pmbus: Add driver for Maxim MAX31785 Intelligent Fan Controller
The Maxim MAX31785 is a PMBus device providing closed-loop, multi-channel
fan management with temperature and remote voltage sensing. It supports
various fan control features, including PWM frequency control, temperature
hysteresis, dual tachometer measurements, and fan health monitoring.
This patch presents a basic driver using only the existing features of the
PMBus subsystem.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
[groeck: Modified description to clarify that fan control is not yet provided]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
diff --git a/Documentation/hwmon/max31785 b/Documentation/hwmon/max31785
new file mode 100644
index 0000000..45fb609
--- /dev/null
+++ b/Documentation/hwmon/max31785
@@ -0,0 +1,51 @@
+Kernel driver max31785
+======================
+
+Supported chips:
+ * Maxim MAX31785, MAX31785A
+ Prefix: 'max31785' or 'max31785a'
+ Addresses scanned: -
+ Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX31785.pdf
+
+Author: Andrew Jeffery <andrew@aj.id.au>
+
+Description
+-----------
+
+The Maxim MAX31785 is a PMBus device providing closed-loop, multi-channel fan
+management with temperature and remote voltage sensing. Various fan control
+features are provided, including PWM frequency control, temperature hysteresis,
+dual tachometer measurements, and fan health monitoring.
+
+For dual rotor fan configuration, the MAX31785 exposes the slowest rotor of the
+two in the fan[1-4]_input attributes.
+
+Usage Notes
+-----------
+
+This driver does not probe for PMBus devices. You will have to instantiate
+devices explicitly.
+
+Sysfs attributes
+----------------
+
+fan[1-4]_alarm Fan alarm.
+fan[1-4]_fault Fan fault.
+fan[1-4]_input Fan RPM.
+
+in[1-6]_crit Critical maximum output voltage
+in[1-6]_crit_alarm Output voltage critical high alarm
+in[1-6]_input Measured output voltage
+in[1-6]_label "vout[18-23]"
+in[1-6]_lcrit Critical minimum output voltage
+in[1-6]_lcrit_alarm Output voltage critical low alarm
+in[1-6]_max Maximum output voltage
+in[1-6]_max_alarm Output voltage high alarm
+in[1-6]_min Minimum output voltage
+in[1-6]_min_alarm Output voltage low alarm
+
+temp[1-11]_crit Critical high temperature
+temp[1-11]_crit_alarm Chip temperature critical high alarm
+temp[1-11]_input Measured temperature
+temp[1-11]_max Maximum temperature
+temp[1-11]_max_alarm Chip temperature high alarm