This instroduces comments that explain the purpose, parameters and return codes
of a few fdt support functions, that are used to fill the fdt.

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Acked-by: Simon Glass <sjg@chromium.org>

Before device-tree, the device serial number used to be passed to the kernel
using ATAGs (on ARM). This is now deprecated and all the handover to the kernel
should now be done using device-tree. Thus, this passes the serial-number
property to the kernel using the serial-number property of the root node, as
expected by the kernel.

The serial number is a string that somewhat represents the device's serial
number. It might come from some form of storage (e.g. an eeprom) and be
programmed at factory-time by the manufacturer or come from identification
bits available in e.g. the SoC.

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Reviewed-by: Simon Glass <sgj@chromium.org>

Add 'fdt_fixup_display' function to fixup device-tree native-mode property
of display-timings node to select timings for a specific display.
This is useful if a device-tree has configurations for multiple
display timings for undetectable displays.

see kernel Documentation/devicetree/bindings/video/display-timing.txt

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Acked-by: Simon Glass <sjg@chromium.org>

Commit 90bac29a76bc8d649b41a55f2786c0abef9bb2c1 claims to fix this bug
that was introduced in commit a92fd6577ea17751ead9b50243e3c562125cf581
but doesn't actually make the change that the commit message describes.

Actually fix the bug this time.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Acked-by: Simon Glass <sjg@chromium.org>

Add a generic helper to fill and enable simplefb nodes.

The first user of this will be the sunxi display code.

lcd_dt_simplefb_configure_node is also a good candidate to be converted
to use this, but that requires someone to run some tests first, as
lcd_dt_simplefb_configure_node does not honor #address-cells and #size-cells,
but simply assumes 1 and 1 for both.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Simon Glass <sjg@chromium.org>

Add an additional function for adding information to the device tree before
booting. This permits additions which are not board-specific.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Anatolij Gustschin <agust@denx.de>
Reviewed-by: Tom Rini <trini@ti.com>

The message about needing to reset should be printed no matter what error
is printed. Also, an error should always be printed.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Anatolij Gustschin <agust@denx.de>
Reviewed-by: Tom Rini <trini@ti.com>

This function is useful for ensuring that a node exists. Export it so it
can be used more widely.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Anatolij Gustschin <agust@denx.de>
Reviewed-by: Tom Rini <trini@ti.com>

This function can fail if the device tree runs out of space. Rather than
silently booting with an incomplete device tree, allow the failure to be
detected.

Unfortunately this involves changing a lot of places in the code. I have
not changed behvaiour to return an error where one is not currently
returned, to avoid unexpected breakage.

Eventually it would be nice to allow boards to register functions to be
called to update the device tree. This would avoid all the many functions
to do this. However it's not clear yet if this should be done using driver
model or with a linker list. This work is left for later.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Anatolij Gustschin <agust@denx.de>