clk: ingenic: Support specifying "wait for clock stable" delay

Some clocks need a small delay after being ungated to run stable, as
using them too soon might result in hardware lockups.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/ingenic/cgu.c

@@ -512,6 +512,9 @@ static int ingenic_clk_enable(struct clk_hw *hw)
 		spin_lock_irqsave(&cgu->lock, flags);
 		ingenic_cgu_gate_set(cgu, &clk_info->gate, false);
 		spin_unlock_irqrestore(&cgu->lock, flags);
+
+		if (clk_info->gate.delay_us)
+			udelay(clk_info->gate.delay_us);
 	}
 
 	return 0;

drivers/clk/ingenic/cgu.h

@@ -112,11 +112,13 @@ struct ingenic_cgu_fixdiv_info {
  * @reg: offset of the gate control register within the CGU
  * @bit: offset of the bit in the register that controls the gate
  * @clear_to_gate: if set, the clock is gated when the bit is cleared
+ * @delay_us: delay in microseconds after which the clock is considered stable
  */
 struct ingenic_cgu_gate_info {
 	unsigned reg;
 	u8 bit;
 	bool clear_to_gate;
+	u16 delay_us;
 };
 
 /**