linux-kernel - [PATCH] PM: sleep: Add helpers to allow a device to remain powered-on

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Date:   Thu, 10 Aug 2023 18:21:19 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     "Rafael J . Wysocki" <rafael@...nel.org>, linux-pm@...r.kernel.org
Cc:     "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Tony Lindgren <tony@...mide.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Patrice Chotard <patrice.chotard@...com>,
        Peng Fan <peng.fan@....com>,
        Ajay Agarwal <ajayagarwal@...gle.com>,
        Michael Shavit <mshavit@...gle.com>,
        Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
        linux-kernel@...r.kernel.org, Ulf Hansson <ulf.hansson@...aro.org>
Subject: [PATCH] PM: sleep: Add helpers to allow a device to remain powered-on

On some platforms a device and its corresponding PM domain, may need to
remain powered-on during system wide suspend, to support various use cases.
For example, when the console_suspend_enabled flag is unset for a serial
controller, the corresponding device may need to remain powered on. Other
use cases exists too.

In fact, we already have the mechanism in the PM core to deal with these
kind of use cases. However, the current naming of the corresponding
functions/flags clearly suggests these should be use for system wakeup.
See device_wakeup_path(), device_set_wakeup_path and
dev->power.wakeup_path.

As a way to extend the use of the existing mechanism, let's introduce two
new helpers functions, device_awake_path() and device_set_awake_path(). At
this point, let them act as wrappers of the existing functions. Ideally,
when all users have been converted to use the new helpers, we may decide to
drop the old ones and rename the flag.

Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
---
 include/linux/pm_wakeup.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/linux/pm_wakeup.h b/include/linux/pm_wakeup.h
index 77f4849e3418..6eb9adaef52b 100644
--- a/include/linux/pm_wakeup.h
+++ b/include/linux/pm_wakeup.h
@@ -194,6 +194,16 @@ static inline void pm_wakeup_dev_event(struct device *dev, unsigned int msec,

 #endif /* !CONFIG_PM_SLEEP */

+static inline bool device_awake_path(struct device *dev)
+{
+	return device_wakeup_path(dev);
+}
+
+static inline void device_set_awake_path(struct device *dev)
+{
+	device_set_wakeup_path(dev);
+}
+
 static inline void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)
 {
 	return pm_wakeup_ws_event(ws, msec, false);
-- 
2.34.1