clk: sunxi-ng: gate: Support common pre-dividers

Some clock gates have a pre-divider between the source input and the
gate itself. A notable example is the HSIC 12 MHz clock found on the
A83T, which has the 24 MHz main oscillator as its input, and a /2
pre-divider.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

diff --git a/drivers/clk/sunxi-ng/ccu_gate.c b/drivers/clk/sunxi-ng/ccu_gate.c
index 8a81f9d4a89fc9b5e8a109fca1daca3771e38cf3..cd069d5da2150e116d043a06e86597e4a2264f85 100644 (file)
--- a/drivers/clk/sunxi-ng/ccu_gate.c
+++ b/drivers/clk/sunxi-ng/ccu_gate.c
@@ -75,8 +75,55 @@ static int ccu_gate_is_enabled(struct clk_hw *hw)
        return ccu_gate_helper_is_enabled(&cg->common, cg->enable);
 }
 
+static unsigned long ccu_gate_recalc_rate(struct clk_hw *hw,
+                                         unsigned long parent_rate)
+{
+       struct ccu_gate *cg = hw_to_ccu_gate(hw);
+       unsigned long rate = parent_rate;
+
+       if (cg->common.features & CCU_FEATURE_ALL_PREDIV)
+               rate /= cg->common.prediv;
+
+       return rate;
+}
+
+static long ccu_gate_round_rate(struct clk_hw *hw, unsigned long rate,
+                               unsigned long *prate)
+{
+       struct ccu_gate *cg = hw_to_ccu_gate(hw);
+       int div = 1;
+
+       if (cg->common.features & CCU_FEATURE_ALL_PREDIV)
+               div = cg->common.prediv;
+
+       if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
+               unsigned long best_parent = rate;
+
+               if (cg->common.features & CCU_FEATURE_ALL_PREDIV)
+                       best_parent *= div;
+               *prate = clk_hw_round_rate(clk_hw_get_parent(hw), best_parent);
+       }
+
+       return *prate / div;
+}
+
+static int ccu_gate_set_rate(struct clk_hw *hw, unsigned long rate,
+                            unsigned long parent_rate)
+{
+       /*
+        * We must report success but we can do so unconditionally because
+        * clk_factor_round_rate returns values that ensure this call is a
+        * nop.
+        */
+
+       return 0;
+}
+
 const struct clk_ops ccu_gate_ops = {
        .disable        = ccu_gate_disable,
        .enable         = ccu_gate_enable,
        .is_enabled     = ccu_gate_is_enabled,
+       .round_rate     = ccu_gate_round_rate,
+       .set_rate       = ccu_gate_set_rate,
+       .recalc_rate    = ccu_gate_recalc_rate,
 };