Date:   Fri, 21 May 2021 13:56:34 +0200
From:   Robert Marko <robert.marko@...tura.hr>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     jdelvare@...e.com, corbet@....net, linux-hwmon@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Luka Perkov <luka.perkov@...tura.hr>, jmp@...phyte.org,
        Paul Menzel <pmenzel@...gen.mpg.de>,
        Donald Buczek <buczek@...gen.mpg.de>
Subject: Re: [PATCH 1/3] hwmon: (pmbus) Add driver for Delta DPS-920AB PSU

On Fri, May 21, 2021 at 12:56 PM Guenter Roeck <linux@...ck-us.net> wrote:
>
> On 5/21/21 1:36 AM, Robert Marko wrote:
> > On Wed, May 19, 2021 at 3:19 PM Guenter Roeck <linux@...ck-us.net> wrote:
> >>
> >> On 5/19/21 5:38 AM, Robert Marko wrote:
> >>> On Fri, Apr 30, 2021 at 3:48 PM Guenter Roeck <linux@...ck-us.net> wrote:
> >>>>
> >>>> On Fri, Apr 30, 2021 at 03:27:33PM +0200, Robert Marko wrote:
> >>>>> This adds support for the Delta DPS-920AB PSU.
> >>>>>
> >>>>> Only missing feature is fan control which the PSU supports.
> >>>>>
> >>>>> Signed-off-by: Robert Marko <robert.marko@...tura.hr>
> >>>>> ---
> >>>>>    Documentation/hwmon/dps920ab.rst | 80 ++++++++++++++++++++++++++++++++
> >>>>>    Documentation/hwmon/index.rst    |  1 +
> >>>>>    drivers/hwmon/pmbus/Kconfig      |  9 ++++
> >>>>>    drivers/hwmon/pmbus/Makefile     |  1 +
> >>>>>    drivers/hwmon/pmbus/dps920ab.c   | 63 +++++++++++++++++++++++++
> >>>>>    5 files changed, 154 insertions(+)
> >>>>>    create mode 100644 Documentation/hwmon/dps920ab.rst
> >>>>>    create mode 100644 drivers/hwmon/pmbus/dps920ab.c
> >>>>>
> >>>>> diff --git a/Documentation/hwmon/dps920ab.rst b/Documentation/hwmon/dps920ab.rst
> >>>>> new file mode 100644
> >>>>> index 000000000000..df0aef530c7e
> >>>>> --- /dev/null
> >>>>> +++ b/Documentation/hwmon/dps920ab.rst
> >>>>> @@ -0,0 +1,80 @@
> >>>>> +.. SPDX-License-Identifier: GPL-2.0-or-later
> >>>>> +
> >>>>> +Kernel driver dps920ab
> >>>>> +========================
> >>>>> +
> >>>>> +Supported chips:
> >>>>> +
> >>>>> +  * Delta DPS920AB
> >>>>> +
> >>>>> +    Prefix: 'dps920ab'
> >>>>> +
> >>>>> +    Addresses scanned: -
> >>>>> +
> >>>>> +Authors:
> >>>>> +    Robert Marko <robert.marko@...tura.hr>
> >>>>> +
> >>>>> +
> >>>>> +Description
> >>>>> +-----------
> >>>>> +
> >>>>> +This driver implements support for Delta DPS920AB 920W 54V DC single output
> >>>>> +power supply with PMBus support.
> >>>>> +
> >>>>> +The driver is a client driver to the core PMBus driver.
> >>>>> +Please see Documentation/hwmon/pmbus.rst for details on PMBus client drivers.
> >>>>> +
> >>>>> +
> >>>>> +Usage Notes
> >>>>> +-----------
> >>>>> +
> >>>>> +This driver does not auto-detect devices. You will have to instantiate the
> >>>>> +devices explicitly. Please see Documentation/i2c/instantiating-devices.rst for
> >>>>> +details.
> >>>>> +
> >>>>> +
> >>>>> +Sysfs entries
> >>>>> +-------------
> >>>>> +
> >>>>> +======================= ======================================================
> >>>>> +curr1_label          "iin"
> >>>>> +curr1_input          Measured input current
> >>>>> +curr1_crit           Critical maximum current
> >>>>> +curr1_crit_alarm     Current critical high alarm
> >>>>> +
> >>>>> +curr2_label          "iout1"
> >>>>> +curr2_input          Measured output current
> >>>>> +curr2_crit           Critical maximum current
> >>>>> +curr2_crit_alarm     Current critical high alarm
> >>>>> +
> >>>>> +in1_label            "vin"
> >>>>> +in1_input            Measured input voltage
> >>>>> +in1_lcrit            Critical minimum input voltage
> >>>>> +in1_lcrit_alarm              Input voltage critical low alarm
> >>>>> +in1_crit             Critical maximum input voltage
> >>>>> +in1_crit_alarm               Input voltage critical high alarm
> >>>>> +
> >>>>> +in2_label            "vout1"
> >>>>> +in2_input            Measured output voltage
> >>>>> +in2_lcrit            Critical minimum output voltage
> >>>>> +in2_lcrit_alarm              Output voltage critical low alarm
> >>>>> +in2_crit             Critical maximum output voltage
> >>>>> +in2_crit_alarm               Output voltage critical high alarm
> >>>>> +
> >>>>> +power1_label         "pin"
> >>>>> +power1_input         Measured input power
> >>>>> +power1_alarm         Input power high alarm
> >>>>> +
> >>>>> +power2_label         "pout1"
> >>>>> +power2_input         Measured output power
> >>>>> +
> >>>>> +temp[1-2]_input              Measured temperature
> >>>>> +temp[1-2]_crit               Critical high temperature
> >>>>> +temp[1-2]_crit_alarm Chip temperature critical high alarm
> >>>>> +temp[1-2]_max                Maximum temperature
> >>>>> +temp[1-2]_max_alarm  Chip temperature high alarm
> >>>>> +
> >>>>> +fan1_alarm           Fan 1 warning.
> >>>>> +fan1_fault           Fan 1 fault.
> >>>>> +fan1_input           Fan 1 speed in RPM.
> >>>>> +======================= ======================================================
> >>>>> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> >>>>> index 8d5a2df1ecb6..b24436f22052 100644
> >>>>> --- a/Documentation/hwmon/index.rst
> >>>>> +++ b/Documentation/hwmon/index.rst
> >>>>> @@ -54,6 +54,7 @@ Hardware Monitoring Kernel Drivers
> >>>>>       dell-smm-hwmon
> >>>>>       dme1737
> >>>>>       drivetemp
> >>>>> +   dps920ab
> >>>>>       ds1621
> >>>>>       ds620
> >>>>>       emc1403
> >>>>> diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
> >>>>> index 32d2fc850621..865ade0aa205 100644
> >>>>> --- a/drivers/hwmon/pmbus/Kconfig
> >>>>> +++ b/drivers/hwmon/pmbus/Kconfig
> >>>>> @@ -66,6 +66,15 @@ config SENSORS_IBM_CFFPS
> >>>>>           This driver can also be built as a module. If so, the module will
> >>>>>           be called ibm-cffps.
> >>>>>
> >>>>> +config SENSORS_DPS920AB
> >>>>> +     tristate "Delta DPS920AB Power Supply"
> >>>>> +     help
> >>>>> +       If you say yes here you get hardware monitoring support for Delta
> >>>>> +       DPS920AB Power Supplies.
> >>>>> +
> >>>>> +       This driver can also be built as a module. If so, the module will
> >>>>> +       be called dps920ab.
> >>>>> +
> >>>>>    config SENSORS_INSPUR_IPSPS
> >>>>>         tristate "INSPUR Power System Power Supply"
> >>>>>         help
> >>>>> diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
> >>>>> index 6a4ba0fdc1db..f59ba0123d68 100644
> >>>>> --- a/drivers/hwmon/pmbus/Makefile
> >>>>> +++ b/drivers/hwmon/pmbus/Makefile
> >>>>> @@ -9,6 +9,7 @@ obj-$(CONFIG_SENSORS_ADM1266) += adm1266.o
> >>>>>    obj-$(CONFIG_SENSORS_ADM1275)        += adm1275.o
> >>>>>    obj-$(CONFIG_SENSORS_BEL_PFE)        += bel-pfe.o
> >>>>>    obj-$(CONFIG_SENSORS_IBM_CFFPS)      += ibm-cffps.o
> >>>>> +obj-$(CONFIG_SENSORS_DPS920AB)       += dps920ab.o
> >>>>>    obj-$(CONFIG_SENSORS_INSPUR_IPSPS) += inspur-ipsps.o
> >>>>>    obj-$(CONFIG_SENSORS_IR35221)        += ir35221.o
> >>>>>    obj-$(CONFIG_SENSORS_IR38064)        += ir38064.o
> >>>>> diff --git a/drivers/hwmon/pmbus/dps920ab.c b/drivers/hwmon/pmbus/dps920ab.c
> >>>>> new file mode 100644
> >>>>> index 000000000000..d579ed9f879c
> >>>>> --- /dev/null
> >>>>> +++ b/drivers/hwmon/pmbus/dps920ab.c
> >>>>> @@ -0,0 +1,63 @@
> >>>>> +// SPDX-License-Identifier: GPL-2.0-or-later
> >>>>> +/*
> >>>>> + * Driver for Delta DPS920AB PSU
> >>>>> + *
> >>>>> + * Copyright (C) 2021 Delta Networks, Inc.
> >>>>> + * Copyright (C) 2021 Sartura Ltd.
> >>>>> + */
> >>>>> +
> >>>>> +#include <linux/i2c.h>
> >>>>> +#include <linux/module.h>
> >>>>> +#include <linux/of_device.h>
> >>>>> +#include "pmbus.h"
> >>>>> +
> >>>>> +static struct pmbus_driver_info dps920ab_info = {
> >>>>> +     .pages = 1,
> >>>>> +
> >>>>> +     .format[PSC_VOLTAGE_IN] = linear,
> >>>>> +     .format[PSC_VOLTAGE_OUT] = linear,
> >>>>> +     .format[PSC_CURRENT_IN] = linear,
> >>>>> +     .format[PSC_CURRENT_OUT] = linear,
> >>>>> +     .format[PSC_POWER] = linear,
> >>>>> +     .format[PSC_FAN] = linear,
> >>>>> +     .format[PSC_TEMPERATURE] = linear,
> >>>>> +
> >>>>> +     .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN  |
> >>>>> +     PMBUS_HAVE_VOUT  | PMBUS_HAVE_STATUS_VOUT   |
> >>>>> +     PMBUS_HAVE_IOUT  | PMBUS_HAVE_STATUS_IOUT   |
> >>>>> +     PMBUS_HAVE_TEMP  | PMBUS_HAVE_TEMP2         |
> >>>>> +     PMBUS_HAVE_PIN   | PMBUS_HAVE_POUT          |
> >>>>> +     PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12  |
> >>>>> +     PMBUS_HAVE_STATUS_INPUT | PMBUS_HAVE_STATUS_TEMP,
> >>>>> +};
> >>>>> +
> >>>>> +static int dps920ab_probe(struct i2c_client *client)
> >>>>> +{
> >>>>> +     if (!i2c_check_functionality(client->adapter,
> >>>>> +                                  I2C_FUNC_SMBUS_BYTE_DATA |
> >>>>> +                                  I2C_FUNC_SMBUS_WORD_DATA))
> >>>>> +             return -ENODEV;
> >>>>
> >>>> This check is done in pmbus_do_probe(), and repeating it here does not add
> >>>> any value.
> >>>
> >>> Ok, makes sense.
> >>>>
> >>>> That makes me wonder: Is this driver needed in the first place, or could
> >>>> it be added to drivers/hwmon/pmbus/pmbus.c ?
> >>>
> >>> It could be added as a generic driver, but that creates properties in
> >>> the sysfs that this thing
> >>> does not support like 3 voltage readings, 3 fans, and so on.
> >>>
> >>
> >> Can you be more specific ? What additional unsupported attributes
> >> are added, and why ? Are you saying the PSU reports registers as
> >> existing which do not really exist ? If so, which registers are those ?
> >
> > Sure, when core does probing and autodiscovery, then the following
> > sysfs attributes are created:
> >>
> >> curr1_crit         fan3_fault       in3_min_alarm      temp1_max
> >> curr1_crit_alarm   fan3_input       in3_rated_max      temp1_max_alarm
> >> curr1_input        fan3_target      in3_rated_min      temp1_min
> >> curr1_label        in1_crit         name               temp1_min_alarm
> >> curr1_max          in1_crit_alarm   of_node            temp1_rated_max
> >> curr1_max_alarm    in1_input        power              temp2_crit
> >> curr1_rated_max    in1_label        power1_alarm       temp2_crit_alarm
> >> curr2_crit         in1_lcrit        power1_input       temp2_input
> >> curr2_crit_alarm   in1_lcrit_alarm  power1_label       temp2_lcrit
> >> curr2_input        in1_max          power1_max         temp2_lcrit_alarm
> >> curr2_label        in1_max_alarm    power1_rated_max   temp2_max
> >> curr2_lcrit        in1_min          power2_cap         temp2_max_alarm
> >> curr2_lcrit_alarm  in1_min_alarm    power2_cap_alarm   temp2_min
> >> curr2_max          in1_rated_max    power2_crit        temp2_min_alarm
> >> curr2_max_alarm    in1_rated_min    power2_crit_alarm  temp2_rated_max
> >> curr2_rated_max    in2_input        power2_input       temp3_crit
> >> device             in2_label        power2_label       temp3_crit_alarm
> >> fan1_alarm         in3_crit         power2_max         temp3_input
> >> fan1_fault         in3_crit_alarm   power2_max_alarm   temp3_lcrit
> >> fan1_input         in3_input        power2_rated_max   temp3_lcrit_alarm
> >> fan1_target        in3_label        subsystem          temp3_max
> >> fan2_alarm         in3_lcrit        temp1_crit         temp3_max_alarm
> >> fan2_fault         in3_lcrit_alarm  temp1_crit_alarm   temp3_min
> >> fan2_input         in3_max          temp1_input        temp3_min_alarm
> >> fan2_target        in3_max_alarm    temp1_lcrit        temp3_rated_max
> >> fan3_alarm         in3_min          temp1_lcrit_alarm  uevent
> >
> > The following return -1, or -500 so they are not supported.
> > * fan2
> > * in2
> >
> > Weirdly, with the external driver both fan2 and in2 are enabled and work fine,
> > but when auto probing they are fan3 and in3.
> >
> > temp3 actually seems to return a valid temperature despite it not being used in
> > the vendor driver that features were picked from.
> >
>
> Can you run "grep . *" in the hwmon directory so I can see actual values ?
>
Sure:
>
> curr1_crit:-500
> curr1_crit_alarm:0
> curr1_input:195
> curr1_label:iin
> curr1_max:-500
> curr1_max_alarm:0
> curr1_rated_max:-500
> curr2_crit:-500
> curr2_crit_alarm:0
> curr2_input:320
> curr2_label:iout1
> curr2_lcrit:-500
> curr2_lcrit_alarm:0
> curr2_max:18625
> curr2_max_alarm:0
> curr2_rated_max:16875
> grep: device: Is a directory
> fan1_alarm:0
> fan1_fault:0
> fan1_input:10000
> fan1_target:0
> fan2_alarm:1
> fan2_fault:1
> fan2_input:-1
> fan2_target:-1
> fan3_alarm:1
> fan3_fault:1
> fan3_input:-1
> fan3_target:-1
> in1_crit:-500
> in1_crit_alarm:0
> in1_input:245250
> in1_label:vin
> in1_lcrit:-500
> in1_lcrit_alarm:0
> in1_max:-500
> in1_max_alarm:0
> in1_min:-500
> in1_min_alarm:0
> in1_rated_max:-500
> in1_rated_min:-500
> in2_input:-500
> in2_label:vcap
> in3_crit:255996
> in3_crit_alarm:0
> in3_input:54511
> in3_label:vout1
> in3_lcrit:255996
> in3_lcrit_alarm:0
> in3_max:255996
> in3_max_alarm:0
> in3_min:255996
> in3_min_alarm:0
> in3_rated_max:56136
> in3_rated_min:52863
> name:dps920ab
> grep: of_node: Is a directory
> grep: power: Is a directory
> power1_alarm:0
> power1_input:33250000
> power1_label:pin
> power1_max:-500000
> power1_rated_max:-500000
> power2_cap:-500000
> power2_cap_alarm:0
> power2_crit:-500000
> power2_crit_alarm:0
> power2_input:17750000
> power2_label:pout1
> power2_max:-500000
> power2_max_alarm:0
> power2_rated_max:920000000
> grep: subsystem: Is a directory
> temp1_crit:-500
> temp1_crit_alarm:0
> temp1_input:23000
> temp1_lcrit:-500
> temp1_lcrit_alarm:0
> temp1_max:-500
> temp1_max_alarm:0
> temp1_min:-500
> temp1_min_alarm:0
> temp1_rated_max:-500
> temp2_crit:-500
> temp2_crit_alarm:0
> temp2_input:26000
> temp2_lcrit:-500
> temp2_lcrit_alarm:0
> temp2_max:-500
> temp2_max_alarm:0
> temp2_min:-500
> temp2_min_alarm:0
> temp2_rated_max:-500
> temp3_crit:-500
> temp3_crit_alarm:0
> temp3_input:30000
> temp3_lcrit:-500
> temp3_lcrit_alarm:0
> temp3_max:-500
> temp3_max_alarm:0
> temp3_min:-500
> temp3_min_alarm:0
> temp3_rated_max:-500
> uevent:OF_NAME=psu
> uevent:OF_FULLNAME=/ap806/config-space@...00000/i2c@...000/psu@5a
> uevent:OF_COMPATIBLE_0=delta,dps920ab
> uevent:OF_COMPATIBLE_N=1


> Thanks,
> Guenter
>
> >>
> >> In this context, I have a hard time finding a reference for
> >> this power supply. Do you have a datasheet or some other documents
> >> you can share ?
> >
> > Unfortunately, I don't have a datasheet as that would have made this way easier.
> > It was all based on the vendor "driver" from DENT:
> > https://github.com/dentproject/dentOS/blob/main/packages/platforms/delta/arm64/tn48m/tn48m-poe/modules/builds/src/arm64-delta-tn48m-poe-psu.c
> >
> > I will try asking Delta for the datasheet.
> > Regards,
> > Robert
> >
> >>
> >> Thanks,
> >> Guenter
> >>
> >>> Is it okay to keep it as a separate driver then?
> >>>
> >>> Regards,
> >>> Robert
> >>>>
> >>>> Thanks,
> >>>> Guenter
> >>>>
> >>>>> +
> >>>>> +     return pmbus_do_probe(client, &dps920ab_info);
> >>>>> +}
> >>>>> +
> >>>>> +static const struct of_device_id __maybe_unused dps920ab_of_match[] = {
> >>>>> +     { .compatible = "delta,dps920ab", },
> >>>>> +     {}
> >>>>> +};
> >>>>> +
> >>>>> +MODULE_DEVICE_TABLE(of, dps920ab_of_match);
> >>>>> +
> >>>>> +static struct i2c_driver dps920ab_driver = {
> >>>>> +     .driver = {
> >>>>> +                .name = "dps920ab",
> >>>>> +                .of_match_table = of_match_ptr(dps920ab_of_match),
> >>>>> +     },
> >>>>> +     .probe_new = dps920ab_probe,
> >>>>> +};
> >>>>> +
> >>>>> +module_i2c_driver(dps920ab_driver);
> >>>>> +
> >>>>> +MODULE_AUTHOR("Robert Marko <robert.marko@...tura.hr>");
> >>>>> +MODULE_DESCRIPTION("PMBus driver for Delta DPS920AB PSU");
> >>>>> +MODULE_LICENSE("GPL");
> >>>>> --
> >>>>> 2.31.1
> >>>>>
> >>>
> >>>
> >>>
> >>
> >
> >
>


-- 
Robert Marko
Staff Embedded Linux Engineer
Sartura Ltd.
Lendavska ulica 16a
10000 Zagreb, Croatia
Email: robert.marko@...tura.hr
Web: www.sartura.hr

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