clk: Add rate constraints to clocks

Adds a way for clock consumers to set maximum and minimum rates. This
can be used for thermal drivers to set minimum rates, or by misc.
drivers to set maximum rates to assure a minimum performance level.

Changes the signature of the determine_rate callback by adding the
parameters min_rate and max_rate.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
[sboyd@codeaurora.org: set req_rate in __clk_init]
Signed-off-by: Michael Turquette <mturquette@linaro.org>
[mturquette@linaro.org: min/max rate for sun6i_ahb1_clk_determine_rate
                        migrated clk-private.h changes to clk.c]

3 files changed, 46 insertions, 3 deletions

diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 12f13b0673af..17dd6e9439d1 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -175,9 +175,12 @@ struct clk_ops {
                                         unsigned long parent_rate);
         long            (*round_rate)(struct clk_hw *hw, unsigned long rate,
                                         unsigned long *parent_rate);
-        long            (*determine_rate)(struct clk_hw *hw, unsigned long rate,
-                                        unsigned long *best_parent_rate,
-                                        struct clk_hw **best_parent_hw);
+        long            (*determine_rate)(struct clk_hw *hw,
+                                          unsigned long rate,
+                                          unsigned long min_rate,
+                                          unsigned long max_rate,
+                                          unsigned long *best_parent_rate,
+                                          struct clk_hw **best_parent_hw);
         int             (*set_parent)(struct clk_hw *hw, u8 index);
         u8              (*get_parent)(struct clk_hw *hw);
         int             (*set_rate)(struct clk_hw *hw, unsigned long rate,
@@ -573,9 +576,17 @@ bool __clk_is_prepared(struct clk *clk);
 bool __clk_is_enabled(struct clk *clk);
 struct clk *__clk_lookup(const char *name);
 long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
+                              unsigned long min_rate,
+                              unsigned long max_rate,
                               unsigned long *best_parent_rate,
                               struct clk_hw **best_parent_p);
+unsigned long __clk_determine_rate(struct clk_hw *core,
+                                   unsigned long rate,
+                                   unsigned long min_rate,
+                                   unsigned long max_rate);
 long __clk_mux_determine_rate_closest(struct clk_hw *hw, unsigned long rate,
+                              unsigned long min_rate,
+                              unsigned long max_rate,
                               unsigned long *best_parent_rate,
                               struct clk_hw **best_parent_p);
 
diff --git a/include/linux/clk.h b/include/linux/clk.h
index ba7e9eda4347..8381bbfbc308 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -314,6 +314,34 @@ int clk_set_rate(struct clk *clk, unsigned long rate);
 bool clk_has_parent(struct clk *clk, struct clk *parent);
 
 /**
+ * clk_set_rate_range - set a rate range for a clock source
+ * @clk: clock source
+ * @min: desired minimum clock rate in Hz, inclusive
+ * @max: desired maximum clock rate in Hz, inclusive
+ *
+ * Returns success (0) or negative errno.
+ */
+int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max);
+
+/**
+ * clk_set_min_rate - set a minimum clock rate for a clock source
+ * @clk: clock source
+ * @rate: desired minimum clock rate in Hz, inclusive
+ *
+ * Returns success (0) or negative errno.
+ */
+int clk_set_min_rate(struct clk *clk, unsigned long rate);
+
+/**
+ * clk_set_max_rate - set a maximum clock rate for a clock source
+ * @clk: clock source
+ * @rate: desired maximum clock rate in Hz, inclusive
+ *
+ * Returns success (0) or negative errno.
+ */
+int clk_set_max_rate(struct clk *clk, unsigned long rate);
+
+/**
  * clk_set_parent - set the parent clock source for this clock
  * @clk: clock source
  * @parent: parent clock source
diff --git a/include/linux/clk/ti.h b/include/linux/clk/ti.h
index 310122dcd9b5..0eac65054283 100644
--- a/include/linux/clk/ti.h
+++ b/include/linux/clk/ti.h
@@ -271,6 +271,8 @@ int omap3_noncore_dpll_set_rate_and_parent(struct clk_hw *hw,
                                            u8 index);
 long omap3_noncore_dpll_determine_rate(struct clk_hw *hw,
                                        unsigned long rate,
+                                       unsigned long min_rate,
+                                       unsigned long max_rate,
                                        unsigned long *best_parent_rate,
                                        struct clk_hw **best_parent_clk);
 unsigned long omap4_dpll_regm4xen_recalc(struct clk_hw *hw,
@@ -280,6 +282,8 @@ long omap4_dpll_regm4xen_round_rate(struct clk_hw *hw,
                                     unsigned long *parent_rate);
 long omap4_dpll_regm4xen_determine_rate(struct clk_hw *hw,
                                         unsigned long rate,
+                                        unsigned long min_rate,
+                                        unsigned long max_rate,
                                         unsigned long *best_parent_rate,
                                         struct clk_hw **best_parent_clk);
 u8 omap2_init_dpll_parent(struct clk_hw *hw);