clk: at91: clk-generated: remove useless divisor loop (8c7aa632) · Commits · 戴 / test

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> Signed-off-by:

Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/at91/clk-generated.c

+12 −13

Original line number	Original line	Diff line number	Diff line
	@@ -124,8 +124,11 @@ static int clk_generated_determine_rate(struct clk_hw *hw,
	(gck->range.max && min_rate > gck->range.max))		(gck->range.max && min_rate > gck->range.max))
	continue;		continue;

	for (div = 1; div < GENERATED_MAX_DIV + 2; div++) {		div = DIV_ROUND_CLOSEST(parent_rate, req->rate);
	tmp_rate = DIV_ROUND_CLOSEST(parent_rate, div);		if (!div)
			tmp_rate = parent_rate;
			else
			tmp_rate = parent_rate / div;
	tmp_diff = abs(req->rate - tmp_rate);		tmp_diff = abs(req->rate - tmp_rate);

	if (best_diff < 0 \|\| best_diff > tmp_diff) {		if (best_diff < 0 \|\| best_diff > tmp_diff) {
	@@ -135,10 +138,6 @@ static int clk_generated_determine_rate(struct clk_hw *hw,
	req->best_parent_hw = parent;		req->best_parent_hw = parent;
	}		}

	if (!best_diff \|\| tmp_rate < req->rate)
	break;
	}

	if (!best_diff)		if (!best_diff)
	break;		break;
	}		}

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