[PATCH] firmware: cirrus: cs_dsp: Initialize debugfs_root to invalid

[Richard Fitzgerald <rf@opensource.cirrus.com>]

Initialize debugfs_root to -ENODEV so that if the client never sets a
valid debugfs root the debugfs files will not be created.

A NULL pointer passed to any of the debugfs_create_*() functions means
"create in the root of debugfs". It doesn't mean "ignore".

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
---
 drivers/firmware/cirrus/cs_dsp.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/cirrus/cs_dsp.c b/drivers/firmware/cirrus/cs_dsp.c
index 79d4254d1f9b..9f3d665cfdcf 100644
--- a/drivers/firmware/cirrus/cs_dsp.c
+++ b/drivers/firmware/cirrus/cs_dsp.c
@@ -522,7 +522,7 @@ void cs_dsp_cleanup_debugfs(struct cs_dsp *dsp)
 {
 	cs_dsp_debugfs_clear(dsp);
 	debugfs_remove_recursive(dsp->debugfs_root);
-	dsp->debugfs_root = NULL;
+	dsp->debugfs_root = ERR_PTR(-ENODEV);
 }
 EXPORT_SYMBOL_NS_GPL(cs_dsp_cleanup_debugfs, FW_CS_DSP);
 #else
@@ -2246,6 +2246,11 @@ static int cs_dsp_common_init(struct cs_dsp *dsp)
 
 	mutex_init(&dsp->pwr_lock);
 
+#ifdef CONFIG_DEBUG_FS
+	/* Ensure this is invalid if client never provides a debugfs root */
+	dsp->debugfs_root = ERR_PTR(-ENODEV);
+#endif
+
 	return 0;
 }
 
-- 
2.30.2