Documentation/ABI: Add documentation mlxreg-io sysfs interfaces

Add documentation for mlxreg-io platform driver sysfs interfaces to allow
user space access for system resets control, reset causes monitoring,
programmable devices version reading and device selection control.

Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>

diff --git a/Documentation/ABI/stable/sysfs-driver-mlxreg-io b/Documentation/ABI/stable/sysfs-driver-mlxreg-io
new file mode 100644 (file)
index 0000000..815689b
--- /dev/null
+++ b/Documentation/ABI/stable/sysfs-driver-mlxreg-io
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+What:          /sys/devices/platform/mlxplat/mlxreg-io/hwmon/hwmon*/
+                                                       asic_health
+
+Date:          June 2018
+KernelVersion: 4.19
+Contact:       Vadim Pasternak <vadimpmellanox.com>
+Description:   This file shows ASIC health status. The possible values are:
+               0 - health failed, 2 - health OK, 3 - ASIC in booting state.
+
+               The files are read only.
+
+What:          /sys/devices/platform/mlxplat/mlxreg-io/hwmon/hwmon*/
+                                                       cpld1_version
+                                                       cpld2_version
+
+Date:          June 2018
+KernelVersion: 4.19
+Contact:       Vadim Pasternak <vadimpmellanox.com>
+Description:   These files show with which CPLD versions have been burned
+               on carrier and switch boards.
+
+               The files are read only.
+
+What:          /sys/devices/platform/mlxplat/mlxreg-io/hwmon/hwmon*/select_iio
+Date:          June 2018
+KernelVersion: 4.19
+Contact:       Vadim Pasternak <vadimpmellanox.com>
+Description:   This file allows iio devices selection.
+
+               Attribute select_iio can be written with 0 or with 1. It
+               selects which one of iio devices can be accessed.
+
+               The file is read/write.
+
+What:          /sys/devices/platform/mlxplat/mlxreg-io/hwmon/hwmon*/psu1_on
+               /sys/devices/platform/mlxplat/mlxreg-io/hwmon/hwmon*/psu2_on
+               /sys/devices/platform/mlxplat/mlxreg-io/hwmon/hwmon*/pwr_cycle
+               /sys/devices/platform/mlxplat/mlxreg-io/hwmon/hwmon*/pwr_down
+Date:          June 2018
+KernelVersion: 4.19
+Contact:       Vadim Pasternak <vadimpmellanox.com>
+Description:   These files allow asserting system power cycling, switching
+               power supply units on and off and system's main power domain
+               shutdown.
+               Expected behavior:
+               When pwr_cycle is written 1: auxiliary power domain will go
+               down and after short period (about 1 second) up.
+               When  psu1_on or psu2_on is written 1, related unit will be
+               disconnected from the power source, when written 0 - connected.
+               If both are written 1 - power supplies main power domain will
+               go down.
+               When pwr_down is written 1, system's main power domain will go
+               down.
+
+               The files are write only.
+
+What:          /sys/devices/platform/mlxplat/mlxreg-io/hwmon/hwmon*/
+                                                       reset_aux_pwr_or_ref
+                                                       reset_asic_thermal
+                                                       reset_hotswap_or_wd
+                                                       reset_fw_reset
+                                                       reset_long_pb
+                                                       reset_main_pwr_fail
+                                                       reset_short_pb
+                                                       reset_sw_reset
+Date:          June 2018
+KernelVersion: 4.19
+Contact:       Vadim Pasternak <vadimpmellanox.com>
+Description:   These files show the system reset cause, as following: power
+               auxiliary outage or power refresh, ASIC thermal shutdown,
+               hotswap or watchdog, firmware reset, long press power button,
+               short press power button, software reset. Value 1 in file means
+               this is reset cause, 0 - otherwise. Only one of the above
+               causes could be 1 at the same time, representing only last
+               reset cause.
+
+               The files are read only.