On Sat, Nov 02, 2019 at 02:08:10PM +0000, Jonathan Cameron wrote:
> On Sat, 2 Nov 2019 11:41:25 +0100
> Ladislav Michl <ladis@xxxxxxxxxxxxxx> wrote:
>
> > On Fri, Nov 01, 2019 at 09:47:41PM +0800, YueHaibing wrote:
> > > drivers/iio/accel/st_accel_core.c:1005:44: warning:
> > > mount_matrix_ext_info defined but not used [-Wunused-const-variable=]
> > >
> > > Move it to ifdef to mute this warning.
> > >
> > > Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx>
> > > ---
> > > drivers/iio/accel/st_accel_core.c | 2 ++
> > > 1 file changed, 2 insertions(+)
> > >
> > > diff --git a/drivers/iio/accel/st_accel_core.c b/drivers/iio/accel/st_accel_core.c
> > > index 2e37f8a..bba0717 100644
> > > --- a/drivers/iio/accel/st_accel_core.c
> > > +++ b/drivers/iio/accel/st_accel_core.c
> > > @@ -1002,10 +1002,12 @@ get_mount_matrix(const struct iio_dev *indio_dev,
> > > return adata->mount_matrix;
> > > }
> > >
> > > +#ifdef CONFIG_ACPI
> > > static const struct iio_chan_spec_ext_info mount_matrix_ext_info[] = {
> > > IIO_MOUNT_MATRIX(IIO_SHARED_BY_ALL, get_mount_matrix),
> >
> > So now you do not get any warning for unused get_mount_matrix?
> > (Then it would make more sense to put all that stuff under one ifdef
> > and provide empty apply_acpi_orientation for non ACPI case)
>
> Does the __maybe_unused marking make this go away?
>
> I'd assume that the compiler will manage to drop this either way
> but I guess we should check that.
>
> ifdef magic is always harder to read and potentially fragile in the
> long run. Here we simply want to indicate that in some build
> configurations we might not use this.
This suggestion implies we'll get rid of CONFIG_ACPI completely, which
seems inapproriate looking at size of apply_acpi_orientation function.
And having both CONFIG_ACPI and __maybe_unused does not make much
sense. I had something like that in mind (+COMPILE_TEST perhaps):
diff --git a/drivers/iio/accel/st_accel_core.c b/drivers/iio/accel/st_accel_core.c
index 2e37f8a6d8cf..0e7eac62d618 100644
--- a/drivers/iio/accel/st_accel_core.c
+++ b/drivers/iio/accel/st_accel_core.c
@@ -993,6 +993,7 @@ static const struct iio_trigger_ops st_accel_trigger_ops = {
#define ST_ACCEL_TRIGGER_OPS NULL
#endif
+#ifdef CONFIG_ACPI
static const struct iio_mount_matrix *
get_mount_matrix(const struct iio_dev *indio_dev,
const struct iio_chan_spec *chan)
@@ -1013,7 +1014,6 @@ static const struct iio_chan_spec_ext_info mount_matrix_ext_info[] = {
static int apply_acpi_orientation(struct iio_dev *indio_dev,
struct iio_chan_spec *channels)
{
-#ifdef CONFIG_ACPI
struct st_sensor_data *adata = iio_priv(indio_dev);
struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
struct acpi_device *adev;
@@ -1141,10 +1141,14 @@ static int apply_acpi_orientation(struct iio_dev *indio_dev,
out:
kfree(buffer.pointer);
return ret;
-#else /* !CONFIG_ACPI */
+}
+#else
+static int apply_acpi_orientation(struct iio_dev *indio_dev,
+ struct iio_chan_spec *channels)
+{
return 0;
-#endif
}
+#endif
/*
* st_accel_get_settings() - get sensor settings from device name
> Thanks,
>
> Jonathan
>
>
> >
> > > { },
> > > };
> > > +#endif
> > >
> > > /* Read ST-specific _ONT orientation data from ACPI and generate an
> > > * appropriate mount matrix.
> > > --
> > > 2.7.4
> > >
