Kernel driver emc2305

Supported chips:

Microchip EMC2305, EMC2303, EMC2302, EMC2301

Addresses scanned: I2C 0x27, 0x2c, 0x2d, 0x2e, 0x2f, 0x4c, 0x4d Prefixes: ‘emc2305’

Datasheet: Publicly available at the Microchip website :


This driver implements support for Microchip EMC2301/2/3/5 RPM-based PWM Fan Controller. The EMC2305 Fan Controller supports up to 5 independently controlled PWM fan drives. Fan rotation speeds are reported in RPM. The driver supports the RPM-based PWM control to keep a fan at the desired speed. The driver provides the possibility to have one common PWM interface for all FANs or up to the maximum available or configured independent PWMs.

The driver provides the following sysfs interfaces in hwmon subsystem:

fan[1-5]_fault RO files for tachometers TACH1-TACH5 fault indication
fan[1-5]_input RO files for tachometers TACH1-TACH5 input (in RPM)
pwm[1-5] RW file for fan[1-5] target duty cycle (0..255)

sysfs interfaces in thermal subsystem:

cur_state RW file for the current cooling state of the cooling device (0..max_state)
max_state RO file for the maximum cooling state of the cooling device