6.12-stable review patch. If anyone has any objections, please let me know.
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From: Thomas Weißschuh linux@weissschuh.net
commit c28dc9fc24f5fa802d44ef7620a511035bdd803e upstream.
ECs implementing the v2 command will not stop charging when the end threshold is reached. Instead they will begin discharging until the start threshold is reached, leading to permanent charge and discharge cycles. This defeats the point of the charge control mechanism.
Avoid the issue by hiding the start threshold on v2 systems. Instead on those systems program the EC with start == end which forces the EC to reach and stay at that level.
v1 does not support thresholds and v3 works correctly, at least judging from the code.
Reported-by: Thomas Koch linrunner@gmx.net Fixes: c6ed48ef5259 ("power: supply: add ChromeOS EC based charge control driver") Cc: stable@vger.kernel.org Signed-off-by: Thomas Weißschuh linux@weissschuh.net Link: https://lore.kernel.org/r/20241208-cros_charge-control-v2-v1-3-8d168d0f08a3@... Signed-off-by: Sebastian Reichel sebastian.reichel@collabora.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/power/supply/cros_charge-control.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/drivers/power/supply/cros_charge-control.c b/drivers/power/supply/cros_charge-control.c index 108b121db442..9b0a7500296b 100644 --- a/drivers/power/supply/cros_charge-control.c +++ b/drivers/power/supply/cros_charge-control.c @@ -139,6 +139,10 @@ static ssize_t cros_chctl_store_threshold(struct device *dev, struct cros_chctl_ return -EINVAL;
if (is_end_threshold) { + /* Start threshold is not exposed, use fixed value */ + if (priv->cmd_version == 2) + priv->current_start_threshold = val == 100 ? 0 : val; + if (val < priv->current_start_threshold) return -EINVAL; priv->current_end_threshold = val; @@ -234,12 +238,10 @@ static umode_t cros_chtl_attr_is_visible(struct kobject *kobj, struct attribute { struct cros_chctl_priv *priv = cros_chctl_attr_to_priv(attr, n);
- if (priv->cmd_version < 2) { - if (n == CROS_CHCTL_ATTR_START_THRESHOLD) - return 0; - if (n == CROS_CHCTL_ATTR_END_THRESHOLD) - return 0; - } + if (n == CROS_CHCTL_ATTR_START_THRESHOLD && priv->cmd_version < 3) + return 0; + else if (n == CROS_CHCTL_ATTR_END_THRESHOLD && priv->cmd_version < 2) + return 0;
return attr->mode; }