i2c: omap: wakeup the controller during suspend() callback

A device may need the controller up during suspend_noirq() or
resume_noirq().
But if the controller is autosuspended, there is no way to wakeup it during
suspend_noirq() or resume_noirq() because runtime pm is disabled at this
time.

The suspend() callback wakes up the controller, so it is available until
its suspend_noirq() callback (pm_runtime_force_suspend()).
During the resume, it's restored by resume_noirq() callback
(pm_runtime_force_resume()). Then resume() callback enables autosuspend.

So the controller is up during a little time slot in suspend and resume
sequences even if it's not used.

Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Thomas Richard <thomas.richard@bootlin.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>

diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 410c8b37f768537a8033ea29a6bcfa3e210c5df1..35a3f0a64986455932f9029c93dd810ab3d71f0b 100644 (file)
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -1574,9 +1574,31 @@ static int omap_i2c_runtime_resume(struct device *dev)
        return 0;
 }
 
+static int omap_i2c_suspend(struct device *dev)
+{
+       /*
+        * If the controller is autosuspended, there is no way to wakeup it once
+        * runtime pm is disabled (in suspend_late()).
+        * But a device may need the controller up during suspend_noirq() or
+        * resume_noirq().
+        * Wakeup the controller while runtime pm is enabled, so it is available
+        * until its suspend_noirq(), and from resume_noirq().
+        */
+       return pm_runtime_resume_and_get(dev);
+}
+
+static int omap_i2c_resume(struct device *dev)
+{
+       pm_runtime_mark_last_busy(dev);
+       pm_runtime_put_autosuspend(dev);
+
+       return 0;
+}
+
 static const struct dev_pm_ops omap_i2c_pm_ops = {
        NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
                                  pm_runtime_force_resume)
+       SYSTEM_SLEEP_PM_OPS(omap_i2c_suspend, omap_i2c_resume)
        RUNTIME_PM_OPS(omap_i2c_runtime_suspend,
                       omap_i2c_runtime_resume, NULL)
 };