linux_dsm_epyc7002/include
Andrew Lunn 1323061a01 net: phy: sfp: Add HWMON support for module sensors
SFP modules can contain a number of sensors. The EEPROM also contains
recommended alarm and critical values for each sensor, and indications
of if these have been exceeded. Export this information via
HWMON. Currently temperature, VCC, bias current, transmit power, and
possibly receiver power is supported.

The sensors in the modules can either return calibrate or uncalibrated
values. Uncalibrated values need to be manipulated, using coefficients
provided in the SFP EEPROM. Uncalibrated receive power values require
floating point maths in order to calibrate them. Performing this in
the kernel is hard. So if the SFP module indicates it uses
uncalibrated values, RX power is not made available.

With this hwmon device, it is possible to view the sensor values using
lm-sensors programs:

in0:          +3.29 V  (crit min =  +2.90 V, min =  +3.00 V)
                       (max =  +3.60 V, crit max =  +3.70 V)
temp1:        +33.0°C  (low  =  -5.0°C, high = +80.0°C)
                       (crit low = -10.0°C, crit = +85.0°C)
power1:      1000.00 nW (max = 794.00 uW, min =  50.00 uW)  ALARM (LCRIT)
                       (lcrit =  40.00 uW, crit = 1000.00 uW)
curr1:        +0.00 A  (crit min =  +0.00 A, min =  +0.00 A)  ALARM (LCRIT, MIN)
                       (max =  +0.01 A, crit max =  +0.01 A)

The scaling sensors performs on the bias current is not particularly
good. The raw values are more useful:

curr1:
  curr1_input: 0.000
  curr1_min: 0.002
  curr1_max: 0.010
  curr1_lcrit: 0.000
  curr1_crit: 0.011
  curr1_min_alarm: 1.000
  curr1_max_alarm: 0.000
  curr1_lcrit_alarm: 1.000
  curr1_crit_alarm: 0.000

In order to keep the I2C overhead to a minimum, the constant values,
such as limits and calibration coefficients are read once at module
insertion time. Thus only reading *_input and *_alarm properties
requires i2c read operations.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-18 10:02:02 +09:00
..
acpi
asm-generic
clocksource
crypto
drm
dt-bindings
keys
kvm
linux net: phy: sfp: Add HWMON support for module sensors 2018-07-18 10:02:02 +09:00
math-emu
media
memory
misc
net tls: Add rx inline crypto offload 2018-07-16 00:13:11 -07:00
pcmcia
ras
rdma
scsi
soc
sound
target
trace net: core: unwrap skb list receive slightly further 2018-07-04 14:06:19 +09:00
uapi Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2018-07-14 18:47:44 -07:00
video
xen