| Message ID | b9d92004d22f745e8acde0599359d67538c006a9.1500968090.git-series.quentin.schulz@free-electrons.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 25/07/2017 at 09:37, Quentin Schulz wrote: > The driver requests the current clk rate of each of its parent clocks to > decide whether a clock rate is suitable or not. It does not request > determine_rate from a parent clock which could request a rate change in > parent clock (i.e. there is no parent rate propagation). > > We know the rate we want (passed along req argument of the function) and > the parent clock rate, thus we know the closest rounded divisor, we > don't need to iterate over the available divisors to find the best one > for a given clock. > > Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com> > Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com> Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com> > --- > drivers/clk/at91/clk-generated.c | 25 ++++++++++++------------- > 1 file changed, 12 insertions(+), 13 deletions(-) > > diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c > index f0b7ae9..ef4b4e0 100644 > --- a/drivers/clk/at91/clk-generated.c > +++ b/drivers/clk/at91/clk-generated.c > @@ -124,19 +124,18 @@ static int clk_generated_determine_rate(struct clk_hw *hw, > (gck->range.max && min_rate > gck->range.max)) > continue; > > - for (div = 1; div < GENERATED_MAX_DIV + 2; div++) { > - tmp_rate = DIV_ROUND_CLOSEST(parent_rate, div); > - tmp_diff = abs(req->rate - tmp_rate); > - > - if (best_diff < 0 || best_diff > tmp_diff) { > - best_rate = tmp_rate; > - best_diff = tmp_diff; > - req->best_parent_rate = parent_rate; > - req->best_parent_hw = parent; > - } > - > - if (!best_diff || tmp_rate < req->rate) > - break; > + div = DIV_ROUND_CLOSEST(parent_rate, req->rate); > + if (!div) > + tmp_rate = parent_rate; > + else > + tmp_rate = parent_rate / div; > + tmp_diff = abs(req->rate - tmp_rate); > + > + if (best_diff < 0 || best_diff > tmp_diff) { > + best_rate = tmp_rate; > + best_diff = tmp_diff; > + req->best_parent_rate = parent_rate; > + req->best_parent_hw = parent; > } > > if (!best_diff) >
diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c index f0b7ae9..ef4b4e0 100644 --- a/drivers/clk/at91/clk-generated.c +++ b/drivers/clk/at91/clk-generated.c @@ -124,19 +124,18 @@ static int clk_generated_determine_rate(struct clk_hw *hw, (gck->range.max && min_rate > gck->range.max)) continue; - for (div = 1; div < GENERATED_MAX_DIV + 2; div++) { - tmp_rate = DIV_ROUND_CLOSEST(parent_rate, div); - tmp_diff = abs(req->rate - tmp_rate); - - if (best_diff < 0 || best_diff > tmp_diff) { - best_rate = tmp_rate; - best_diff = tmp_diff; - req->best_parent_rate = parent_rate; - req->best_parent_hw = parent; - } - - if (!best_diff || tmp_rate < req->rate) - break; + div = DIV_ROUND_CLOSEST(parent_rate, req->rate); + if (!div) + tmp_rate = parent_rate; + else + tmp_rate = parent_rate / div; + tmp_diff = abs(req->rate - tmp_rate); + + if (best_diff < 0 || best_diff > tmp_diff) { + best_rate = tmp_rate; + best_diff = tmp_diff; + req->best_parent_rate = parent_rate; + req->best_parent_hw = parent; } if (!best_diff)