linux-kernel - Re: [PATCH] iio: hid-sensor-prox: Merge information from different channels

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Message-ID: <20241208163851.41c47c3f@jic23-huawei>
Date: Sun, 8 Dec 2024 16:38:51 +0000
From: Jonathan Cameron <jic23@...nel.org>
To: Ricardo Ribalda <ribalda@...omium.org>
Cc: Jiri Kosina <jikos@...nel.org>, Srinivas Pandruvada
 <srinivas.pandruvada@...ux.intel.com>, Lars-Peter Clausen
 <lars@...afoo.de>, Jonathan Cameron <Jonathan.Cameron@...wei.com>,
 linux-input@...r.kernel.org, linux-iio@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH] iio: hid-sensor-prox: Merge information from different
 channels

On Thu, 05 Dec 2024 12:59:20 +0000
Ricardo Ribalda <ribalda@...omium.org> wrote:

> The device only provides a single scale, frequency and hysteresis for
> all the channels. Fix the info_mask_* to match the reality of the
> device.
> 
> Without this patch:
> in_attention_scale
> in_attention_hysteresis
> in_attention_input
> in_attention_offset
> in_attention_sampling_frequency
> in_proximity_scale
> in_proximity_sampling_frequency
> in_proximity_offset
> in_proximity0_raw
> in_proximity_hysteresis
> 
> With this patch:
> hysteresis
> scale
> sampling_frequency
> in_attention_input
> in_attention_offset
> in_proximity0_offset
> in_proximity0_raw
> 
> Fixes: 596ef5cf654b ("iio: hid-sensor-prox: Add support for more channels")
> Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>

whilst perhaps not ideal use of the ABI, what is there today is not wrong
as such.  If the ABI above was all introduce in the recent patch I might
be fine adjusting it as you suggestion. However it wasn't, in_proximity_scale
has been there a long time so this would be an ABI change.
Those are generally only ok if there is a bug.

Drivers are always allowed to provide finer granularity than necessary
so in this case I don't see this as a bug.

Jonathan


> ---
>  drivers/iio/light/hid-sensor-prox.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/light/hid-sensor-prox.c b/drivers/iio/light/hid-sensor-prox.c
> index e8e7b2999b4c..f21d2da4c7f9 100644
> --- a/drivers/iio/light/hid-sensor-prox.c
> +++ b/drivers/iio/light/hid-sensor-prox.c
> @@ -49,9 +49,11 @@ static const u32 prox_sensitivity_addresses[] = {
>  #define PROX_CHANNEL(_is_proximity, _channel) \
>  	{\
>  		.type = _is_proximity ? IIO_PROXIMITY : IIO_ATTENTION,\
> -		.info_mask_separate = _is_proximity ? BIT(IIO_CHAN_INFO_RAW) :\
> -				      BIT(IIO_CHAN_INFO_PROCESSED),\
> -		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |\
> +		.info_mask_separate = \
> +		(_is_proximity ? BIT(IIO_CHAN_INFO_RAW) :\
> +				BIT(IIO_CHAN_INFO_PROCESSED)) |\
> +		BIT(IIO_CHAN_INFO_OFFSET),\
> +		.info_mask_shared_by_all = \
>  		BIT(IIO_CHAN_INFO_SCALE) |\
>  		BIT(IIO_CHAN_INFO_SAMP_FREQ) |\
>  		BIT(IIO_CHAN_INFO_HYSTERESIS),\
> 
> ---
> base-commit: 40384c840ea1944d7c5a392e8975ed088ecf0b37
> change-id: 20241203-fix-hid-sensor-62e1979ecd03
> 
> Best regards,