Re: [PATCH v2] iio: st_sensors: make scale channels also shared by type

[Jonathan Cameron <jic23@kernel.org>]

On Thu, 23 Apr 2020 14:17:15 +0200
Gaëtan André <rvlander@gaetanandre.eu> wrote:

> Scale channels are available by axis. For example for accelerometers,
> in_accel_x_scale, in_accel_y_scale and in_accel_z_scale are available.
> 
> However, they should be shared by type as documented in
> Documentation/ABI/testing/sysfs-bus-iio.
> 
> For each sensor (acceleros, gyros and magnetos) only one value is specified
> for all the axes.
> 
> Existing, by axis, entries are preserved in order to to leave the old ABI
> untouched.
As I mentioned in v1, there isn't a strict ABI rule that says that we must
do the shared form

+CC'd Bastien for comment on what userspace is assuming and whether we should
push this back to stable or not.

Thanks,

Jonathan

> 
> Signed-off-by: Gaëtan André <rvlander@gaetanandre.eu>
> ---
> v1->v2: add comment explaining why we are doing both.
> 
>  include/linux/iio/common/st_sensors.h | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/include/linux/iio/common/st_sensors.h b/include/linux/iio/common/st_sensors.h
> index 33e939977444..42663fbab085 100644
> --- a/include/linux/iio/common/st_sensors.h
> +++ b/include/linux/iio/common/st_sensors.h
> @@ -46,12 +46,19 @@
>  #define ST_SENSORS_MAX_NAME			17
>  #define ST_SENSORS_MAX_4WAI			8
>  
> +/*
> + * Scale channels are configured both by type and by axis.
> + * - By axis to keep the previous ABI and flexibility.
> + * - By type because it is how some userland
> + * applications are expecting them (ex: iio-sensor-proxy).
> + */
>  #define ST_SENSORS_LSM_CHANNELS(device_type, mask, index, mod, \
>  					ch2, s, endian, rbits, sbits, addr) \
>  { \
>  	.type = device_type, \
>  	.modified = mod, \
>  	.info_mask_separate = mask, \
> +	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
>  	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
>  	.scan_index = index, \
>  	.channel2 = ch2, \
> 
> base-commit: 2de8c02349f02d014e51b43f306d28fc7a23ea6e