Unless we put the device to sleep when not it use, it wastes
6mA.
If the device is asleep on probe, the 'id' register
sometimes mis-reads - so reset first. If the device responds
at all a command sent to the address, it is almost certainly
the correct device already.
Acked-by: Manuel Stahl <manuel.stahl@xxxxxxxxxxxxxxxxx>
Acked-by: Hartmut Knaack <knaack.h@xxxxxx>
Signed-off-by: NeilBrown <neil@xxxxxxxxxx>
---
v1 of this was sent in November. I got some useful feedback, but then got distracted
by something. Sorry for the long gap.
NeilBrown
diff --git a/drivers/iio/gyro/itg3200_core.c b/drivers/iio/gyro/itg3200_core.c
index 6a8020d48140..f0fd94055d88 100644
--- a/drivers/iio/gyro/itg3200_core.c
+++ b/drivers/iio/gyro/itg3200_core.c
@@ -223,6 +223,10 @@ static int itg3200_initial_setup(struct iio_dev *indio_dev)
int ret;
u8 val;
+ ret = itg3200_reset(indio_dev);
+ if (ret)
+ goto err_ret;
+
ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_ADDRESS, &val);
if (ret)
goto err_ret;
@@ -233,10 +237,6 @@ static int itg3200_initial_setup(struct iio_dev *indio_dev)
goto err_ret;
}
- ret = itg3200_reset(indio_dev);
- if (ret)
- goto err_ret;
-
ret = itg3200_enable_full_scale(indio_dev);
err_ret:
return ret;
@@ -351,6 +351,26 @@ static int itg3200_remove(struct i2c_client *client)
return 0;
}
+static int __maybe_unused itg3200_suspend(struct device *dev)
+{
+ struct iio_dev *indio_dev = dev_get_drvdata(dev);
+ struct itg3200 *st = iio_priv(indio_dev);
+
+ dev_dbg(&st->i2c->dev, "suspend device");
+
+ return itg3200_write_reg_8(indio_dev, ITG3200_REG_POWER_MANAGEMENT,
+ ITG3200_SLEEP);
+}
+
+static int __maybe_unused itg3200_resume(struct device *dev)
+{
+ struct iio_dev *indio_dev = dev_get_drvdata(dev);
+
+ return itg3200_initial_setup(indio_dev);
+}
+
+static SIMPLE_DEV_PM_OPS(itg3200_pm_ops, itg3200_suspend, itg3200_resume);
+
static const struct i2c_device_id itg3200_id[] = {
{ "itg3200", 0 },
{ }
@@ -361,6 +381,7 @@ static struct i2c_driver itg3200_driver = {
.driver = {
.owner = THIS_MODULE,
.name = "itg3200",
+ .pm = &itg3200_pm_ops,
},
.id_table = itg3200_id,
.probe = itg3200_probe,
Attachment:
pgpQj6lhGn8uJ.pgp
Description: OpenPGP digital signature
