ARM: OMAP: PM: Lock clocks list while generating summary

Commit a5302572 (OMAP: Add debugfs
node to show the summary of all clocks) introduced clock summary,
however, we are interested in seeing snapshot of the clock state, not
in dynamically changing clock configurations as the data provided by
clock summary will then be useless for debugging configuration
issues. So, hold the common lock when dumping the clock summary.

Cc: Paul Walmsley <paul@pwsan.com>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>
[nm@ti.com: added commit message]
Signed-off-by: Nishanth Menon <nm@ti.com>
[paul@pwsan.com: minor edits to commit message]
Signed-off-by: Paul Walmsley <paul@pwsan.com>

arch/arm/plat-omap/clock.c

@@ -461,6 +461,7 @@ static int clk_dbg_show_summary(struct seq_file *s, void *unused)
 	struct clk *c;
 	struct clk *pa;
 
+	mutex_lock(&clocks_mutex);
 	seq_printf(s, "%-30s %-30s %-10s %s\n",
 		"clock-name", "parent-name", "rate", "use-count");
 
@@ -469,6 +470,7 @@ static int clk_dbg_show_summary(struct seq_file *s, void *unused)
 		seq_printf(s, "%-30s %-30s %-10lu %d\n",
 			c->name, pa ? pa->name : "none", c->rate, c->usecount);
 	}
+	mutex_unlock(&clocks_mutex);
 
 	return 0;
 }