On Mon, Jun 27, 2022 at 5:41 PM Doug Anderson <dianders@xxxxxxxxxxxx> wrote:
>
> Hi,
>
> On Sat, Jun 25, 2022 at 3:24 PM Gwendal Grignou <gwendal@xxxxxxxxxxxx> wrote:
> >
> > Instead of registering callback to process sensor events right at
> > initialization time, wait for the sensor to be register in the iio
> > subsystem.
> >
> > Events can come at probe time (in case the kernel rebooted abruptly
> > without switching the sensor off for instance), and be sent to IIO core
> > before the sensor is fully registered.
> >
> > Reported-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
> > Signed-off-by: Gwendal Grignou <gwendal@xxxxxxxxxxxx>
> > ---
> > Changes since v1:
> > - renamed from "iio: cros: Add cros_ec_sensors_core_register"
> > - Call devm_iio_device_register() inside cros_ec_sensors_core_register.
> >
> > drivers/iio/accel/cros_ec_accel_legacy.c | 4 +-
> > .../cros_ec_sensors/cros_ec_lid_angle.c | 4 +-
> > .../common/cros_ec_sensors/cros_ec_sensors.c | 6 +-
> > .../cros_ec_sensors/cros_ec_sensors_core.c | 58 ++++++++++++++-----
> > drivers/iio/light/cros_ec_light_prox.c | 6 +-
> > drivers/iio/pressure/cros_ec_baro.c | 6 +-
> > .../linux/iio/common/cros_ec_sensors_core.h | 7 ++-
> > 7 files changed, 60 insertions(+), 31 deletions(-)
> >
> > diff --git a/drivers/iio/accel/cros_ec_accel_legacy.c b/drivers/iio/accel/cros_ec_accel_legacy.c
> > index 1c0171f26e99e..0f403342b1fc0 100644
> > --- a/drivers/iio/accel/cros_ec_accel_legacy.c
> > +++ b/drivers/iio/accel/cros_ec_accel_legacy.c
> > @@ -215,7 +215,7 @@ static int cros_ec_accel_legacy_probe(struct platform_device *pdev)
> > return -ENOMEM;
> >
> > ret = cros_ec_sensors_core_init(pdev, indio_dev, true,
> > - cros_ec_sensors_capture, NULL);
> > + cros_ec_sensors_capture);
> > if (ret)
> > return ret;
> >
> > @@ -235,7 +235,7 @@ static int cros_ec_accel_legacy_probe(struct platform_device *pdev)
> > state->sign[CROS_EC_SENSOR_Z] = -1;
> > }
> >
> > - return devm_iio_device_register(dev, indio_dev);
> > + return cros_ec_sensors_core_register(dev, indio_dev, NULL);
>
> In the case where the last argument is NULL then the new
> cros_ec_sensors_core_register() is always equivalent to the old
> devm_iio_device_register(), right? ...but I guess it's more idiomatic
> to always use the cros_ec version, so I'm OK with this.
Yes, it is equivalent.
>
>
> > @@ -372,6 +358,46 @@ int cros_ec_sensors_core_init(struct platform_device *pdev,
> > }
> > EXPORT_SYMBOL_GPL(cros_ec_sensors_core_init);
> >
> > +/**
> > + * cros_ec_sensors_core_register() - Register callback to FIFO and IIO when
> > + * sensor is ready.
> > + * It must be called at the end of the sensor probe routine.
> > + * @dev: device created for the sensor
> > + * @indio_dev: iio device structure of the device
> > + * @push_data: function to call when cros_ec_sensorhub receives
> > + * a sample for that sensor.
> > + *
> > + * Return: 0 on success, -errno on failure.
> > + */
> > +int cros_ec_sensors_core_register(struct device *dev,
> > + struct iio_dev *indio_dev,
> > + cros_ec_sensorhub_push_data_cb_t push_data)
> > +{
> > + struct cros_ec_sensor_platform *sensor_platform = dev_get_platdata(dev);
> > + struct cros_ec_sensorhub *sensor_hub = dev_get_drvdata(dev->parent);
> > + struct platform_device *pdev = to_platform_device(dev);
> > + struct cros_ec_dev *ec = sensor_hub->ec;
> > + int ret = 0;
>
> nit: don't init "ret" to 0 when you simply assign it right below.
Done
>
>
> > + ret = devm_iio_device_register(dev, indio_dev);
> > + if (ret)
> > + return ret;
> > +
> > + if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO) &&
> > + push_data != NULL) {
>
> I think the check for push_data should be first so it can short
> circuit and avoid the call to cros_ec_check_features(), right?
>
> In the past I've been yelled at for using "!= NULL" and told that
> thing should simply be "&& push_data". I'll leave it up to you about
> whether it's something that should be changed here.
>
> Also: you can reduce indentation of the function and simply if you just do:
>
> if (!push_data || !cros_ec_check_features(...))
> return 0;
Done.
>
> -Doug
