[PATCH] arm: omap2plus: unidle devices which are about to probe

[Felipe Balbi]

in order to make HWMOD and pm_runtime agree on the
initial state of the device, we will unidle the device
and call pm_runtime_set_active() to tell pm_runtime
that the device is really active.

By the time driver's probe() is reached, a call to
pm_runtime_get_sync() will not cause driver's
->runtime_resume() method to be called at first, only
after a successful ->runtime_suspend().

Note that we must prevent pm_runtime transitions while
driver is probing otherwise drivers would be suspended
as soon as they call pm_runtime_use_autosuspend(). By
calling pm_runtime_forbid() before probe() and
pm_runtime_allow() after probe() we 'fix' that detail.

Note that this patch was inspired by PCI's pci_pm_init().

Signed-off-by: Felipe Balbi <balbi at ti.com>
---

boot tested on top of today's Linus master
6d128e1e72bf082542e85f72e6b7ddd704193588 with OMAP4
panda. Reached console prompt and, after setting a
proper autosuspend delay, consoles autosuspend just
fine.

It needs to be tested on other platforms.

ps: note that we also call pm_runtime_set_suspended(dev)
from our late_initcall() to disable devices so that pm_runtime
and HWMOD continue to aggree on device's state.

 arch/arm/mach-omap2/omap_device.c | 44 +++++++++++++++++++++++++++++++++++----
 1 file changed, 40 insertions(+), 4 deletions(-)

diff --git a/arch/arm/mach-omap2/omap_device.c b/arch/arm/mach-omap2/omap_device.c
index 5cc9287..cb1fc1d 100644
--- a/arch/arm/mach-omap2/omap_device.c
+++ b/arch/arm/mach-omap2/omap_device.c
@@ -178,6 +178,26 @@ odbfd_exit:
 	return ret;
 }
 
+static void omap_device_pm_init(struct platform_device *pdev)
+{
+	omap_device_enable(pdev);
+	pm_runtime_forbid(&pdev->dev);
+	pm_runtime_set_active(&pdev->dev);
+	device_enable_async_suspend(&pdev->dev);
+}
+
+static void omap_device_pm_allow(struct platform_device *pdev)
+{
+	pm_runtime_allow(&pdev->dev);
+}
+
+static void omap_device_pm_exit(struct platform_device *pdev)
+{
+	device_disable_async_suspend(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	omap_device_idle(pdev);
+}
+
 static int _omap_device_notifier_call(struct notifier_block *nb,
 				      unsigned long event, void *dev)
 {
@@ -189,16 +209,31 @@ static int _omap_device_notifier_call(struct notifier_block *nb,
 		if (pdev->archdata.od)
 			omap_device_delete(pdev->archdata.od);
 		break;
+	case BUS_NOTIFY_BIND_DRIVER:
+		if (pdev->archdata.od)
+			omap_device_pm_init(pdev);
+		break;
+	case BUS_NOTIFY_BOUND_DRIVER:
+		if (pdev->archdata.od)
+			omap_device_pm_allow(pdev);
+		break;
+	case BUS_NOTIFY_UNBOUND_DRIVER:
+		if (pdev->archdata.od)
+			omap_device_pm_exit(pdev);
+		break;
 	case BUS_NOTIFY_ADD_DEVICE:
 		if (pdev->dev.of_node)
 			omap_device_build_from_dt(pdev);
-		/* fall through */
+		break;
 	default:
-		od = to_omap_device(pdev);
-		if (od)
-			od->_driver_status = event;
+		/* nothing */
+		break;
 	}
 
+	od = to_omap_device(pdev);
+	if (od)
+		od->_driver_status = event;
+
 	return NOTIFY_DONE;
 }
 
@@ -855,6 +890,7 @@ static int __init omap_device_late_idle(struct device *dev, void *data)
 			dev_warn(dev, "%s: enabled but no driver.  Idling\n",
 				 __func__);
 			omap_device_idle(pdev);
+			pm_runtime_set_suspended(dev);
 		}
 	}
 
-- 
1.8.2.1