[PATCH v6 06/28] clk: Skip clamping when rounding if there's no boundaries

Maxime Ripard
2022-07-11T15:24:44Z

Commit 948fb0969eae ("clk: Always clamp the rounded rate") recently
started to clamp the request rate in the clk_rate_request passed as an
argument of clk_core_determine_round_nolock() with the min_rate and
max_rate fields of that same request.

While the clk_rate_requests created by the framework itself always have
those fields set, some drivers will create it themselves and don't
always fill min_rate and max_rate.

In such a case, we end up clamping the rate with a minimum and maximum
of 0, thus always rounding the rate to 0.

Let's skip the clamping if both min_rate and max_rate are set to 0 and
complain so that it gets fixed.

Fixes: 948fb0969eae ("clk: Always clamp the rounded rate")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
drivers/clk/clk.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index a5e0ab8bd6be..9d63163244d4 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1341,7 +1341,19 @@ static int clk_core_determine_round_nolock(struct clk_core *core,
if (!core)
return 0;

- req->rate = clamp(req->rate, req->min_rate, req->max_rate);
+ /*
+ * Some clock providers hand-craft their clk_rate_requests and
+ * might not fill min_rate and max_rate.
+ *
+ * If it's the case, clamping the rate is equivalent to setting
+ * the rate to 0 which is bad. Skip the clamping but complain so
+ * that it gets fixed, hopefully.
+ */
+ if (!req->min_rate && !req->max_rate)
+ pr_warn("%s: %s: clk_rate_request has initialized min or max rate.\n",
+ __func__, core->name);
+ else
+ req->rate = clamp(req->rate, req->min_rate, req->max_rate);

/*
* At this point, core protection will be disabled
--
2.36.1