clk: divider: Add re-usable determine_rate implementations

These are useful when running on 32-bit systems to increase the upper
supported frequency limit. clk_ops.round_rate returns a signed long
which limits the maximum rate on 32-bit systems to 2^31 (or approx.
2.14GHz). clk_ops.determine_rate internally uses an unsigned long so
the maximum rate on 32-bit systems is 2^32 or approx. 4.29GHz.

To avoid code-duplication switch over divider_{ro_,}round_rate_parent
to use the new divider_{ro_,}determine_rate functions.

Reviewed-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20210627223959.188139-2-martin.blumenstingl@googlemail.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index 3449972..87ba496 100644 (file)
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -343,16 +343,63 @@ static int clk_divider_bestdiv(struct clk_hw *hw, struct clk_hw *parent,
        return bestdiv;
 }
 
+int divider_determine_rate(struct clk_hw *hw, struct clk_rate_request *req,
+                          const struct clk_div_table *table, u8 width,
+                          unsigned long flags)
+{
+       int div;
+
+       div = clk_divider_bestdiv(hw, req->best_parent_hw, req->rate,
+                                 &req->best_parent_rate, table, width, flags);
+
+       req->rate = DIV_ROUND_UP_ULL((u64)req->best_parent_rate, div);
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(divider_determine_rate);
+
+int divider_ro_determine_rate(struct clk_hw *hw, struct clk_rate_request *req,
+                             const struct clk_div_table *table, u8 width,
+                             unsigned long flags, unsigned int val)
+{
+       int div;
+
+       div = _get_div(table, val, flags, width);
+
+       /* Even a read-only clock can propagate a rate change */
+       if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
+               if (!req->best_parent_hw)
+                       return -EINVAL;
+
+               req->best_parent_rate = clk_hw_round_rate(req->best_parent_hw,
+                                                         req->rate * div);
+       }
+
+       req->rate = DIV_ROUND_UP_ULL((u64)req->best_parent_rate, div);
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(divider_ro_determine_rate);
+
 long divider_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
                               unsigned long rate, unsigned long *prate,
                               const struct clk_div_table *table,
                               u8 width, unsigned long flags)
 {
-       int div;
+       struct clk_rate_request req = {
+               .rate = rate,
+               .best_parent_rate = *prate,
+               .best_parent_hw = parent,
+       };
+       int ret;
 
-       div = clk_divider_bestdiv(hw, parent, rate, prate, table, width, flags);
+       ret = divider_determine_rate(hw, &req, table, width, flags);
+       if (ret)
+               return ret;
 
-       return DIV_ROUND_UP_ULL((u64)*prate, div);
+       *prate = req.best_parent_rate;
+
+       return req.rate;
 }
 EXPORT_SYMBOL_GPL(divider_round_rate_parent);
 
@@ -361,23 +408,23 @@ long divider_ro_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
                                  const struct clk_div_table *table, u8 width,
                                  unsigned long flags, unsigned int val)
 {
-       int div;
-
-       div = _get_div(table, val, flags, width);
+       struct clk_rate_request req = {
+               .rate = rate,
+               .best_parent_rate = *prate,
+               .best_parent_hw = parent,
+       };
+       int ret;
 
-       /* Even a read-only clock can propagate a rate change */
-       if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
-               if (!parent)
-                       return -EINVAL;
+       ret = divider_ro_determine_rate(hw, &req, table, width, flags, val);
+       if (ret)
+               return ret;
 
-               *prate = clk_hw_round_rate(parent, rate * div);
-       }
+       *prate = req.best_parent_rate;
 
-       return DIV_ROUND_UP_ULL((u64)*prate, div);
+       return req.rate;
 }
 EXPORT_SYMBOL_GPL(divider_ro_round_rate_parent);
 
-
 static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
                                unsigned long *prate)
 {

diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 162a2e5..d83b829 100644 (file)
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -629,6 +629,12 @@ long divider_ro_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
                                  unsigned long rate, unsigned long *prate,
                                  const struct clk_div_table *table, u8 width,
                                  unsigned long flags, unsigned int val);
+int divider_determine_rate(struct clk_hw *hw, struct clk_rate_request *req,
+                          const struct clk_div_table *table, u8 width,
+                          unsigned long flags);
+int divider_ro_determine_rate(struct clk_hw *hw, struct clk_rate_request *req,
+                             const struct clk_div_table *table, u8 width,
+                             unsigned long flags, unsigned int val);
 int divider_get_val(unsigned long rate, unsigned long parent_rate,
                const struct clk_div_table *table, u8 width,
                unsigned long flags);