Enable temperature sensor support for DDR5

[nasbdh9]

Compile the SPD5118 module to allow users to load it.

After loading the module, as long as the system exposes the relevant I2C interface and the memory complies with the SPD5118 standard, it should be possible to read the memory module temperature.

[amotin]

Debian's kernel config does not have this option. Wonder if it was added later, or they don't have it for a reason. Also on most of server systems things like that should be monitored by BMC, while at least on some older hardware direct access to memory controller's I2C could be dangerous.

[nasbdh9]

This is a new driver added in kernel 6.11, which mainly standardizes memory temperature readings. Whether SPD can be written directly in the operating system depends on the design of the memory SPD chip and has little to do with this driver.

Server systems usually have protection mechanisms such as CLTT, and the memory SPD itself is not directly exposed to the operating system.

[amotin]

I am not about SPD. IIRC the bus where the sensor reside did not have proper arbitration to prevent simultaneous access by OS and CPU microcode.

[nasbdh9]

prevent simultaneous access by OS and CPU microcode.

I'm not sure how this relates to CPU microcode.
OS itself has automatically loaded i2c_piix4, spd5118 driver simply adds a hwmon interface to detected bus.