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[v3,04/18] i2c: omap: wakeup the controller during suspend() callback

Message ID 20240102-j7200-pcie-s2r-v3-4-5c2e4a3fac1f@bootlin.com (mailing list archive)
State New, archived
Headers show
Series Add suspend to ram support for PCIe on J7200 | expand

Commit Message

Thomas Richard Feb. 15, 2024, 3:17 p.m. UTC
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.

Signed-off-by: Thomas Richard <thomas.richard@bootlin.com>
---
 drivers/i2c/busses/i2c-omap.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

Comments

Andy Shevchenko Feb. 15, 2024, 3:30 p.m. UTC | #1
On Thu, Feb 15, 2024 at 04:17:49PM +0100, Thomas Richard wrote:
> 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.

...

> +	/*
> +	 * 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().
> +	 */

It's a bit random line lengths...
Can you repack this to be more condensed?
diff mbox series

Patch

diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 42165ef57946..c11deb285114 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -1575,9 +1575,31 @@  static int __maybe_unused 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 = {
 	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
 				      pm_runtime_force_resume)
+	SET_SYSTEM_SLEEP_PM_OPS(omap_i2c_suspend, omap_i2c_resume)
 	SET_RUNTIME_PM_OPS(omap_i2c_runtime_suspend,
 			   omap_i2c_runtime_resume, NULL)
 };