fix tmp102 negative calculation

[ssieb]

What does this implement/fix?

Corrects the change in #6316.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Other

Related issue or feature (if applicable): fixes

Pull request in esphome-docs with documentation (if applicable): esphome/esphome-docs#

Test Environment

• ESP32
• ESP32 IDF
• ESP8266
• RP2040
• BK72xx
• RTL87xx

Example entry for config.yaml:

# Example config.yaml

Checklist:

• The code change is tested and works locally.
• Tests have been added to verify that the new code works (under tests/ folder).

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in esphome-docs.

[probot-esphome]

Hey there @timsavage, mind taking a look at this pull request as it has been labeled with an integration (tmp102) you are listed as a code owner for? Thanks!
_{^{(message by CodeOwnersMention)}}

[timsavage]

What is the reason for removing this code here?

[timsavage]

This is required to move the high bit to allow for negative numbers.

[timsavage]

I suspect a proper fix might be to look at the example in the SparkFun library here.

Check if the device is in 12 or 13bit mode and apply the correct bit manipulation.

[ssieb]

That code isn't moving anything. The high bit is already set, it's a 2s-complement number and the right shift will work correctly. The only change that was required was the data type change. The code that I removed actually modified the value. It would only matter if it was a very negative temperature, but it was incorrect.