bus: ti-sysc: Add suspend and resume handling

This allows us to idle the module on suspend after the children
are suspended.
Signed-off-by: Tony Lindgren <tony@atomide.com>

drivers/bus/ti-sysc.c

@@ -58,6 +58,7 @@ static const char * const clock_names[] = { "fck", "ick", };
  * @cfg: interconnect target module configuration
  * @name: name if available
  * @revision: interconnect target module revision
+ * @needs_resume: runtime resume needed on resume from suspend
  */
 struct sysc {
 	struct device *dev;
@@ -71,6 +72,8 @@ struct sysc {
 	struct sysc_config cfg;
 	const char *name;
 	u32 revision;
+	bool enabled;
+	bool needs_resume;
 };
 
 static u32 sysc_read(struct sysc *ddata, int offset)
@@ -497,7 +500,38 @@ static int __maybe_unused sysc_runtime_resume(struct device *dev)
 	return 0;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int sysc_suspend(struct device *dev)
+{
+	struct sysc *ddata;
+
+	ddata = dev_get_drvdata(dev);
+
+	if (!ddata->enabled)
+		return 0;
+
+	ddata->needs_resume = true;
+
+	return sysc_runtime_suspend(dev);
+}
+
+static int sysc_resume(struct device *dev)
+{
+	struct sysc *ddata;
+
+	ddata = dev_get_drvdata(dev);
+	if (ddata->needs_resume) {
+		ddata->needs_resume = false;
+
+		return sysc_runtime_resume(dev);
+	}
+
+	return 0;
+}
+#endif
+
 static const struct dev_pm_ops sysc_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(sysc_suspend, sysc_resume)
 	SET_RUNTIME_PM_OPS(sysc_runtime_suspend,
 			   sysc_runtime_resume,
 			   NULL)