier_call_chain(&hdmi_notifier, HDMI_CONNECTED, &base);
+}
+EXPORT_SYMBOL_GPL(hdmi_event_connect);
+
+void hdmi_event_disconnect(struct device *dev)
+{
+	struct hdmi_event_base base;
+
+	base.source = dev;
+
+	blocking_notifier_call_chain(&hdmi_notifier, HDMI_DISCONNECTED, &base);
+}
+EXPORT_SYMBOL_GPL(hdmi_event_disconnect);
+
+void hdmi_event_new_edid(struct device *dev, const void *edid, size_t size)
+{
+	struct hdmi_event_new_edid new_edid;
+
+	new_edid.base.source = dev;
+	new_edid.edid = edid;
+	new_edid.size = size;
+
+	blocking_notifier_call_chain(&hdmi_notifier, HDMI_NEW_EDID, &new_edid);
+}
+EXPORT_SYMBOL_GPL(hdmi_event_new_edid);
+
+void hdmi_event_new_eld(struct device *dev, const void *eld)
+{
+	struct hdmi_event_new_eld new_eld;
+
+	new_eld.base.source = dev;
+	memcpy(new_eld.eld, eld, sizeof(new_eld.eld));
+
+	blocking_notifier_call_chain(&hdmi_notifier, HDMI_NEW_ELD, &new_eld);
+}
+EXPORT_SYMBOL_GPL(hdmi_event_new_eld);
diff --git a/include/linux/hdmi-not.h b/include/linux/hdmi-not.h
new file mode 100644
index 0000000..940ece45
--- /dev/null
+++ b/include/linux/hdmi-not.h
@@ -0,0 +1,39 @@
+#include <linux/types.h>
+
+enum {
+	HDMI_CONNECTED,
+	HDMI_DISCONNECTED,
+	HDMI_NEW_EDID,
+	HDMI_NEW_ELD,
+};
+
+struct hdmi_event_base {
+	struct device *source;
+};
+
+struct hdmi_event_new_edid {
+	struct hdmi_event_base base;
+	const void *edid;
+	size_t size;
+};
+
+struct hdmi_event_new_eld {
+	struct hdmi_event_base base;
+	unsigned char eld[128];
+};
+
+union hdmi_event {
+	struct hdmi_event_base base;
+	struct hdmi_event_new_edid edid;
+	struct hdmi_event_new_eld eld;
+};
+
+struct notifier_block;
+
+int hdmi_register_notifier(struct notifier_block *nb);
+int hdmi_unregister_notifier(struct notifier_block *nb);
+
+void hdmi_event_connect(struct device *dev);
+void hdmi_event_disconnect(struct device *dev);
+void hdmi_event_new_edid(struct device *dev, const void *edid, size_t size);
+void hdmi_event_new_eld(struct device *dev, const void *eld);
-- 
2.6.2