bus: ti-sysc: Add support for disabling module without legacy mode

We must not assert reset for modules with no child device drivers
until in runtime_suspend. Otherwise register access will fail without
legacy mode helping us.

Let's add a flag for disable_on_idle and move the reset driver
handling to runtime suspend and resume. We can then also use the
disable_on_idle flag to reconfigure sysconfig register for PM
modes requesting it.

Let's also make the other flags use bitfield while at it instead of
bool.
Tested-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

drivers/bus/ti-sysc.c

@@ -89,9 +89,10 @@ struct sysc {
 	struct ti_sysc_cookie cookie;
 	const char *name;
 	u32 revision;
-	bool enabled;
-	bool needs_resume;
-	bool child_needs_resume;
+	unsigned int enabled:1;
+	unsigned int needs_resume:1;
+	unsigned int child_needs_resume:1;
+	unsigned int disable_on_idle:1;
 	struct delayed_work idle_work;
 };
 
@@ -1021,6 +1022,9 @@ static int __maybe_unused sysc_runtime_suspend_legacy(struct device *dev,
 		dev_err(dev, "%s: could not idle: %i\n",
 			__func__, error);
 
+	if (ddata->disable_on_idle)
+		reset_control_assert(ddata->rsts);
+
 	return 0;
 }
 
@@ -1030,6 +1034,9 @@ static int __maybe_unused sysc_runtime_resume_legacy(struct device *dev,
 	struct ti_sysc_platform_data *pdata;
 	int error;
 
+	if (ddata->disable_on_idle)
+		reset_control_deassert(ddata->rsts);
+
 	pdata = dev_get_platdata(ddata->dev);
 	if (!pdata)
 		return 0;
@@ -1077,6 +1084,9 @@ static int __maybe_unused sysc_runtime_suspend(struct device *dev)
 err_allow_idle:
 	sysc_clkdm_allow_idle(ddata);
 
+	if (ddata->disable_on_idle)
+		reset_control_assert(ddata->rsts);
+
 	return error;
 }
 
@@ -1090,6 +1100,9 @@ static int __maybe_unused sysc_runtime_resume(struct device *dev)
 	if (ddata->enabled)
 		return 0;
 
+	if (ddata->disable_on_idle)
+		reset_control_deassert(ddata->rsts);
+
 	sysc_clkdm_deny_idle(ddata);
 
 	if (sysc_opt_clks_needed(ddata)) {
@@ -2306,7 +2319,7 @@ static int sysc_probe(struct platform_device *pdev)
 	}
 
 	if (!of_get_available_child_count(ddata->dev->of_node))
-		reset_control_assert(ddata->rsts);
+		ddata->disable_on_idle = true;
 
 	return 0;