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SubjectRe: [RFC PATCH 1/2] power: Charger-Manager: add initial Charger-Manager driver
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On Thu, Nov 17, 2011 at 6:13 PM, Donggeun Kim <dg77.kim@samsung.com> wrote:
> Because battery health monitoring should be done even when suspended,
> it needs to wake up and suspend periodically. Thus, userspace battery
> monitoring may incur too much overhead; every device and task is woken
> up periodically. Charger Manager uses suspend-again to provide
> in-suspend monitoring.
>
> This patch allows to monitor battery health in-suspend state.
>
> Signed-off-by: Donggeun Kim <dg77.kim@samsung.com>
> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> ---
>  Documentation/power/charger-manager.txt |  150 ++++++
>  drivers/power/Kconfig                   |    9 +
>  drivers/power/Makefile                  |    1 +
>  drivers/power/charger-manager.c         |  771 +++++++++++++++++++++++++++++++
>  include/linux/power/charger-manager.h   |  131 ++++++
>  5 files changed, 1062 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/power/charger-manager.txt
>  create mode 100644 drivers/power/charger-manager.c
>  create mode 100644 include/linux/power/charger-manager.h
>
> diff --git a/Documentation/power/charger-manager.txt b/Documentation/power/charger-manager.txt
> new file mode 100644
> index 0000000..99630e5
> --- /dev/null
> +++ b/Documentation/power/charger-manager.txt
> @@ -0,0 +1,150 @@
> +Charger Manager
> +       (C) 2011 MyungJoo Ham <myungjoo.ham@samsung.com>, GPL
> +
> +Charger Manager provides in-kernel battery charger management that
> +requires temperature monitoring during suspend-to-RAM state
> +and where each battery may have multiple chargers attached and the userland
> +wants to look at the aggregated information of the multiple chargers.
> +
> +Charger Manager is a platform_driver with power-supply-class entries.
> +An instance of Charger Manager (a platform-device created with Charger-Manager)
> +represents an independent battery with chargers. If there are multiple
> +batteries with their own chargers acting independently in a system,
> +the system may need multiple instances of Charger Manager.
> +
> +1. Introduction
> +===============
> +
> +Charger Manager supports the following:
> +
> +* Support for multiple chargers (e.g., a device with USB, AC, and solar panels)
> +       A system may have multiple chargers (or power sources) and some of
> +       they may be activated at the same time. Each charger may have its
> +       own power-supply-class and each power-supply-class can provide
> +       different information about the battery status. This framework
> +       aggregates charger-related information from multiple sources and
> +       shows combined information as a single power-supply-class.
> +
> +* Support for in suspend-to-RAM polling (with suspend_again callback)
> +       While the battery is being charged and the system is in suspend-to-RAM,
> +       we may need to monitor the battery health by looking at the ambient or
> +       battery temperature. We can accomplish this by waking up the system
> +       periodically. However, such a method wakes up devices unncessary for
> +       monitoring the battery health and tasks, and user processes that are
> +       supposed to be kept suspended. That, in turn, incurs unnecessary power
> +       consumption and slow down charging process. Or even, such peak power
> +       consumption can stop chargers in the middle of charging
> +       (external power input < device power consumption), which not
> +       only affects the charging time, but the lifespan of the battery.
> +
> +       Charger Manager provides a function "cm_suspend_again" that can be
> +       used as suspend_again callback of platform_suspend_ops. If the platform
> +       requires tasks other than cm_suspend_again, it may implement its own
> +       suspend_again callback that calls cm_suspend_again in the middle.
> +       Normally, the platform will need to resume and suspend some devices
> +       that are used by Charger Manager.
> +
> +2. Global Charger-Manager Data related with suspend_again
> +========================================================
> +In order to setup Charger Manager with suspend-again feature
> +(in-suspend monitoring), the user should provide charger_global_desc
> +with setup_charger_manager(struct charger_global_desc *).
> +This charger_global_desc data for in-suspend monitoring is global
> +as the name suggests. Thus, the user needs to provide only once even
> +if there are multiple batteries. If there are multiple batteries, the
> +multiple instances of Charger Manager share the same charger_global_desc
> +and it will manage in-suspend monitoring for all instances of Charger Manager.
> +
> +The user needs to provide all the three entries properly in order to activate
> +in-suspend monitoring:
> +
> +struct charger_global_desc {
> +
> +char *rtc;
> +       : The name of rtc (e.g., "rtc0") used to wakeup the system from
> +       suspend for Charger Manager. The alarm interrupt (AIE) of the rtc
> +       should be able to wake up the system from suspend. Charger Manager
> +       saves and restores the alarm value and use the previously-defined
> +       alarm if it is going to go off earlier than Charger Manager so that
> +       Charger Manager does not interfere with previously-defined alarms.
> +
> +bool (*is_rtc_only_wakeup_reason)(void);
> +       : This callback should let CM know whether
> +       the wakeup-from-suspend is caused only by the alarm of "rtc" in the
> +       same struct. If there is any other wakeup source triggered the
> +       wakeup, it should return false. If the "rtc" is the only wakeup
> +       reason, it should return true.
> +};
> +
> +3. How to setup suspend_again
> +=============================
> +Charger Manager provides a function "extern bool cm_suspend_again(void)".
> +When cm_suspend_again is called, it monitors every battery. The suspend_ops
> +callback of the system's platform_suspend_ops can call cm_suspend_again
> +function to know whether Charger Manager wants to suspend again or not.
> +If there are no other devices or tasks that want to use suspend_again
> +feature, the platform_suspend_ops may directly refer to cm_suspend_again
> +for its suspend_again callback.
> +
> +The cm_suspend_again() returns true (meaning "I want to suspend again")
> +if the system was woken up by Charger Manager and the polling
> +(in-suspend monitoring) results in "normal".
> +
> +4. Charger-Manager Data (struct charger_desc)
> +=============================================
> +For each battery charged independently from other batteries (if a series of
> +batteries are charged by a single charger, they are counted as one independent
> +battery), an instance of Charger Manager is attached to it.
> +
> +struct charger_desc {
> +
> +enum polling_modes polling_mode;
> +       : CM_POLL_DISABLE: do not poll this battery.
> +         CM_POLL_ALWAYS: always poll this battery.
> +         CM_POLL_EXTERNAL_POWER_ONLY: poll this battery if and only if
> +                                      an external power source is attached.
> +         CM_POLL_CHARGING_ONLY: poll this battery if and only if the
> +                                battery is being charged.
> +
> +unsigned int polling_interval_ms;
> +       : Required polling interval in ms. Charger Manager will poll
> +       this battery every polling_interval_ms or more frequently.
> +
> +enum data_source battery_present;
> +       CM_FUEL_GAUGE: get battery presence information from fuel gauge.
> +       CM_CHARGER_STAT: get battery presence from chargers.
> +
> +char **psy_charger_stat;
> +       : An array ending with NULL that has power-supply-class names of
> +       chargers. Each power-supply-class should provide "PRESENT" (if
> +       battery_present is "CM_CHARGER_STAT"), "ONLINE" (shows whether an
> +       external power source is attached or not), and "STATUS" (shows whether
> +       the battery is {"FULL" or not FULL} or {"FULL", "Charging",
> +       "Discharging", "NotCharging"}).
> +
> +int num_charger_regulators;
> +struct regulator_bulk_data *charger_regulators;
> +       : Regulators representing the chargers in the form for
> +       regulator framework's bulk functions.
> +
> +char *psy_fuel_gauge;
> +       : Power-supply-class name of the fuel gauge.
> +
> +int (*is_temperature_error)(int *mC);
> +       : This callback returns 0 if the temperature is safe for charging,
> +       a positive number if it is too hot to charge, and a negative number
> +       if it is too cold to charge. With the variable mC, the callback returns
> +       the temperature in 1/1000 of centigrade.
> +};
> +
> +5. Other Considerations
> +=======================
> +
> +At the charger/battery-related events such as battery-pulled-out,
> +charger-pulled-out, charger-inserted, DCIN-over/under-voltage, charger-stopped,
> +and others critical to chargers, the system should be configured to wake up.
> +At least the following should wake up the system from a suspend:
> +a) charger-on/off b) external-power-in/out c) battery-in/out (while charging)
> +
> +It is usually accomplished by configuring the PMIC as a wakeup source.
> +
> diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
> index 9f88641..eb96b40 100644
> --- a/drivers/power/Kconfig
> +++ b/drivers/power/Kconfig
> @@ -236,6 +236,15 @@ config CHARGER_GPIO
>          This driver can be build as a module. If so, the module will be
>          called gpio-charger.
>
> +config CHARGER_MANAGER
> +        tristate "Battery charger manager for multiple chargers"
> +        help
> +          Say Y to enable charger-manager support, which allows multiple
> +          chargers attached to a battery and multiple batteries attached to a
> +          system. The charger-manager also can monitor charging status in
> +          runtime and in suspend-to-RAM by waking up the system periodically
> +          with help of suspend_again support.
> +
>  config CHARGER_MAX8997
>        tristate "Maxim MAX8997/MAX8966 PMIC battery charger driver"
>        depends on MFD_MAX8997 && REGULATOR_MAX8997
> diff --git a/drivers/power/Makefile b/drivers/power/Makefile
> index b4af13d..d3b24e9 100644
> --- a/drivers/power/Makefile
> +++ b/drivers/power/Makefile
> @@ -36,5 +36,6 @@ obj-$(CONFIG_CHARGER_ISP1704) += isp1704_charger.o
>  obj-$(CONFIG_CHARGER_MAX8903)  += max8903_charger.o
>  obj-$(CONFIG_CHARGER_TWL4030)  += twl4030_charger.o
>  obj-$(CONFIG_CHARGER_GPIO)     += gpio-charger.o
> +obj-$(CONFIG_CHARGER_MANAGER)  += charger-manager.o
>  obj-$(CONFIG_CHARGER_MAX8997)  += max8997_charger.o
>  obj-$(CONFIG_CHARGER_MAX8998)  += max8998_charger.o
> diff --git a/drivers/power/charger-manager.c b/drivers/power/charger-manager.c
> new file mode 100644
> index 0000000..5006756
> --- /dev/null
> +++ b/drivers/power/charger-manager.c
> @@ -0,0 +1,771 @@
> +/* linux/drivers/power/charger-manager.c
> + *
> + * Copyright (C) 2011 Samsung Electronics Co., Ltd.
> + * MyungJoo Ham <myungjoo.ham@samsung.com>
> + *
> + * This driver enables to monitor battery health and control charger
> + * during suspend-to-mem.
> + * Charger manager depends on other devices. register this later than
> + * the depending devices.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> +**/
> +
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/irq.h>
> +#include <linux/interrupt.h>
> +#include <linux/rtc.h>
> +#include <linux/slab.h>
> +#include <linux/workqueue.h>
> +#include <linux/platform_device.h>
> +#include <linux/power/charger-manager.h>
> +#include <linux/regulator/consumer.h>
> +
> +/*
> + * Regard CM_JIFFIES_SMALL jiffies is small enough to ignore for
> + * delayed works so that we can run delayed works with CM_JIFFIES_SMALL
> + * without any delays.
> + */
> +#define        CM_JIFFIES_SMALL        (2)
> +
> +/* If y is valid (> 0) and smaller than x, do x = y */
> +#define CM_MIN_VALID(x, y)     x = (((y > 0) && ((x) > (y))) ? (y) : (x))
> +
> +/*
> + * Regard CM_RTC_SMALL (sec) is small enough to ignore error in invoking
> + * rtc alarm. It should be 2 or larger
> + */
> +#define CM_RTC_SMALL           (2)
> +
> +#define UEVENT_BUF_SIZE                32
> +
> +static LIST_HEAD(cm_list);
> +static DEFINE_MUTEX(cm_list_mtx);
> +
> +/* About in-suspend (suspend-again) monitoring */
> +static struct rtc_device *rtc_dev;
> +static struct rtc_wkalrm rtc_wkalarm_save; /* Backup RTC alarm */
> +static unsigned long rtc_wkalarm_save_; /* 0 if not available */
> +static bool cm_suspended;
> +static bool cm_rtc_set;
> +static unsigned long cm_suspend_duration_ms;
> +
> +/* Global charger-manager description */
> +static struct charger_global_desc *g_desc; /* init with setup_charger_manager */
> +
> +/**
> + * is_batt_present - See if the battery presents in place.
> + * @cm: the Charger Manager representing the battery.
> + */
> +static bool is_batt_present(struct charger_manager *cm)
> +{
> +       union power_supply_propval val;
> +       bool present = false;
> +       int i, ret;
> +
> +       switch (cm->desc->battery_present) {
> +       case CM_FUEL_GAUGE:
> +               ret = cm->fuel_gauge->get_property(cm->fuel_gauge,
> +                               POWER_SUPPLY_PROP_PRESENT, &val);
> +               if (ret == 0 && val.intval)
> +                       present = true;
> +               break;
> +       case CM_CHARGER_STAT:
> +               for (i = 0; cm->charger_stat[i]; i++) {
> +                       ret = cm->charger_stat[i]->get_property(
> +                                       cm->charger_stat[i],
> +                                       POWER_SUPPLY_PROP_PRESENT, &val);
> +                       if (ret == 0 && val.intval) {
> +                               present = true;
> +                               break;
> +                       }
> +               }
> +               break;
> +       }
> +
> +       return present;
> +}
> +
> +/**
> + * is_ext_pwr_online - See if an external power source is attached to charge
> + * @cm: the Charger Manager representing the battery.
> + *
> + * Returns true if at least one of the chargers of the battery has an external
> + * power source attached to charge the battery regardless of whether it is
> + * actually charging or not.
> + */
> +static bool is_ext_pwr_online(struct charger_manager *cm)
> +{
> +       union power_supply_propval val;
> +       bool online = false;
> +       int i, ret;
> +
> +       /* If at least one of them has one, it's yes. */
> +       for (i = 0; cm->charger_stat[i]; i++) {
> +               ret = cm->charger_stat[i]->get_property(
> +                               cm->charger_stat[i],
> +                               POWER_SUPPLY_PROP_ONLINE, &val);
> +               if (ret == 0 && val.intval) {
> +                       online = true;
> +                       break;
> +               }
> +       }
> +
> +       return online;
> +}
> +
> +/**
> + * is_charging - Returns true if the battery is being charged.
> + * @cm: the Charger Manager representing the battery.
> + */
> +static bool is_charging(struct charger_manager *cm)
> +{
> +       int i, ret;
> +       bool charging = false;
> +       union power_supply_propval val;
> +
> +       /* If there is no battery, it cannot be charged */
> +       if (!is_batt_present(cm))
> +               return false;
> +
> +       /* If at least one of the charger is charging, return yes */
> +       for (i = 0; cm->charger_stat[i]; i++) {
> +               /* 1. The charger sholuld not be DISABLED */
> +               if (cm->emergency_stop)
> +                       continue;
> +               if (!cm->charger_enabled)
> +                       continue;
> +
> +               /* 2. The charger should be online (ext-power) */
> +               ret = cm->charger_stat[i]->get_property(
> +                               cm->charger_stat[i],
> +                               POWER_SUPPLY_PROP_ONLINE, &val);
> +               if (ret) {
> +                       dev_warn(cm->dev, "Cannot read ONLINE value from %s.\n",
> +                                       cm->desc->psy_charger_stat[i]);
> +                       continue;
> +               }
> +               if (val.intval == 0)
> +                       continue;
> +
> +               /*
> +                * 3. The charger should not be FULL, DISCHARGING,
> +                * or NOT_CHARGING.
> +                */
> +               ret = cm->charger_stat[i]->get_property(
> +                               cm->charger_stat[i],
> +                               POWER_SUPPLY_PROP_STATUS, &val);
> +               if (ret) {
> +                       dev_warn(cm->dev, "Cannot read STATUS value from %s.\n",
> +                                       cm->desc->psy_charger_stat[i]);
> +                       continue;
> +               }
> +               if (val.intval == POWER_SUPPLY_STATUS_FULL ||
> +                               val.intval == POWER_SUPPLY_STATUS_DISCHARGING ||
> +                               val.intval == POWER_SUPPLY_STATUS_NOT_CHARGING)
> +                       continue;
> +
> +               /* Then, this is charging. */
> +               charging = true;
> +               break;
> +       }
> +
> +       return charging;
> +}
> +
> +/**
> + * is_polling_required - Return true if need to continue polling for this CM.
> + * @cm: the Charger Manager representing the battery.
> + */
> +static bool is_polling_required(struct charger_manager *cm)
> +{
> +       switch (cm->desc->polling_mode) {
> +       case CM_POLL_DISABLE:
> +               return false;
> +       case CM_POLL_ALWAYS:
> +               return true;
> +       case CM_POLL_EXTERNAL_POWER_ONLY:
> +               return is_ext_pwr_online(cm);
> +       case CM_POLL_CHARGING_ONLY:
> +               return is_charging(cm);
> +       default:
> +               dev_warn(cm->dev, "Incorrect polling_mode (%d)\n",
> +                       cm->desc->polling_mode);
> +       }
> +
> +       return false;
> +}
> +
> +/**
> + * try_charger_enable - Enable/Disable chargers altogether
> + * @cm: the Charger Manager representing the battery.
> + * @enable: true: enable / false: disable
> + *
> + * Note that Charger Manager keeps the charger enabled regardless whether
> + * the charger is charging or not (because battery is full or no external
> + * power source exists) except when CM needs to disable chargers forcibly
> + * bacause of emergency causes; when the battery is overheated or too cold.
> + */
> +static int try_charger_enable(struct charger_manager *cm, bool enable)
> +{
> +       int err = 0, i;
> +       struct charger_desc *desc = cm->desc;
> +
> +       /* Ignore if it's redundent command */
> +       if (enable && cm->charger_enabled)
> +               return 0;
> +       if (!enable && !cm->charger_enabled)
> +               return 0;
> +
> +       if (enable) {
> +               if (cm->emergency_stop)
> +                       return -EAGAIN;
> +               err = regulator_bulk_enable(desc->num_charger_regulators,
> +                                       desc->charger_regulators);
> +       } else {
> +               /*
> +                * Abnormal battery state - Stop charging forcibly,
> +                * even if charger was enabled at the other places
> +                */
> +               err = regulator_bulk_disable(desc->num_charger_regulators,
> +                                       desc->charger_regulators);
> +
> +               for (i = 0; i < desc->num_charger_regulators; i++) {
> +                       if (regulator_is_enabled(
> +                                   desc->charger_regulators[i].consumer)) {
> +                               regulator_force_disable(
> +                                       desc->charger_regulators[i].consumer);
> +                               dev_warn(cm->dev,
> +                                       "Disable regulator(%s) forcibly.\n",
> +                                       desc->charger_regulators[i].supply);
> +                       }
> +               }
> +       }
> +
> +       if (!err)
> +               cm->charger_enabled = enable;
> +
> +       return err;
> +}
> +
> +/**
> + * uevent_notify - Let users know something has changed.
> + * @cm: the Charger Manager representing the battery.
> + * @event: the event string.
> + *
> + * If @event is null, it implies that uevent_notify is called
> + * by resume function. When called in the resume function, cm_suspended
> + * should be already reset to false in order to let uevent_notify
> + * notify the recent event during the suspend to users. While
> + * suspended, uevent_notify does not notify users, but tracks
> + * events so that uevent_notify can notify users later after resumed.
> + */
> +static void uevent_notify(struct charger_manager *cm, const char *event)
> +{
> +       static char env_str[UEVENT_BUF_SIZE + 1] = "";
> +       static char env_str_save[UEVENT_BUF_SIZE + 1] = "";
> +
> +       if (cm_suspended) {
> +               /* Nothing in suspended-event buffer */
> +               if (env_str_save[0] == 0) {
> +                       if (!strncmp(env_str, event, UEVENT_BUF_SIZE))
> +                               return; /* status not changed */
> +                       strncpy(env_str_save, event, UEVENT_BUF_SIZE);
> +                       return;
> +               }
> +
> +               if (!strncmp(env_str_save, event, UEVENT_BUF_SIZE))
> +                       return; /* Duplicated. */
> +               else
> +                       strncpy(env_str_save, event, UEVENT_BUF_SIZE);
> +
> +               return;
> +       }
> +
> +       if (event == NULL) {
> +               /* No messages pending */
> +               if (!env_str_save[0])
> +                       return;
> +
> +               strncpy(env_str, env_str_save, UEVENT_BUF_SIZE);
> +               kobject_uevent(&cm->dev->kobj, KOBJ_CHANGE);
> +               env_str_save[0] = 0;
> +
> +               return;
> +       }
> +
> +       /* status not changed */
> +       if (!strncmp(env_str, event, UEVENT_BUF_SIZE))
> +               return;
> +
> +       /* save the status and notify the update */
> +       strncpy(env_str, event, UEVENT_BUF_SIZE);
> +       kobject_uevent(&cm->dev->kobj, KOBJ_CHANGE);
> +
> +       dev_info(cm->dev, event);
> +}
> +
> +/**
> + * _cm_monitor - Monitor the temperature and return true for exceptions.
> + * @cm: the Charger Manager representing the battery.
> + *
> + * Returns true if there is an event to notify for the battery.
> + * (True if the status of "emergency_stop" changes)
> + */
> +static bool _cm_monitor(struct charger_manager *cm)
> +{
> +       struct charger_desc *desc = cm->desc;
> +       int temp = desc->is_temperature_error(&cm->last_temp_mC);
> +
> +       dev_dbg(cm->dev, "monitoring (%2.2d.%3.3dC)\n",
> +               cm->last_temp_mC / 1000, cm->last_temp_mC % 1000);
> +
> +       /* It has been stopped already */
> +       if (temp && cm->emergency_stop)
> +               return false;
> +
> +       /* It has been charging already */
> +       if (!temp && !cm->emergency_stop)
> +               return false;
> +
> +       if (temp) {
> +               cm->emergency_stop = temp;
> +               if (!try_charger_enable(cm, false)) {
> +                       if (temp > 0)
> +                               uevent_notify(cm, "OVERHEAT");
> +                       else
> +                               uevent_notify(cm, "COLD");
> +               }
> +       } else {
> +               cm->emergency_stop = 0;
> +               if (!try_charger_enable(cm, true))
> +                       uevent_notify(cm, "CHARGING");
> +       }
> +
> +       return true;
> +}
> +
> +/**
> + * cm_monitor - Monitor every battery.
> + *
> + * Returns true if there is an event to notify from any of the batteries.
> + * (True if the status of "emergency_stop" changes)
> + */
> +static bool cm_monitor(void)
> +{
> +       bool stop = false;
> +       struct charger_manager *cm;
> +
> +       mutex_lock(&cm_list_mtx);
> +
> +       list_for_each_entry(cm, &cm_list, entry)
> +               stop |= _cm_monitor(cm);
> +
> +       mutex_unlock(&cm_list_mtx);
> +
> +       return stop;
> +}
> +
> +/**
> + * cm_setup_timer - For in-suspend monitoring setup wakeup alarm
> + *                 for suspend_again.
> + *
> + * Returns true if the alarm is set for Charger Manager to use.
> + * Returns false if
> + *     cm_setup_timer fails to set an alarm,
> + *     cm_setup_timer does not need to set an alarm for Charger Manager,
> + *     or an alarm previously configured is to be used.
> + */
> +static bool cm_setup_timer(void)
> +{
> +       struct charger_manager *cm;
> +       unsigned int wakeup_ms = UINT_MAX;
> +       bool ret = false;
> +
> +       mutex_lock(&cm_list_mtx);
> +
> +       list_for_each_entry(cm, &cm_list, entry) {
> +               /* Skip if polling is not required for this CM */
> +               if (!is_polling_required(cm) && !cm->emergency_stop)
> +                       continue;
> +               if (cm->desc->polling_interval_ms == 0)
> +                       continue;
> +               CM_MIN_VALID(wakeup_ms, cm->desc->polling_interval_ms);
> +       }
> +
> +       mutex_unlock(&cm_list_mtx);
> +
> +       if (wakeup_ms < UINT_MAX && wakeup_ms > 0) {
> +               pr_info("Charger Manager wakeup timer: %u ms.\n", wakeup_ms);
> +               if (rtc_dev) {
> +                       struct rtc_wkalrm tmp;
> +                       unsigned long time, now;
> +                       unsigned long add = DIV_ROUND_UP(wakeup_ms, 1000);
> +
> +                       /*
> +                        * Set alarm with the polling interval (wakeup_ms)
> +                        * except when rtc_wkalarm_save comes first.
> +                        * However, the alarm time should be NOW +
> +                        * CM_RTC_SMALL or later.
> +                        */
> +                       tmp.enabled = 1;
> +                       rtc_read_time(rtc_dev, &tmp.time);
> +                       rtc_tm_to_time(&tmp.time, &now);
> +                       if (add < CM_RTC_SMALL)
> +                               add = CM_RTC_SMALL;
> +                       time = now + add;
> +
> +                       ret = true;
> +
> +                       if (rtc_wkalarm_save.enabled && rtc_wkalarm_save_ &&
> +                           rtc_wkalarm_save_ < time) {
> +                               if (rtc_wkalarm_save_ < now + CM_RTC_SMALL)
> +                                       time = now + CM_RTC_SMALL;
> +                               else
> +                                       time = rtc_wkalarm_save_;
> +
> +                               /* The timer is not appointed by CM */
> +                               ret = false;
> +                       }
> +
> +                       pr_info("Waking up after %lu secs.\n",
> +                                       time - now);
> +
> +                       rtc_time_to_tm(time, &tmp.time);
> +                       rtc_set_alarm(rtc_dev, &tmp);
> +                       cm_suspend_duration_ms += wakeup_ms;
> +                       return ret;
> +               }
> +       }
> +
> +       if (rtc_dev)
> +               rtc_set_alarm(rtc_dev, &rtc_wkalarm_save);
> +       return false;
> +}
> +
> +/**
> + * cm_suspend_again - Determine whether suspend again or not
> + *
> + * Returns true if the system should be suspended again
> + * Returns false if the system should be woken up
> + */
> +bool cm_suspend_again(void)
> +{
> +       struct charger_manager *cm;
> +       bool ret = false;
> +
> +       if (!g_desc)
> +               return false;
> +       if (!g_desc->is_rtc_only_wakeup_reason)
> +               return false;
> +       if (!g_desc->is_rtc_only_wakeup_reason())
> +               return false;
> +       if (!cm_rtc_set)
> +               return false;
> +
> +       if (cm_monitor())
> +               goto out;
> +
> +       ret = true;
> +       mutex_lock(&cm_list_mtx);
> +       list_for_each_entry(cm, &cm_list, entry) {
> +               if (cm->status_save_ext_pwr_inserted != is_ext_pwr_online(cm) ||
> +                   cm->status_save_batt != is_batt_present(cm))
> +                       ret = false;
> +       }
> +       mutex_unlock(&cm_list_mtx);
> +
> +       cm_rtc_set = cm_setup_timer();
> +out:
> +       /* It's about the time when the non-CM appointed timer goes off */
> +       if (rtc_wkalarm_save.enabled) {
> +               unsigned long now;
> +               struct rtc_time tmp;
> +
> +               rtc_read_time(rtc_dev, &tmp);
> +               rtc_tm_to_time(&tmp, &now);
> +
> +               if (rtc_wkalarm_save_ &&
> +                   now + CM_RTC_SMALL >= rtc_wkalarm_save_)
> +                       return false;
> +       }
> +       return ret;
> +}
> +EXPORT_SYMBOL_GPL(cm_suspend_again);
> +
> +/**
> + * setup_charger_manager - initialize charger_global_desc data
> + * @gd: pointer to instance of charger_global_desc
> + */
> +int setup_charger_manager(struct charger_global_desc *gd)
> +{
> +       if (!gd)
> +               return -EINVAL;
> +
> +       if (rtc_dev)
> +               rtc_class_close(rtc_dev);
> +       rtc_dev = NULL;
> +       g_desc = NULL;
> +
> +       if (!gd->is_rtc_only_wakeup_reason) {
> +               pr_err("The callback is_wktimer_only_wkreason is not given.\n");
> +               return -EINVAL;
> +       }
> +
> +       if (gd->rtc) {
> +               rtc_dev = rtc_class_open(gd->rtc);
> +               if (IS_ERR_OR_NULL(rtc_dev)) {
> +                       rtc_dev = NULL;
> +                       /* Retry at probe. RTC may be not registered yet */
> +               }
> +       } else {
> +               pr_warn("No wktimer is given for charger manager."
> +                       "In-suspend monitoring won't work.\n");
> +       }
> +
> +       g_desc = gd;
> +       return 0;
> +}
> +EXPORT_SYMBOL_GPL(setup_charger_manager);
> +
> +static int charger_manager_probe(struct platform_device *pdev)
> +{
> +       struct charger_desc *desc = dev_get_platdata(&pdev->dev);
> +       struct charger_manager *cm;
> +       int ret = 0, i;
> +
> +       if (g_desc && !rtc_dev && g_desc->rtc) {
> +               rtc_dev = rtc_class_open(g_desc->rtc);
> +               if (IS_ERR_OR_NULL(rtc_dev)) {
> +                       rtc_dev = NULL;
> +                       dev_err(&pdev->dev, "Cannot get RTC %s.\n",
> +                               g_desc->rtc);
> +                       ret = -ENODEV;
> +                       goto err_alloc;
> +               }
> +       }
> +
> +       if (!desc) {
> +               dev_err(&pdev->dev, "No platform data (desc) found.\n");
> +               ret = -ENODEV;
> +               goto err_alloc;
> +       }
> +
> +       cm = kzalloc(sizeof(struct charger_manager), GFP_KERNEL);
> +       if (!cm) {
> +               dev_err(&pdev->dev, "Cannot allocate memory.\n");
> +               ret = -ENOMEM;
> +               goto err_alloc;
> +       }
> +
> +       /* Basic Values. Unspecified are Null or 0 */
> +       cm->dev = &pdev->dev;
> +       cm->desc = desc;
> +       cm->last_temp_mC = INT_MIN; /* denotes "unmeasured, yet" */
> +
> +       if (!desc->charger_regulators || desc->num_charger_regulators < 1) {
> +               ret = -EINVAL;
> +               dev_err(&pdev->dev, "charger_regulators undefined.\n");
> +               goto err_no_charger;
> +       }
> +
> +       ret = regulator_bulk_get(&pdev->dev, desc->num_charger_regulators,
> +                                desc->charger_regulators);
> +       if (ret) {
> +               dev_err(&pdev->dev, "Cannot get charger regulators.\n");
> +               goto err_no_charger;
> +       }
> +
> +       if (!desc->psy_charger_stat || !desc->psy_charger_stat[0]) {
> +               dev_err(&pdev->dev, "No power supply defined.\n");
> +               ret = -EINVAL;
> +               goto err_no_charger_stat;
> +       }
> +
> +       for (i = 0; desc->psy_charger_stat[i]; i++)
> +               /* Counting index only */ ;
> +
> +       cm->charger_stat = kzalloc(sizeof(struct power_supply *) * (i + 1),
> +                                  GFP_KERNEL);
> +       if (!cm->charger_stat) {
> +               ret = -ENOMEM;
> +               goto err_no_charger_stat;
> +       }
> +
> +       for (i = 0; desc->psy_charger_stat[i]; i++) {
> +               cm->charger_stat[i] = power_supply_get_by_name(
> +                                       desc->psy_charger_stat[i]);
> +               if (!cm->charger_stat[i]) {
> +                       dev_err(&pdev->dev, "Cannot find power supply "
> +                                       "\"%s\"\n",
> +                                       desc->psy_charger_stat[i]);
> +                       ret = -ENODEV;
> +                       goto err_chg_stat;
> +               }
> +       }
> +
> +       cm->fuel_gauge = power_supply_get_by_name(desc->psy_fuel_gauge);
> +       if (!cm->fuel_gauge) {
> +               dev_err(&pdev->dev, "Cannot find power supply \"%s\"\n",
> +                               desc->psy_fuel_gauge);
> +               ret = -ENODEV;
> +               goto err_chg_stat;
> +       }
> +
> +       if (desc->polling_interval_ms == 0 ||
> +           msecs_to_jiffies(desc->polling_interval_ms) <= CM_JIFFIES_SMALL) {
> +               dev_err(&pdev->dev, "polling_interval_ms is too small\n");
> +               ret = -EINVAL;
> +               goto err_chg_stat;
> +       }
> +
> +       if (!desc->is_temperature_error) {
> +               dev_err(&pdev->dev, "there is no is_temperature_error\n");
> +               ret = -EINVAL;
> +               goto err_chg_stat;
> +       }
> +
> +       platform_set_drvdata(pdev, cm);
> +
> +       ret = try_charger_enable(cm, true);
> +       if (ret) {
> +               dev_err(&pdev->dev, "Cannot enable charger regulators\n");
> +               goto err_chg_stat;
> +       }
> +
> +       /* Add to the list */
> +       mutex_lock(&cm_list_mtx);
> +       list_add(&cm->entry, &cm_list);
> +       mutex_unlock(&cm_list_mtx);
> +
> +       return 0;
> +
> +err_chg_stat:
> +       kfree(cm->charger_stat);
> +err_no_charger_stat:
> +       if (desc->charger_regulators)
> +               regulator_bulk_free(desc->num_charger_regulators,
> +                                       desc->charger_regulators);
> +err_no_charger:
> +       kfree(cm);
> +err_alloc:
> +       return ret;
> +}
> +
> +static int __devexit charger_manager_remove(struct platform_device *pdev)
> +{
> +       struct charger_manager *cm = platform_get_drvdata(pdev);
> +       struct charger_desc *desc = cm->desc;
> +
> +       /* Remove from the list */
> +       mutex_lock(&cm_list_mtx);
> +       list_del(&cm->entry);
> +       mutex_unlock(&cm_list_mtx);
> +
> +       kfree(cm->charger_stat);
> +       if (desc->charger_regulators)
> +               regulator_bulk_free(desc->num_charger_regulators,
> +                                       desc->charger_regulators);
> +       kfree(cm);
> +       return 0;
> +}
> +
> +const struct platform_device_id charger_manager_id[] = {
> +       { "charger-manager", 0 },
> +       { },
> +};
> +
> +static int cm_suspend_prepare(struct device *dev)
> +{
> +       struct platform_device *pdev = container_of(dev, struct platform_device,
> +                                                   dev);
> +       struct charger_manager *cm = platform_get_drvdata(pdev);
> +
> +       if (!cm_suspended) {
> +               if (rtc_dev) {
> +                       struct rtc_time tmp;
> +                       unsigned long now;
> +
> +                       rtc_read_alarm(rtc_dev, &rtc_wkalarm_save);
> +                       rtc_read_time(rtc_dev, &tmp);
> +
> +                       if (rtc_wkalarm_save.enabled) {
> +                               rtc_tm_to_time(&rtc_wkalarm_save.time,
> +                                              &rtc_wkalarm_save_);
> +                               rtc_tm_to_time(&tmp, &now);
> +                               if (now > rtc_wkalarm_save_)
> +                                       rtc_wkalarm_save_ = 0;
> +                       } else {
> +                               rtc_wkalarm_save_ = 0;
> +                       }
> +               }
> +               cm_suspended = true;
> +       }
Donggeun,

I think that this patch is good for saving energy for charging while
suspend. I think that this driver also works under android. I have
some concerns on rtc wakeup.

As we know, RTC event doesn't link to timer events in kernel. But
Android did. Android transfered timer event to rtc event while it
suspend. So it will occupy one rtc device.

Whatever the device is phone or tablet, it may cost another rtc device
if it wants to implement power-up alarm feature. If we want to support
the charger manager feature, we have to add another rtc device. I
think that it's very hard to find any current platform with three rtc
devices. How about implement the similar mechanism like android?
Charger manager can register wakeup event into alarm mechanism like
android. And we only need two rtc devices.

Loop more guys: list-arm-kernel & linaro.

Thanks
Haojian

> +
> +       cm->status_save_ext_pwr_inserted = is_ext_pwr_online(cm);
> +       cm->status_save_batt = is_batt_present(cm);
> +
> +       if (!cm_rtc_set) {
> +               cm_suspend_duration_ms = 0;
> +               cm_rtc_set = cm_setup_timer();
> +       }
> +
> +       return 0;
> +}
> +
> +static void cm_suspend_complete(struct device *dev)
> +{
> +       struct platform_device *pdev = container_of(dev, struct platform_device,
> +                                                   dev);
> +       struct charger_manager *cm = platform_get_drvdata(pdev);
> +
> +       if (cm_suspended) {
> +               if (rtc_dev) {
> +                       struct rtc_wkalrm tmp;
> +
> +                       rtc_read_alarm(rtc_dev, &tmp);
> +                       rtc_wkalarm_save.pending = tmp.pending;
> +                       rtc_set_alarm(rtc_dev, &rtc_wkalarm_save);
> +               }
> +               cm_suspended = false;
> +               cm_rtc_set = false;
> +       }
> +
> +       uevent_notify(cm, NULL);
> +}
> +
> +static const struct dev_pm_ops charger_manager_pm = {
> +       .prepare        = cm_suspend_prepare,
> +       .complete       = cm_suspend_complete,
> +};
> +
> +static struct platform_driver charger_manager_driver = {
> +       .driver = {
> +               .name = "charger-manager",
> +               .owner = THIS_MODULE,
> +               .pm = &charger_manager_pm,
> +       },
> +       .probe = charger_manager_probe,
> +       .remove = __devexit_p(charger_manager_remove),
> +       .id_table = charger_manager_id,
> +};
> +
> +static int __init charger_manager_init(void)
> +{
> +       return platform_driver_register(&charger_manager_driver);
> +}
> +late_initcall(charger_manager_init);
> +
> +static void __exit charger_manager_cleanup(void)
> +{
> +       platform_driver_unregister(&charger_manager_driver);
> +}
> +module_exit(charger_manager_cleanup);
> +
> +MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
> +MODULE_DESCRIPTION("Charger Manager");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("charger-manager");
> diff --git a/include/linux/power/charger-manager.h b/include/linux/power/charger-manager.h
> new file mode 100644
> index 0000000..c91e208
> --- /dev/null
> +++ b/include/linux/power/charger-manager.h
> @@ -0,0 +1,131 @@
> +/* linux/include/linux/power/charger-manager.h
> + *
> + * Copyright (C) 2011 Samsung Electronics Co., Ltd.
> + * MyungJoo.Ham <myungjoo.ham@samsung.com>
> + *
> + * Charger Manager.
> + * This framework enables to control and multiple chargers and to
> + * monitor charging even in the context of suspend-to-RAM with
> + * an interface combining the chargers.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> +**/
> +
> +#ifndef _CHARGER_MANAGER_H
> +#define _CHARGER_MANAGER_H
> +
> +#include <linux/power_supply.h>
> +
> +enum data_source {
> +       CM_FUEL_GAUGE,
> +       CM_CHARGER_STAT,
> +};
> +
> +enum polling_modes {
> +       CM_POLL_DISABLE = 0,
> +       CM_POLL_ALWAYS,
> +       CM_POLL_EXTERNAL_POWER_ONLY,
> +       CM_POLL_CHARGING_ONLY,
> +};
> +
> +/**
> + * struct charger_global_desc
> + * @rtc: the name of RTC used to wake up the system from suspend.
> + * @is_rtc_only_wakeup_reason:
> + *     If the system is woken up by waekup-sources other than the RTC or
> + *     callbacks, Charger Manager should recognize with
> + *     is_rtc_only_wakeup_reason() returning false.
> + *     If the RTC given to CM is the only wakeup reason,
> + *     is_rtc_only_wakeup_reason should return true.
> + */
> +struct charger_global_desc {
> +       char *rtc;
> +
> +       bool (*is_rtc_only_wakeup_reason)(void);
> +};
> +
> +/**
> + * struct charger_desc
> + * @polling_mode:
> + *     Determine which polling mode will be used
> + * @polling_interval_ms: interval in millisecond at which
> + *     charger manager will monitor battery health
> + * @battery_present:
> + *     Specify where information for existance of battery can be obtained
> + * @psy_charger_stat: the names of power-supply for chargers
> + * @num_charger_regulator: the number of entries in charger_regulators
> + * @charger_regulators: array of regulator_bulk_data for chargers
> + * @psy_fuel_gauge: the name of power-supply for fuel gauge
> + * @is_temperature_error:
> + *     Determine whether the status is overheat or cold or normal.
> + *     return_value > 0: overheat
> + *     return_value == 0: normal
> + *     return_value < 0: cold
> + */
> +struct charger_desc {
> +       enum polling_modes polling_mode;
> +       unsigned int polling_interval_ms;
> +
> +       enum data_source battery_present;
> +
> +       char **psy_charger_stat;
> +
> +       int num_charger_regulators;
> +       struct regulator_bulk_data *charger_regulators;
> +
> +       char *psy_fuel_gauge;
> +
> +       int (*is_temperature_error)(int *mC);
> +};
> +
> +#define PSY_NAME_MAX   30
> +
> +/**
> + * struct charger_manager
> + * @entry: entry for list
> + * @dev: device pointer
> + * @desc: instance of charger_desc
> + * @fuel_gauge: power_supply for fuel gauge
> + * @charger_stat: array of power_supply for chargers
> + * @charger_enabled: the state of charger
> + * @emergency_stop:
> + *     When setting true, stop charging
> + * @last_temp_mC: the measured temperature in milli-Celsius
> + * @status_save_ext_pwr_inserted:
> + *     saved status of external power before entering suspend-to-RAM
> + * @status_save_batt:
> + *     saved status of battery before entering suspend-to-RAM
> + */
> +struct charger_manager {
> +       struct list_head entry;
> +       struct device *dev;
> +       struct charger_desc *desc;
> +
> +       struct power_supply *fuel_gauge;
> +       struct power_supply **charger_stat;
> +
> +       bool charger_enabled;
> +
> +       int emergency_stop;
> +       int last_temp_mC;
> +
> +       bool status_save_ext_pwr_inserted;
> +       bool status_save_batt;
> +};
> +
> +#ifdef CONFIG_CHARGER_MANAGER
> +extern int setup_charger_manager(struct charger_global_desc *gd);
> +extern bool cm_suspend_again(void);
> +#else
> +static void __maybe_unused setup_charger_manager(struct charger_global_desc *gd)
> +{ }
> +
> +static bool __maybe_unused cm_suspend_again(void)
> +{
> +       return false;
> +}
> +#endif
> +
> +#endif /* _CHARGER_MANAGER_H */
> --
> 1.7.4.1
>
> --
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