mfd: Add Raspberry Pi Sense HAT core driver

[XECDesign]

joystick: Add Raspberry Pi Sense HAT joystick driver
fbdev: Add Raspberry Pi Sense HAT framebuffer driver
configs: Enable Raspberry Pi Sense HAT modules
overlays: Provide a Raspberry Pi Sense HAT overlay for older Raspberry Pi models

[pelwell]

If you use the managed version (devm_gpiod_get) then you don't need to call gpiod_put.

[pelwell]

Can you add an entry to the overlays/README file?

[XECDesign]

I guess I shouldn't squash the changes until you and Dom are okay to merge it, to keep the changes easier to track

[pelwell]

I think at this stage it would help if you did squash. Dom hasn't looked at it yet, and it would save time if he just saw the "final" version.

[XECDesign]

done

[XECDesign]

@notro If you get a chance, would you be willing to take a look at the framebuffer section? The documentation assumes more knowledge of traditional graphics hw than I possess, so there's a lot of guesswork in the code.

[pelwell]

It looks OK to me, apart from the commit message which is enormous. Either rewrite it completely or just add a summary title line, but make sure you put a blank line after the first line.

[notro]

diff --git a/drivers/video/fbdev/rpisense-fb.c b/drivers/video/fbdev/rpisense-fb.c

+static void *rvmalloc(unsigned long size)
+{
+   void *mem;
+   unsigned long adr;
+   size = PAGE_ALIGN(size);
+   mem = vmalloc_32(size);
+   if (!mem)
+       return NULL;
+
+   memset(mem, 0, size); /* Clear the ram out, no junk to the user */
+   adr = (unsigned long) mem;
+   while (size > 0) {
+       SetPageReserved(vmalloc_to_page((void *)adr));
+       adr += PAGE_SIZE;
+       size -= PAGE_SIZE;
+   }
+
+   return mem;
+}

I have seen this type of code in out-of-tree fb drivers, but not in mainline.
In my fbtft drivers I just use vzalloc(size) to allocate the framebuffer memory, no SetPageReserved().

[notro]

@XECDesign Some kernel coding style issues you might wanna look into: https://gist.github.com/notro/c73b9342e52f89494311

[XECDesign]

Ah, didn't know about checkpatch script. Thanks.

[XECDesign]

fixed

[P33M]

@pelwell ping - ok to merge?

[pelwell]

Is it picky to ask for the overlay makefile addition to also be in alphabetical order, like the others?

[XECDesign]

Done