Re: AM5749: tty serial 8250 omap driver crash

[Tony Lindgren <tony@atomide.com>]

* Tony Lindgren <tony@atomide.com> [220214 07:43]:
> Looks like the following script to just toggle the module state locks
> up things for me on beagle-x15 very fast. So yeah now I'm able to
> reproduce the issue. Seems like the module is not ready right after
> enabling it live we've seen for dra7 iva for example.

Looks like the following patch is also needed for uarts to avoid unbind
clock_unprepare warnings. But even with this patch dra7 uarts won't behave.
On unbind, there will be a clock "l4per-clkctrl:0128:0: failed to disable"
warning. Looks like after that any following clock enable does not seem to
work and that will cause the register access errors.

Looks like this is a dra7 specific issue as a similar test script on omap4
duovero keeps on going instead.

Regards,

Tony

8< --------------
diff --git a/drivers/bus/ti-sysc.c b/drivers/bus/ti-sysc.c
--- a/drivers/bus/ti-sysc.c
+++ b/drivers/bus/ti-sysc.c
@@ -3381,7 +3381,9 @@ static int sysc_remove(struct platform_device *pdev)
 	struct sysc *ddata = platform_get_drvdata(pdev);
 	int error;
 
-	cancel_delayed_work_sync(&ddata->idle_work);
+	/* Device can still be enabled, see deferred idle quirk in probe */
+	if (cancel_delayed_work_sync(&ddata->idle_work))
+		ti_sysc_idle(&ddata->idle_work.work);
 
 	error = pm_runtime_resume_and_get(ddata->dev);
 	if (error < 0) {