power: supply: bq257xx: Fix VSYSMIN clamping logic

The minimal system voltage (VSYSMIN) is meant to protect the battery from
dangerous over-discharge. When the device tree provides a value for the
minimum design voltage of the battery, the user should not be allowed to
set a lower VSYSMIN, as that would defeat the purpose of this protection.

Flip the clamping logic when setting VSYSMIN to ensure that battery design
voltage is respected.

Cc: stable@vger.kernel.org
Fixes: 1cc017b7f9c7 ("power: supply: bq257xx: Add support for BQ257XX charger")
Tested-by: Chris Morgan <macromorgan@hotmail.com>
Signed-off-by: Alexey Charkov <alchark@flipper.net>
Link: https://patch.msgid.link/20260603-bq25792-v7-2-d487bed276d0@flipper.net
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

diff --git a/drivers/power/supply/bq257xx_charger.c b/drivers/power/supply/bq257xx_charger.c
index 02c7d8b61e82b68423e19b706c8e665902713eb8..7ca4ae6109027ac42b726b4c39425fc83c9f39fa 100644 (file)
--- a/drivers/power/supply/bq257xx_charger.c
+++ b/drivers/power/supply/bq257xx_charger.c
@@ -128,9 +128,8 @@ static int bq25703_get_min_vsys(struct bq257xx_chg *pdata, int *intval)
  * @vsys: voltage value to set in uV.
  *
  * This function takes a requested minimum system voltage value, clamps
- * it between the minimum supported value by the charger and a user
- * defined minimum system value, and then writes the value to the
- * appropriate register.
+ * it between the user defined minimum system value and the maximum supported
+ * value by the charger, and then writes the value to the appropriate register.
  *
  * Return: Returns 0 on success or error if an error occurs.
  */
@@ -139,7 +138,7 @@ static int bq25703_set_min_vsys(struct bq257xx_chg *pdata, int vsys)
        unsigned int reg;
        int vsys_min = pdata->vsys_min;
 
-       vsys = clamp(vsys, BQ25703_MINVSYS_MIN_UV, vsys_min);
+       vsys = clamp(vsys, vsys_min, BQ25703_MINVSYS_MAX_UV);
        reg = ((vsys - BQ25703_MINVSYS_MIN_UV) / BQ25703_MINVSYS_STEP_UV);
        reg = FIELD_PREP(BQ25703_MINVSYS_MASK, reg);