Re: [PATCH 1/2] hwmon: add Delta AHE-50DC fan control module driver

[Zev Weiss <zev@bewilderbeest.net>]

On Mon, Dec 06, 2021 at 03:02:49PM PST, Guenter Roeck wrote:
>On 12/6/21 2:44 PM, 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
>>
>>Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
>>---
>
>[ ... ]
>
>>+
>>+static const u8 AHE50DC_FAN_TEMP_REGS[] = { 0x8d, 0x8e, 0x8f, 0xd0 };
>>+static const u8 AHE50DC_FAN_SPEED_REGS[] = { 0x90, 0x91, 0x92, 0x93 };
>>+static const u8 AHE50DC_FAN_FAN_STATUS_REGS[] = { 0x81, 0x82 };
>>+#define AHE50DC_FAN_VIN_REG 0x88
>>+#define AHE50DC_FAN_CHIP_STATUS_REG 0x79
>
>PMBus registers:
>
>	PMBUS_STATUS_WORD               = 0x79,
>
>	PMBUS_STATUS_FAN_12             = 0x81,
>	PMBUS_STATUS_FAN_34             = 0x82,
>
>	PMBUS_READ_VIN                  = 0x88,
>
>        PMBUS_READ_TEMPERATURE_1        = 0x8D,
>        PMBUS_READ_TEMPERATURE_2        = 0x8E,
>        PMBUS_READ_TEMPERATURE_3        = 0x8F,
>        PMBUS_READ_FAN_SPEED_1          = 0x90,
>        PMBUS_READ_FAN_SPEED_2          = 0x91,
>        PMBUS_READ_FAN_SPEED_3          = 0x92,
>        PMBUS_READ_FAN_SPEED_4          = 0x93,
>
>This is quite obviously a PMBus device. Why not use the PMBus driver ?
>
>Guenter

Ah, so it appears -- not familiar enough with the constants to recognize 
it immediately I suppose (and wasn't expecting PMBus on this particular 
device).  Let me try that.


Thanks,
Zev