On Sun, 09 Jun 2019, Life is hard, and then you die wrote:

On Tue, May 07, 2019 at 01:24:15PM +0100, Lee Jones wrote:

quoted

On Sun, 21 Apr 2019, Ronald Tschalär wrote:

quoted

The iBridge device provides access to several devices, including:
- the Touch Bar
- the iSight webcam
- the light sensor
- the fingerprint sensor

This driver provides the core support for managing the iBridge device
and the access to the underlying devices. In particular, since the
functionality for the touch bar and light sensor is exposed via USB HID
interfaces, and the same HID device is used for multiple functions, this
driver provides a multiplexing layer that allows multiple HID drivers to
be registered for a given HID device. This allows the touch bar and ALS
driver to be separated out into their own modules.

Signed-off-by: Ronald Tschalär <redacted>
---
 drivers/mfd/Kconfig               |  15 +
 drivers/mfd/Makefile              |   1 +
 drivers/mfd/apple-ibridge.c       | 883 ++++++++++++++++++++++++++++++

I haven't taken a thorough look through, but I can tell you that the
vast majority of what you're trying to do here does not belong in
MFD.  MFD drivers are used to register child devices.  Almost all
functionality or 'real work' should be contained in the drivers the
MFD registers, not in the MFD parent itself.  You will need to move
all 'real work' out into the subordinate device drivers for
acceptance.

Thanks for your feedback. That was/is the idea: the actual Touch Bar
and ALS driver code is in separate modules - what is left in the
appple-ibridge mfd driver is a fairly generic hid driver
demultiplexer. However, that could be moved out into it's own
helper/module.

Having said that, it looks like the preference is to do all of this as
a hid driver with virtual hid devices instead of as an mfd driver.

Sounds like a better approach.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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