linux-kernel - [PATCH] platform/chrome: Don't treat RTC events as wakeup sources

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Message-Id: <20201030232523.2654478-1-swboyd@chromium.org>
Date:   Fri, 30 Oct 2020 16:25:23 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Benson Leung <bleung@...omium.org>,
        Enric Balletbo i Serra <enric.balletbo@...labora.com>
Cc:     linux-kernel@...r.kernel.org, Guenter Roeck <groeck@...omium.org>,
        Alessandro Zummo <a.zummo@...ertech.it>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        linux-rtc@...r.kernel.org
Subject: [PATCH] platform/chrome: Don't treat RTC events as wakeup sources

The EC sends an RTC host event when the RTC fires, but we don't need to
treat that as a wakeup event here. The RTC class already properly
handles activating and deactivating a wakeup source in rtc_update_irq()
by calling pm_stay_awake() at the start of processing and pm_relax()
once all expired RTC timers have been processed. This reduces one wakeup
increment but not much else. I noticed this while debugging RTC wakeups
and how they always incremented the wakeup count by two instead of one
because this is duplicated.

Cc: Guenter Roeck <groeck@...omium.org>
Cc: Alessandro Zummo <a.zummo@...ertech.it>
Cc: Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc: <linux-rtc@...r.kernel.org>
Signed-off-by: Stephen Boyd <swboyd@...omium.org>
---

I wonder if it makes more sense to look for certain events and treat
them as wakeup sources? It may be that most of the time an EC event
can be pm_relax()ed too and only need to be held active until the
processing is over? I haven't looked beyond this situation.

 drivers/platform/chrome/cros_ec_proto.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
index 0ecee8b8773d..7c92a6e22d75 100644
--- a/drivers/platform/chrome/cros_ec_proto.c
+++ b/drivers/platform/chrome/cros_ec_proto.c
@@ -742,12 +742,16 @@ int cros_ec_get_next_event(struct cros_ec_device *ec_dev,
 		 * Sensor events need to be parsed by the sensor sub-device.
 		 * Defer them, and don't report the wakeup here.
 		 */
-		if (event_type == EC_MKBP_EVENT_SENSOR_FIFO)
-			*wake_event = false;
-		/* Masked host-events should not count as wake events. */
-		else if (host_event &&
-			 !(host_event & ec_dev->host_event_wake_mask))
+		if (event_type == EC_MKBP_EVENT_SENSOR_FIFO) {
 			*wake_event = false;
+		} else if (host_event) {
+			/* rtc_update_irq() already handles wakeup events. */
+			if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_RTC))
+				*wake_event = false;
+			/* Masked host-events should not count as wake events. */
+			if (!(host_event & ec_dev->host_event_wake_mask))
+				*wake_event = false;
+		}
 	}
 
 	return ret;
-- 
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