1.\" 2.\" This file and its contents are supplied under the terms of the 3.\" Common Development and Distribution License ("CDDL"), version 1.0. 4.\" You may only use this file in accordance with the terms of version 5.\" 1.0 of the CDDL. 6.\" 7.\" A full copy of the text of the CDDL should have accompanied this 8.\" source. A copy of the CDDL is also available via the Internet at 9.\" http://www.illumos.org/license/CDDL. 10.\" 11.\" 12.\" Copyright 2025 Oxide Computer Company 13.\" 14.Dd October 4, 2025 15.Dt EE100X 4D 16.Os 17.Sh NAME 18.Nm ee100x 19.Nd DDR4 serial presence detect driver 20.Sh SYNOPSIS 21.Pa /dev/eeprom/ee100x/*/eeprom 22.Sh DESCRIPTION 23The 24.Nm 25driver supports the I2C EEPROMs found on DDR4 DIMMs. 26The driver provides read-only access to the SPD 27.Pq serial presence detect 28EEPROM through a character device powered by the 29.Xr eedev 4D 30driver. 31These devices are generally found at 7-bit addresses between 0x50 and 320x57. 33The lower three bits of the address are used to indicate which DIMM the 34device is found on 35.Pq ranging from 0 to 7 . 36.Pp 37The SPD device contains 512 bytes of memory that are organized into two 38pages of 256 bytes each. 39Devices can be found under 40.Pa /dev/eeprom/ee100x . 41Contents of the SPD data can be decoded with 42.Xr libjedec 3LIB . 43.Sh FILES 44.Bl -tag -width Pa 45.It Pa /dev/eeprom/spd511x/*/eeprom 46EEPROM character device file. 47.It Pa /kernel/drv/amd64/ee100x 48Device driver (x86) 49.El 50.Sh SEE ALSO 51.Xr libjedec 3LIB , 52.Xr eedev 4D , 53.Xr spd511x 4D , 54.Xr i2cadm 8 55.Rs 56.%Q JEDEC Solid State Technology Association 57.%T Definitions of the EE1004-v 4 Kbit Serial Presence Detect (SPD) EEPROM and TSE2004av 4 Kbit SPD EEPROM with Temperature Sensor (TS) for Memory Module Applications 58.%N JESD21-C Release 26 59.Re 60