[PATCH] power: supply: core: Add kerneldoc to battery struct

[PATCH] power: supply: core: Add kerneldoc to battery struct

[Linus Walleij]

This complements the struct power_supply_battery_info with
extensive kerneldoc explaining the different semantics of the
fields, including an overview of the CC/CV charging concepts
implicit in some of the struct members.

This is done to first establish semantics before I can
add more charging methods by breaking out the CC/CV parameters
to its own struct.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 include/linux/power_supply.h | 209 +++++++++++++++++++++++++++++++----
 1 file changed, 186 insertions(+), 23 deletions(-)

diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index 9ca1f120a211..671730c5279f 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -342,37 +342,200 @@ struct power_supply_resistance_temp_table {
 
 #define POWER_SUPPLY_OCV_TEMP_MAX 20
 
-/*
+/**
+ * struct power_supply_battery_info - information about batteries
+ * @technology: from the POWER_SUPPLY_TECHNOLOGY_* enum
+ * @energy_full_design_uwh: energy content when fully charged in microwatt
+ *   hours
+ * @charge_full_design_uah: charge content when fully charged in microampere
+ *   hours
+ * @voltage_min_design_uv: minimum voltage across the poles when the battery
+ *   is at minimum voltage level in microvolts. If the voltage drops below this
+ *   level the battery will need precharging when using CC/CV charging.
+ * @voltage_max_design_uv: voltage across the poles when the battery is fully
+ *   charged in microvolts. This is the "nominal voltage" i.e. the voltage
+ *   printed on the label of the battery.
+ * @tricklecharge_current_ua: the tricklecharge current used when trickle
+ *   charging the battery in microamperes. This is the charging phase when the
+ *   battery is fully charged and we just trickle in some current to keep the
+ *   voltage up between constant_charge_voltage_max_uv and overvoltage_limit_uv.
+ * @precharge_current_ua: current to use in the precharge phase in microamperes,
+ *   the precharge rate is limited by limiting the current to this value.
+ * @precharge_voltage_max_uv: the maximum voltage allowed when precharging in
+ *   microvolts. When we pass this voltage we will nominally switch over to the
+ *   next charging phase defined by constant_charge_current_ua and
+ *   constant_charge_voltage_max_uv.
+ * @charge_term_current_ua: when the current in the CV (constant voltage)
+ *   charging phase drops below this value in microamperes the charging will
+ *   terminate completely and not restart until the voltage over the battery
+ *   poles reach charge_restart_voltage_uv unless we use trickle charging.
+ * @charge_restart_voltage_uv: when the battery has been fully charged by
+ *   CC/CV charging and charging has been disabled, and the voltage subsequently
+ *   drops below this value in microvolts, the charging will be restarted
+ *   (typically using CV charging).
+ * @overvoltage_limit_uv: when tricklecharging the battery can temporarily
+ *   exceed the nominal voltage voltage_max_design_uv. The tricklecharginging
+ *   must stop when we reach this value, not to restart unless we get back
+ *   down to constant_charge_voltage_max_uv.
+ * @constant_charge_current_max_ua: current in microamperes to use in the CC
+ *   (constant current) charging phase. The charging rate is limited
+ *   by this current. This is the main charging phase and as the current is
+ *   constant into the battery the voltage slowly ascends to
+ *   constant_charge_voltage_max_uv.
+ * @constant_charge_voltage_max_uv: voltage in microvolts signifying the end of
+ *   the CC (constant current) charging phase and the beginning of the CV
+ *   (constant voltage) charging phase.
+ * @factory_internal_resistance_uohm: the internal resistance of the battery
+ *   at fabrication time, expressed in microohms. This resistance will vary
+ *   depending on the lifetime and charge of the battery, so this is just a
+ *   nominal ballpark figure.
+ * @ocv_temp: array indicating the open circuit voltage (OCV) capacity
+ *   temperature indices. This is an array of temperatures in degrees celsius
+ *   indicating which capacity table to used for a certain temperature, since
+ *   the capacity for reasons of chemistry will be different at different
+ *   temperatures. Determining capacity is a multivariate problem and the
+ *   temperature is the first variable we determine.
+ * @temp_ambient_alert_min: the battery will go outside of operating conditions
+ *   when the ambient temperature goes below this temperature in degrees
+ *   celsius.
+ * @temp_ambient_alert_max: the battery will go outside of operating conditions
+ *   when the ambient temperature goes above this temperature in degrees
+ *   celsius.
+ * @temp_alert_min: the battery should issue an alert if the internal
+ *   temperature goes below this temperature in degrees celsius.
+ * @temp_alert_max: the battery should issue an alert if the internal
+ *   temperature goes above this temperature in degrees celsius.
+ * @temp_min: the battery will go outside of operating conditions when
+ *   the internal temperature goes below this temperature in degrees celsius.
+ *   Normally this means the system should shut down.
+ * @temp_max: the battery will go outside of operating conditions when
+ *   the internal temperature goes above this temperature in degrees celsius.
+ *   Normally this means the system should shut down.
+ * @ocv_table: for each entry in ocv_temp there is a corresponding entry in
+ *   ocv_table and a size for each entry in ocv_table_size. These arrays
+ *   determine the capacity in percent in relation to the voltage in microvolts
+ *   at the indexed temperature.
+ * @ocv_table_size: for each entry in ocv_temp this array is giving the size of
+ *   each entry in the array of capacity arrays in ocv_table.
+ * @resist_table: this is a table that correlates a resistance to an internal
+ *   temperature of a battery. This can be achieved by a separate thermistor to
+ *   supply voltage on a third terminal on a battery which is the most
+ *   reliable. An external thermistor can also be used sometimes.
+ * @resist_table_size: the number of items in the resist table.
+ *
  * This is the recommended struct to manage static battery parameters,
  * populated by power_supply_get_battery_info(). Most platform drivers should
  * use these for consistency.
+ *
  * Its field names must correspond to elements in enum power_supply_property.
  * The default field value is -EINVAL.
- * Power supply class itself doesn't use this.
+ *
+ * The charging parameters here assumes a CC/CV charging scheme. This method
+ * is most common with Lithium Ion batteries (other methods are possible) and
+ * looks as follows:
+ *
+ * ^ Battery voltage
+ * |                                                   overvoltage_limit_uv
+ * |                                                    ..          ..
+ * |                    ................................  ....   ..   ..
+ * |                 .. constant_charge_voltage_max_uv        ...
+ * |              ..
+ * |             .
+ * |            .
+ * |           .
+ * |          .
+ * |         .
+ * |     .. precharge_voltage_max_uv
+ * |  ..
+ * |.
+ * +------------------------------------------------------------------> time
+ *
+ * ^ Current into the battery
+ * |
+ * |      ............. constant_charge_current_max_ua
+ * |      .            .
+ * |      .             .
+ * |      .              .
+ * |      .               .
+ * |      .                ..
+ * |      .                  ....
+ * |      .                       .....
+ * |      .                            .......  charge_term_current_ua
+ * |      .                                   ..........
+ * |....... precharge_current_ua                       . tricklecharge_current_ua
+ * |                                                   ...      ....
+ * |                                                     .      .  .
+ * +-----------------------------------------------------------------> time
+ *
+ * These diagrams are synchronized on time and the voltage and current
+ * follow each other.
+ *
+ * With CC/CV charging commence over time like this for an empty battery:
+ *
+ * 1. First a small initial pre-charge current (precharge_current_ua)
+ *    is applied if the voltage is below precharge_voltage_max_uv until we
+ *    reach precharge_voltage_max_uv. CATION: in some text this is referred
+ *    to as "trickle charging" but the use in the Linux kernel is differen
+ *    see below!
+ *
+ * 2. Then the main charging current is applied, which is called the constant
+ *    current (CC) phase. A current regulator is set up to allow
+ *    constant_charge_current_max_ua of current to flow into the battery.
+ *    The chemical reaction in the battery will make the voltage go up as
+ *    charge goes into the battery. This current is applied until we reach
+ *    the constant_charge_voltage_max_uv voltage.
+ *
+ * 3. At this voltage we switch over to the constant voltage (CV) phase. This
+ *    means we allow current to go into the battery, but we keep the voltage
+ *    fixed. This current will continue to charge the battery while keeping
+ *    the voltage the same. A chemical reaction in the battery goes on
+ *    storing energy without affecting the voltage. Over time the current
+ *    will slowly drop and when we reach charge_term_current_ua we will
+ *    end the constant voltage phase.
+ *
+ * After this the battery is fully charged, and if we do not support trickle
+ * charging, the charging will not restart until power dissapation make the
+ * voltage fall so that we reach charge_restart_voltage_uv and at this point
+ * we restart charging at the appropriate phase, usually this will be inside
+ * the CV phase.
+ *
+ * If we support trickle charging the voltage is however kept high after
+ * the CV phase with a very low current. This is meant to let some charge
+ * "trickle in" for usage while the charger is still connected, mainly for
+ * dissipation for the power consuming entity while connected to the
+ * charger. We allow extra charge to trickle in so that the voltage can
+ * occasionally rise up to overvoltage_limit_uv, and if this happens even
+ * trickle charging is disabled and no current goes into the battery.
+ *
+ * Trickle- and any other charging MUST terminate if the overvoltage_limit_uv
+ * is ever reached. Overcharging Lithium Ion cells can be DANGEROUS and lead
+ * to fire or explosions.
+ *
+ * The power supply class itself doesn't use this struct as of now.
  */
 
 struct power_supply_battery_info {
-	unsigned int technology;	    /* from the enum above */
-	int energy_full_design_uwh;	    /* microWatt-hours */
-	int charge_full_design_uah;	    /* microAmp-hours */
-	int voltage_min_design_uv;	    /* microVolts */
-	int voltage_max_design_uv;	    /* microVolts */
-	int tricklecharge_current_ua;	    /* microAmps */
-	int precharge_current_ua;	    /* microAmps */
-	int precharge_voltage_max_uv;	    /* microVolts */
-	int charge_term_current_ua;	    /* microAmps */
-	int charge_restart_voltage_uv;	    /* microVolts */
-	int overvoltage_limit_uv;	    /* microVolts */
-	int constant_charge_current_max_ua; /* microAmps */
-	int constant_charge_voltage_max_uv; /* microVolts */
-	int factory_internal_resistance_uohm;   /* microOhms */
-	int ocv_temp[POWER_SUPPLY_OCV_TEMP_MAX];/* celsius */
-	int temp_ambient_alert_min;             /* celsius */
-	int temp_ambient_alert_max;             /* celsius */
-	int temp_alert_min;                     /* celsius */
-	int temp_alert_max;                     /* celsius */
-	int temp_min;                           /* celsius */
-	int temp_max;                           /* celsius */
+	unsigned int technology;
+	int energy_full_design_uwh;
+	int charge_full_design_uah;
+	int voltage_min_design_uv;
+	int voltage_max_design_uv;
+	int tricklecharge_current_ua;
+	int precharge_current_ua;
+	int precharge_voltage_max_uv;
+	int charge_term_current_ua;
+	int charge_restart_voltage_uv;
+	int overvoltage_limit_uv;
+	int constant_charge_current_max_ua;
+	int constant_charge_voltage_max_uv;
+	int factory_internal_resistance_uohm;
+	int ocv_temp[POWER_SUPPLY_OCV_TEMP_MAX];
+	int temp_ambient_alert_min;
+	int temp_ambient_alert_max;
+	int temp_alert_min;
+	int temp_alert_max;
+	int temp_min;
+	int temp_max;
 	struct power_supply_battery_ocv_table *ocv_table[POWER_SUPPLY_OCV_TEMP_MAX];
 	int ocv_table_size[POWER_SUPPLY_OCV_TEMP_MAX];
 	struct power_supply_resistance_temp_table *resist_table;
-- 
2.31.1

Re: [PATCH] power: supply: core: Add kerneldoc to battery struct

[Randy Dunlap]

Hi,

On 11/4/21 5:30 PM, Linus Walleij wrote:
> This complements the struct power_supply_battery_info with
> extensive kerneldoc explaining the different semantics of the
> fields, including an overview of the CC/CV charging concepts
> implicit in some of the struct members.
> 
> This is done to first establish semantics before I can
> add more charging methods by breaking out the CC/CV parameters
> to its own struct.
> 
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
>   include/linux/power_supply.h | 209 +++++++++++++++++++++++++++++++----
>   1 file changed, 186 insertions(+), 23 deletions(-)
> 
> diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
> index 9ca1f120a211..671730c5279f 100644
> --- a/include/linux/power_supply.h
> +++ b/include/linux/power_supply.h
> @@ -342,37 +342,200 @@ struct power_supply_resistance_temp_table {
>   
>   #define POWER_SUPPLY_OCV_TEMP_MAX 20
>   
> -/*
> +/**
> + * struct power_supply_battery_info - information about batteries
> + * @technology: from the POWER_SUPPLY_TECHNOLOGY_* enum
> + * @energy_full_design_uwh: energy content when fully charged in microwatt
> + *   hours
> + * @charge_full_design_uah: charge content when fully charged in microampere
> + *   hours
> + * @voltage_min_design_uv: minimum voltage across the poles when the battery
> + *   is at minimum voltage level in microvolts. If the voltage drops below this
> + *   level the battery will need precharging when using CC/CV charging.
> + * @voltage_max_design_uv: voltage across the poles when the battery is fully
> + *   charged in microvolts. This is the "nominal voltage" i.e. the voltage
> + *   printed on the label of the battery.
> + * @tricklecharge_current_ua: the tricklecharge current used when trickle
> + *   charging the battery in microamperes. This is the charging phase when the
> + *   battery is fully charged and we just trickle in some current to keep the
> + *   voltage up between constant_charge_voltage_max_uv and overvoltage_limit_uv.
> + * @precharge_current_ua: current to use in the precharge phase in microamperes,
> + *   the precharge rate is limited by limiting the current to this value.
> + * @precharge_voltage_max_uv: the maximum voltage allowed when precharging in
> + *   microvolts. When we pass this voltage we will nominally switch over to the
> + *   next charging phase defined by constant_charge_current_ua and
> + *   constant_charge_voltage_max_uv.
> + * @charge_term_current_ua: when the current in the CV (constant voltage)
> + *   charging phase drops below this value in microamperes the charging will
> + *   terminate completely and not restart until the voltage over the battery
> + *   poles reach charge_restart_voltage_uv unless we use trickle charging.
> + * @charge_restart_voltage_uv: when the battery has been fully charged by
> + *   CC/CV charging and charging has been disabled, and the voltage subsequently
> + *   drops below this value in microvolts, the charging will be restarted
> + *   (typically using CV charging).
> + * @overvoltage_limit_uv: when tricklecharging the battery can temporarily
> + *   exceed the nominal voltage voltage_max_design_uv. The tricklecharginging
> + *   must stop when we reach this value, not to restart unless we get back
> + *   down to constant_charge_voltage_max_uv.
> + * @constant_charge_current_max_ua: current in microamperes to use in the CC
> + *   (constant current) charging phase. The charging rate is limited
> + *   by this current. This is the main charging phase and as the current is
> + *   constant into the battery the voltage slowly ascends to
> + *   constant_charge_voltage_max_uv.
> + * @constant_charge_voltage_max_uv: voltage in microvolts signifying the end of
> + *   the CC (constant current) charging phase and the beginning of the CV
> + *   (constant voltage) charging phase.
> + * @factory_internal_resistance_uohm: the internal resistance of the battery
> + *   at fabrication time, expressed in microohms. This resistance will vary
> + *   depending on the lifetime and charge of the battery, so this is just a
> + *   nominal ballpark figure.
> + * @ocv_temp: array indicating the open circuit voltage (OCV) capacity
> + *   temperature indices. This is an array of temperatures in degrees celsius

                                                            preferably    Celsius

> + *   indicating which capacity table to used for a certain temperature, since
> + *   the capacity for reasons of chemistry will be different at different
> + *   temperatures. Determining capacity is a multivariate problem and the
> + *   temperature is the first variable we determine.
> + * @temp_ambient_alert_min: the battery will go outside of operating conditions
> + *   when the ambient temperature goes below this temperature in degrees
> + *   celsius.
> + * @temp_ambient_alert_max: the battery will go outside of operating conditions
> + *   when the ambient temperature goes above this temperature in degrees
> + *   celsius.

Ditto. et al.

> + * @temp_alert_min: the battery should issue an alert if the internal
> + *   temperature goes below this temperature in degrees celsius.
> + * @temp_alert_max: the battery should issue an alert if the internal
> + *   temperature goes above this temperature in degrees celsius.
> + * @temp_min: the battery will go outside of operating conditions when
> + *   the internal temperature goes below this temperature in degrees celsius.
> + *   Normally this means the system should shut down.
> + * @temp_max: the battery will go outside of operating conditions when
> + *   the internal temperature goes above this temperature in degrees celsius.
> + *   Normally this means the system should shut down.
> + * @ocv_table: for each entry in ocv_temp there is a corresponding entry in
> + *   ocv_table and a size for each entry in ocv_table_size. These arrays
> + *   determine the capacity in percent in relation to the voltage in microvolts
> + *   at the indexed temperature.
> + * @ocv_table_size: for each entry in ocv_temp this array is giving the size of
> + *   each entry in the array of capacity arrays in ocv_table.
> + * @resist_table: this is a table that correlates a resistance to an internal
> + *   temperature of a battery. This can be achieved by a separate thermistor to
> + *   supply voltage on a third terminal on a battery which is the most
> + *   reliable. An external thermistor can also be used sometimes.
> + * @resist_table_size: the number of items in the resist table.
> + *
>    * This is the recommended struct to manage static battery parameters,
>    * populated by power_supply_get_battery_info(). Most platform drivers should
>    * use these for consistency.
> + *
>    * Its field names must correspond to elements in enum power_supply_property.
>    * The default field value is -EINVAL.
> - * Power supply class itself doesn't use this.
> + *
> + * The charging parameters here assumes a CC/CV charging scheme. This method

                                    assume

> + * is most common with Lithium Ion batteries (other methods are possible) and
> + * looks as follows:
> + *
> + * ^ Battery voltage
...
> + * +------------------------------------------------------------------> time
> + *
> + * ^ Current into the battery
...
> + * +-----------------------------------------------------------------> time
> + *
> + * These diagrams are synchronized on time and the voltage and current
> + * follow each other.
> + *
> + * With CC/CV charging commence over time like this for an empty battery:
> + *
> + * 1. First a small initial pre-charge current (precharge_current_ua)
> + *    is applied if the voltage is below precharge_voltage_max_uv until we
> + *    reach precharge_voltage_max_uv. CATION: in some text this is referred

                                          CAUTION:        texts
(although CATION is a word!)

> + *    to as "trickle charging" but the use in the Linux kernel is differen

                                                                      different

> + *    see below!
> + *
> + * 2. Then the main charging current is applied, which is called the constant
> + *    current (CC) phase. A current regulator is set up to allow
> + *    constant_charge_current_max_ua of current to flow into the battery.
> + *    The chemical reaction in the battery will make the voltage go up as
> + *    charge goes into the battery. This current is applied until we reach
> + *    the constant_charge_voltage_max_uv voltage.
> + *
> + * 3. At this voltage we switch over to the constant voltage (CV) phase. This
> + *    means we allow current to go into the battery, but we keep the voltage
> + *    fixed. This current will continue to charge the battery while keeping
> + *    the voltage the same. A chemical reaction in the battery goes on
> + *    storing energy without affecting the voltage. Over time the current
> + *    will slowly drop and when we reach charge_term_current_ua we will
> + *    end the constant voltage phase.
> + *
> + * After this the battery is fully charged, and if we do not support trickle
> + * charging, the charging will not restart until power dissapation make the

                                                           dissipation makes

> + * voltage fall so that we reach charge_restart_voltage_uv and at this point
> + * we restart charging at the appropriate phase, usually this will be inside
> + * the CV phase.


Tested-by: Randy Dunlap <rdunlap@infradead.org>

and if (when :) you fix these, you can add

Acked-by: Randy Dunlap <rdunlap@infradead.org>


Thanks for doing this.

-- 
~Randy

Re: [PATCH] power: supply: core: Add kerneldoc to battery struct

[Sebastian Reichel]

[-- Attachment #1: Type: text/plain, Size: 10351 bytes --]

Hi,

On Thu, Nov 04, 2021 at 07:20:24PM -0700, Randy Dunlap wrote:
> Hi,
> 
> On 11/4/21 5:30 PM, Linus Walleij wrote:
> > This complements the struct power_supply_battery_info with
> > extensive kerneldoc explaining the different semantics of the
> > fields, including an overview of the CC/CV charging concepts
> > implicit in some of the struct members.
> > 
> > This is done to first establish semantics before I can
> > add more charging methods by breaking out the CC/CV parameters
> > to its own struct.
> > 
> > Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> > ---
> >   include/linux/power_supply.h | 209 +++++++++++++++++++++++++++++++----
> >   1 file changed, 186 insertions(+), 23 deletions(-)
> > 
> > diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
> > index 9ca1f120a211..671730c5279f 100644
> > --- a/include/linux/power_supply.h
> > +++ b/include/linux/power_supply.h
> > @@ -342,37 +342,200 @@ struct power_supply_resistance_temp_table {
> >   #define POWER_SUPPLY_OCV_TEMP_MAX 20
> > -/*
> > +/**
> > + * struct power_supply_battery_info - information about batteries
> > + * @technology: from the POWER_SUPPLY_TECHNOLOGY_* enum
> > + * @energy_full_design_uwh: energy content when fully charged in microwatt
> > + *   hours
> > + * @charge_full_design_uah: charge content when fully charged in microampere
> > + *   hours
> > + * @voltage_min_design_uv: minimum voltage across the poles when the battery
> > + *   is at minimum voltage level in microvolts. If the voltage drops below this
> > + *   level the battery will need precharging when using CC/CV charging.
> > + * @voltage_max_design_uv: voltage across the poles when the battery is fully
> > + *   charged in microvolts. This is the "nominal voltage" i.e. the voltage
> > + *   printed on the label of the battery.
> > + * @tricklecharge_current_ua: the tricklecharge current used when trickle
> > + *   charging the battery in microamperes. This is the charging phase when the
> > + *   battery is fully charged and we just trickle in some current to keep the
> > + *   voltage up between constant_charge_voltage_max_uv and overvoltage_limit_uv.
> > + * @precharge_current_ua: current to use in the precharge phase in microamperes,
> > + *   the precharge rate is limited by limiting the current to this value.
> > + * @precharge_voltage_max_uv: the maximum voltage allowed when precharging in
> > + *   microvolts. When we pass this voltage we will nominally switch over to the
> > + *   next charging phase defined by constant_charge_current_ua and
> > + *   constant_charge_voltage_max_uv.
> > + * @charge_term_current_ua: when the current in the CV (constant voltage)
> > + *   charging phase drops below this value in microamperes the charging will
> > + *   terminate completely and not restart until the voltage over the battery
> > + *   poles reach charge_restart_voltage_uv unless we use trickle charging.
> > + * @charge_restart_voltage_uv: when the battery has been fully charged by
> > + *   CC/CV charging and charging has been disabled, and the voltage subsequently
> > + *   drops below this value in microvolts, the charging will be restarted
> > + *   (typically using CV charging).
> > + * @overvoltage_limit_uv: when tricklecharging the battery can temporarily
> > + *   exceed the nominal voltage voltage_max_design_uv. The tricklecharginging
> > + *   must stop when we reach this value, not to restart unless we get back
> > + *   down to constant_charge_voltage_max_uv.
> > + * @constant_charge_current_max_ua: current in microamperes to use in the CC
> > + *   (constant current) charging phase. The charging rate is limited
> > + *   by this current. This is the main charging phase and as the current is
> > + *   constant into the battery the voltage slowly ascends to
> > + *   constant_charge_voltage_max_uv.
> > + * @constant_charge_voltage_max_uv: voltage in microvolts signifying the end of
> > + *   the CC (constant current) charging phase and the beginning of the CV
> > + *   (constant voltage) charging phase.
> > + * @factory_internal_resistance_uohm: the internal resistance of the battery
> > + *   at fabrication time, expressed in microohms. This resistance will vary
> > + *   depending on the lifetime and charge of the battery, so this is just a
> > + *   nominal ballpark figure.
> > + * @ocv_temp: array indicating the open circuit voltage (OCV) capacity
> > + *   temperature indices. This is an array of temperatures in degrees celsius
> 
>                                                            preferably    Celsius
> 
> > + *   indicating which capacity table to used for a certain temperature, since
> > + *   the capacity for reasons of chemistry will be different at different
> > + *   temperatures. Determining capacity is a multivariate problem and the
> > + *   temperature is the first variable we determine.
> > + * @temp_ambient_alert_min: the battery will go outside of operating conditions
> > + *   when the ambient temperature goes below this temperature in degrees
> > + *   celsius.
> > + * @temp_ambient_alert_max: the battery will go outside of operating conditions
> > + *   when the ambient temperature goes above this temperature in degrees
> > + *   celsius.
> 
> Ditto. et al.
> 
> > + * @temp_alert_min: the battery should issue an alert if the internal
> > + *   temperature goes below this temperature in degrees celsius.
> > + * @temp_alert_max: the battery should issue an alert if the internal
> > + *   temperature goes above this temperature in degrees celsius.
> > + * @temp_min: the battery will go outside of operating conditions when
> > + *   the internal temperature goes below this temperature in degrees celsius.
> > + *   Normally this means the system should shut down.
> > + * @temp_max: the battery will go outside of operating conditions when
> > + *   the internal temperature goes above this temperature in degrees celsius.
> > + *   Normally this means the system should shut down.
> > + * @ocv_table: for each entry in ocv_temp there is a corresponding entry in
> > + *   ocv_table and a size for each entry in ocv_table_size. These arrays
> > + *   determine the capacity in percent in relation to the voltage in microvolts
> > + *   at the indexed temperature.
> > + * @ocv_table_size: for each entry in ocv_temp this array is giving the size of
> > + *   each entry in the array of capacity arrays in ocv_table.
> > + * @resist_table: this is a table that correlates a resistance to an internal
> > + *   temperature of a battery. This can be achieved by a separate thermistor to
> > + *   supply voltage on a third terminal on a battery which is the most
> > + *   reliable. An external thermistor can also be used sometimes.
> > + * @resist_table_size: the number of items in the resist table.
> > + *
> >    * This is the recommended struct to manage static battery parameters,
> >    * populated by power_supply_get_battery_info(). Most platform drivers should
> >    * use these for consistency.
> > + *
> >    * Its field names must correspond to elements in enum power_supply_property.
> >    * The default field value is -EINVAL.
> > - * Power supply class itself doesn't use this.
> > + *
> > + * The charging parameters here assumes a CC/CV charging scheme. This method
> 
>                                    assume
> 
> > + * is most common with Lithium Ion batteries (other methods are possible) and
> > + * looks as follows:
> > + *
> > + * ^ Battery voltage
> ...
> > + * +------------------------------------------------------------------> time
> > + *
> > + * ^ Current into the battery
> ...
> > + * +-----------------------------------------------------------------> time
> > + *
> > + * These diagrams are synchronized on time and the voltage and current
> > + * follow each other.
> > + *
> > + * With CC/CV charging commence over time like this for an empty battery:
> > + *
> > + * 1. First a small initial pre-charge current (precharge_current_ua)
> > + *    is applied if the voltage is below precharge_voltage_max_uv until we
> > + *    reach precharge_voltage_max_uv. CATION: in some text this is referred
> 
>                                          CAUTION:        texts
> (although CATION is a word!)
> 
> > + *    to as "trickle charging" but the use in the Linux kernel is differen
> 
>                                                                      different
> 
> > + *    see below!
> > + *
> > + * 2. Then the main charging current is applied, which is called the constant
> > + *    current (CC) phase. A current regulator is set up to allow
> > + *    constant_charge_current_max_ua of current to flow into the battery.
> > + *    The chemical reaction in the battery will make the voltage go up as
> > + *    charge goes into the battery. This current is applied until we reach
> > + *    the constant_charge_voltage_max_uv voltage.
> > + *
> > + * 3. At this voltage we switch over to the constant voltage (CV) phase. This
> > + *    means we allow current to go into the battery, but we keep the voltage
> > + *    fixed. This current will continue to charge the battery while keeping
> > + *    the voltage the same. A chemical reaction in the battery goes on
> > + *    storing energy without affecting the voltage. Over time the current
> > + *    will slowly drop and when we reach charge_term_current_ua we will
> > + *    end the constant voltage phase.
> > + *
> > + * After this the battery is fully charged, and if we do not support trickle
> > + * charging, the charging will not restart until power dissapation make the
> 
>                                                           dissipation makes
> 
> > + * voltage fall so that we reach charge_restart_voltage_uv and at this point
> > + * we restart charging at the appropriate phase, usually this will be inside
> > + * the CV phase.
> 
> 
> Tested-by: Randy Dunlap <rdunlap@infradead.org>
> 
> and if (when :) you fix these, you can add
> 
> Acked-by: Randy Dunlap <rdunlap@infradead.org>
> 
> Thanks for doing this.

Thanks Linus, LGTM and is appreciated a lot :)
Also thanks you for the review Randy!

-- Sebastian

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Re: [PATCH] power: supply: core: Add kerneldoc to battery struct

[Linus Walleij]

Hi Randy,

thanks for your review, I incorporated all of them, but I have one
question:

On Fri, Nov 5, 2021 at 3:20 AM Randy Dunlap <rdunlap@infradead.org> wrote:

> > + * @ocv_temp: array indicating the open circuit voltage (OCV) capacity
> > + *   temperature indices. This is an array of temperatures in degrees celsius
>
>                                                             preferably    Celsius

I understand spelling Celsius with big C (he was even Swedish, I should know...)
but what is "preferably" here?

If the idea is to reuse these properties between different chargers and
batteries we should rather state that this has to be Celsius or
we will have trouble.

Since no driver is using this yet I think it is fine to mandate Celsius?

Or am I misunderstanding the comment?

Yours,
Linus Walleij

Re: [PATCH] power: supply: core: Add kerneldoc to battery struct

[Randy Dunlap]

On 11/8/21 2:50 PM, Linus Walleij wrote:
> Hi Randy,
> 
> thanks for your review, I incorporated all of them, but I have one
> question:
> 
> On Fri, Nov 5, 2021 at 3:20 AM Randy Dunlap <rdunlap@infradead.org> wrote:
> 
>>> + * @ocv_temp: array indicating the open circuit voltage (OCV) capacity
>>> + *   temperature indices. This is an array of temperatures in degrees celsius
>>
>>                                                              preferably    Celsius
> 
> I understand spelling Celsius with big C (he was even Swedish, I should know...)
> but what is "preferably" here?
> 
> If the idea is to reuse these properties between different chargers and
> batteries we should rather state that this has to be Celsius or
> we will have trouble.
> 
> Since no driver is using this yet I think it is fine to mandate Celsius?
> 
> Or am I misunderstanding the comment?

Yes, misunderstanding, I think.
I just meant that "Celsius" is preferable.
Sorry for the confusion.

-- 
~Randy