clk: Switch from __clk_determine_rate to clk_core_round_rate_nolock

clk_mux_determine_rate_flags() will call into __clk_determine_rate()
with a clk_hw pointer, while it has access to the clk_core pointer
already.

This leads to back and forth between clk_hw and clk_core, while
__clk_determine_rate will only call clk_core_round_rate_nolock() with
the clk_core pointer it retrieved from the clk_hw.

Let's simplify things a bit by calling into clk_core_round_rate_nolock
directly.

Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com> # imx8mp
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> # exynos4210, meson g12b
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220816112530.1837489-19-maxime@cerno.tech
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Author: mripard

drivers/clk/clk.c

@@ -536,6 +536,9 @@ static bool mux_is_better_rate(unsigned long rate, unsigned long now,
 	return now <= rate && now > best;
 }
 
+static int clk_core_round_rate_nolock(struct clk_core *core,
+				      struct clk_rate_request *req);
+
 int clk_mux_determine_rate_flags(struct clk_hw *hw,
 				 struct clk_rate_request *req,
 				 unsigned long flags)
@@ -549,8 +552,12 @@ int clk_mux_determine_rate_flags(struct clk_hw *hw,
 	if (core->flags & CLK_SET_RATE_NO_REPARENT) {
 		parent = core->parent;
 		if (core->flags & CLK_SET_RATE_PARENT) {
-			ret = __clk_determine_rate(parent ? parent->hw : NULL,
-						   &parent_req);
+			if (!parent) {
+				req->rate = 0;
+				return 0;
+			}
+
+			ret = clk_core_round_rate_nolock(parent, &parent_req);
 			if (ret)
 				return ret;
 
@@ -573,7 +580,7 @@ int clk_mux_determine_rate_flags(struct clk_hw *hw,
 
 		if (core->flags & CLK_SET_RATE_PARENT) {
 			parent_req = *req;
-			ret = __clk_determine_rate(parent->hw, &parent_req);
+			ret = clk_core_round_rate_nolock(parent, &parent_req);
 			if (ret)
 				continue;
 		} else {