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bq20z75: Add support for external notification
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Adding support for external power change notification. One problem found
is that there is a lag time before the sensor will return a new status.
To ensure that we only fire off the power_supply_changed event when the
status returned from the sensor is actually different, we delay sending
the the notification, and instead poll on it looking for a change. The
amount of time to poll is configurable via platform data.

Signed-off-by: Rhyland Klein <rklein@nvidia.com>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
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Rhyland Klein authored and Anton Vorontsov committed Jul 8, 2011
1 parent 906649d commit 58ddafa
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Showing 2 changed files with 95 additions and 9 deletions.
101 changes: 92 additions & 9 deletions drivers/power/bq20z75.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -152,6 +152,10 @@ struct bq20z75_info {
bool gpio_detect;
bool enable_detection;
int irq;
int last_state;
int poll_time;
struct delayed_work work;
int ignore_changes;
};

static int bq20z75_read_word_data(struct i2c_client *client, u8 address)
Expand Down Expand Up @@ -279,6 +283,7 @@ static int bq20z75_get_battery_property(struct i2c_client *client,
int reg_offset, enum power_supply_property psp,
union power_supply_propval *val)
{
struct bq20z75_info *bq20z75_device = i2c_get_clientdata(client);
s32 ret;

ret = bq20z75_read_word_data(client,
Expand All @@ -293,15 +298,24 @@ static int bq20z75_get_battery_property(struct i2c_client *client,
if (ret >= bq20z75_data[reg_offset].min_value &&
ret <= bq20z75_data[reg_offset].max_value) {
val->intval = ret;
if (psp == POWER_SUPPLY_PROP_STATUS) {
if (ret & BATTERY_FULL_CHARGED)
val->intval = POWER_SUPPLY_STATUS_FULL;
else if (ret & BATTERY_FULL_DISCHARGED)
val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
else if (ret & BATTERY_DISCHARGING)
val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
else
val->intval = POWER_SUPPLY_STATUS_CHARGING;
if (psp != POWER_SUPPLY_PROP_STATUS)
return 0;

if (ret & BATTERY_FULL_CHARGED)
val->intval = POWER_SUPPLY_STATUS_FULL;
else if (ret & BATTERY_FULL_DISCHARGED)
val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
else if (ret & BATTERY_DISCHARGING)
val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
else
val->intval = POWER_SUPPLY_STATUS_CHARGING;

if (bq20z75_device->poll_time == 0)
bq20z75_device->last_state = val->intval;
else if (bq20z75_device->last_state != val->intval) {
cancel_delayed_work_sync(&bq20z75_device->work);
power_supply_changed(&bq20z75_device->power_supply);
bq20z75_device->poll_time = 0;
}
} else {
if (psp == POWER_SUPPLY_PROP_STATUS)
Expand Down Expand Up @@ -545,6 +559,60 @@ static irqreturn_t bq20z75_irq(int irq, void *devid)
return IRQ_HANDLED;
}

static void bq20z75_external_power_changed(struct power_supply *psy)
{
struct bq20z75_info *bq20z75_device;

bq20z75_device = container_of(psy, struct bq20z75_info, power_supply);

if (bq20z75_device->ignore_changes > 0) {
bq20z75_device->ignore_changes--;
return;
}

/* cancel outstanding work */
cancel_delayed_work_sync(&bq20z75_device->work);

schedule_delayed_work(&bq20z75_device->work, HZ);
bq20z75_device->poll_time = bq20z75_device->pdata->poll_retry_count;
}

static void bq20z75_delayed_work(struct work_struct *work)
{
struct bq20z75_info *bq20z75_device;
s32 ret;

bq20z75_device = container_of(work, struct bq20z75_info, work.work);

ret = bq20z75_read_word_data(bq20z75_device->client,
bq20z75_data[REG_STATUS].addr);
/* if the read failed, give up on this work */
if (ret < 0) {
bq20z75_device->poll_time = 0;
return;
}

if (ret & BATTERY_FULL_CHARGED)
ret = POWER_SUPPLY_STATUS_FULL;
else if (ret & BATTERY_FULL_DISCHARGED)
ret = POWER_SUPPLY_STATUS_NOT_CHARGING;
else if (ret & BATTERY_DISCHARGING)
ret = POWER_SUPPLY_STATUS_DISCHARGING;
else
ret = POWER_SUPPLY_STATUS_CHARGING;

if (bq20z75_device->last_state != ret) {
bq20z75_device->poll_time = 0;
power_supply_changed(&bq20z75_device->power_supply);
return;
}
if (bq20z75_device->poll_time > 0) {
schedule_delayed_work(&bq20z75_device->work, HZ);
bq20z75_device->poll_time--;
return;
}
}

static int __devinit bq20z75_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
Expand All @@ -566,6 +634,13 @@ static int __devinit bq20z75_probe(struct i2c_client *client,
bq20z75_device->power_supply.num_properties =
ARRAY_SIZE(bq20z75_properties);
bq20z75_device->power_supply.get_property = bq20z75_get_property;
/* ignore first notification of external change, it is generated
* from the power_supply_register call back
*/
bq20z75_device->ignore_changes = 1;
bq20z75_device->last_state = POWER_SUPPLY_STATUS_UNKNOWN;
bq20z75_device->power_supply.external_power_changed =
bq20z75_external_power_changed;

if (pdata) {
bq20z75_device->gpio_detect =
Expand Down Expand Up @@ -625,6 +700,8 @@ static int __devinit bq20z75_probe(struct i2c_client *client,
dev_info(&client->dev,
"%s: battery gas gauge device registered\n", client->name);

INIT_DELAYED_WORK(&bq20z75_device->work, bq20z75_delayed_work);

return 0;

exit_psupply:
Expand All @@ -648,6 +725,9 @@ static int __devexit bq20z75_remove(struct i2c_client *client)
gpio_free(bq20z75_device->pdata->battery_detect);

power_supply_unregister(&bq20z75_device->power_supply);

cancel_delayed_work_sync(&bq20z75_device->work);

kfree(bq20z75_device);
bq20z75_device = NULL;

Expand All @@ -661,6 +741,9 @@ static int bq20z75_suspend(struct i2c_client *client,
struct bq20z75_info *bq20z75_device = i2c_get_clientdata(client);
s32 ret;

if (bq20z75_device->poll_time > 0)
cancel_delayed_work_sync(&bq20z75_device->work);

/* write to manufacturer access with sleep command */
ret = bq20z75_write_word_data(client,
bq20z75_data[REG_MANUFACTURER_DATA].addr,
Expand Down
3 changes: 3 additions & 0 deletions include/linux/power/bq20z75.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -29,11 +29,14 @@
* @battery_detect: GPIO which is used to detect battery presence
* @battery_detect_present: gpio state when battery is present (0 / 1)
* @i2c_retry_count: # of times to retry on i2c IO failure
* @poll_retry_count: # of times to retry looking for new status after
* external change notification
*/
struct bq20z75_platform_data {
int battery_detect;
int battery_detect_present;
int i2c_retry_count;
int poll_retry_count;
};

#endif

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