linux-kernel - [PATCH] clk: Ensure correct consumer's rate boundaries

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Message-Id: <20260109-fix_error_setting_clk_rate_range-v1-1-bae0b40e870f@amlogic.com>
Date: Fri, 09 Jan 2026 11:24:22 +0800
From: Chuan Liu via B4 Relay <devnull+chuan.liu.amlogic.com@...nel.org>
To: Michael Turquette <mturquette@...libre.com>, 
 Stephen Boyd <sboyd@...nel.org>
Cc: linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Chuan Liu <chuan.liu@...ogic.com>
Subject: [PATCH] clk: Ensure correct consumer's rate boundaries

From: Chuan Liu <chuan.liu@...ogic.com>

If we were to have two users of the same clock, doing something like:

clk_set_rate_range(user1, 1000, 2000);
clk_set_rate_range(user2, 3000, 4000);

Even when user2's call returns -EINVAL, the min_rate and max_rate of
user2 are still incorrectly updated. This causes subsequent calls by
user1 to fail when setting the clock rate, as clk_core_get_boundaries()
returns corrupted boundaries (min_rate = 3000, max_rate = 2000).

To prevent this, clk_core_check_boundaries() now rollback to the old
boundaries when the check fails.

Signed-off-by: Chuan Liu <chuan.liu@...ogic.com>
---
 drivers/clk/clk.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 85d2f2481acf..0dfb16bf3f31 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2710,13 +2710,17 @@ static int clk_set_rate_range_nolock(struct clk *clk,
 	 */
 	rate = clamp(rate, min, max);
 	ret = clk_core_set_rate_nolock(clk->core, rate);
+
+out:
 	if (ret) {
-		/* rollback the changes */
+		/*
+		 * Rollback the consumer’s old boundaries if check_boundaries or
+		 * set_rate fails.
+		 */
 		clk->min_rate = old_min;
 		clk->max_rate = old_max;
 	}
 
-out:
 	if (clk->exclusive_count)
 		clk_core_rate_protect(clk->core);
 

---
base-commit: 7f98ab9da046865d57c102fd3ca9669a29845f67
change-id: 20260107-fix_error_setting_clk_rate_range-d928da67af90

Best regards,
-- 
Chuan Liu <chuan.liu@...ogic.com>