Messages in this thread | | | Subject | Re: [PATCH v3 1/2] hwmon: (pmbus) Add Delta AHE-50DC fan control module driver | From | Guenter Roeck <> | Date | Tue, 7 Dec 2021 11:44:01 -0800 |
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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. > >> >>> Signed-off-by: Zev Weiss <zev@bewilderbeest.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@bewilderbeest.net> >>> +L: linux-hwmon@vger.kernel.org >>> +S: Maintained >>> +F: drivers/hwmon/pmbus/delta-ahe50dc-fan.c >>> + >>> DELTA DPS920AB PSU DRIVER >>> M: Robert Marko <robert.marko@sartura.hr> >>> L: linux-hwmon@vger.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@bewilderbeest.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.
Can you check this with real hardware, by any chance ?
>> >>> + .func[0] = PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_TEMP3 | >>> + PMBUS_HAVE_VIN | PMBUS_HAVE_FAN12 | PMBUS_HAVE_FAN34 | >>> + PMBUS_HAVE_STATUS_FAN12 | PMBUS_HAVE_STATUS_FAN34 | PMBUS_PAGE_VIRTUAL, >>> + .func[1] = PMBUS_HAVE_TEMP | PMBUS_PAGE_VIRTUAL, >>> + .read_word_data = ahe50dc_fan_read_word_data, >>> +}; >>> + >>> +static struct pmbus_platform_data ahe50dc_fan_data = { >>> + .flags = PMBUS_NO_CAPABILITY, >>> +}; >> >> Is that necessary ? It should only be used if trying to read CAPABILITY >> reports bad data. > > Unfortunately it does seem to be needed -- CAPABILITY returns 0xff, but despite having bit 7 set the device mangles all subsequent transactions by returning bad PEC bytes if we enable I2C_CLIENT_PEC. Actually, none of the fields in that CAPABILITY value seem to accurately reflect the device's observed behavior; I'm pretty sure 0xff is just what it returns when it doesn't support something (I think the bad PECs it sends are all 0xff too). > > I'll add an explanatory comment in v4. > > Please do.
Thanks, Guenter
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