clk: bcm-2835: Pick the closest clock rate

[ Upstream commit 5517357a4733d7cf7c17fc79d0530cfa47add372 ]

The driver currently tries to pick the closest rate that is lower than
the rate being requested.

This causes an issue with clk_set_min_rate() since it actively checks
for the rounded rate to be above the minimum that was just set.

Let's change the logic a bit to pick the closest rate to the requested
rate, no matter if it's actually higher or lower.

Fixes: 6d18b8adbe67 ("clk: bcm2835: Support for clock parent selection")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Reviewed-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
Tested-by: Nicolas Saenz Julienne <nsaenz@kernel.org> # boot and basic functionality
Tested-by: Michael Stapelberg <michael@stapelberg.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210922125419.4125779-2-maxime@cerno.tech
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index a254512..bf97b2b 100644 (file)
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -1216,7 +1216,7 @@ static int bcm2835_clock_determine_rate(struct clk_hw *hw,
                rate = bcm2835_clock_choose_div_and_prate(hw, i, req->rate,
                                                          &div, &prate,
                                                          &avgrate);
-               if (rate > best_rate && rate <= req->rate) {
+               if (abs(req->rate - rate) < abs(req->rate - best_rate)) {
                        best_parent = parent;
                        best_prate = prate;
                        best_rate = rate;