NeilBrown schrieb am 24.02.2015 um 03:24:
>
> 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.st...@iis.fraunhofer.de>
> Acked-by: Hartmut Knaack <knaac...@gmx.de>
I don't recall acking on this. Anyway, no objection on the patch content.
Hartmut
> Signed-off-by: NeilBrown <n...@brown.name>
>
> ---
> 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,
>
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