Hi Joel, thanks for having a look at this.

On Wed, 2021-04-07 at 20:03 -0400, Joel Savitz wrote:
> From: Joel Savitz <joelsavitz@gmail.com>
> 
> This is a forward port of the Rapsberry Pi Sense Hat driver from the
> downstream Raspberry Pi kernel tree.
> 
> I have slightly consolidated things and done some quick testing of this
> driver on Fedora (which comes with the device tree blobs), and I want to
> do a bit more testing before submiting the driver for inclusion in
> mainline Linux.
> 
> I would like to get some feedback from the community on what may need to
> be improved, fixed, or changed as early as possible, so this is a request
> for comments.
> 
> Signed-off-by: Joel Savitz <joelsavitz@gmail.com>
> ---

Some random comments:

 - Can you share more info on the HW, is this a uC on the other side? etc...
 - A driver that depends on DT should have bindings.
 - Please have a look at a modern MFD device handles things. New APIs appeared.
   See for example the 'atc260x' driver available in linux-next.
 - Try to use regmap so as not having to export functions across modules.
 - No need to explicitly schedule the interrupt in the joystick driver. New IRQ
   APIs can handle that. See devm_request_threaded_irq().
 - I don't think adding new FB drivers is possible, the whole subsystem is in
   the process of being deprecated. I believe there is an equivalent framework
   in DRM to cater for these simple FB devices.

Regards,
Nicolas