clk: tegra: clk-super: Add restore-context support

This patch implements restore_context for clk_super_mux and clk_super.

During system supend, core power goes off the and context of Tegra
CAR registers is lost.

So on system resume, context of super clock registers are restored
to have them in same state as before suspend.
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/clk/tegra/clk-super.c

@@ -124,9 +124,21 @@ static int clk_super_set_parent(struct clk_hw *hw, u8 index)
 	return err;
 }
 
+static void clk_super_mux_restore_context(struct clk_hw *hw)
+{
+	int parent_id;
+
+	parent_id = clk_hw_get_parent_index(hw);
+	if (WARN_ON(parent_id < 0))
+		return;
+
+	clk_super_set_parent(hw, parent_id);
+}
+
 static const struct clk_ops tegra_clk_super_mux_ops = {
 	.get_parent = clk_super_get_parent,
 	.set_parent = clk_super_set_parent,
+	.restore_context = clk_super_mux_restore_context,
 };
 
 static long clk_super_round_rate(struct clk_hw *hw, unsigned long rate,
@@ -162,12 +174,27 @@ static int clk_super_set_rate(struct clk_hw *hw, unsigned long rate,
 	return super->div_ops->set_rate(div_hw, rate, parent_rate);
 }
 
+static void clk_super_restore_context(struct clk_hw *hw)
+{
+	struct tegra_clk_super_mux *super = to_clk_super_mux(hw);
+	struct clk_hw *div_hw = &super->frac_div.hw;
+	int parent_id;
+
+	parent_id = clk_hw_get_parent_index(hw);
+	if (WARN_ON(parent_id < 0))
+		return;
+
+	super->div_ops->restore_context(div_hw);
+	clk_super_set_parent(hw, parent_id);
+}
+
 const struct clk_ops tegra_clk_super_ops = {
 	.get_parent = clk_super_get_parent,
 	.set_parent = clk_super_set_parent,
 	.set_rate = clk_super_set_rate,
 	.round_rate = clk_super_round_rate,
 	.recalc_rate = clk_super_recalc_rate,
+	.restore_context = clk_super_restore_context,
 };
 
 struct clk *tegra_clk_register_super_mux(const char *name,