[PATCH] power: supply: bd71828: add input current limit property

[PATCH] power: supply: bd71828: add input current limit property

[Andreas Kemnade]

Add input current property to be able to work around issues created by
automatic input limiting and have some control.
Disabling the automatic management is another step.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
---
 drivers/power/supply/bd71828-power.c | 62 ++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/drivers/power/supply/bd71828-power.c b/drivers/power/supply/bd71828-power.c
index 0e00acb589937..5e78faa0a4aaf 100644
--- a/drivers/power/supply/bd71828-power.c
+++ b/drivers/power/supply/bd71828-power.c
@@ -24,6 +24,7 @@
 #define BD7182x_MASK_CONF_PON			BIT(0)
 #define BD71815_MASK_CONF_XSTB			BIT(1)
 #define BD7182x_MASK_BAT_STAT			0x3f
+#define BD7182x_MASK_ILIM			0x3f
 #define BD7182x_MASK_DCIN_STAT			0x07
 
 #define BD7182x_MASK_WDT_AUTO			0x40
@@ -48,9 +49,11 @@ struct pwr_regs {
 	unsigned int vbat_avg;
 	unsigned int ibat;
 	unsigned int ibat_avg;
+	unsigned int ilim_stat;
 	unsigned int btemp_vth;
 	unsigned int chg_state;
 	unsigned int bat_temp;
+	unsigned int dcin_set;
 	unsigned int dcin_stat;
 	unsigned int dcin_online_mask;
 	unsigned int dcin_collapse_limit;
@@ -66,9 +69,11 @@ static const struct pwr_regs pwr_regs_bd71828 = {
 	.vbat_avg = BD71828_REG_VBAT_U,
 	.ibat = BD71828_REG_IBAT_U,
 	.ibat_avg = BD71828_REG_IBAT_AVG_U,
+	.ilim_stat = BD71828_REG_ILIM_STAT,
 	.btemp_vth = BD71828_REG_VM_BTMP_U,
 	.chg_state = BD71828_REG_CHG_STATE,
 	.bat_temp = BD71828_REG_BAT_TEMP,
+	.dcin_set = BD71828_REG_DCIN_SET,
 	.dcin_stat = BD71828_REG_DCIN_STAT,
 	.dcin_online_mask = BD7182x_MASK_DCIN_DET,
 	.dcin_collapse_limit = BD71828_REG_DCIN_CLPS,
@@ -441,6 +446,7 @@ static int bd71828_charger_get_property(struct power_supply *psy,
 	struct bd71828_power *pwr = dev_get_drvdata(psy->dev.parent);
 	u32 vot;
 	u16 tmp;
+	int t;
 	int online;
 	int ret;
 
@@ -459,6 +465,20 @@ static int bd71828_charger_get_property(struct power_supply *psy,
 		vot = tmp;
 		/* 5 milli volt steps */
 		val->intval = 5000 * vot;
+		break;
+	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+		if (!pwr->regs->ilim_stat)
+			return -ENODATA;
+
+		ret = regmap_read(pwr->regmap, pwr->regs->ilim_stat, &t);
+		if (ret)
+			return ret;
+
+		t++;
+		val->intval = (t & BD7182x_MASK_ILIM) * 50000;
+		if (val->intval > 2000000)
+			val->intval = 2000000;
+
 		break;
 	default:
 		return -EINVAL;
@@ -467,6 +487,45 @@ static int bd71828_charger_get_property(struct power_supply *psy,
 	return 0;
 }
 
+static int bd71828_charger_set_property(struct power_supply *psy,
+					enum power_supply_property psp,
+					const union power_supply_propval *val)
+{
+	struct bd71828_power *pwr = dev_get_drvdata(psy->dev.parent);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+		if (val->intval > 2000000)
+			return -EINVAL;
+
+		if (val->intval < 50000)
+			return -EINVAL;
+
+		if (!pwr->regs->dcin_set)
+			return -EINVAL;
+
+		return regmap_update_bits(pwr->regmap, pwr->regs->dcin_set,
+					  BD7182x_MASK_ILIM,
+					  val->intval / 50000 - 1);
+		break;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int bd71828_charger_property_is_writeable(struct power_supply *psy,
+						 enum power_supply_property psp)
+{
+	struct bd71828_power *pwr = dev_get_drvdata(psy->dev.parent);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+		return !!(pwr->regs->dcin_set);
+	default:
+		return false;
+	}
+}
+
 static int bd71828_battery_get_property(struct power_supply *psy,
 					enum power_supply_property psp,
 					union power_supply_propval *val)
@@ -571,6 +630,7 @@ static int bd71828_battery_property_is_writeable(struct power_supply *psy,
 
 /** @brief ac properties */
 static const enum power_supply_property bd71828_charger_props[] = {
+	POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT,
 	POWER_SUPPLY_PROP_ONLINE,
 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
 };
@@ -600,6 +660,8 @@ static const struct power_supply_desc bd71828_ac_desc = {
 	.properties	= bd71828_charger_props,
 	.num_properties	= ARRAY_SIZE(bd71828_charger_props),
 	.get_property	= bd71828_charger_get_property,
+	.set_property	= bd71828_charger_set_property,
+	.property_is_writeable   = bd71828_charger_property_is_writeable,
 };
 
 static const struct power_supply_desc bd71828_bat_desc = {

---
base-commit: 7aaa8047eafd0bd628065b15757d9b48c5f9c07d
change-id: 20260401-bd-inp-limit-3acb51e15e9c

Best regards,
--  
Andreas Kemnade <andreas@kemnade.info>

Re: [PATCH] power: supply: bd71828: add input current limit property

[Sebastian Reichel]

On Wed, 01 Apr 2026 23:17:05 +0200, Andreas Kemnade wrote:
> Add input current property to be able to work around issues created by
> automatic input limiting and have some control.
> Disabling the automatic management is another step.
> 
> 

Applied, thanks!

[1/1] power: supply: bd71828: add input current limit property
      commit: be353c6729d087925da702cf8c0ad3cb1ae53dec

Best regards,
-- 
Sebastian Reichel <sebastian.reichel@collabora.com>

Re: [PATCH] power: supply: bd71828: add input current limit property

[Matti Vaittinen]

On 02/04/2026 00:17, Andreas Kemnade wrote:
> Add input current property to be able to work around issues created by
> automatic input limiting and have some control.
> Disabling the automatic management is another step.
> 
> Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
> ---
>   drivers/power/supply/bd71828-power.c | 62 ++++++++++++++++++++++++++++++++++++
>   1 file changed, 62 insertions(+)
> 
> diff --git a/drivers/power/supply/bd71828-power.c b/drivers/power/supply/bd71828-power.c
> index 0e00acb589937..5e78faa0a4aaf 100644
> --- a/drivers/power/supply/bd71828-power.c
> +++ b/drivers/power/supply/bd71828-power.c
> @@ -24,6 +24,7 @@
>   #define BD7182x_MASK_CONF_PON			BIT(0)
>   #define BD71815_MASK_CONF_XSTB			BIT(1)
>   #define BD7182x_MASK_BAT_STAT			0x3f
> +#define BD7182x_MASK_ILIM			0x3f
>   #define BD7182x_MASK_DCIN_STAT			0x07
>   
>   #define BD7182x_MASK_WDT_AUTO			0x40
> @@ -48,9 +49,11 @@ struct pwr_regs {
>   	unsigned int vbat_avg;
>   	unsigned int ibat;
>   	unsigned int ibat_avg;
> +	unsigned int ilim_stat;
>   	unsigned int btemp_vth;
>   	unsigned int chg_state;
>   	unsigned int bat_temp;
> +	unsigned int dcin_set;
>   	unsigned int dcin_stat;
>   	unsigned int dcin_online_mask;
>   	unsigned int dcin_collapse_limit;
> @@ -66,9 +69,11 @@ static const struct pwr_regs pwr_regs_bd71828 = {
>   	.vbat_avg = BD71828_REG_VBAT_U,
>   	.ibat = BD71828_REG_IBAT_U,
>   	.ibat_avg = BD71828_REG_IBAT_AVG_U,
> +	.ilim_stat = BD71828_REG_ILIM_STAT,
>   	.btemp_vth = BD71828_REG_VM_BTMP_U,
>   	.chg_state = BD71828_REG_CHG_STATE,
>   	.bat_temp = BD71828_REG_BAT_TEMP,
> +	.dcin_set = BD71828_REG_DCIN_SET,

Hi Andreas / Sebastian,

Sorry for belated review (although, I don't think this did float on the 
list quite THAT long...)

I believe this is the ILIM_STAT register in the data sheet, at address 
0x6d, right? (The bit field is named as: LIM_DCIN_STAT[5:0]). If so, 
then I have a follow-up question in the setter...

>   	.dcin_stat = BD71828_REG_DCIN_STAT,
>   	.dcin_online_mask = BD7182x_MASK_DCIN_DET,
>   	.dcin_collapse_limit = BD71828_REG_DCIN_CLPS,
> @@ -441,6 +446,7 @@ static int bd71828_charger_get_property(struct power_supply *psy,
>   	struct bd71828_power *pwr = dev_get_drvdata(psy->dev.parent);
>   	u32 vot;
>   	u16 tmp;
> +	int t;
>   	int online;
>   	int ret;
>   
> @@ -459,6 +465,20 @@ static int bd71828_charger_get_property(struct power_supply *psy,
>   		vot = tmp;
>   		/* 5 milli volt steps */
>   		val->intval = 5000 * vot;
> +		break;
> +	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
> +		if (!pwr->regs->ilim_stat)
> +			return -ENODATA;
> +
> +		ret = regmap_read(pwr->regmap, pwr->regs->ilim_stat, &t);
> +		if (ret)
> +			return ret;
> +
> +		t++;
> +		val->intval = (t & BD7182x_MASK_ILIM) * 50000;
> +		if (val->intval > 2000000)
> +			val->intval = 2000000;

I would have preferred using the linear-ranges here.

> +
>   		break;
>   	default:
>   		return -EINVAL;
> @@ -467,6 +487,45 @@ static int bd71828_charger_get_property(struct power_supply *psy,
>   	return 0;
>   }
>   
> +static int bd71828_charger_set_property(struct power_supply *psy,
> +					enum power_supply_property psp,
> +					const union power_supply_propval *val)
> +{
> +	struct bd71828_power *pwr = dev_get_drvdata(psy->dev.parent);
> +
> +	switch (psp) {
> +	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
> +		if (val->intval > 2000000)
> +			return -EINVAL;
> +
> +		if (val->intval < 50000)
> +			return -EINVAL;
> +

I would have preferred using the linear ranges here as well. That'd help 
if we support this in the other variants.

> +		if (!pwr->regs->dcin_set)
> +			return -EINVAL;
> +
> +		return regmap_update_bits(pwr->regmap, pwr->regs->dcin_set,
> +					  BD7182x_MASK_ILIM,
> +					  val->intval / 50000 - 1);

The "burning question" I have is - how well this has been verified? I 
ask because the data-sheet version which I read (rev 0p17, DS2 draft) 
marks this register as a read-only. I know my data-sheet, targeting the 
design-sample 2 of bd71828 (not bd71879) is ancient. It may be this is 
an error in the data-sheet but I had to ask anyways...

> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static int bd71828_charger_property_is_writeable(struct power_supply *psy,
> +						 enum power_supply_property psp)
> +{
> +	struct bd71828_power *pwr = dev_get_drvdata(psy->dev.parent);
> +
> +	switch (psp) {
> +	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
> +		return !!(pwr->regs->dcin_set);
> +	default:
> +		return false;
> +	}
> +}
> +
>   static int bd71828_battery_get_property(struct power_supply *psy,
>   					enum power_supply_property psp,
>   					union power_supply_propval *val)
> @@ -571,6 +630,7 @@ static int bd71828_battery_property_is_writeable(struct power_supply *psy,
>   
>   /** @brief ac properties */
>   static const enum power_supply_property bd71828_charger_props[] = {
> +	POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT,
>   	POWER_SUPPLY_PROP_ONLINE,
>   	POWER_SUPPLY_PROP_VOLTAGE_NOW,
>   };
> @@ -600,6 +660,8 @@ static const struct power_supply_desc bd71828_ac_desc = {
>   	.properties	= bd71828_charger_props,
>   	.num_properties	= ARRAY_SIZE(bd71828_charger_props),
>   	.get_property	= bd71828_charger_get_property,
> +	.set_property	= bd71828_charger_set_property,
> +	.property_is_writeable   = bd71828_charger_property_is_writeable,
>   };
>   
>   static const struct power_supply_desc bd71828_bat_desc = {
> 
> ---
> base-commit: 7aaa8047eafd0bd628065b15757d9b48c5f9c07d
> change-id: 20260401-bd-inp-limit-3acb51e15e9c
> 
> Best regards,
> --
> Andreas Kemnade <andreas@kemnade.info>

Yours,
	-- Matti


-- 
---
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

~~ When things go utterly wrong vim users can always type :help! ~~

Re: [PATCH] power: supply: bd71828: add input current limit property

[Matti Vaittinen]

On 07/04/2026 08:34, Matti Vaittinen wrote:
> On 02/04/2026 00:17, Andreas Kemnade wrote:

// snip

>> +    .ilim_stat = BD71828_REG_ILIM_STAT,
>>       .btemp_vth = BD71828_REG_VM_BTMP_U,
>>       .chg_state = BD71828_REG_CHG_STATE,
>>       .bat_temp = BD71828_REG_BAT_TEMP,
>> +    .dcin_set = BD71828_REG_DCIN_SET,
> 
> Hi Andreas / Sebastian,
> 
> Sorry for belated review (although, I don't think this did float on the 
> list quite THAT long...)
> 
> I believe this is the ILIM_STAT register in the data sheet, at address 
> 0x6d, right? (The bit field is named as: LIM_DCIN_STAT[5:0]). If so, 
> then I have a follow-up question in the setter...

// snip

>> +        return regmap_update_bits(pwr->regmap, pwr->regs->dcin_set,
>> +                      BD7182x_MASK_ILIM,
>> +                      val->intval / 50000 - 1);
> 
> The "burning question" I have is - how well this has been verified? I 
> ask because the data-sheet version which I read (rev 0p17, DS2 draft) 
> marks this register as a read-only. I know my data-sheet, targeting the 
> design-sample 2 of bd71828 (not bd71879) is ancient. It may be this is 
> an error in the data-sheet but I had to ask anyways...

Please, ignore this bit. I somehow misread the patch. It is the DCIN_SET 
which is used here, not the ILIM_STAT. Logic seems correct!

I would still prefer the linear-ranges, especially if other variants 
support this. But the logic seems correct. Sorry for the noise.

Yours,
	-- Matti

---
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

~~ When things go utterly wrong vim users can always type :help! ~~

Re: [PATCH] power: supply: bd71828: add input current limit property

[Matti Vaittinen]

On 02/04/2026 00:17, Andreas Kemnade wrote:
> Add input current property to be able to work around issues created by
> automatic input limiting and have some control.
> Disabling the automatic management is another step.
> 

Hi Andreas!
Long time no chat :)

First of all, thanks for the work you do with the BD71828/79! I do 
admire the effort you're willing to put on it :)

I decided to just take a quick look at the BD71815 and BD72720, which 
can be operated using the same driver. I didn't see similar control on 
BD71815 data-sheet, so I just decided not to dig it further for now.

What comes to the BD72720, there is something:

The BD72720 has a VBUS_INLIM, which is a configurable current limit for 
the bus. This, I believe does NOT directly correspond to the DCIN limit. 
It _probably_ has similar impact when the DCIN is supplied, and when it 
is powerful enough to run the system. However, I believe the VBUS 
current limit is also having an impact when setup is powered from the 
battery, or when it is in "battery assist" -mode, (where the battery is 
used to "complement" the DCIN, if the DCIN isn't strong enough to power 
the system).

I am afraid I don't know your use-case for the control of the DCIN input 
limit well enough to decide, if the BD72720 would need something similar 
- or if the VBUS_INLIM should be tied to the same knob. If you have the 
enthusiasm to write some more words ... I am keen on learning! :)

Yours,
	-- Matti

-- 
---
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

~~ When things go utterly wrong vim users can always type :help! ~~