From: Guenter Roeck <linux@roeck-us.net>
To: Robert Hancock <hancock@sedsystems.ca>,
monstr@monstr.eu, Michal Simek <michal.simek@xilinx.com>
Cc: linux-hwmon@vger.kernel.org
Subject: Re: Linux driver for IRPS5401 - status reg not found
Date: Thu, 9 Apr 2020 14:23:44 -0700 [thread overview]
Message-ID: <ff6483cf-7513-8a2c-f686-5c6782fa50cc@roeck-us.net> (raw)
In-Reply-To: <8afd61bc-9a67-0f22-2931-5ac9d084ee3f@sedsystems.ca>
On 4/9/20 8:30 AM, Robert Hancock wrote:
> On 2020-04-09 9:16 a.m., Guenter Roeck wrote:
>> Hi Michal,
>>
>> On 4/9/20 7:29 AM, Michal Simek wrote:
>> [ ... ]
>>>
>>> Just to let you know issue is with i2c driver. Here is my output for the
>>> record.
>>>
>> Thanks a lot for the update.
>>
>>> irps5401-i2c-3-43
>>> Adapter: i2c-0-mux (chan_id 2)
>>> vin1: 11.56 V (min = +9.00 V, crit max = +14.00 V)
>>> vin2: 11.56 V (min = +9.00 V, crit max = +14.00 V)
>>> vin3: 11.56 V (min = +9.00 V, crit max = +14.00 V)
>>> vin4: N/A
>>
>> This is interesting; it means that the rail is not active (?) or
>> not supported, or maybe even that the driver has a bug. The second
>> chip reports a value here, so I guess the rail is inactive.
>> If possible, it would be desirable to detect this during probe
>> and not try to report values for this rail. It would be great if
>> you can find the time to figure out what is going on.
>
> I would assume that either that rail is not used in that board design and was disabled in the non-volatile config on the chip, or alternately the chip allows combining outputs C and D (i.e. 3 and 4) into a single output in which case only one will report valid data. Not sure offhand if there is a way to detect those cases from the PMBus interface at probe time.
>
I think it may be the output disable register (0x38). One would have
to know the i2c address, read the register, and set page bits
accordingly. Overall, I am not sure if it is worth the trouble.
Maybe we should just just add a note to the driver documentation.
Thanks,
Guenter
next prev parent reply other threads:[~2020-04-09 21:23 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-30 11:33 Linux driver for IRPS5401 - status reg not found Michal Simek
2020-03-30 15:24 ` Guenter Roeck
2020-03-30 15:42 ` Robert Hancock
2020-03-30 18:48 ` Guenter Roeck
2020-03-30 19:09 ` Robert Hancock
2020-03-30 19:48 ` Guenter Roeck
2020-03-31 12:38 ` Michal Simek
2020-04-09 14:29 ` Michal Simek
2020-04-09 15:16 ` Guenter Roeck
2020-04-09 15:30 ` Robert Hancock
2020-04-09 21:23 ` Guenter Roeck [this message]
2020-04-10 7:19 ` Michal Simek
2020-03-30 15:46 ` Michal Simek
2020-03-30 16:52 ` Guenter Roeck
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