linux-kernel - Re: [PATCH 2/2] power: supply: qcom_battmgr: support disabling charge control

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Message-ID: <88535058-f385-4fb0-9b4a-bf6d854f7107@oss.qualcomm.com>
Date: Mon, 17 Nov 2025 13:22:51 +0800
From: Fenglin Wu <fenglin.wu@....qualcomm.com>
To: Val Packett <val@...kett.cool>, Sebastian Reichel <sre@...nel.org>,
        Neil Armstrong <neil.armstrong@...aro.org>
Cc: Sebastian Reichel <sebastian.reichel@...labora.com>,
        linux-arm-msm@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] power: supply: qcom_battmgr: support disabling charge
 control


On 10/13/2025 7:32 AM, Val Packett wrote:
> Existing userspace (in particular, upower) disables charge control by
> setting the start threshold to 0 and the stop threshold to 100.
>
> Handle that by actually setting the enable bit to 0 when a start
> threshold of 0 was requested.
>
> Fixes: cc3e883a0625 ("power: supply: qcom_battmgr: Add charge control support")
> Signed-off-by: Val Packett <val@...kett.cool>
> ---
>   drivers/power/supply/qcom_battmgr.c | 12 ++++++++----
>   1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/power/supply/qcom_battmgr.c b/drivers/power/supply/qcom_battmgr.c
> index c8028606bba0..e6f01e0122e1 100644
> --- a/drivers/power/supply/qcom_battmgr.c
> +++ b/drivers/power/supply/qcom_battmgr.c
> @@ -257,6 +257,7 @@ struct qcom_battmgr_info {
>   	unsigned int capacity_warning;
>   	unsigned int cycle_count;
>   	unsigned int charge_count;
> +	bool charge_ctrl_enable;
>   	unsigned int charge_ctrl_start;
>   	unsigned int charge_ctrl_end;
>   	char model_number[BATTMGR_STRING_LEN];
> @@ -659,13 +660,13 @@ static int qcom_battmgr_bat_get_property(struct power_supply *psy,
>   }
>   
>   static int qcom_battmgr_set_charge_control(struct qcom_battmgr *battmgr,
> -					   u32 target_soc, u32 delta_soc)
> +					   bool enable, u32 target_soc, u32 delta_soc)
>   {
>   	struct qcom_battmgr_charge_ctrl_request request = {
>   		.hdr.owner = cpu_to_le32(PMIC_GLINK_OWNER_BATTMGR),
>   		.hdr.type = cpu_to_le32(PMIC_GLINK_REQ_RESP),
>   		.hdr.opcode = cpu_to_le32(BATTMGR_CHG_CTRL_LIMIT_EN),
> -		.enable = cpu_to_le32(1),
> +		.enable = cpu_to_le32(enable),
>   		.target_soc = cpu_to_le32(target_soc),
>   		.delta_soc = cpu_to_le32(delta_soc),
>   	};
> @@ -677,6 +678,7 @@ static int qcom_battmgr_set_charge_start_threshold(struct qcom_battmgr *battmgr,
>   {
>   	u32 target_soc, delta_soc;
>   	int ret;
> +	bool enable = start_soc != 0;
>   
>   	start_soc = clamp(start_soc, CHARGE_CTRL_START_THR_MIN, CHARGE_CTRL_START_THR_MAX);
>   
> @@ -696,9 +698,10 @@ static int qcom_battmgr_set_charge_start_threshold(struct qcom_battmgr *battmgr,
>   	}
>   
>   	mutex_lock(&battmgr->lock);
> -	ret = qcom_battmgr_set_charge_control(battmgr, target_soc, delta_soc);
> +	ret = qcom_battmgr_set_charge_control(battmgr, enable, target_soc, delta_soc);
>   	mutex_unlock(&battmgr->lock);
>   	if (!ret) {
> +		battmgr->info.charge_ctrl_enable = enable;
>   		battmgr->info.charge_ctrl_start = start_soc;
>   		battmgr->info.charge_ctrl_end = target_soc;
>   	}
> @@ -710,6 +713,7 @@ static int qcom_battmgr_set_charge_end_threshold(struct qcom_battmgr *battmgr, i
>   {
>   	u32 delta_soc = CHARGE_CTRL_DELTA_SOC;
>   	int ret;
> +	bool enable = battmgr->info.charge_ctrl_enable;
Can you initialize "battmgr->info.charge_ctrl_enable" in 
"qcom_battmgr_charge_control_thresholds_init()" based on the value 
reading from the nvmem cell? Otherwise, it would have a false value by 
default and a single write to the end threshold would result disabling 
the charging control instead.
>   
>   	end_soc = clamp(end_soc, CHARGE_CTRL_END_THR_MIN, CHARGE_CTRL_END_THR_MAX);
>   
> @@ -717,7 +721,7 @@ static int qcom_battmgr_set_charge_end_threshold(struct qcom_battmgr *battmgr, i
>   		delta_soc = end_soc - battmgr->info.charge_ctrl_start;
>   
>   	mutex_lock(&battmgr->lock);
> -	ret = qcom_battmgr_set_charge_control(battmgr, end_soc, delta_soc);
> +	ret = qcom_battmgr_set_charge_control(battmgr, enable, end_soc, delta_soc);
>   	mutex_unlock(&battmgr->lock);
>   	if (!ret) {
>   		battmgr->info.charge_ctrl_start = end_soc - delta_soc;