[PATCH 4/5] power: supply: bq27xxx: Look for status change on external power change

[Paul Kocialkowski]

This introduces a dedicated status change work to look for power
status change. It is triggered by external power change notifications
and periodically retries detecting a power status change for 5 seconds.

This is largely inspired by a similar mechanism from the sbs-battery
driver.

Signed-off-by: Paul Kocialkowski <cont...@paulk.fr>
---
 drivers/power/supply/bq27xxx_battery.c | 38 ++++++++++++++++++++++++++++++++--
 include/linux/power/bq27xxx_battery.h  |  3 +++
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/drivers/power/supply/bq27xxx_battery.c 
b/drivers/power/supply/bq27xxx_battery.c
index 926bd58344d9..cade00df6162 100644
--- a/drivers/power/supply/bq27xxx_battery.c
+++ b/drivers/power/supply/bq27xxx_battery.c
@@ -1190,6 +1190,11 @@ static int bq27xxx_battery_status(struct 
bq27xxx_device_info *di,
                        status = POWER_SUPPLY_STATUS_CHARGING;
        }
 
+       if (di->status_retry == 0 && di->status_change_reference != status) {
+               di->status_change_reference = status;
+               power_supply_changed(di->bat);
+       }
+
        val->intval = status;
 
        return 0;
@@ -1340,12 +1345,38 @@ static int bq27xxx_battery_get_property(struct 
power_supply *psy,
        return ret;
 }
 
+static void bq27xxx_status_change(struct work_struct *work)
+{
+       struct bq27xxx_device_info *di =
+                       container_of(work, struct bq27xxx_device_info,
+                                    status_work.work);
+       union power_supply_propval val;
+       int ret;
+
+       bq27xxx_battery_update(di);
+
+       ret = bq27xxx_battery_status(di, &val);
+       if (ret < 0)
+               return;
+
+       if (di->status_change_reference != val.intval) {
+               di->status_change_reference = val.intval;
+               power_supply_changed(di->bat);
+       }
+
+       if (di->status_retry > 0) {
+               di->status_retry--;
+               schedule_delayed_work(&di->status_work, HZ);
+       }
+}
+
 static void bq27xxx_external_power_changed(struct power_supply *psy)
 {
        struct bq27xxx_device_info *di = power_supply_get_drvdata(psy);
 
-       cancel_delayed_work_sync(&di->poll_work);
-       schedule_delayed_work(&di->poll_work, 0);
+       cancel_delayed_work_sync(&di->status_work);
+       schedule_delayed_work(&di->status_work, HZ);
+       di->status_retry = 5;
 }
 
 int bq27xxx_battery_setup(struct bq27xxx_device_info *di)
@@ -1357,8 +1388,10 @@ int bq27xxx_battery_setup(struct bq27xxx_device_info *di)
        psy_cfg.of_node = di->of_node;
 
        INIT_DELAYED_WORK(&di->poll_work, bq27xxx_battery_poll);
+       INIT_DELAYED_WORK(&di->status_work, bq27xxx_status_change);
        mutex_init(&di->lock);
        di->regs = bq27xxx_regs[di->chip];
+       di->status_change_reference = POWER_SUPPLY_STATUS_UNKNOWN;
 
        psy_desc = devm_kzalloc(di->dev, sizeof(*psy_desc), GFP_KERNEL);
        if (!psy_desc)
@@ -1400,6 +1433,7 @@ void bq27xxx_battery_teardown(struct bq27xxx_device_info 
*di)
        poll_interval = 0;
 
        cancel_delayed_work_sync(&di->poll_work);
+       cancel_delayed_work_sync(&di->status_work);
 
        power_supply_unregister(di->bat);
 
diff --git a/include/linux/power/bq27xxx_battery.h 
b/include/linux/power/bq27xxx_battery.h
index 0a9af513165a..16d604681ace 100644
--- a/include/linux/power/bq27xxx_battery.h
+++ b/include/linux/power/bq27xxx_battery.h
@@ -67,6 +67,9 @@ struct bq27xxx_device_info {
        int charge_design_full;
        unsigned long last_update;
        struct delayed_work poll_work;
+       struct delayed_work status_work;
+       int status_retry;
+       int status_change_reference;
        struct power_supply *bat;
        struct list_head list;
        struct mutex lock;
-- 
2.12.2