clknode_get_parent
p_clk = clknode_get_parent(clk);
p_clk = clknode_get_parent(clk);
parentnode = clknode_get_parent(clknode);
struct clknode *clknode_get_parent(struct clknode *clk);
parent_clk = clknode_get_parent(clk);
parent_clk = clknode_get_parent(clk);