Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752664AbdHNWhW (ORCPT ); Mon, 14 Aug 2017 18:37:22 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:56374 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752275AbdHNWhT (ORCPT ); Mon, 14 Aug 2017 18:37:19 -0400 Date: Mon, 14 Aug 2017 15:37:17 -0700 From: Guenter Roeck To: Eddie James Cc: robh+dt@kernel.org, jdelvare@suse.com, linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org, mark.rutland@arm.com, devicetree@vger.kernel.org, corbet@lwn.net, linux-doc@vger.kernel.org, "Edward A. James" Subject: Re: [PATCH v3 3/3] Documentation: hwmon: Document the IBM CFF power supply Message-ID: <20170814223717.GA21561@roeck-us.net> References: <1502724390-17411-1-git-send-email-eajames@linux.vnet.ibm.com> <1502724390-17411-4-git-send-email-eajames@linux.vnet.ibm.com> <20170814185308.GA11090@roeck-us.net> <0d016c77-4e3e-b9df-b131-604ab6f15e4c@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0d016c77-4e3e-b9df-b131-604ab6f15e4c@linux.vnet.ibm.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Authenticated_sender: guenter@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: guenter@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: guenter@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5022 Lines: 133 On Mon, Aug 14, 2017 at 02:26:20PM -0500, Eddie James wrote: > > > On 08/14/2017 01:53 PM, Guenter Roeck wrote: > >On Mon, Aug 14, 2017 at 10:26:30AM -0500, Eddie James wrote: > >>From: "Edward A. James" > >> > >>Signed-off-by: Edward A. James > >>--- > >> Documentation/hwmon/ibm-cffps | 54 +++++++++++++++++++++++++++++++++++++++++++ > >> 1 file changed, 54 insertions(+) > >> create mode 100644 Documentation/hwmon/ibm-cffps > >> > >>diff --git a/Documentation/hwmon/ibm-cffps b/Documentation/hwmon/ibm-cffps > >>new file mode 100644 > >>index 0000000..e091ff2 > >>--- /dev/null > >>+++ b/Documentation/hwmon/ibm-cffps > >>@@ -0,0 +1,54 @@ > >>+Kernel driver ibm-cffps > >>+======================= > >>+ > >>+Supported chips: > >>+ * IBM Common Form Factor power supply > >>+ > >>+Author: Eddie James > >>+ > >>+Description > >>+----------- > >>+ > >>+This driver supports IBM Common Form Factor (CFF) power supplies. This driver > >>+is a client to the core PMBus driver. > >>+ > >>+Usage Notes > >>+----------- > >>+ > >>+This driver does not auto-detect devices. You will have to instantiate the > >>+devices explicitly. Please see Documentation/i2c/instantiating-devices for > >>+details. > >>+ > >>+Sysfs entries > >>+------------- > >>+ > >>+The following attributes are supported: > >>+ > >>+curr1_alarm Output current over-current fault. > >>+curr1_input Measured output current in mA. > >>+curr1_label "iout1" > >>+ > >>+fan1_alarm Fan 1 warning. > >>+fan1_fault Fan 1 fault. > >>+fan1_input Fan 1 speed in RPM. > >>+fan2_alarm Fan 2 warning. > >>+fan2_fault Fan 2 fault. > >>+fan2_input Fan 2 speed in RPM. > >>+ > >>+in1_alarm Input voltage under-voltage fault. > >Just noticed. Are you sure you mean 'fault' here and below ? > >'alarm' attributes normally report an over- or under- condition, > >but not a fault. Faults should be reported with 'fault' attributes. > >In PMBus lingo (which doesn't distinguish a real 'fault' from > >a critical over- or under- condition), the "FAULT" condition > >usually maps with the 'crit_alarm' or 'lcrit_alarm' attributes. > >Also, under-voltages would normally be reported as min_alarm > >or clrit_alarm, not in_alarm. > > Thanks, I better change this doc to "alarm." The spec reports all these as > "faults" but many of them are merely over-temp or over-voltage, etc, and > should be "alarm" to be consistent with PMBus. > > The problem with this power supply is that it doesn't report any "limits." > So unless I set up my read_byte function to return some limits, we can't get > any lower or upper limits and therefore won't get the crit_alarm, > lcrit_alarm, etc. Do you think I should "fake" the limits in the driver? > Good question. Are the limits documented ? If yes, that would make sense. I am quite sure that limits are word registers, though. Guenter > > > >>+in1_input Measured input voltage in mV. > >>+in1_label "vin" > >>+in2_alarm Output voltage over-voltage fault. > >>+in2_input Measured output voltage in mV. > >>+in2_label "vout1" > >>+ > >>+power1_alarm Input fault. > >Another example; this maps to PMBUS_PIN_OP_WARN_LIMIT which is an > >input power alarm, not an indication of a fault condition. > > Hm, with my latest changes to look at the higher byte of STATUS_WORD, it > looks like we now have the same name for both the pin generic alarm > attribute and the pin_limit_attr... So in this device's case, it would map > to PB_STATUS_INPUT bit of STATUS_WORD. Didn't think about that... any > suggestions? Can't really change the name of the limit one without breaking > people's code... > > > > >>+power1_input Measured input power in uW. > >>+power1_label "pin" > >>+ > >>+temp1_alarm PSU inlet ambient temperature over-temperature fault. > >>+temp1_input Measured PSU inlet ambient temp in millidegrees C. > >>+temp2_alarm Secondary rectifier temp over-temperature fault. > >Interestingly, PMBus does not distinguish between a critical temperature > >alarm and an actual "fault". Makes me wonder if the IBM PS reports > >CFFPS_MFR_THERMAL_FAULT if there is an actual fault (chip or sensor failure), > >or if it has the same meaning as PB_TEMP_OT_FAULT, ie an excessively high > >temperature. > > Will change these to "alarm" in the doc too. > > > > >If it is a real fault (a detected sensor failure), we should possibly > >consider adding a respective "virtual" temperature status flag. The same > >is true for other status bits reported in the manufacturer status > >register if any of those reflect a "real" fault, ie a chip failure. > > Yea, that would probably be helpful. The CFFPS_MFR_THERMAL_FAULT bit is a > fault (so the spec says), but I'm not sure what is triggering it. > > Thanks, > Eddie > > > > >>+temp2_input Measured secondary rectifier temp in millidegrees C. > >>+temp3_alarm ORing FET temperature over-temperature fault. > >>+temp3_input Measured ORing FET temperature in millidegrees C. > >>-- > >>1.8.3.1 > >> >