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Message-ID: <Ya/X46owU78iVbSO@hatter.bewilderbeest.net>
Date: Tue, 7 Dec 2021 13:53:39 -0800
From: Zev Weiss <zev@...ilderbeest.net>
To: Guenter Roeck <linux@...ck-us.net>
Cc: linux-hwmon@...r.kernel.org, Jean Delvare <jdelvare@...e.com>,
openbmc@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/2] hwmon: (pmbus) Add Delta AHE-50DC fan control
module driver
On Tue, Dec 07, 2021 at 11:44:01AM PST, Guenter Roeck wrote:
>On 12/7/21 11:22 AM, Zev Weiss wrote:
>>On Tue, Dec 07, 2021 at 09:50:15AM PST, Guenter Roeck wrote:
>>>On Mon, Dec 06, 2021 at 11:15:20PM -0800, Zev Weiss wrote:
>>>>This device is an integrated module of the Delta AHE-50DC Open19 power
>>>>shelf. For lack of proper documentation, this driver has been developed
>>>>referencing an existing (GPL) driver that was included in a code release
>>>>from LinkedIn [1]. It provides four fan speeds, four temperatures, and
>>>>one voltage reading, as well as a handful of warning and fault
>>>>indicators.
>>>>
>>>>[1] https://github.com/linkedin/o19-bmc-firmware/blob/master/meta-openbmc/meta-linkedin/meta-deltapower/recipes-kernel/fancontrol-mod/files/fancontrol.c
>>>>
>>>
>>>Hmm, that reference isn't really accurate anymore. I think it would be
>>>better to just say that the device was found to be PMBus compliant.
>>
>>Sure, will do.
>>
>
> Makes me wonder: How do you know that the referenced driver is for
> Delta AHE-50DC ?
We'd been waiting for the source code for the software it ships with for
a while, and were finally provided with that repo; everything I've
observed from the factory software is consistent with the code in that
driver. A sampling:
# no modinfo command available, but...
root@...-oob:~# strings -n8 /lib/modules/4.1.51-deltapower/extra/fancontrol.ko | head
fancontrol
license=GPL
description=FANCTRL Driver
author=Ping Mao <pmao@...kedin.com>
alias=i2c:fancontrol
depends=i2c_dev_sysfs
vermagic=4.1.51-deltapower mod_unload ARMv5 p2v8
fancontrol
status_word
bit 2: Temparature Warning
root@...-oob:~# cd /sys/bus/i2c/drivers/fancontrol/8-0030
root@...-oob:/sys/bus/i2c/drivers/fancontrol/8-0030# grep . fan* temp* vin
fan1_2_status:0
fan1_speed:7860
fan2_speed:7860
fan3_4_status:0
fan3_speed:7680
fan4_speed:7560
temperature1:292
temperature2:278
temperature3:286
temperature4:302
vin:12251
>>>
>>>>Signed-off-by: Zev Weiss <zev@...ilderbeest.net>
>>>>---
>>>> MAINTAINERS | 6 ++
>>>> drivers/hwmon/pmbus/Kconfig | 12 ++++
>>>> drivers/hwmon/pmbus/Makefile | 1 +
>>>> drivers/hwmon/pmbus/delta-ahe50dc-fan.c | 84 +++++++++++++++++++++++++
>>>> 4 files changed, 103 insertions(+)
>>>> create mode 100644 drivers/hwmon/pmbus/delta-ahe50dc-fan.c
>>>>
>>>>diff --git a/MAINTAINERS b/MAINTAINERS
>>>>index 0ac052200ecb..8bb7ba52d2f5 100644
>>>>--- a/MAINTAINERS
>>>>+++ b/MAINTAINERS
>>>>@@ -5425,6 +5425,12 @@ W: https://linuxtv.org
>>>> T: git git://linuxtv.org/media_tree.git
>>>> F: drivers/media/platform/sti/delta
>>>>
>>>>+DELTA AHE-50DC FAN CONTROL MODULE DRIVER
>>>>+M: Zev Weiss <zev@...ilderbeest.net>
>>>>+L: linux-hwmon@...r.kernel.org
>>>>+S: Maintained
>>>>+F: drivers/hwmon/pmbus/delta-ahe50dc-fan.c
>>>>+
>>>> DELTA DPS920AB PSU DRIVER
>>>> M: Robert Marko <robert.marko@...tura.hr>
>>>> L: linux-hwmon@...r.kernel.org
>>>>diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
>>>>index ffb609cee3a4..937e1c2c11e7 100644
>>>>--- a/drivers/hwmon/pmbus/Kconfig
>>>>+++ b/drivers/hwmon/pmbus/Kconfig
>>>>@@ -66,6 +66,18 @@ config SENSORS_BPA_RS600
>>>> This driver can also be built as a module. If so, the module will
>>>> be called bpa-rs600.
>>>>
>>>>+config SENSORS_DELTA_AHE50DC_FAN
>>>>+ tristate "Delta AHE-50DC fan control module"
>>>>+ depends on I2C
>>>>+ select REGMAP_I2C
>>
>>And I realize I neglected to drop the depends & select lines here when moving this bit into the pmbus directory...
>>
>>>>+ help
>>>>+ If you say yes here you get hardware monitoring support for
>>>>+ the integrated fan control module of the Delta AHE-50DC
>>>>+ Open19 power shelf.
>>>>+
>>>>+ This driver can also be built as a module. If so, the module
>>>>+ will be called delta-ahe50dc-fan.
>>>>+
>>>> config SENSORS_FSP_3Y
>>>> tristate "FSP/3Y-Power power supplies"
>>>> help
>>>>diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
>>>>index 0ed4d596a948..a56b2897288d 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_BPA_RS600) += bpa-rs600.o
>>>>+obj-$(CONFIG_SENSORS_DELTA_AHE50DC_FAN) += delta-ahe50dc-fan.o
>>>> obj-$(CONFIG_SENSORS_FSP_3Y) += fsp-3y.o
>>>> obj-$(CONFIG_SENSORS_IBM_CFFPS) += ibm-cffps.o
>>>> obj-$(CONFIG_SENSORS_DPS920AB) += dps920ab.o
>>>>diff --git a/drivers/hwmon/pmbus/delta-ahe50dc-fan.c b/drivers/hwmon/pmbus/delta-ahe50dc-fan.c
>>>>new file mode 100644
>>>>index 000000000000..07b1e7c5f5f5
>>>>--- /dev/null
>>>>+++ b/drivers/hwmon/pmbus/delta-ahe50dc-fan.c
>>>>@@ -0,0 +1,84 @@
>>>>+// SPDX-License-Identifier: GPL-2.0
>>>>+/*
>>>>+ * Delta AHE-50DC power shelf fan control module driver
>>>>+ *
>>>>+ * Copyright 2021 Zev Weiss <zev@...ilderbeest.net>
>>>>+ */
>>>>+
>>>>+#include <linux/kernel.h>
>>>>+#include <linux/module.h>
>>>>+#include <linux/i2c.h>
>>>>+#include <linux/pmbus.h>
>>>
>>>Alphabetic include file order please.
>>
>>Ack, will fix.
>>
>>>
>>>>+
>>>>+#include "pmbus.h"
>>>>+
>>>>+#define AHE50DC_PMBUS_READ_TEMP4 0xd0
>>>>+
>>>>+static int ahe50dc_fan_read_word_data(struct i2c_client *client, int page, int phase, int reg)
>>>>+{
>>>>+ /* temp1 in (virtual) page 1 is remapped to mfr-specific temp4 */
>>>>+ if (page == 1) {
>>>>+ if (reg == PMBUS_READ_TEMPERATURE_1)
>>>>+ return i2c_smbus_read_word_data(client, AHE50DC_PMBUS_READ_TEMP4);
>>>>+ return -EOPNOTSUPP;
>>>>+ }
>>>>+ return -ENODATA;
>>>>+}
>>>>+
>>>>+static struct pmbus_driver_info ahe50dc_fan_info = {
>>>>+ .pages = 2,
>>>>+ .format[PSC_FAN] = direct,
>>>>+ .format[PSC_TEMPERATURE] = direct,
>>>>+ .format[PSC_VOLTAGE_IN] = direct,
>>>>+ .m[PSC_FAN] = 1,
>>>>+ .b[PSC_FAN] = 0,
>>>>+ .R[PSC_FAN] = 0,
>>>>+ .m[PSC_TEMPERATURE] = 1,
>>>>+ .b[PSC_TEMPERATURE] = 0,
>>>>+ .R[PSC_TEMPERATURE] = 1,
>>>>+ .m[PSC_VOLTAGE_IN] = 1,
>>>>+ .b[PSC_VOLTAGE_IN] = 0,
>>>>+ .R[PSC_VOLTAGE_IN] = 3,
>>>
>>>How did you determine the exponents ? The referenced driver
>>>doesn't seem to make a difference between voltage and temperature
>>>exponents (nor fan speed, which is a bit odd).
>>
>>Lacking documentation, the honest answer here is that I just sort of eyeballed it. However, after doing so, I dug through the code dump a bit more and found some userspace unit-conversion bits that appear to confirm what I arrived at:
>>
>>https://github.com/linkedin/o19-bmc-firmware/blob/master/meta-openbmc/meta-linkedin/meta-deltapower/recipes-deltapower/platform-lib/files/powershelf/powershelf_fan.c
>>
>>(Lines 107, and 153/161/169/177.)
>>
>
>Brr. Well, why use a standard API/ABI if one can invent a non-standard one.
>
It's...not the only bit of gratuitous wheel-reinvention we've come
across in this particular system.
>Can you check this with real hardware, by any chance ?
>
If you mean running that code on it, yes -- here's the userspace utility
that invokes that library routine:
root@...-oob:~# fan-util.sh
fan1 speed: 7860 RPM
fan2 speed: 7860 RPM
fan3 speed: 7620 RPM
fan4 speed: 7560 RPM
temperature1: 29.20 C
temperature2: 27.80 C
temperature3: 28.50 C
temperature4: 30.20 C
vin_undervolt_fault: no
overtemperature_warning: no
fan_fault: no
fan_warning: no
fan_status: ok
That fan-util.sh script being this:
https://github.com/linkedin/o19-bmc-firmware/blob/master/meta-openbmc/meta-linkedin/meta-deltapower/recipes-deltapower/liutils/files/fan-util.sh
which invokes this:
https://github.com/linkedin/o19-bmc-firmware/blob/master/meta-openbmc/meta-linkedin/meta-deltapower/recipes-deltapower/liutils/files/fan-ctrl/fan-util.c
(which calls into the routine in powershelf_fan.c linked above).
Zev
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