drm/tegra: hdmi: Make sure clock is enabled before dumping registers

The debugfs register dumping function did not enable the HDMI clock.
This led to a possible system hang when reading the debugfs entry
while no HDMI cable was connected to the system. This patch makes
sure that the clock is enabled during the read.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/host1x/drm/hdmi.c

@@ -904,6 +904,11 @@ static int tegra_hdmi_show_regs(struct seq_file *s, void *data)
 {
 	struct drm_info_node *node = s->private;
 	struct tegra_hdmi *hdmi = node->info_ent->data;
+	int err;
+
+	err = clk_enable(hdmi->clk);
+	if (err)
+		return err;
 
 #define DUMP_REG(name)						\
 	seq_printf(s, "%-56s %#05x %08lx\n", #name, name,	\
@@ -1069,6 +1074,8 @@ static int tegra_hdmi_show_regs(struct seq_file *s, void *data)
 
 #undef DUMP_REG
 
+	clk_disable(hdmi->clk);
+
 	return 0;
 }