1.. SPDX-License-Identifier: GPL-2.0-only 2 3Kernel driver sl28cpld 4====================== 5 6Supported chips: 7 8 * Kontron sl28cpld 9 10 Prefix: 'sl28cpld' 11 12 Datasheet: not available 13 14Authors: Michael Walle <michael@walle.cc> 15 16Description 17----------- 18 19The sl28cpld is a board management controller which also exposes a hardware 20monitoring controller. At the moment this controller supports a single fan 21supervisor. In the future there might be other flavours and additional 22hardware monitoring might be supported. 23 24The fan supervisor has a 7 bit counter register and a counter period of 1 25second. If the 7 bit counter overflows, the supervisor will automatically 26switch to x8 mode to support a wider input range at the loss of 27granularity. 28 29Sysfs entries 30------------- 31 32The following attributes are supported. 33 34======================= ======================================================== 35fan1_input Fan RPM. Assuming 2 pulses per revolution. 36======================= ======================================================== 37