commands/*: Replace license and copyright boilerplate by SPDX identfiers ...

While at it also drop references to the non-existing CREDITS file and do
some small rearrangements for some uniform formatting.
(SPDX-License-Identifier first, then copyright texts and then an empty
line.)

The advantage is that these specifiers are machine-parseable which helps
license conformance.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

driver: Add device_detect_all() function ...

Add a device_detect_all function to detect all devices and use it
in the detect command. This makes the functionality reusable in other
code.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

detect command: Drop -e option ...

The -e option is not that useful. Normally, when a device cannot
be detected, then there should be no reason to not try to detect
other devices. When a user is interested in a particular detect
result, detect can still be called with that (and only that)
device.
We could also argue that the user should not care about the result
of the detect call, but instead check if the desired device is
present afterwards.
Drop handling of the -e option, but still ignore it for compatibility
reasons.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

commands: detect: use device_detect_by_name ...

Instead of looking up the device ourselves let device_detect_by_name
do the work.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

commands: harmonize in-barebox documentation ...

This patch does probably too much, but it's hard (and very
cumbersome/time consuming) to break it out. What is does is this:

* each command has one short description, e.g. "list MUX configuration"
* made sure the short descriptions start lowercase
* each command has one usage. That string contains just the
  options, e.g. "[-npn]". It's not part of the long help text.
* that is, it doesn't say "[OPTIONS]" anymore, every usable option
  is listed by character in this (short) option string (the long
  description is in the long help text, as before)
* help texts have been reworked, to make them
  - sometimes smaller
  - sometimes describe the options better
  - more often present themselves in a nicer format
* all long help texts are now created with BUSYBOX_CMD_HELP_
  macros, no more 'static const __maybe_unused char cmd_foobar_help[]'
* made sure the long help texts starts uppercase
* because cmdtp->name and cmdtp->opts together provide the new usage,
  all "Usage: foobar" texts have been removed from the long help texts
* BUSYBOX_CMD_HELP_TEXT() provides the trailing newline by itself, this
  is nicer in the source code
* BUSYBOX_CMD_HELP_OPT() provides the trailing newline by itself
* made sure no line gets longer than 77 characters
* delibertely renamed cmdtp->usage, so that we can get compile-time
  errors (e.g. in out-of-tree modules that use register_command()
* the 'help' command can now always emit the usage, even without
  compiled long help texts
* 'help -v' gives a list of commands with their short description, this
  is similar like the old "help" command before my patchset
* 'help -a' gives out help of all commands

Signed-off-by: Holger Schurig <holgerschurig@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

commands: group 'help' output ...

The old output of "help" was just producing a long list, that usually
scrolled of the screen (even on a X11 terminal). This list is more
compact, and also sorted by groups.

The old output format (plus grouping) is now available with 'help -v'.

Example:

   Information commands:
     ?, devinfo, help, iomem, meminfo, version
   Boot commands:
     boot, bootm, go, loadb, loads, loadx, loady, saves, uimage
   ...

Signed-off-by: Holger Schurig <holgerschurig@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

treewide: Add missing includes ...

A lot of files rely on include/driver.h including include/of.h (and
this including include/errno.h. include the files explicitly so we can
eventually get rid of including of.h from driver.h

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

detect command: Add missing help text for -a option ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

detect command: Add -a option to detect all devices ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

devices: add detect mechanism ...

We often encounter the situation where slow devices should not be
probed during startup since probing is slow and maybe unnecessary
for unused devices. With MMC we have the 'probe' device parameter,
for ata we have the same, for USB we have the 'usb' command. Overall
this is not very consistent.
With MMC there is the additional problem that the probe parameter
is attached to the logical device when we often have the information
which physical device we want to probe.
This patch adds a 'detect' callback for devices and adds a command
to detect devices and to list the devices which are actually detecable.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>