bq27x00: Poll battery state

This patch adds support for polling the battery state and generating a
power_supply_changed() event if it has changed.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Grazvydas Ignotas <notasas@gmail.com>

1 files changed, 53 insertions, 5 deletions

diff --git a/drivers/power/bq27x00_battery.c b/drivers/power/bq27x00_battery.c
index dbe3fcb3b0ba..25350fcbadb3 100644
--- a/drivers/power/bq27x00_battery.c
+++ b/drivers/power/bq27x00_battery.c
@@ -74,10 +74,13 @@ struct bq27x00_device_info {
 
         struct bq27x00_reg_cache cache;
         unsigned long last_update;
+        struct delayed_work work;
 
         struct power_supply     bat;
 
         struct bq27x00_access_methods bus;
+
+        struct mutex lock;
 };
 
 static enum power_supply_property bq27x00_battery_props[] = {
@@ -93,6 +96,11 @@ static enum power_supply_property bq27x00_battery_props[] = {
         POWER_SUPPLY_PROP_TECHNOLOGY,
 };
 
+static unsigned int poll_interval = 360;
+module_param(poll_interval, uint, 0644);
+MODULE_PARM_DESC(poll_interval, "battery poll interval in seconds - " \
+                                "0 disables polling");
+
 /*
  * Common code for BQ27x00 devices
  */
@@ -169,6 +177,21 @@ static void bq27x00_update(struct bq27x00_device_info *di)
         di->last_update = jiffies;
 }
 
+static void bq27x00_battery_poll(struct work_struct *work)
+{
+        struct bq27x00_device_info *di =
+                container_of(work, struct bq27x00_device_info, work.work);
+
+        bq27x00_update(di);
+
+        if (poll_interval > 0) {
+                /* The timer does not have to be accurate. */
+                set_timer_slack(&di->work.timer, poll_interval * HZ / 4);
+                schedule_delayed_work(&di->work, poll_interval * HZ);
+        }
+}
+
+
 /*
  * Return the battery temperature in tenths of degree Celsius
  * Or < 0 if something fails.
@@ -283,8 +306,12 @@ static int bq27x00_battery_get_property(struct power_supply *psy,
         int ret = 0;
         struct bq27x00_device_info *di = to_bq27x00_device_info(psy);
 
-        if (time_is_before_jiffies(di->last_update + 5 * HZ))
-                bq27x00_update(di);
+        mutex_lock(&di->lock);
+        if (time_is_before_jiffies(di->last_update + 5 * HZ)) {
+                cancel_delayed_work_sync(&di->work);
+                bq27x00_battery_poll(&di->work.work);
+        }
+        mutex_unlock(&di->lock);
 
         if (psp != POWER_SUPPLY_PROP_PRESENT && di->cache.flags < 0)
                 return -ENODEV;
@@ -327,6 +354,14 @@ static int bq27x00_battery_get_property(struct power_supply *psy,
         return ret;
 }
 
+static void bq27x00_external_power_changed(struct power_supply *psy)
+{
+        struct bq27x00_device_info *di = to_bq27x00_device_info(psy);
+
+        cancel_delayed_work_sync(&di->work);
+        schedule_delayed_work(&di->work, 0);
+}
+
 static int bq27x00_powersupply_init(struct bq27x00_device_info *di)
 {
         int ret;
@@ -335,7 +370,10 @@ static int bq27x00_powersupply_init(struct bq27x00_device_info *di)
         di->bat.properties = bq27x00_battery_props;
         di->bat.num_properties = ARRAY_SIZE(bq27x00_battery_props);
         di->bat.get_property = bq27x00_battery_get_property;
-        di->bat.external_power_changed = NULL;
+        di->bat.external_power_changed = bq27x00_external_power_changed;
+
+        INIT_DELAYED_WORK(&di->work, bq27x00_battery_poll);
+        mutex_init(&di->lock);
 
         ret = power_supply_register(di->dev, &di->bat);
         if (ret) {
@@ -350,6 +388,15 @@ static int bq27x00_powersupply_init(struct bq27x00_device_info *di)
         return 0;
 }
 
+static void bq27x00_powersupply_unregister(struct bq27x00_device_info *di)
+{
+        cancel_delayed_work_sync(&di->work);
+
+        power_supply_unregister(&di->bat);
+
+        mutex_destroy(&di->lock);
+}
+
 
 /* i2c specific code */
 #ifdef CONFIG_BATTERY_BQ27X00_I2C
@@ -457,7 +504,7 @@ static int bq27x00_battery_remove(struct i2c_client *client)
 {
         struct bq27x00_device_info *di = i2c_get_clientdata(client);
 
-        power_supply_unregister(&di->bat);
+        bq27x00_powersupply_unregister(di);
 
         kfree(di->bat.name);
 
@@ -590,7 +637,8 @@ static int __devexit bq27000_battery_remove(struct platform_device *pdev)
 {
         struct bq27x00_device_info *di = platform_get_drvdata(pdev);
 
-        power_supply_unregister(&di->bat);
+        bq27x00_powersupply_unregister(di);
+
         platform_set_drvdata(pdev, NULL);
         kfree(di);