Re: [3/5] clk: divider: add divider_ro_round_rate helper

From: David Lechner
Date: Thu Jan 11 2018 - 18:08:26 EST


On 01/05/2018 11:09 AM, Jerome Brunet wrote:
Like divider_round_rate, a couple a of driver are doing more or less
the same operation to round the rate of the divider when it is read-only.

We can factor this code so let's provide an helper function for this

Perhaps you could also make use of this new helper here (clk-divider.c):

const struct clk_ops clk_divider_ro_ops = {
.recalc_rate = clk_divider_recalc_rate,
.round_rate = clk_divider_round_rate,
};
EXPORT_SYMBOL_GPL(clk_divider_ro_ops);


Signed-off-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx>
---
drivers/clk/clk-divider.c | 43 ++++++++++++++++++++++++++++---------------
include/linux/clk-provider.h | 15 +++++++++++++++
2 files changed, 43 insertions(+), 15 deletions(-)

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index a851d3e04c7f..3eb2b27f3513 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -344,29 +344,42 @@ long divider_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
}
EXPORT_SYMBOL_GPL(divider_round_rate_parent);

It is nice to have documentation comments on public functions. Especially
in this case where @prate is an in/out parameter and @table is optional.

+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 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 (!parent)
+ return -EINVAL;
+
+ *prate = clk_hw_round_rate(parent, rate * div);
+ }
+
+ return DIV_ROUND_UP_ULL((u64)*prate, div);
+}
+EXPORT_SYMBOL_GPL(divider_ro_round_rate_parent);
+
+
static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
struct clk_divider *divider = to_clk_divider(hw);
- struct clk_hw *hw_parent = clk_hw_get_parent(hw);
- int bestdiv;
+ u32 val;
/* if read only, just return current value */
if (divider->flags & CLK_DIVIDER_READ_ONLY) {
- bestdiv = clk_readl(divider->reg) >> divider->shift;
- bestdiv &= div_mask(divider->width);
- bestdiv = _get_div(divider->table, bestdiv, divider->flags,
- divider->width);
-
- /* Even a read-only clock can propagate a rate change */
- if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
- if (!hw_parent)
- return -EINVAL;
-
- *prate = clk_hw_round_rate(hw_parent, rate * bestdiv);
- }
+ val = clk_readl(divider->reg) >> divider->shift;
+ val &= div_mask(divider->width);
- return DIV_ROUND_UP_ULL((u64)*prate, bestdiv);
+ return divider_ro_round_rate(hw, rate, prate, divider->table,
+ divider->width, divider->flags,
+ val);
}
return divider_round_rate(hw, rate, prate, divider->table,
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 175a62a15619..eb2c3a035e98 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -417,6 +417,10 @@ 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);
+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_get_val(unsigned long rate, unsigned long parent_rate,
const struct clk_div_table *table, u8 width,
unsigned long flags);
@@ -772,6 +776,17 @@ static inline long divider_round_rate(struct clk_hw *hw, unsigned long rate,
rate, prate, table, width, flags);
}

Same here (about documentation comment).

+static inline long divider_ro_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate,
+ const struct clk_div_table *table,
+ u8 width, unsigned long flags,
+ unsigned int val)
+{
+ return divider_ro_round_rate_parent(hw, clk_hw_get_parent(hw),
+ rate, prate, table, width, flags,
+ val);
+}
+
/*
* FIXME clock api without lock protection
*/