[PATCH] platform/chrome: Expose resume result via sysfs

[Evan Green]

For ECs that support it, the EC returns the number of slp_s0
transitions and whether or not there was a timeout in the resume
response. Expose the last resume result to usermode via sysfs so
that usermode can detect and report S0ix timeouts.

Signed-off-by: Evan Green <evgreen@xxxxxxxxxxxx>
---

Enric, I'm not sure if this conflicts with your giant refactoring.
I can rebase this on your series, but patchwork doesn't have patch
2 of your series, so you'd have to point me to a tree.

---
 drivers/mfd/cros_ec.c                   |  6 +++++-
 drivers/platform/chrome/cros_ec_sysfs.c | 17 +++++++++++++++++
 include/linux/mfd/cros_ec.h             |  1 +
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
index bd2bcdd4718b..64a2d3adc729 100644
--- a/drivers/mfd/cros_ec.c
+++ b/drivers/mfd/cros_ec.c
@@ -110,12 +110,16 @@ static int cros_ec_sleep_event(struct cros_ec_device *ec_dev, u8 sleep_event)
 
 	/* For now, report failure to transition to S0ix with a warning. */
 	if (ret >= 0 && ec_dev->host_sleep_v1 &&
-	    (sleep_event == HOST_SLEEP_EVENT_S0IX_RESUME))
+	    (sleep_event == HOST_SLEEP_EVENT_S0IX_RESUME)) {
+		ec_dev->last_resume_result =
+			buf.u.resp1.resume_response.sleep_transitions;
+
 		WARN_ONCE(buf.u.resp1.resume_response.sleep_transitions &
 			  EC_HOST_RESUME_SLEEP_TIMEOUT,
 			  "EC detected sleep transition timeout. Total slp_s0 transitions: %d",
 			  buf.u.resp1.resume_response.sleep_transitions &
 			  EC_HOST_RESUME_SLEEP_TRANSITIONS_MASK);
+	}
 
 	return ret;
 }
diff --git a/drivers/platform/chrome/cros_ec_sysfs.c b/drivers/platform/chrome/cros_ec_sysfs.c
index 3edb237bf8ed..2deca98c7a7a 100644
--- a/drivers/platform/chrome/cros_ec_sysfs.c
+++ b/drivers/platform/chrome/cros_ec_sysfs.c
@@ -308,18 +308,35 @@ static ssize_t kb_wake_angle_store(struct device *dev,
 	return count;
 }
 
+/* Last resume result */
+static ssize_t last_resume_result_show(struct device *dev,
+				       struct device_attribute *attr, char *buf)
+{
+	struct cros_ec_dev *ec = to_cros_ec_dev(dev);
+	int ret;
+
+	ret = scnprintf(buf,
+			PAGE_SIZE,
+			"0x%x\n",
+			ec->ec_dev->last_resume_result);
+
+	return ret;
+}
+
 /* Module initialization */
 
 static DEVICE_ATTR_RW(reboot);
 static DEVICE_ATTR_RO(version);
 static DEVICE_ATTR_RO(flashinfo);
 static DEVICE_ATTR_RW(kb_wake_angle);
+static DEVICE_ATTR_RO(last_resume_result);
 
 static struct attribute *__ec_attrs[] = {
 	&dev_attr_kb_wake_angle.attr,
 	&dev_attr_reboot.attr,
 	&dev_attr_version.attr,
 	&dev_attr_flashinfo.attr,
+	&dev_attr_last_resume_result.attr,
 	NULL,
 };
 
diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index cfa78bb4990f..d50ade418a83 100644
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -163,6 +163,7 @@ struct cros_ec_device {
 	struct ec_response_get_next_event_v1 event_data;
 	int event_size;
 	u32 host_event_wake_mask;
+	u32 last_resume_result;
 };
 
 /**
-- 
2.20.1