Commit 7da7fd7e authored Jun 13, 2024 by Thomas Richard Committed by Andi Shyti Jul 09, 2024

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>

parent 2cb21a62

drivers/i2c/busses/i2c-omap.c

+22 −0

Original line number	Diff line number	Diff line
		@@ -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)
		};