Re: [PATCH 2/3] power_supply: Introduce PSE compliant algorithm

[edubezval@xxxxxxxxx]

Hello Jenny,

On Wed, Aug 13, 2014 at 8:09 AM, Jenny TC <jenny.tc@xxxxxxxxx> wrote:
> As per Product Safety Engineering (PSE) specification for battery charging, the
> battery characteristics and thereby the charging rates can vary on different
> temperature zones. This patch introduces a PSE compliant charging algorithm with
> maintenance charging support. The algorithm can be selected by the power supply
> charging driver based on the type of the battery charging profile.
>
> Signed-off-by: Jenny TC <jenny.tc@xxxxxxxxx>
> ---
>  drivers/power/Kconfig                      |   15 ++
>  drivers/power/Makefile                     |    1 +
>  drivers/power/charging_algo_pse.c          |  216 ++++++++++++++++++++++++++++
>  include/linux/power/power_supply_charger.h |   66 +++++++++
>  4 files changed, 298 insertions(+)
>  create mode 100644 drivers/power/charging_algo_pse.c
>
> diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
> index f679f82..54a0321 100644
> --- a/drivers/power/Kconfig
> +++ b/drivers/power/Kconfig
> @@ -22,6 +22,21 @@ config POWER_SUPPLY_CHARGER
>           drivers to keep the charging logic outside and the charger driver
>           just need to abstract the charger hardware.
>
> +config POWER_SUPPLY_CHARGING_ALGO_PSE
> +       bool "PSE compliant charging algorithm"
> +       depends on POWER_SUPPLY_CHARGER
> +       help
> +         Say Y here to select Product Safety Engineering (PSE) compliant
> +         charging algorithm. As per PSE standard the battery characteristics
> +         and thereby the charging rates can vary on different temperature
> +         zones. Select this if your charging algorithm need to change the
> +         charging parameters based on the battery temperature and the battery
> +         charging profile follows the struct psy_pse_chrg_prof definition.
> +         This  config will enable PSE compliant charging algorithm with
> +         maintenance charging support. At runtime the algorithm will be
> +         selected by the psy charger driver based on the type of the battery
> +         charging profile.
> +
>  config PDA_POWER
>         tristate "Generic PDA/phone power driver"
>         depends on !S390
> diff --git a/drivers/power/Makefile b/drivers/power/Makefile
> index 405f0f4..77535fd 100644
> --- a/drivers/power/Makefile
> +++ b/drivers/power/Makefile
> @@ -8,6 +8,7 @@ obj-$(CONFIG_POWER_SUPPLY)      += power_supply.o
>  obj-$(CONFIG_GENERIC_ADC_BATTERY)      += generic-adc-battery.o
>
>  obj-$(CONFIG_POWER_SUPPLY_CHARGER) += power_supply_charger.o
> +obj-$(CONFIG_POWER_SUPPLY_CHARGING_ALGO_PSE) += charging_algo_pse.o
>  obj-$(CONFIG_PDA_POWER)                += pda_power.o
>  obj-$(CONFIG_APM_POWER)                += apm_power.o
>  obj-$(CONFIG_MAX8925_POWER)    += max8925_power.o
> diff --git a/drivers/power/charging_algo_pse.c b/drivers/power/charging_algo_pse.c
> new file mode 100644
> index 0000000..cbedebe
> --- /dev/null
> +++ b/drivers/power/charging_algo_pse.c
> @@ -0,0 +1,216 @@
> +/*
> + * Copyright (C) 2014 Intel Corporation
> + *
> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; version 2 of the License.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.        See the GNU
> + * General Public License for more details.
> + *
> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + * Author: Jenny TC <jenny.tc@xxxxxxxxx>
> + */
> +
> +#include <linux/module.h>
> +#include <linux/types.h>
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/power_supply.h>
> +#include <linux/thermal.h>

Why do you need thermal.h here?

In theory, if you are creating thermal zones or cooling devices with
your generic psi driver, then I agree, we need a link with thermal
subsystem. But I cannot see how the code below is using the thermal
code.


> +#include "power_supply.h"
> +#include "power_supply_charger.h"
> +
> +/* 98% of CV is considered as voltage to detect Full */
> +#define FULL_CV_MIN 98
> +
> +/*
> + * Offset to exit from maintenance charging. In maintenance charging
> + * if the volatge is less than the (maintenance_lower_threshold -
> + * MAINT_EXIT_OFFSET) then system can switch to normal charging
> + */
> +
> +#define MAINT_EXIT_OFFSET 50  /* mV */
> +
> +static int get_tempzone(struct psy_pse_chrg_prof *pse_mod_bprof,
> +               int temp)
> +{
> +       int i = 0, temp_range_cnt;
> +
> +       temp_range_cnt =  pse_mod_bprof->temp_mon_ranges;
> +
> +       if (!temp_range_cnt || temp_range_cnt > BATT_TEMP_NR_RNG)
> +               return -EINVAL;
> +
> +       /* Basic validity check. Ensure zones are in decreasing order */
> +
> +       for (i = 0; i < temp_range_cnt - 1; i++) {
> +               if (pse_mod_bprof->temp_mon_range[i].temp_max <=
> +                               pse_mod_bprof->temp_mon_range[i + 1].temp_max)
> +                       return -EINVAL;
> +       }
> +
> +       if (pse_mod_bprof->temp_mon_range[i].temp_max <=
> +                                       pse_mod_bprof->temp_min)
> +               return -EINVAL;
> +
> +       if ((temp < pse_mod_bprof->temp_min) ||
> +                       (temp > pse_mod_bprof->temp_mon_range[0].temp_max))
> +               return -EINVAL;
> +
> +       for (i = 0; i < temp_range_cnt; i++)
> +               if (temp > pse_mod_bprof->temp_mon_range[i].temp_max)
> +                       break;
> +       return i-1;
> +}
> +
> +static inline bool is_charge_terminated(long volt, long cur,
> +                               long iterm, unsigned long cv)
> +{
> +       return (cur > 0) && (cur <= iterm) &&
> +                               ((volt * 100)  >= (FULL_CV_MIN * cv));
> +}
> +
> +static inline bool is_battery_full(struct psy_batt_context *batt_cxt,
> +               struct psy_pse_chrg_prof *pse_mod_bprof, unsigned long cv)
> +{
> +       int i;
> +       struct psy_batt_props batt_props;
> +
> +       batt_props =  batt_cxt->batt_props;
> +
> +       /*
> +        * Software full detection. Check the battery charge current to detect
> +        * battery Full. The voltage also verified to avoid false charge
> +        * full detection.
> +        */
> +       for (i = MAX_CUR_VOLT_SAMPLES - 1; i >= 0; --i) {
> +
> +               if (!(is_charge_terminated(batt_cxt->voltage_now_cache[i],
> +                               batt_cxt->current_now_cache[i],
> +                               pse_mod_bprof->chrg_term_mA, cv)))
> +                       return false;
> +       }
> +
> +       return true;
> +}
> +
> +static int  pse_get_bat_thresholds(struct psy_batt_chrg_prof  bprof,
> +                       struct psy_batt_thresholds *bat_thresh)
> +{
> +       struct psy_pse_chrg_prof *pse_mod_bprof =
> +                       (struct psy_pse_chrg_prof *) bprof.batt_prof;
> +
> +       if ((bprof.chrg_prof_type != PSY_CHRG_PROF_PSE) || (!pse_mod_bprof))
> +               return -EINVAL;
> +
> +       bat_thresh->iterm = pse_mod_bprof->chrg_term_mA;
> +       bat_thresh->temp_min = pse_mod_bprof->temp_min;
> +       bat_thresh->temp_max = pse_mod_bprof->temp_mon_range[0].temp_max;
> +
> +       return 0;
> +}
> +
> +static enum psy_algo_stat pse_get_next_cc_cv(struct psy_batt_context *batt_cxt,
> +       struct psy_batt_chrg_prof  bprof, unsigned long *cc, unsigned long *cv)
> +{
> +       int tzone;
> +       struct psy_pse_chrg_prof *pse_mod_bprof;
> +       struct psy_batt_props batt_props;
> +       enum psy_algo_stat algo_stat;
> +       int maint_exit_volt;
> +
> +       pse_mod_bprof = (struct psy_pse_chrg_prof *) bprof.batt_prof;
> +       algo_stat = batt_cxt->algo_stat;
> +
> +       batt_props = batt_cxt->batt_props;
> +
> +       *cc = *cv = 0;
> +
> +       /*
> +        * If STATUS is discharging, assume that charger is not connected.
> +        * If charger is not connected, no need to take any action.
> +        * If charge profile type is not PSY_CHRG_PROF_PSE or the charge profile
> +        * is not present, no need to take any action.
> +        */
> +
> +       if (!pse_mod_bprof)
> +               return PSY_ALGO_STAT_NOT_CHARGE;
> +
> +       tzone = get_tempzone(pse_mod_bprof, batt_props.temperature);
> +       if (tzone < 0)
> +               return PSY_ALGO_STAT_NOT_CHARGE;
> +
> +       /*
> +        * Change the algo status to not charging, if battery is
> +        * not really charging or less than maintenance exit threshold.
> +        * This way algorithm can switch to normal charging if current
> +        * status is full/maintenance.
> +        */
> +       maint_exit_volt = pse_mod_bprof->
> +                               temp_mon_range[tzone].maint_chrg_volt_min -
> +                               MAINT_EXIT_OFFSET;
> +
> +       if ((batt_props.status == POWER_SUPPLY_STATUS_DISCHARGING) ||
> +               (batt_props.status == POWER_SUPPLY_STATUS_NOT_CHARGING) ||
> +                       batt_props.voltage_now < maint_exit_volt) {
> +
> +               algo_stat = PSY_ALGO_STAT_NOT_CHARGE;
> +
> +       }
> +
> +       /* read cc and cv based on temperature and algorithm status */
> +       if (algo_stat == PSY_ALGO_STAT_FULL ||
> +                       algo_stat == PSY_ALGO_STAT_MAINT) {
> +
> +               /*
> +                * if status is full and voltage is lower than maintenance lower
> +                * threshold change status to maintenance
> +                */
> +
> +               if (algo_stat == PSY_ALGO_STAT_FULL &&
> +                       (batt_props.voltage_now <=
> +                       pse_mod_bprof->temp_mon_range[tzone]
> +                                               .maint_chrg_volt_min))
> +                               algo_stat = PSY_ALGO_STAT_MAINT;
> +
> +               /* Read maintenance CC and CV */
> +               if (algo_stat == PSY_ALGO_STAT_MAINT) {
> +                       *cv = pse_mod_bprof->temp_mon_range
> +                                       [tzone].maint_chrg_volt_max;
> +                       *cc = pse_mod_bprof->temp_mon_range
> +                                       [tzone].maint_chrg_cur;
> +               }
> +       } else {
> +               *cv = pse_mod_bprof->temp_mon_range[tzone].full_chrg_vol;
> +               *cc = pse_mod_bprof->temp_mon_range[tzone].full_chrg_cur;
> +               algo_stat = PSY_ALGO_STAT_CHARGE;
> +       }
> +
> +       if (is_battery_full(batt_cxt, pse_mod_bprof, *cv)) {
> +               *cc = *cv = 0;
> +               algo_stat = PSY_ALGO_STAT_FULL;
> +       }
> +
> +       return algo_stat;
> +}
> +
> +struct psy_charging_algo pse_algo = {
> +       .name = "pse-algo",
> +       .chrg_prof_type = PSY_CHRG_PROF_PSE,
> +       .get_next_cc_cv = pse_get_next_cc_cv,
> +       .get_batt_thresholds = pse_get_bat_thresholds,
> +};
> +static int __init pse_algo_init(void)
> +{
> +       power_supply_register_charging_algo(&pse_algo);
> +       return 0;
> +}
> +
> +module_init(pse_algo_init);
> diff --git a/include/linux/power/power_supply_charger.h b/include/linux/power/power_supply_charger.h
> index f1b9567..1718198 100644
> --- a/include/linux/power/power_supply_charger.h
> +++ b/include/linux/power/power_supply_charger.h
> @@ -94,8 +94,74 @@ enum battery_events {
>
>  enum psy_batt_chrg_prof_type {
>         PSY_CHRG_PROF_NONE = 0,
> +       PSY_CHRG_PROF_PSE,
>  };
>
> +/* Product Safety Engineering (PSE) compliant charging profile */
> +
> +/**
> + * struct psy_ps_temp_chg_table - charging temperature zones definition
> + * @temp_max: upper temperature limit for each zone in Degree Celsius
> + * @full_chrg_vol: charge voltage till battery full in mV
> + * @full_chrg_cur: charge current till battery full in mA
> + * @maint_chrg_volt_min: voltage at which maintenance charging should
> + *             start in mV
> + * @maint_chrg_volt_max: voltage at which maintenance charging should
> + *     stop in mV. This is the charging voltage in maintenance charging mode
> + * @maint_chrg_cur: charge current in maintenance charging mode
> + *
> + * Charging temperature zone definition to decide the charging parameters on
> + * each zone. An array of the structure is used to define multiple temperature
> + * zones
> + */
> +
> +struct psy_ps_temp_chg_table {
> +       short int temp_max;
> +       short int full_chrg_vol;
> +       short int full_chrg_cur;
> +       short int maint_chrg_volt_min;
> +       short int maint_chrg_volt_max;
> +       short int maint_chrg_cur;
> +} __packed;
> +
> +#define BATTID_STR_LEN         8
> +#define BATT_TEMP_NR_RNG       6
> +
> +/**
> + * struct psy_pse_chrg_prof - PSE charging profile structure
> + * @batt_id: battery identifier
> + * @battery_type: as defined in POWER_SUPPLY_TECHNOLOGY_*
> + * @capacity: battery capacity in mAh
> + * @voltage_max: maximum battery volatge in mV
> + * @chrg_term_ma: charge termination current in mA
> + * @low_batt_mv: Low battery level voltage in mV
> + * @disch_temp_max: maximum operating temperature when battery is discharging
> + *             in degree Celsius
> + * @disch_temp_min: lowest operating temperature when battery is discharging
> + *     in degree Celsius
> + * @temp_mon_ranges: number of temperature zones
> + * @psy_ps_temp_chg_table: temperature zone table array
> + * @temp_min: minimum charging temperature
> + *
> + * PSE compliant charging profile which can be stored in battery EEPROM
> + * (if digital battery interface like MIPI BIF/SDQ supported) or in secondary
> + * storage to support analog battery (with BSI sensing support)
> + */
> +
> +struct psy_pse_chrg_prof {
> +       char batt_id[BATTID_STR_LEN];
> +       u16 battery_type;
> +       u16 capacity;
> +       u16 voltage_max;
> +       u16 chrg_term_mA;
> +       u16 low_batt_mV;
> +       s8 disch_temp_max;
> +       s8 disch_temp_min;
> +       u16 temp_mon_ranges;
> +       struct psy_ps_temp_chg_table temp_mon_range[BATT_TEMP_NR_RNG];
> +       s8 temp_min;
> +} __packed;
> +
>  /**
>   * struct psy_batt_chrg_prof - power supply charging profile structure
>   * @chrg_prof_type: charging profile type
> --
> 1.7.9.5
>
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-- 
Eduardo Bezerra Valentin
--
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