drm: omapdrm: dss: Support passing private data to debugfs show handlers

To simplify implementation of debugfs seq_file show handlers, the driver
passes the pointer to the show function through the debugfs_create_file
data pointer. This prevents using the pointer to pass driver private
data to the show handler, and requires all handlers to use global
variables to access private data.

To prepare for the removal of global private data in the driver, rework
the debugfs infrastructure to allow passing a private data pointer to
show handlers.

The price to pay is explicit removal of debugfs files to free the
internally allocated memory. This is desirable anyway as debugfs entries
should be removed when a component driver is unbound, otherwise crashes
will occur due to access to freed memory when the components will be
dynamically allocated instead of stored in global variables.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>

1 files changed, 21 insertions, 10 deletions

diff --git a/drivers/gpu/drm/omapdrm/dss/dss.h b/drivers/gpu/drm/omapdrm/dss/dss.h
index 89d708e8e970..ec8e40e09141 100644
--- a/drivers/gpu/drm/omapdrm/dss/dss.h
+++ b/drivers/gpu/drm/omapdrm/dss/dss.h
@@ -25,6 +25,10 @@
 
 #include "omapdss.h"
 
+struct dss_debugfs_entry;
+struct platform_device;
+struct seq_file;
+
 #define MAX_DSS_LCD_MANAGERS	3
 #define MAX_NUM_DSI		2
 
@@ -233,9 +237,6 @@ struct dss_lcd_mgr_config {
 	int lcden_sig_polarity;
 };
 
-struct seq_file;
-struct platform_device;
-
 #define DSS_SZ_REGS			SZ_512
 
 struct dss_device {
@@ -261,6 +262,11 @@ struct dss_device {
 
 	const struct dss_features *feat;
 
+	struct {
+		struct dss_debugfs_entry *clk;
+		struct dss_debugfs_entry *dss;
+	} debugfs;
+
 	struct dss_pll	*video1_pll;
 	struct dss_pll	*video2_pll;
 };
@@ -283,12 +289,20 @@ static inline bool dss_mgr_is_lcd(enum omap_channel id)
 
 /* DSS */
 #if defined(CONFIG_OMAP2_DSS_DEBUGFS)
-int dss_debugfs_create_file(const char *name, void (*write)(struct seq_file *));
+struct dss_debugfs_entry *dss_debugfs_create_file(const char *name,
+		int (*show_fn)(struct seq_file *s, void *data), void *data);
+void dss_debugfs_remove_file(struct dss_debugfs_entry *entry);
 #else
-static inline int dss_debugfs_create_file(const char *name,
-					  void (*write)(struct seq_file *))
+static inline struct dss_debugfs_entry *
+dss_debugfs_create_file(const char *name,
+			int (*show_fn)(struct seq_file *s, void *data),
+			void *data)
+{
+	return NULL;
+}
+
+static inline void dss_debugfs_remove_file(struct dss_debugfs_entry *entry)
 {
-	return 0;
 }
 #endif /* CONFIG_OMAP2_DSS_DEBUGFS */
 
@@ -360,9 +374,6 @@ static inline void sdi_uninit_port(struct device_node *port)
 
 #ifdef CONFIG_OMAP2_DSS_DSI
 
-struct dentry;
-struct file_operations;
-
 void dsi_dump_clocks(struct seq_file *s);
 
 void dsi_irq_handler(void);