Re: [PATCH RFC] i2c: i801: Add i801_register_jc42, similar to i2c_register_spd

Jean Delvare
2023-11-19T08:39:05Z

Hi Heiner,

On Wed, 15 Nov 2023 12:00:18 +0100, Heiner Kallweit wrote:
> After thinking once more about it I think we have to do it from the
> ee1004 driver for DDR4. For DDR3 from at24. Only this way we can read
> the "temp sensor present" flag from SPD. E.g. for ee1004 the SPD EEPROM
> may be switched to the second page and we have to switch it to the first
> page first.

We indeed need to read the EEPROM data at some point. My initial
thinking was to instantiate the at24 or ee1004 device first (from
i2c-smbus), then read the value from the EEPROM and instantiate the
jc42 device (still from i2c-smbus). This requires an internal read
function. I think we already have that in at24, because it uses the
nvmem framework, but ee1004 lacks it as far as I can see.

But anyway, if you have another approach which works, that's equally
fine with me.

> I'll send a RFC patch for this. Unfortunately I have no RAM with temp
> sensor to test it.

Neither do I :-(

--
Jean Delvare
SUSE L3 Support