ARM: OMAP4: clock: add support for determine_rate for omap4 regm4xen DPLL

Similarly to OMAP3 noncore DPLL, the implementation of this DPLL clock
type is wrong. This patch adds basic functionality for determine_rate
for this clock type which will be taken into use in the patches following
later.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>

2 files changed, 45 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/dpll44xx.c b/arch/arm/mach-omap2/dpll44xx.c
index 4613f1e86988..535822fcf4bb 100644
--- a/arch/arm/mach-omap2/dpll44xx.c
+++ b/arch/arm/mach-omap2/dpll44xx.c
@@ -207,3 +207,44 @@ out:
 
         return dd->last_rounded_rate;
 }
+
+/**
+ * omap4_dpll_regm4xen_determine_rate - determine rate for a DPLL
+ * @hw: pointer to the clock to determine rate for
+ * @rate: target rate for the DPLL
+ * @best_parent_rate: pointer for returning best parent rate
+ * @best_parent_clk: pointer for returning best parent clock
+ *
+ * Determines which DPLL mode to use for reaching a desired rate.
+ * Checks whether the DPLL shall be in bypass or locked mode, and if
+ * locked, calculates the M,N values for the DPLL via round-rate.
+ * Returns a positive clock rate with success, negative error value
+ * in failure.
+ */
+long omap4_dpll_regm4xen_determine_rate(struct clk_hw *hw, unsigned long rate,
+                                        unsigned long *best_parent_rate,
+                                        struct clk **best_parent_clk)
+{
+        struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+        struct dpll_data *dd;
+
+        if (!hw || !rate)
+                return -EINVAL;
+
+        dd = clk->dpll_data;
+        if (!dd)
+                return -EINVAL;
+
+        if (__clk_get_rate(dd->clk_bypass) == rate &&
+            (dd->modes & (1 << DPLL_LOW_POWER_BYPASS))) {
+                *best_parent_clk = dd->clk_bypass;
+        } else {
+                rate = omap4_dpll_regm4xen_round_rate(hw, rate,
+                                                      best_parent_rate);
+                *best_parent_clk = dd->clk_ref;
+        }
+
+        *best_parent_rate = rate;
+
+        return rate;
+}
diff --git a/include/linux/clk/ti.h b/include/linux/clk/ti.h
index 6f9fb77ffdd5..abc702a73aca 100644
--- a/include/linux/clk/ti.h
+++ b/include/linux/clk/ti.h
@@ -270,6 +270,10 @@ unsigned long omap4_dpll_regm4xen_recalc(struct clk_hw *hw,
 long omap4_dpll_regm4xen_round_rate(struct clk_hw *hw,
                                     unsigned long target_rate,
                                     unsigned long *parent_rate);
+long omap4_dpll_regm4xen_determine_rate(struct clk_hw *hw,
+                                        unsigned long rate,
+                                        unsigned long *best_parent_rate,
+                                        struct clk **best_parent_clk);
 u8 omap2_init_dpll_parent(struct clk_hw *hw);
 unsigned long omap3_dpll_recalc(struct clk_hw *hw, unsigned long parent_rate);
 long omap2_dpll_round_rate(struct clk_hw *hw, unsigned long target_rate,