[char-misc-next 2/4 V5] watchdog: mei_wdt: add activation debugfs entry

[Tomas Winkler <tomas.winkler@intel.com>]

Add entry for displaying whether the device has activated or
deactivated watchdog fw application.

cat <debugfs>/mei_wdt/activation
activated | deactivated

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
---
V3: new in the series
V4: Rebase the code over patchset : "watchdog: Replace driver based refcounting"
V5: rebase
 drivers/watchdog/mei_wdt.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/watchdog/mei_wdt.c b/drivers/watchdog/mei_wdt.c
index 9addf8902f74..b93474ec34a1 100644
--- a/drivers/watchdog/mei_wdt.c
+++ b/drivers/watchdog/mei_wdt.c
@@ -497,6 +497,28 @@ static void mei_wdt_event(struct mei_cl_device *cldev,
 
 #if IS_ENABLED(CONFIG_DEBUG_FS)
 
+static ssize_t mei_dbgfs_read_activation(struct file *file, char __user *ubuf,
+					size_t cnt, loff_t *ppos)
+{
+	struct mei_wdt *wdt = file->private_data;
+	const size_t bufsz = 32;
+	char buf[32];
+	ssize_t pos;
+
+	mutex_lock(&wdt->reg_lock);
+	pos = scnprintf(buf, bufsz, "%s\n",
+		__mei_wdt_is_registered(wdt) ? "activated" : "deactivated");
+	mutex_unlock(&wdt->reg_lock);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, pos);
+}
+
+static const struct file_operations dbgfs_fops_activation = {
+	.open    = simple_open,
+	.read    = mei_dbgfs_read_activation,
+	.llseek  = generic_file_llseek,
+};
+
 static ssize_t mei_dbgfs_read_state(struct file *file, char __user *ubuf,
 				    size_t cnt, loff_t *ppos)
 {
@@ -536,6 +558,11 @@ static int dbgfs_register(struct mei_wdt *wdt)
 	if (!f)
 		goto err;
 
+	f = debugfs_create_file("activation",  S_IRUSR,
+				dir, wdt, &dbgfs_fops_activation);
+	if (!f)
+		goto err;
+
 	return 0;
 err:
 	dbgfs_unregister(wdt);
-- 
2.4.3