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clk: divider: Implement and wire up .determine_rate by default 

.determine_rate is meant to replace .round_rate. The former comes with a
benefit which is especially relevant on 32-bit systems: since
.determine_rate uses an "unsigned long" (compared to a "signed long"
which is used by .round_rate) the maximum value on 32-bit systems
increases from 2^31 (or approx. 2.14GHz) to 2^32 (or approx. 4.29GHz).

Implement .determine_rate in addition to .round_rate so drivers that are
using clk_divider_{ro_,}ops can benefit from this by default. Keep the
.round_rate callback for now since some drivers rely on
clk_divider_ops.round_rate being implemented.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20210702225145.2643303-2-martin.blumenstingl@googlemail.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
This commit is contained in:
Martin Blumenstingl 2021-07-03 00:51:40 +02:00 committed by Stephen Boyd
parent e73f0f0ee7
commit 69a00fb3d6
1 changed files with 23 additions and 0 deletions
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23
drivers/clk/clk-divider.c
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@ -446,6 +446,27 @@ static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
divider->width, divider->flags);
}
static int clk_divider_determine_rate(struct clk_hw *hw,
struct clk_rate_request *req)
{
struct clk_divider *divider = to_clk_divider(hw);
/* if read only, just return current value */
if (divider->flags & CLK_DIVIDER_READ_ONLY) {
u32 val;
val = clk_div_readl(divider) >> divider->shift;
val &= clk_div_mask(divider->width);
return divider_ro_determine_rate(hw, req, divider->table,
divider->width,
divider->flags, val);
}
return divider_determine_rate(hw, req, divider->table, divider->width,
divider->flags);
}
int divider_get_val(unsigned long rate, unsigned long parent_rate,
const struct clk_div_table *table, u8 width,
unsigned long flags)
@ -501,6 +522,7 @@ static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
const struct clk_ops clk_divider_ops = {
.recalc_rate = clk_divider_recalc_rate,
.round_rate = clk_divider_round_rate,
.determine_rate = clk_divider_determine_rate,
.set_rate = clk_divider_set_rate,
};
EXPORT_SYMBOL_GPL(clk_divider_ops);
@ -508,6 +530,7 @@ EXPORT_SYMBOL_GPL(clk_divider_ops);
const struct clk_ops clk_divider_ro_ops = {
.recalc_rate = clk_divider_recalc_rate,
.round_rate = clk_divider_round_rate,
.determine_rate = clk_divider_determine_rate,
};
EXPORT_SYMBOL_GPL(clk_divider_ro_ops);