mirror of
https://github.com/torvalds/linux.git
synced 2024-11-22 04:02:20 +00:00
25dff444c6
Add support for reading SPD NVMEM data from SPD5118 (Jedec JESD300) compliant memory modules. NVMEM write operation is not supported. NVMEM support is optional. If CONFIG_NVMEM is disabled, the driver will still instantiate but not provide NVMEM attribute files. Reviewed-by: Thomas Weißschuh <linux@weissschuh.net> Tested-by: Armin Wolf <W_Armin@gmx.de> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
64 lines
1.9 KiB
ReStructuredText
64 lines
1.9 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0-or-later
|
|
|
|
Kernel driver spd5118
|
|
=====================
|
|
|
|
Supported chips:
|
|
|
|
* SPD5118 (JEDEC JESD300) compliant temperature sensor chips
|
|
|
|
JEDEC standard download:
|
|
https://www.jedec.org/standards-documents/docs/jesd300-5b01
|
|
(account required)
|
|
|
|
|
|
Prefix: 'spd5118'
|
|
|
|
Addresses scanned: I2C 0x50 - 0x57
|
|
|
|
Author:
|
|
Guenter Roeck <linux@roeck-us.net>
|
|
|
|
|
|
Description
|
|
-----------
|
|
|
|
This driver implements support for SPD5118 (JEDEC JESD300) compliant temperature
|
|
sensors, which are used on many DDR5 memory modules. Some systems use the sensor
|
|
to prevent memory overheating by automatically throttling the memory controller.
|
|
|
|
The driver auto-detects SPD5118 compliant chips, but can also be instantiated
|
|
using devicetree/firmware nodes.
|
|
|
|
A SPD5118 compliant chip supports a single temperature sensor. Critical minimum,
|
|
minimum, maximum, and critical temperature can be configured. There are alarms
|
|
for low critical, low, high, and critical thresholds.
|
|
|
|
|
|
Hardware monitoring sysfs entries
|
|
---------------------------------
|
|
|
|
======================= ==================================
|
|
temp1_input Temperature (RO)
|
|
temp1_lcrit Low critical high temperature (RW)
|
|
temp1_min Minimum temperature (RW)
|
|
temp1_max Maximum temperature (RW)
|
|
temp1_crit Critical high temperature (RW)
|
|
|
|
temp1_lcrit_alarm Temperature low critical alarm
|
|
temp1_min_alarm Temperature low alarm
|
|
temp1_max_alarm Temperature high alarm
|
|
temp1_crit_alarm Temperature critical alarm
|
|
======================= ==================================
|
|
|
|
Alarm attributes are sticky until read and will be cleared afterwards
|
|
unless the alarm condition still applies.
|
|
|
|
|
|
SPD (Serial Presence Detect) support
|
|
------------------------------------
|
|
|
|
The driver also supports reading the SPD NVRAM on SPD5118 compatible chips.
|
|
SPD data is available from the 'eeprom' binary attribute file attached to the
|
|
chip's I2C device.
|