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Message-Id: <1305846004-11895-1-git-send-email-rklein@nvidia.com>
Date: Thu, 19 May 2011 16:00:03 -0700
From: Rhyland Klein <rklein@...dia.com>
To: cbouatmailru@...il.com
Cc: bleung@...gle.com, olof@...om.net, linux-kernel@...r.kernel.org,
Rhyland Klein <rklein@...dia.com>
Subject: [PATCH 1/2] power: bq20z75: support external notification
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@...dia.com>
---
drivers/power/bq20z75.c | 103 +++++++++++++++++++++++++++++++++++++----
include/linux/power/bq20z75.h | 3 +
2 files changed, 97 insertions(+), 9 deletions(-)
diff --git a/drivers/power/bq20z75.c b/drivers/power/bq20z75.c
index 506585e..9c5e5be 100644
--- a/drivers/power/bq20z75.c
+++ b/drivers/power/bq20z75.c
@@ -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)
@@ -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,
@@ -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)
@@ -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)
{
@@ -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 =
@@ -625,6 +700,10 @@ skip_gpio:
dev_info(&client->dev,
"%s: battery gas gauge device registered\n", client->name);
+ INIT_DELAYED_WORK(&bq20z75_device->work, bq20z75_delayed_work);
+
+ bq20z75_device->enable_detection = true;
+
return 0;
exit_psupply:
@@ -648,6 +727,9 @@ 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;
@@ -661,6 +743,9 @@ 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,
diff --git a/include/linux/power/bq20z75.h b/include/linux/power/bq20z75.h
index b0843b6..1398eb0 100644
--- a/include/linux/power/bq20z75.h
+++ b/include/linux/power/bq20z75.h
@@ -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
--
1.7.5.1
--
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