linux-kernel - [PATCH 1/2] power: supply: qcom_battmgr: clamp charge control thresholds

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Message-ID: <20251012233333.19144-3-val@packett.cool>
Date: Sun, 12 Oct 2025 20:32:18 -0300
From: Val Packett <val@...kett.cool>
To: Sebastian Reichel <sre@...nel.org>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Fenglin Wu <fenglin.wu@....qualcomm.com>
Cc: Val Packett <val@...kett.cool>,
	Sebastian Reichel <sebastian.reichel@...labora.com>,
	linux-arm-msm@...r.kernel.org,
	linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] power: supply: qcom_battmgr: clamp charge control thresholds

The sysfs API documentation says that drivers "round written values to
the nearest supported value" for charge_control_end_threshold.

Let's do this for both thresholds, as userspace (e.g. upower) generally
does not expect these writes to fail at all.

Fixes: cc3e883a0625 ("power: supply: qcom_battmgr: Add charge control support")
Signed-off-by: Val Packett <val@...kett.cool>
---
 drivers/power/supply/qcom_battmgr.c | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/drivers/power/supply/qcom_battmgr.c b/drivers/power/supply/qcom_battmgr.c
index 3c2837ef3461..c8028606bba0 100644
--- a/drivers/power/supply/qcom_battmgr.c
+++ b/drivers/power/supply/qcom_battmgr.c
@@ -678,12 +678,7 @@ static int qcom_battmgr_set_charge_start_threshold(struct qcom_battmgr *battmgr,
 	u32 target_soc, delta_soc;
 	int ret;
 
-	if (start_soc < CHARGE_CTRL_START_THR_MIN ||
-	    start_soc > CHARGE_CTRL_START_THR_MAX) {
-		dev_err(battmgr->dev, "charge control start threshold exceed range: [%u - %u]\n",
-			CHARGE_CTRL_START_THR_MIN, CHARGE_CTRL_START_THR_MAX);
-		return -EINVAL;
-	}
+	start_soc = clamp(start_soc, CHARGE_CTRL_START_THR_MIN, CHARGE_CTRL_START_THR_MAX);
 
 	/*
 	 * If the new start threshold is larger than the old end threshold,
@@ -716,12 +711,7 @@ static int qcom_battmgr_set_charge_end_threshold(struct qcom_battmgr *battmgr, i
 	u32 delta_soc = CHARGE_CTRL_DELTA_SOC;
 	int ret;
 
-	if (end_soc < CHARGE_CTRL_END_THR_MIN ||
-	    end_soc > CHARGE_CTRL_END_THR_MAX) {
-		dev_err(battmgr->dev, "charge control end threshold exceed range: [%u - %u]\n",
-			CHARGE_CTRL_END_THR_MIN, CHARGE_CTRL_END_THR_MAX);
-		return -EINVAL;
-	}
+	end_soc = clamp(end_soc, CHARGE_CTRL_END_THR_MIN, CHARGE_CTRL_END_THR_MAX);
 
 	if (battmgr->info.charge_ctrl_start && end_soc > battmgr->info.charge_ctrl_start)
 		delta_soc = end_soc - battmgr->info.charge_ctrl_start;
-- 
2.51.0