OMAP4: DSS: add generic notifier mechanism

A callback can be registered by the dssdev client in order to be
notified of resolution changes, for example an external monitor
that is hot-plugged.

Multiple clients can now register for notification from one
dssdev, and the notification mechanism can be extended in the
future to add other events.

This is a port of Rob Clark's <rob@ti.com> original patch.

Signed-off-by: Sebastien Jan <s-jan@ti.com>

3 files changed, 60 insertions, 1 deletions

diff --git a/drivers/video/omap2/dss/core.c b/drivers/video/omap2/dss/core.c
index 1aa2ed1e786..19075085f96 100644
--- a/drivers/video/omap2/dss/core.c
+++ b/drivers/video/omap2/dss/core.c
@@ -491,6 +491,9 @@ int omap_dss_register_device(struct omap_dss_device *dssdev)
 	dssdev->dev.parent = &dss_bus;
 	dssdev->dev.release = omap_dss_dev_release;
 	dev_set_name(&dssdev->dev, "display%d", dev_num++);
+
+	BLOCKING_INIT_NOTIFIER_HEAD(&dssdev->notifier);
+
 	return device_register(&dssdev->dev);
 }
 
diff --git a/drivers/video/omap2/dss/display.c b/drivers/video/omap2/dss/display.c
index a85a6f38b40..fa9df604387 100644
--- a/drivers/video/omap2/dss/display.c
+++ b/drivers/video/omap2/dss/display.c
@@ -26,6 +26,7 @@
 #include <linux/module.h>
 #include <linux/jiffies.h>
 #include <linux/platform_device.h>
+#include <linux/slab.h>
 
 #include <plat/display.h>
 #include "dss.h"
@@ -614,3 +615,51 @@ void omap_dss_stop_device(struct omap_dss_device *dssdev)
 }
 EXPORT_SYMBOL(omap_dss_stop_device);
 
+/* since omap_dss_update_size can be called in irq context, schedule work from
+ * work-queue to deliver notification to client..
+ */
+struct notify_work {
+	struct work_struct work;
+	struct omap_dss_device *dssdev;
+	enum omap_dss_event evt;
+};
+
+static void notify_worker(struct work_struct *work)
+{
+	struct notify_work *nw =
+		container_of(work, struct notify_work, work);
+	struct omap_dss_device *dssdev = nw->dssdev;
+	blocking_notifier_call_chain(&dssdev->notifier, nw->evt, dssdev);
+	kfree(work);
+}
+
+/**
+ * Called by lower level driver to notify about a change in resolution, etc.
+ */
+void omap_dss_notify(struct omap_dss_device *dssdev, enum omap_dss_event evt)
+{
+	struct notify_work *nw =
+			kmalloc(sizeof(struct notify_work), GFP_KERNEL);
+	if (nw) {
+		INIT_WORK(&nw->work, notify_worker);
+		nw->dssdev = dssdev;
+		nw->evt = evt;
+		schedule_work(&nw->work);
+	}
+}
+EXPORT_SYMBOL(omap_dss_notify);
+
+void omap_dss_add_notify(struct omap_dss_device *dssdev,
+		struct notifier_block *nb)
+{
+	blocking_notifier_chain_register(&dssdev->notifier, nb);
+}
+EXPORT_SYMBOL(omap_dss_add_notify);
+
+void omap_dss_remove_notify(struct omap_dss_device *dssdev,
+		struct notifier_block *nb)
+{
+	blocking_notifier_chain_unregister(&dssdev->notifier, nb);
+}
+EXPORT_SYMBOL(omap_dss_remove_notify);
+
diff --git a/drivers/video/omap2/dss/hdmi.c b/drivers/video/omap2/dss/hdmi.c
index 0d44f070ef3..71900d44a4f 100644
--- a/drivers/video/omap2/dss/hdmi.c
+++ b/drivers/video/omap2/dss/hdmi.c
@@ -1104,6 +1104,7 @@ static void hdmi_enable_clocks(int enable)
 static int hdmi_power_on(struct omap_dss_device *dssdev)
 {
 	int r, code = 0;
+	int dirty = true;
 	struct hdmi_pll_info pll_data;
 	struct omap_video_timings *p;
 	int clkin, n, phy;
@@ -1119,8 +1120,10 @@ static int hdmi_power_on(struct omap_dss_device *dssdev)
 		dssdev->panel.timings.y_res);
 
 	if (!hdmi.custom_set) {
+		code = get_timings_index();
 		DSSDBG("Read EDID as no EDID is not set on poweron\n");
 		hdmi_read_edid(p);
+		dirty = get_timings_index() != code;
 	}
 	code = get_timings_index();
 	dssdev->panel.timings = cea_vesa_timings[code].timings;
@@ -1134,7 +1137,11 @@ static int hdmi_power_on(struct omap_dss_device *dssdev)
 
 	hdmi_wp_video_start(0);
 
-	/* config the PLL and PHY first */
+ 	if (dirty) {
+		omap_dss_notify(dssdev, OMAP_DSS_SIZE_CHANGE);
+ 	}
+ 
+ 	/* config the PLL and PHY first */
 	r = hdmi_pll_program(&pll_data);
 	if (r) {
 		DSSDBG("Failed to lock PLL\n");