linux-kernel - [PATCH v5 05/20] drm/bridge: ti-sn65dsi86: Clean debugfs code

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Date:   Fri, 23 Apr 2021 09:58:51 -0700
From:   Douglas Anderson <dianders@...omium.org>
To:     Andrzej Hajda <a.hajda@...sung.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...l.net>,
        Sam Ravnborg <sam@...nborg.org>, Wolfram Sang <wsa@...nel.org>
Cc:     linux-arm-msm@...r.kernel.org, robdclark@...omium.org,
        Stanislav Lisovskiy <stanislav.lisovskiy@...el.com>,
        Stephen Boyd <swboyd@...omium.org>,
        Steev Klimaszewski <steev@...i.org>,
        Linus W <linus.walleij@...aro.org>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        linux-i2c@...r.kernel.org,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        dri-devel@...ts.freedesktop.org,
        Douglas Anderson <dianders@...omium.org>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>,
        Robert Foss <robert.foss@...aro.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v5 05/20] drm/bridge: ti-sn65dsi86: Clean debugfs code

Let's cleanup the debugfs code to:
- Check for errors.
- Use devm to manage freeing, which also means we don't need to store
  a pointer in our structure.

Signed-off-by: Douglas Anderson <dianders@...omium.org>
---
Bjorn: I left off your tag on this patch since I made changes compared
to v4. Can you re-add if it still looks OK? This is now ordered
_after_ the pm_runtime patch so I believe the ordering problem you
pointed out should be fixed as well?

Changes in v5:
- Don't print debugfs creation errors.
- Handle NULL from debugfs_create_dir() which is documented possible.

 drivers/gpu/drm/bridge/ti-sn65dsi86.c | 33 +++++++++++++++++----------
 1 file changed, 21 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index 44d8395505f0..8aa36074aab9 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -118,7 +118,6 @@
  * @aux:          Our aux channel.
  * @bridge:       Our bridge.
  * @connector:    Our connector.
- * @debugfs:      Used for managing our debugfs.
  * @host_node:    Remote DSI node.
  * @dsi:          Our MIPI DSI source.
  * @edid:         Detected EDID of eDP panel.
@@ -146,7 +145,6 @@ struct ti_sn65dsi86 {
 	struct drm_dp_aux		aux;
 	struct drm_bridge		bridge;
 	struct drm_connector		connector;
-	struct dentry			*debugfs;
 	struct edid			*edid;
 	struct device_node		*host_node;
 	struct mipi_dsi_device		*dsi;
@@ -245,18 +243,31 @@ static int status_show(struct seq_file *s, void *data)
 
 DEFINE_SHOW_ATTRIBUTE(status);
 
-static void ti_sn65dsi86_debugfs_init(struct ti_sn65dsi86 *pdata)
+static void ti_sn65dsi86_debugfs_remove(void *data)
 {
-	pdata->debugfs = debugfs_create_dir(dev_name(pdata->dev), NULL);
-
-	debugfs_create_file("status", 0600, pdata->debugfs, pdata,
-			&status_fops);
+	debugfs_remove_recursive(data);
 }
 
-static void ti_sn65dsi86_debugfs_remove(struct ti_sn65dsi86 *pdata)
+static void ti_sn65dsi86_debugfs_init(struct ti_sn65dsi86 *pdata)
 {
-	debugfs_remove_recursive(pdata->debugfs);
-	pdata->debugfs = NULL;
+	struct device *dev = pdata->dev;
+	struct dentry *debugfs;
+	int ret;
+
+	debugfs = debugfs_create_dir(dev_name(dev), NULL);
+
+	/*
+	 * We might get an error back if debugfs wasn't enabled in the kernel
+	 * so let's just silently return upon failure.
+	 */
+	if (IS_ERR_OR_NULL(debugfs))
+		return;
+
+	ret = devm_add_action_or_reset(dev, ti_sn65dsi86_debugfs_remove, debugfs);
+	if (ret)
+		return;
+
+	debugfs_create_file("status", 0600, debugfs, pdata, &status_fops);
 }
 
 /* Connector funcs */
@@ -1316,8 +1327,6 @@ static int ti_sn65dsi86_remove(struct i2c_client *client)
 
 	kfree(pdata->edid);
 
-	ti_sn65dsi86_debugfs_remove(pdata);
-
 	drm_bridge_remove(&pdata->bridge);
 
 	of_node_put(pdata->host_node);
-- 
2.31.1.498.g6c1eba8ee3d-goog