1.. SPDX-License-Identifier: GPL-2.0-or-later 2 3Kernel driver spd5118 4===================== 5 6Supported chips: 7 8 * SPD5118 (JEDEC JESD300) compliant temperature sensor chips 9 10 JEDEC standard download: 11 https://www.jedec.org/standards-documents/docs/jesd300-5b01 12 (account required) 13 14 15 Prefix: 'spd5118' 16 17 Addresses scanned: I2C 0x50 - 0x57 18 19Author: 20 Guenter Roeck <linux@roeck-us.net> 21 22 23Description 24----------- 25 26This driver implements support for SPD5118 (JEDEC JESD300) compliant temperature 27sensors, which are used on many DDR5 memory modules. Some systems use the sensor 28to prevent memory overheating by automatically throttling the memory controller. 29 30The driver auto-detects SPD5118 compliant chips, but can also be instantiated 31using devicetree/firmware nodes. 32 33A SPD5118 compliant chip supports a single temperature sensor. Critical minimum, 34minimum, maximum, and critical temperature can be configured. There are alarms 35for low critical, low, high, and critical thresholds. 36 37 38Hardware monitoring sysfs entries 39--------------------------------- 40 41======================= ================================== 42temp1_input Temperature (RO) 43temp1_lcrit Low critical high temperature (RW) 44temp1_min Minimum temperature (RW) 45temp1_max Maximum temperature (RW) 46temp1_crit Critical high temperature (RW) 47 48temp1_lcrit_alarm Temperature low critical alarm 49temp1_min_alarm Temperature low alarm 50temp1_max_alarm Temperature high alarm 51temp1_crit_alarm Temperature critical alarm 52======================= ================================== 53 54Alarm attributes are sticky until read and will be cleared afterwards 55unless the alarm condition still applies. 56 57 58SPD (Serial Presence Detect) support 59------------------------------------ 60 61The driver also supports reading the SPD NVRAM on SPD5118 compatible chips. 62SPD data is available from the 'eeprom' binary attribute file attached to the 63chip's I2C device. 64