Re: [PATCH v3 5/8] iio: magnetometer: yas530: Change data type of calibration coefficients

[Jakob Hauser <jahau@rocketmail.com>]

Hi Jonathan,

On 18.06.22 16:56, Jonathan Cameron wrote:
> On Sat, 18 Jun 2022 02:13:13 +0200
> Jakob Hauser <jahau@rocketmail.com> wrote:
> 
>> This is a preparation for adding YAS537 variant.
>>
>> YAS537 uses other data types on the calibration coefficients [1] than YAS530 [2]
>> and YAS532 [3].
>>
>> On YAS537, at least for a4 and a7 this could matter because 8-bit unsigned data
>> from the register gets stored into a signed data type, therefore this should be
>> 8-bit as well.
>>
>> For YAS530/532, on the other hand, it doesn't seem to matter. The size of a2-a9
>> and k is smaller than 8-bit at extraction, also the applied math is low. And
>> Cx/Cy1/Cy2, now being defined as signed 16-bit, are extracted as unsigned 8-bit
>> and undergo only minor math.
> Ok. If this is harmless to existing drivers fair enough, though my personal
> inclination would have been to take the easier approach of making the
> new variant sign extend on variable load (sign_extend_32() and similar)
> just so we didn't need to check the older parts weren't affected.

I didn't know that operation :) Let's take this.

Not sure how to handle the "Reviewed-by:" tags. Even though it's a small
patch, it gets modified a lot. Therefore I'd remove the tags of Linus
and Andy.

Kind regards,
Jakob