[PATCH v5 02/28] clk: Skip clamping when rounding if there's no boundaries

From: Maxime Ripard <maxime@cerno.tech>
To: linux-clk@vger.kernel.org,
	Mike Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>
Cc: Yassine Oudjana <y.oudjana@protonmail.com>,
	Naresh Kamboju <naresh.kamboju@linaro.org>,
	Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
	Tony Lindgren <tony@atomide.com>,
	Neil Armstrong <narmstrong@baylibre.com>,
	Alexander Stein <alexander.stein@ew.tq-group.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Jerome Brunet <jbrunet@baylibre.com>,
	Maxime Ripard <maxime@cerno.tech>
Subject: [PATCH v5 02/28] clk: Skip clamping when rounding if there's no boundaries
Date: Mon, 16 May 2022 15:25:01 +0200	[thread overview]
Message-ID: <20220516132527.328190-3-maxime@cerno.tech> (raw)
In-Reply-To: <20220516132527.328190-1-maxime@cerno.tech>

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 2a32fa9f7618..d46c00bbedea 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

