[PATCH 1/3] power: supply: bq27xxx: fix sign of current_now for newer ICs

[PATCH 1/3] power: supply: bq27xxx: fix sign of current_now for newer ICs

[Matthias Schiffer]

Commit cd060b4d0868 ("power: supply: bq27xxx: fix polarity of current_now")
changed the sign of current_now for all bq27xxx variants, but on BQ28Z610
I'm now seeing negated values *with* that patch.

The GTA04/Openmoko device that was used for testing uses a BQ27000 or
BQ27010 IC, so I assume only the BQ27XXX_O_ZERO code path was incorrect.
Revert the behaviour for newer ICs.

Fixes: cd060b4d0868 "power: supply: bq27xxx: fix polarity of current_now"
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
---

@Andreas Kemnade: It would be great to get a confirmation that the
Openmoko battery indeed uses BQ27000/BQ27010 - I was having some trouble
finding that information.


 drivers/power/supply/bq27xxx_battery.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/power/supply/bq27xxx_battery.c b/drivers/power/supply/bq27xxx_battery.c
index 4c4a7b1c64c5..cb6ebd2f905e 100644
--- a/drivers/power/supply/bq27xxx_battery.c
+++ b/drivers/power/supply/bq27xxx_battery.c
@@ -1827,7 +1827,7 @@ static int bq27xxx_battery_current(struct bq27xxx_device_info *di,
 		val->intval = curr * BQ27XXX_CURRENT_CONSTANT / BQ27XXX_RS;
 	} else {
 		/* Other gauges return signed value */
-		val->intval = -(int)((s16)curr) * 1000;
+		val->intval = (int)((s16)curr) * 1000;
 	}
 
 	return 0;
-- 
2.17.1

[PATCH 2/3] power: supply: bq27xxx: fix power_avg

[Matthias Schiffer]

On all newer bq27xxx ICs, the AveragePower register contains a signed
value; in addition to handling the raw value as unsigned, the driver
code also didn't convert it to µW as expected.

At least for the BQ28Z610, the reference manual incorrectly states that
the value is in units of 1mA and not 10mA. I have no way of knowing
whether the manuals of other supported ICs contain the same error, or if
there are models that actually use 1mA. At least, the new code shouldn't
be *less* correct than the old version for any device.

power_avg is removed from the cache structure, se we don't have to
extend it to store both a signed value and an error code. Always getting
an up-to-date value may be desirable anyways, as it avoids inconsistent
current and power readings when switching between charging and
discharging.

Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
---
 drivers/power/supply/bq27xxx_battery.c | 51 ++++++++++++++------------
 include/linux/power/bq27xxx_battery.h  |  1 -
 2 files changed, 27 insertions(+), 25 deletions(-)

diff --git a/drivers/power/supply/bq27xxx_battery.c b/drivers/power/supply/bq27xxx_battery.c
index cb6ebd2f905e..20e1dc8a87cf 100644
--- a/drivers/power/supply/bq27xxx_battery.c
+++ b/drivers/power/supply/bq27xxx_battery.c
@@ -1661,27 +1661,6 @@ static int bq27xxx_battery_read_time(struct bq27xxx_device_info *di, u8 reg)
 	return tval * 60;
 }
 
-/*
- * Read an average power register.
- * Return < 0 if something fails.
- */
-static int bq27xxx_battery_read_pwr_avg(struct bq27xxx_device_info *di)
-{
-	int tval;
-
-	tval = bq27xxx_read(di, BQ27XXX_REG_AP, false);
-	if (tval < 0) {
-		dev_err(di->dev, "error reading average power register  %02x: %d\n",
-			BQ27XXX_REG_AP, tval);
-		return tval;
-	}
-
-	if (di->opts & BQ27XXX_O_ZERO)
-		return (tval * BQ27XXX_POWER_CONSTANT) / BQ27XXX_RS;
-	else
-		return tval;
-}
-
 /*
  * Returns true if a battery over temperature condition is detected
  */
@@ -1769,8 +1748,6 @@ void bq27xxx_battery_update(struct bq27xxx_device_info *di)
 		}
 		if (di->regs[BQ27XXX_REG_CYCT] != INVALID_REG_ADDR)
 			cache.cycle_count = bq27xxx_battery_read_cyct(di);
-		if (di->regs[BQ27XXX_REG_AP] != INVALID_REG_ADDR)
-			cache.power_avg = bq27xxx_battery_read_pwr_avg(di);
 
 		/* We only have to read charge design full once */
 		if (di->charge_design_full <= 0)
@@ -1833,6 +1810,32 @@ static int bq27xxx_battery_current(struct bq27xxx_device_info *di,
 	return 0;
 }
 
+/*
+ * Get the average power in µW
+ * Return < 0 if something fails.
+ */
+static int bq27xxx_battery_pwr_avg(struct bq27xxx_device_info *di,
+				   union power_supply_propval *val)
+{
+	int power;
+
+	power = bq27xxx_read(di, BQ27XXX_REG_AP, false);
+	if (power < 0) {
+		dev_err(di->dev,
+			"error reading average power register %02x: %d\n",
+			BQ27XXX_REG_AP, power);
+		return power;
+	}
+
+	if (di->opts & BQ27XXX_O_ZERO)
+		val->intval = (power * BQ27XXX_POWER_CONSTANT) / BQ27XXX_RS;
+	else
+		/* Other gauges return a signed value in units of 10mW */
+		val->intval = (int)((s16)power) * 10000;
+
+	return 0;
+}
+
 static int bq27xxx_battery_status(struct bq27xxx_device_info *di,
 				  union power_supply_propval *val)
 {
@@ -2020,7 +2023,7 @@ static int bq27xxx_battery_get_property(struct power_supply *psy,
 		ret = bq27xxx_simple_value(di->cache.energy, val);
 		break;
 	case POWER_SUPPLY_PROP_POWER_AVG:
-		ret = bq27xxx_simple_value(di->cache.power_avg, val);
+		ret = bq27xxx_battery_pwr_avg(di, val);
 		break;
 	case POWER_SUPPLY_PROP_HEALTH:
 		ret = bq27xxx_simple_value(di->cache.health, val);
diff --git a/include/linux/power/bq27xxx_battery.h b/include/linux/power/bq27xxx_battery.h
index 111a40d0d3d5..8d5f4f40fb41 100644
--- a/include/linux/power/bq27xxx_battery.h
+++ b/include/linux/power/bq27xxx_battery.h
@@ -53,7 +53,6 @@ struct bq27xxx_reg_cache {
 	int capacity;
 	int energy;
 	int flags;
-	int power_avg;
 	int health;
 };
 
-- 
2.17.1

[PATCH 3/3] power: supply: bq27xxx: make status more robust

[Matthias Schiffer]

There are multiple issues in bq27xxx_battery_status():

- On BQ28Q610 is was observed that the "full" flag may be set even while
  the battery is charging or discharging. With the current logic to make
  "full" override everything else, it look a very long time (>20min) for
  the status to change from "full" to "discharging" after unplugging the
  supply on a device with low power consumption
- The POWER_SUPPLY_STATUS_NOT_CHARGING check depends on
  power_supply_am_i_supplied(), which will not work when the supply
  doesn't exist as a separate device known to Linux

We can solve both issues by deriving the status from the current instead
of the flags field. The flags are now only used to distinguish "full"
from "not charging", and to determine the sign of the current on
BQ27XXX_O_ZERO devices.

Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
---
 drivers/power/supply/bq27xxx_battery.c | 88 +++++++++++++-------------
 1 file changed, 43 insertions(+), 45 deletions(-)

diff --git a/drivers/power/supply/bq27xxx_battery.c b/drivers/power/supply/bq27xxx_battery.c
index 20e1dc8a87cf..b62a8cfd9d09 100644
--- a/drivers/power/supply/bq27xxx_battery.c
+++ b/drivers/power/supply/bq27xxx_battery.c
@@ -1777,14 +1777,27 @@ static void bq27xxx_battery_poll(struct work_struct *work)
 		schedule_delayed_work(&di->work, poll_interval * HZ);
 }
 
+static bool bq27xxx_battery_is_full(struct bq27xxx_device_info *di, int flags)
+{
+	if (di->opts & BQ27XXX_O_ZERO)
+		return (flags & BQ27000_FLAG_FC);
+	else if (di->opts & BQ27Z561_O_BITS)
+		return (flags & BQ27Z561_FLAG_FC);
+	else
+		return (flags & BQ27XXX_FLAG_FC);
+}
+
 /*
- * Return the battery average current in µA
+ * Return the battery average current in µA and the status
  * Note that current can be negative signed as well
  * Or 0 if something fails.
  */
-static int bq27xxx_battery_current(struct bq27xxx_device_info *di,
-				   union power_supply_propval *val)
+static int bq27xxx_battery_current_and_status(
+	struct bq27xxx_device_info *di,
+	union power_supply_propval *val_curr,
+	union power_supply_propval *val_status)
 {
+	bool single_flags = (di->opts & BQ27XXX_O_ZERO);
 	int curr;
 	int flags;
 
@@ -1794,17 +1807,39 @@ static int bq27xxx_battery_current(struct bq27xxx_device_info *di,
 		return curr;
 	}
 
+	flags = bq27xxx_read(di, BQ27XXX_REG_FLAGS, single_flags);
+	if (flags < 0) {
+		dev_err(di->dev, "error reading flags\n");
+		return flags;
+	}
+
 	if (di->opts & BQ27XXX_O_ZERO) {
-		flags = bq27xxx_read(di, BQ27XXX_REG_FLAGS, true);
 		if (!(flags & BQ27000_FLAG_CHGS)) {
 			dev_dbg(di->dev, "negative current!\n");
 			curr = -curr;
 		}
 
-		val->intval = curr * BQ27XXX_CURRENT_CONSTANT / BQ27XXX_RS;
+		curr = curr * BQ27XXX_CURRENT_CONSTANT / BQ27XXX_RS;
 	} else {
 		/* Other gauges return signed value */
-		val->intval = (int)((s16)curr) * 1000;
+		curr = (int)((s16)curr) * 1000;
+	}
+
+	if (val_curr)
+		val_curr->intval = curr;
+
+	if (val_status) {
+		if (curr > 0) {
+			val_status->intval = POWER_SUPPLY_STATUS_CHARGING;
+		} else if (curr < 0) {
+			val_status->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+		} else {
+			if (bq27xxx_battery_is_full(di, flags))
+				val_status->intval = POWER_SUPPLY_STATUS_FULL;
+			else
+				val_status->intval =
+					POWER_SUPPLY_STATUS_NOT_CHARGING;
+		}
 	}
 
 	return 0;
@@ -1836,43 +1871,6 @@ static int bq27xxx_battery_pwr_avg(struct bq27xxx_device_info *di,
 	return 0;
 }
 
-static int bq27xxx_battery_status(struct bq27xxx_device_info *di,
-				  union power_supply_propval *val)
-{
-	int status;
-
-	if (di->opts & BQ27XXX_O_ZERO) {
-		if (di->cache.flags & BQ27000_FLAG_FC)
-			status = POWER_SUPPLY_STATUS_FULL;
-		else if (di->cache.flags & BQ27000_FLAG_CHGS)
-			status = POWER_SUPPLY_STATUS_CHARGING;
-		else
-			status = POWER_SUPPLY_STATUS_DISCHARGING;
-	} else if (di->opts & BQ27Z561_O_BITS) {
-		if (di->cache.flags & BQ27Z561_FLAG_FC)
-			status = POWER_SUPPLY_STATUS_FULL;
-		else if (di->cache.flags & BQ27Z561_FLAG_DIS_CH)
-			status = POWER_SUPPLY_STATUS_DISCHARGING;
-		else
-			status = POWER_SUPPLY_STATUS_CHARGING;
-	} else {
-		if (di->cache.flags & BQ27XXX_FLAG_FC)
-			status = POWER_SUPPLY_STATUS_FULL;
-		else if (di->cache.flags & BQ27XXX_FLAG_DSC)
-			status = POWER_SUPPLY_STATUS_DISCHARGING;
-		else
-			status = POWER_SUPPLY_STATUS_CHARGING;
-	}
-
-	if ((status == POWER_SUPPLY_STATUS_DISCHARGING) &&
-	    (power_supply_am_i_supplied(di->bat) > 0))
-		status = POWER_SUPPLY_STATUS_NOT_CHARGING;
-
-	val->intval = status;
-
-	return 0;
-}
-
 static int bq27xxx_battery_capacity_level(struct bq27xxx_device_info *di,
 					  union power_supply_propval *val)
 {
@@ -1960,7 +1958,7 @@ static int bq27xxx_battery_get_property(struct power_supply *psy,
 
 	switch (psp) {
 	case POWER_SUPPLY_PROP_STATUS:
-		ret = bq27xxx_battery_status(di, val);
+		ret = bq27xxx_battery_current_and_status(di, NULL, val);
 		break;
 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 		ret = bq27xxx_battery_voltage(di, val);
@@ -1969,7 +1967,7 @@ static int bq27xxx_battery_get_property(struct power_supply *psy,
 		val->intval = di->cache.flags < 0 ? 0 : 1;
 		break;
 	case POWER_SUPPLY_PROP_CURRENT_NOW:
-		ret = bq27xxx_battery_current(di, val);
+		ret = bq27xxx_battery_current_and_status(di, val, NULL);
 		break;
 	case POWER_SUPPLY_PROP_CAPACITY:
 		ret = bq27xxx_simple_value(di->cache.capacity, val);
-- 
2.17.1

Re: [PATCH 1/3] power: supply: bq27xxx: fix sign of current_now for newer ICs

[Andreas Kemnade]

On Tue, 23 Feb 2021 15:11:20 +0100
Matthias Schiffer <matthias.schiffer@ew.tq-group.com> wrote:

> Commit cd060b4d0868 ("power: supply: bq27xxx: fix polarity of current_now")
> changed the sign of current_now for all bq27xxx variants, but on BQ28Z610
> I'm now seeing negated values *with* that patch.
> 
> The GTA04/Openmoko device that was used for testing uses a BQ27000 or
> BQ27010 IC, so I assume only the BQ27XXX_O_ZERO code path was incorrect.
> Revert the behaviour for newer ICs.
> 
> Fixes: cd060b4d0868 "power: supply: bq27xxx: fix polarity of current_now"
> Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
> ---
> 
> @Andreas Kemnade: It would be great to get a confirmation that the
> Openmoko battery indeed uses BQ27000/BQ27010 - I was having some trouble
> finding that information.
> 
I can confirm that.
here is the corresponding schematic:

http://people.openmoko.org/tony_tu/GTA02/hardware/GTA02/CT-GTA02.pdf

Regards,
Andreas

Re: [PATCH 1/3] power: supply: bq27xxx: fix sign of current_now for newer ICs

[Pali Rohár]

On Tuesday 23 February 2021 15:49:46 Andreas Kemnade wrote:
> On Tue, 23 Feb 2021 15:11:20 +0100
> Matthias Schiffer <matthias.schiffer@ew.tq-group.com> wrote:
> 
> > Commit cd060b4d0868 ("power: supply: bq27xxx: fix polarity of current_now")
> > changed the sign of current_now for all bq27xxx variants, but on BQ28Z610
> > I'm now seeing negated values *with* that patch.
> > 
> > The GTA04/Openmoko device that was used for testing uses a BQ27000 or
> > BQ27010 IC, so I assume only the BQ27XXX_O_ZERO code path was incorrect.
> > Revert the behaviour for newer ICs.
> > 
> > Fixes: cd060b4d0868 "power: supply: bq27xxx: fix polarity of current_now"
> > Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
> > ---
> > 
> > @Andreas Kemnade: It would be great to get a confirmation that the
> > Openmoko battery indeed uses BQ27000/BQ27010 - I was having some trouble
> > finding that information.
> > 
> I can confirm that.
> here is the corresponding schematic:
> 
> http://people.openmoko.org/tony_tu/GTA02/hardware/GTA02/CT-GTA02.pdf
> 
> Regards,
> Andreas

Nokia N900 has BQ27200 connected via i2c. CCing Maemo mailing list maemo-leste@lists.dyne.org

Re: [PATCH 2/3] power: supply: bq27xxx: fix power_avg

[Matthias Schiffer]

On Tue, 2021-02-23 at 15:11 +0100, Matthias Schiffer wrote:
> On all newer bq27xxx ICs, the AveragePower register contains a signed
> value; in addition to handling the raw value as unsigned, the driver
> code also didn't convert it to µW as expected.
> 
> At least for the BQ28Z610, the reference manual incorrectly states that
> the value is in units of 1mA and not 10mA. I have no way of knowing
> whether the manuals of other supported ICs contain the same error, or if
> there are models that actually use 1mA. At least, the new code shouldn't
> be *less* correct than the old version for any device

Ugh, of course this section should talk about mW and not mA. I'll wait
if there is more feedback and then send a v2.


> .
> 
> power_avg is removed from the cache structure, se we don't have to
> extend it to store both a signed value and an error code. Always getting
> an up-to-date value may be desirable anyways, as it avoids inconsistent
> current and power readings when switching between charging and
> discharging.
> 
> Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
> ---
>  drivers/power/supply/bq27xxx_battery.c | 51 ++++++++++++++------------
>  include/linux/power/bq27xxx_battery.h  |  1 -
>  2 files changed, 27 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/power/supply/bq27xxx_battery.c b/drivers/power/supply/bq27xxx_battery.c
> index cb6ebd2f905e..20e1dc8a87cf 100644
> --- a/drivers/power/supply/bq27xxx_battery.c
> +++ b/drivers/power/supply/bq27xxx_battery.c
> @@ -1661,27 +1661,6 @@ static int bq27xxx_battery_read_time(struct bq27xxx_device_info *di, u8 reg)
>  	return tval * 60;
>  }
>  
> -/*
> - * Read an average power register.
> - * Return < 0 if something fails.
> - */
> -static int bq27xxx_battery_read_pwr_avg(struct bq27xxx_device_info *di)
> -{
> -	int tval;
> -
> -	tval = bq27xxx_read(di, BQ27XXX_REG_AP, false);
> -	if (tval < 0) {
> -		dev_err(di->dev, "error reading average power register  %02x: %d\n",
> -			BQ27XXX_REG_AP, tval);
> -		return tval;
> -	}
> -
> -	if (di->opts & BQ27XXX_O_ZERO)
> -		return (tval * BQ27XXX_POWER_CONSTANT) / BQ27XXX_RS;
> -	else
> -		return tval;
> -}
> -
>  /*
>   * Returns true if a battery over temperature condition is detected
>   */
> @@ -1769,8 +1748,6 @@ void bq27xxx_battery_update(struct bq27xxx_device_info *di)
>  		}
>  		if (di->regs[BQ27XXX_REG_CYCT] != INVALID_REG_ADDR)
>  			cache.cycle_count = bq27xxx_battery_read_cyct(di);
> -		if (di->regs[BQ27XXX_REG_AP] != INVALID_REG_ADDR)
> -			cache.power_avg = bq27xxx_battery_read_pwr_avg(di);
>  
>  		/* We only have to read charge design full once */
>  		if (di->charge_design_full <= 0)
> @@ -1833,6 +1810,32 @@ static int bq27xxx_battery_current(struct bq27xxx_device_info *di,
>  	return 0;
>  }
>  
> +/*
> + * Get the average power in µW
> + * Return < 0 if something fails.
> + */
> +static int bq27xxx_battery_pwr_avg(struct bq27xxx_device_info *di,
> +				   union power_supply_propval *val)
> +{
> +	int power;
> +
> +	power = bq27xxx_read(di, BQ27XXX_REG_AP, false);
> +	if (power < 0) {
> +		dev_err(di->dev,
> +			"error reading average power register %02x: %d\n",
> +			BQ27XXX_REG_AP, power);
> +		return power;
> +	}
> +
> +	if (di->opts & BQ27XXX_O_ZERO)
> +		val->intval = (power * BQ27XXX_POWER_CONSTANT) / BQ27XXX_RS;
> +	else
> +		/* Other gauges return a signed value in units of 10mW */
> +		val->intval = (int)((s16)power) * 10000;
> +
> +	return 0;
> +}
> +
>  static int bq27xxx_battery_status(struct bq27xxx_device_info *di,
>  				  union power_supply_propval *val)
>  {
> @@ -2020,7 +2023,7 @@ static int bq27xxx_battery_get_property(struct power_supply *psy,
>  		ret = bq27xxx_simple_value(di->cache.energy, val);
>  		break;
>  	case POWER_SUPPLY_PROP_POWER_AVG:
> -		ret = bq27xxx_simple_value(di->cache.power_avg, val);
> +		ret = bq27xxx_battery_pwr_avg(di, val);
>  		break;
>  	case POWER_SUPPLY_PROP_HEALTH:
>  		ret = bq27xxx_simple_value(di->cache.health, val);
> diff --git a/include/linux/power/bq27xxx_battery.h b/include/linux/power/bq27xxx_battery.h
> index 111a40d0d3d5..8d5f4f40fb41 100644
> --- a/include/linux/power/bq27xxx_battery.h
> +++ b/include/linux/power/bq27xxx_battery.h
> @@ -53,7 +53,6 @@ struct bq27xxx_reg_cache {
>  	int capacity;
>  	int energy;
>  	int flags;
> -	int power_avg;
>  	int health;
>  };
>