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Subject[PATCH v3 1/3] clk: divider: Add re-usable determine_rate implementations
Date
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>
---
drivers/clk/clk-divider.c | 75 +++++++++++++++++++++++++++++-------
include/linux/clk-provider.h | 6 +++
2 files changed, 67 insertions(+), 14 deletions(-)

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index 344997203f0e..87ba4966b0e8 100644
--- 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 162a2e5546a3..d83b829305c0 100644
--- 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);
--
2.32.0
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