d45a9a6d80b8172e8d1c7b3019dc6d75d23e3547 - openbmc/phosphor-power - Gitiles

commit	d45a9a6d80b8172e8d1c7b3019dc6d75d23e3547	[log] [tgz]
author	Shawn McCarney <shawnmm@us.ibm.com>	Tue Dec 10 18:35:44 2019 -0600
committer	Shawn McCarney <shawnmm@us.ibm.com>	Wed Dec 11 00:26:24 2019 -0600
tree	2f0e600d9a1a5fef6ebedde96540416fbca20e39
parent	1d103428e50ec000372e6b1c2bccc8ee92ddbc89 [diff]

i2c: Support explicit open/close and re-open

Add the ability to explicitly open and close the I2CInterface/I2CDevice.
Also add support to re-open the I2CInterface/I2CDevice after it was
closed.

This support is needed for use cases like the following:

* I2C device information (bus and address) is parsed from a
  configuration file at standby.  However, an I2C connection to the
  device should not be opened yet.   The device may not have power until
  the system has been booted.  Additionally, if the device is a FRU,
  it could be replaced (remove + add) while at standby, leading to
  communication errors.

* The device is sometimes bound to a device driver.  The I2C connection
  should only be open during the time periods when the device driver
  is not bound.

Tested:
* Verified create() function with default value of OPEN, explicit value
  of OPEN, and explicit value of CLOSED.
* Verified device interface can be explicitly opened, closed, and
  re-opened.
* Verified read() and write() functions still work when device interface
  is open.
* Verified open() fails with appropriate error if already open.
* Verified read() fails with appropriate error if not open.
* Verified write() fails with appropriate error if not open.
* Verified close() fails with appropriate error if not open.

Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
Change-Id: I0182966f0b0614eac0de69eb95d960035f9d0426

4 files changed

tree: 2f0e600d9a1a5fef6ebedde96540416fbca20e39

README.md

Code for detecting and analyzing power faults on Witherspoon.

To Build

To build this package, do the following steps:

    1. meson build
    2. ninja -C build

To clean the repository again run `rm -rf build`.

Power Supply Monitor and Util JSON config

Several applications in this repository require a PSU JSON config to run. The JSON config file provides information for:

Where to access the pmbus attributes
Which attribute file in pmbus maps to which property and interface in D-Bus
Which kernel device directory is used on which PSU

There is an example psu.json to describe the necessary configurations.

inventoryPMBusAccessType defines the pmbus access type, which tells the service which sysfs type to use to read the attributes. The possible values are:
- Base: The base dir, e.g. /sys/bus/i2c/devices/3-0069/
- Hwmon: The hwmon dir, e.g. /sys/bus/i2c/devices/3-0069/hwmon/hwmonX/
- Debug: The pmbus debug dir, e.g. /sys/kernel/debug/pmbus/hwmonX/
- DeviceDebug: The device debug dir, e.g. '/sys/kernel/debug/./`
- HwmonDeviceDebug: The hwmon device debug dir, e.g. /sys/kernel/debug/pmbus/hwmonX/cffps1/
fruConfigs defines the mapping between the attribute file and the FRU inventory interface and property. The configuration example below indicates that the service will read part_number attribute file from a directory specified by the above pmbus access type, and assign to PartNumber property in xyz.openbmc_project.Inventory.Decorator.Asset interface.
```
  "fruConfigs": [
    {
      "propertyName": "PartNumber",
      "fileName": "part_number",
      "interface": "xyz.openbmc_project.Inventory.Decorator.Asset"
    }
  ]
```
psuDevices defines the kernel device dir for each PSU in inventory. The configuration example below indicates that powersupply0's device is located in /sys/bus/i2c/devices/3-0069.
```
  "psuDevices": {
    "/xyz/openbmc_project/inventory/system/chassis/motherboard/powersupply0" : "/sys/bus/i2c/devices/3-0069",
  }
```