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| author | Maxime COQUELIN <maxime.coquelin@st.com> | 2014-01-29 17:24:08 +0100 |
|---|---|---|
| committer | Mike Turquette <mturquette@linaro.org> | 2014-04-30 20:51:27 +0200 |
| commit | 0e2de78ecdc842218a2b6c422bb4a8ff4d85d11f (patch) | |
| tree | f73422d0e0433a890fe060b400fc528a2784d64b /drivers | |
| parent | clk: divider: Add round to closest divider (diff) | |
| download | linux-0e2de78ecdc842218a2b6c422bb4a8ff4d85d11f.tar.xz linux-0e2de78ecdc842218a2b6c422bb4a8ff4d85d11f.zip | |
clk: divider: Optimize clk_divider_bestdiv loop
Currently, the for-loop used to try all the different dividers to find the
one that best fit tries all the values from 1 to max_div, incrementing by one.
In case of power-of-two, or table based divider, the loop isn't optimal.
Instead of incrementing by one, this patch provides directly the next divider.
Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/clk/clk-divider.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c index c57294563a98..b3c83966be18 100644 --- a/drivers/clk/clk-divider.c +++ b/drivers/clk/clk-divider.c @@ -240,6 +240,18 @@ static bool _is_best_div(struct clk_divider *divider, return now <= rate && now > best; } +static int _next_div(struct clk_divider *divider, int div) +{ + div++; + + if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) + return __roundup_pow_of_two(div); + if (divider->table) + return _round_up_table(divider->table, div); + + return div; +} + static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate, unsigned long *best_parent_rate) { @@ -267,7 +279,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate, */ maxdiv = min(ULONG_MAX / rate, maxdiv); - for (i = 1; i <= maxdiv; i++) { + for (i = 1; i <= maxdiv; i = _next_div(divider, i)) { if (!_is_valid_div(divider, i)) continue; if (rate * i == parent_rate_saved) { |