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...@intel.com>
---
 drivers/power/Kconfig                      |   15 ++
 drivers/power/Makefile                     |    1 +
 drivers/power/charging_algo_pse.c          |  211 ++++++++++++++++++++++++++++
 include/linux/power/power_supply_charger.h |   63 +++++++++
 4 files changed, 290 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..2b13c74
--- /dev/null
+++ b/drivers/power/charging_algo_pse.c
@@ -0,0 +1,211 @@
+/*
+ * Copyright (C) 2012 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...@intel.com>
+ */
+
+#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>
+#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;
+       int temp_range_cnt = min_t(u16, pse_mod_bprof->temp_mon_ranges,
+                                       BATT_TEMP_NR_RNG);
+
+       if ((temp < pse_mod_bprof->temp_low_lim) ||
+               (temp > pse_mod_bprof->temp_mon_range[0].temp_up_lim))
+               return -EINVAL;
+
+       for (i = 0; i < temp_range_cnt; ++i)
+               if (temp > pse_mod_bprof->temp_mon_range[i].temp_up_lim)
+                       break;
+       return i-1;
+}
+
+static inline bool is_charge_terminated(long volt, long cur,
+                               long iterm, unsigned long cv)
+{
+       pr_devel("%s:current=%ld pse_mod_bprof->chrg_term_mA =%ld 
voltage_now=%ld full_cond=%ld",
+                       __func__, cur, iterm, volt * 100, (FULL_CV_MIN * 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.
+       */
+       pr_devel("%s:current=%ld pse_mod_bprof->chrg_term_mA =%d 
batt_props.voltage_now=%ld full_cond=%ld",
+               __func__, batt_props.current_now, (pse_mod_bprof->chrg_term_mA),
+               batt_props.voltage_now * 100, (FULL_CV_MIN * cv));
+
+       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_low_lim;
+       bat_thresh->temp_max = pse_mod_bprof->temp_mon_range[0].temp_up_lim;
+
+       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.
+       */
+
+       pr_devel("%s:battery status = %ld algo_status=%d\n",
+                       __func__, batt_props.status, algo_stat);
+
+       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_vol_ll -
+                               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_vol_ll))
+                               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_vol_ul;
+                       *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;
+}
+
+static int __init pse_algo_init(void)
+{
+       struct psy_charging_algo pse_algo;
+       pse_algo.chrg_prof_type = PSY_CHRG_PROF_PSE;
+       pse_algo.name = "pse_algo";
+       pse_algo.get_next_cc_cv = pse_get_next_cc_cv;
+       pse_algo.get_batt_thresholds = pse_get_bat_thresholds;
+       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 2b59817..8f3797d 100644
--- a/include/linux/power/power_supply_charger.h
+++ b/include/linux/power/power_supply_charger.h
@@ -94,8 +94,71 @@ 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_up_lim: 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_vol_ll: voltage at which maintenance charging should start in mV
+ * @maint_chrg_vol_ul: 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_up_lim;
+       short int full_chrg_vol;
+       short int full_chrg_cur;
+       short int maint_chrg_vol_ll;
+       short int maint_chrg_vol_ul;
+       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_ul: maximum operating temperature when battery is discharging
+ * @disch_temp_ll: lowest operating temperature when battery is discharging
+ * @temp_mon_ranges: number of temperature zones
+ * @psy_ps_temp_chg_table: temperature zone table array
+ * @temp_low_lim: 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_ul;
+       s8 disch_temp_ll;
+       u16 temp_mon_ranges;
+       struct psy_ps_temp_chg_table temp_mon_range[BATT_TEMP_NR_RNG];
+       s8 temp_low_lim;
+} __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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