[PATCH 5.4 038/320] clk: bcm-2835: Pick the closest clock rate

Greg Kroah-Hartman
2022-01-24T19:58:53Z

From: Maxime Ripard <maxime@cerno.tech>

[ 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>
---
drivers/clk/bcm/clk-bcm2835.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index c5486537b9284..b2af320d1b6c5 100644
--- 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;
--
2.34.1