clk: Show symbolic clock flags in debugfs

Currently the virtual "clk_flags" file in debugfs shows the numeric
value of the top-level framework flags for the specified clock.
Hence the user must manually interpret these values.

Moreover, on big-endian 64-bit systems, the wrong half of the value is
shown, due to the cast from "unsigned long *" to "u32 *".

Fix both issues by showing the symbolic flag names instead.
Any non-standard flags are shown as a hex number.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/clk.c

@@ -24,6 +24,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/sched.h>
 #include <linux/clkdev.h>
+#include <linux/stringify.h>
 
 #include "clk.h"
 
@@ -2554,6 +2555,58 @@ static const struct file_operations clk_dump_fops = {
 	.release	= single_release,
 };
 
+static const struct {
+	unsigned long flag;
+	const char *name;
+} clk_flags[] = {
+#define ENTRY(f) { f, __stringify(f) }
+	ENTRY(CLK_SET_RATE_GATE),
+	ENTRY(CLK_SET_PARENT_GATE),
+	ENTRY(CLK_SET_RATE_PARENT),
+	ENTRY(CLK_IGNORE_UNUSED),
+	ENTRY(CLK_IS_BASIC),
+	ENTRY(CLK_GET_RATE_NOCACHE),
+	ENTRY(CLK_SET_RATE_NO_REPARENT),
+	ENTRY(CLK_GET_ACCURACY_NOCACHE),
+	ENTRY(CLK_RECALC_NEW_RATES),
+	ENTRY(CLK_SET_RATE_UNGATE),
+	ENTRY(CLK_IS_CRITICAL),
+	ENTRY(CLK_OPS_PARENT_ENABLE),
+#undef ENTRY
+};
+
+static int clk_flags_dump(struct seq_file *s, void *data)
+{
+	struct clk_core *core = s->private;
+	unsigned long flags = core->flags;
+	unsigned int i;
+
+	for (i = 0; flags && i < ARRAY_SIZE(clk_flags); i++) {
+		if (flags & clk_flags[i].flag) {
+			seq_printf(s, "%s\n", clk_flags[i].name);
+			flags &= ~clk_flags[i].flag;
+		}
+	}
+	if (flags) {
+		/* Unknown flags */
+		seq_printf(s, "0x%lx\n", flags);
+	}
+
+	return 0;
+}
+
+static int clk_flags_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, clk_flags_dump, inode->i_private);
+}
+
+static const struct file_operations clk_flags_fops = {
+	.open		= clk_flags_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
 static int possible_parents_dump(struct seq_file *s, void *data)
 {
 	struct clk_core *core = s->private;
@@ -2610,8 +2663,8 @@ static int clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
 	if (!d)
 		goto err_out;
 
-	d = debugfs_create_x32("clk_flags", S_IRUGO, core->dentry,
-			(u32 *)&core->flags);
+	d = debugfs_create_file("clk_flags", 0444, core->dentry, core,
+				&clk_flags_fops);
 	if (!d)
 		goto err_out;
 

include/linux/clk-provider.h

@@ -20,6 +20,8 @@
  * flags used across common struct clk.  these flags should only affect the
  * top-level framework.  custom flags for dealing with hardware specifics
  * belong in struct clk_foo
+ *
+ * Please update clk_flags[] in drivers/clk/clk.c when making changes here!
  */
 #define CLK_SET_RATE_GATE	BIT(0) /* must be gated across rate change */
 #define CLK_SET_PARENT_GATE	BIT(1) /* must be gated across re-parent */