simplefb: Add simplefb MAINTAINERS entry

During the discussion about adding clock handling code to simplefb, it became
clear that simplefb currently does not have an active maintainer.

I've discussed this with Stephen Warren <swarren@wwwdotorg.org>, the original
author of simplefb, and with his permisson I'm picking up maintainership of
simplefb.

Cc: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Maxime Ripard <maxime.ripard@free-electrons.com>
dt-bindings: Add a clocks property to the simple-framebuffer binding

A simple-framebuffer node represents a framebuffer setup by the firmware /
bootloader. Such a framebuffer may have a number of clocks in use, add a
property to communicate this to the OS.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Mike Turquette <mturquette@linaro.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Maxime Ripard <maxime.ripard@free-electrons.com>

--
Changes in v2:
-Added Reviewed-by: Mike Turquette <mturquette@linaro.org>
Changes in v3:
-Updated description to make clear simplefb deals with more then just memory
simplefb: formalize pseudo palette handling

Signed-off-by: Luc Verhaegen <libv@skynet.be>
Acked-by: Stephen Warren <swarren@nvidia.com>
[hdegoede@redhat.com: drop unnecessary void * cast]
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Maxime Ripard <maxime.ripard@free-electrons.com>
simplefb: add goto error path to probe

While at it update ioremap_wc error return from ENODEV to ENOMEM.

Signed-off-by: Luc Verhaegen <libv@skynet.be>
Acked-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Maxime Ripard <maxime.ripard@free-electrons.com>
simplefb: add clock handling code

This claims and enables clocks listed in the simple framebuffer dt node.
This is needed so that the display engine, in case the required clocks
are known by the kernel code and are described in the dt, will remain
properly enabled.

Signed-off-by: Luc Verhaegen <libv@skynet.be>
[hdegoede@redhat.com: Change clks from list to dynamic array]
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Maxime Ripard <maxime.ripard@free-electrons.com>

--
Changes in v4:
-change clks from linkedlist to dynamic allocated array
-propagate EPROBE_DEFER up from simplefb_clocks_init to simplefb_probe