Re: [PATCH 0/5] mfd: add amd side-band functionality

[Lee Jones <lee@kernel.org>]

On Thu, 30 May 2024, Naveen Krishna Chatradhi wrote:

> From: Akshay Gupta <akshay.gupta@amd.com>
> 
> At present, sbrmi under hwmon subsystem is probed as an i2c 
> driver and reports power.
> 
> However, APML interface defines few other protocols to support
> OOB system management functionality.
> 
> This patchset the following
> 1. Based on hwmon maintainers feedback, move the i2c client
>    probe and sbrmi core functionality to drivers/mfd/
> 2. Add an MFD cell, which probes the hwmon/sbrmi and continues to
>    report power using the symbol exported by the mfd/sbrmi-core.
> 3. Convert i2c to regmap which provides multiple benefits
>    over direct smbus APIs.
> 4. Register a misc device which provides 
>     a. An ioctl interface through node /dev/sbrmiX
>     b. Open-sourced and widely used https://github.com/amd/esmi_oob_library
>        will continue to provide user-space programmable API for the following
>       - Mailbox xfer (already defined in sbrmi_mailbox_xfer())
>       - CPUID access
>       - MCAMSR access
> 
> Akshay Gupta (5):
>   hwmon/mfd sbrmi: Move core sbrmi from hwmon to MFD
>   mfd: sbrmi: Add mfd cell to I2C probe to be used by hwmon
>   mfd/hwmon sbrmi: Use regmap subsystem
>   mfd: sbrmi: Clear sbrmi status register bit SwAlertSts
>   mfd/hwmon: sbrmi: Add support for APML protocols
> 
>  drivers/hwmon/Kconfig         |   1 +
>  drivers/hwmon/sbrmi.c         | 284 +++-----------------
>  drivers/mfd/Kconfig           |   9 +-
>  drivers/mfd/Makefile          |   2 +
>  drivers/mfd/sbrmi-core.c      | 490 ++++++++++++++++++++++++++++++++++

It's not clear to me what any of these 500 lines do, but they do not
look like a good fit for MFD.  Perhaps I'm missing something.  Can you
provide some more information about the device and why you think MFD is
a suitable location for it?

>  drivers/mfd/sbrmi-core.h      |  37 +++
>  drivers/mfd/sbrmi-i2c.c       | 165 ++++++++++++
>  include/linux/mfd/amd-sb.h    |  55 ++++
>  include/uapi/linux/amd-apml.h |  74 +++++
>  9 files changed, 871 insertions(+), 246 deletions(-)
>  create mode 100644 drivers/mfd/sbrmi-core.c
>  create mode 100644 drivers/mfd/sbrmi-core.h
>  create mode 100644 drivers/mfd/sbrmi-i2c.c
>  create mode 100644 include/linux/mfd/amd-sb.h
>  create mode 100644 include/uapi/linux/amd-apml.h
> 
> -- 
> 2.25.1
> 

-- 
Lee Jones [李琼斯]