[PATCH 0/1] platform/surface: platform_profile: handle fan standby state

[PATCH 0/1] platform/surface: platform_profile: handle fan standby state

[Peter Marshall]

This patch extends the Microsoft Surface platform driver to signal the
system's standby state to the SAM, stopping the fan during PM suspend and
restarting it during resume.

Without this change, the fan continues to run during suspend as if the
system was still powered on, and takes a few minutes to slow down and stop
as the chassis cools.

Tested on a Microsoft Surface Pro 9 running kernel 7.3.0.

Peter Marshall (1):
  platform/surface: platform_profile: handle fan standby state

 .../surface/surface_platform_profile.c        | 63 +++++++++++++++++++
 1 file changed, 63 insertions(+)

-- 
2.56.0

[PATCH] platform/surface: platform_profile: handle fan standby state

[Peter Marshall]

Send a fan standby command if a fan is present when entering a PM
suspend transition and set it back to normal during resume.

Signed-off-by: Peter Marshall <pm@petermarshall.ca>
---
 .../surface/surface_platform_profile.c        | 63 +++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/drivers/platform/surface/surface_platform_profile.c b/drivers/platform/surface/surface_platform_profile.c
index 0e479e35e66e..203d21aa715c 100644
--- a/drivers/platform/surface/surface_platform_profile.c
+++ b/drivers/platform/surface/surface_platform_profile.c
@@ -32,6 +32,11 @@ enum ssam_fan_profile {
 	SSAM_FAN_PROFILE_BEST_PERFORMANCE   = 4,
 };
 
+enum ssam_fan_state {
+	SSAM_FAN_STATE_NORMAL  = 1,
+	SSAM_FAN_STATE_STANDBY = 2,
+};
+
 struct ssam_tmp_profile_info {
 	__le32 profile;
 	__le16 unknown1;
@@ -61,6 +66,13 @@ SSAM_DEFINE_SYNC_REQUEST_W(__ssam_fan_profile_set, u8, {
 	.instance_id = 0x01,
 });
 
+SSAM_DEFINE_SYNC_REQUEST_W(__ssam_fan_state_set, u8, {
+	.target_category = SSAM_SSH_TC_FAN,
+	.target_id = SSAM_SSH_TID_SAM,
+	.command_id = 0x0f,
+	.instance_id = 0x01,
+});
+
 static int ssam_tmp_profile_get(struct ssam_device *sdev, enum ssam_tmp_profile *p)
 {
 	struct ssam_tmp_profile_info info;
@@ -88,6 +100,13 @@ static int ssam_fan_profile_set(struct ssam_device *sdev, enum ssam_fan_profile
 	return ssam_retry(__ssam_fan_profile_set, sdev->ctrl, &profile);
 }
 
+static int ssam_fan_state_set(struct ssam_device *sdev, enum ssam_fan_state s)
+{
+	const u8 state = s;
+
+	return ssam_retry(__ssam_fan_state_set, sdev->ctrl, &state);
+}
+
 static int convert_ssam_tmp_to_profile(struct ssam_device *sdev, enum ssam_tmp_profile p)
 {
 	switch (p) {
@@ -236,6 +255,49 @@ static int surface_platform_profile_probe(struct ssam_device *sdev)
 	return PTR_ERR_OR_ZERO(tpd->ppdev);
 }
 
+#ifdef CONFIG_PM_SLEEP
+
+static int surface_platform_profile_pm_prepare(struct device *dev)
+{
+	struct ssam_platform_profile_device *tpd;
+	int status;
+
+	tpd = dev_get_drvdata(dev);
+
+	if (tpd->has_fan) {
+		status = ssam_fan_state_set(tpd->sdev, SSAM_FAN_STATE_STANDBY);
+		if (status)
+			dev_err(&tpd->sdev->dev, "pm: fan standby notification failed");
+	}
+
+	return status;
+}
+
+static void surface_platform_profile_pm_complete(struct device *dev)
+{
+	struct ssam_platform_profile_device *tpd;
+	int status;
+
+	tpd = dev_get_drvdata(dev);
+
+	if (tpd->has_fan) {
+		status = ssam_fan_state_set(tpd->sdev, SSAM_FAN_STATE_NORMAL);
+		if (status)
+			dev_err(&tpd->sdev->dev, "pm: fan resume notification failed");
+	}
+}
+
+static const struct dev_pm_ops surface_platform_profile_pm_ops = {
+	.prepare  = surface_platform_profile_pm_prepare,
+	.complete = surface_platform_profile_pm_complete,
+};
+
+#else /* CONFIG_PM_SLEEP */
+
+static const struct dev_pm_ops surface_platform_profile_pm_ops = { };
+
+#endif /* CONFIG_PM_SLEEP */
+
 static const struct ssam_device_id ssam_platform_profile_match[] = {
 	{ SSAM_SDEV(TMP, SAM, 0x00, 0x01) },
 	{ },
@@ -247,6 +309,7 @@ static struct ssam_device_driver surface_platform_profile = {
 	.match_table = ssam_platform_profile_match,
 	.driver = {
 		.name = "surface_platform_profile",
+		.pm = &surface_platform_profile_pm_ops,
 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
 	},
 };
-- 
2.56.0