USB: musb: Use the correct style for SPDX License Identifier

This patch corrects the SPDX License Identifier style in
header files related to USB Dual Role (OTG-ready) Controller Drivers.
For C header files Documentation/process/license-rules.rst
mandates C-like comments (opposed to C source files where
C++ style should be used).

Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Link: https://lore.kernel.org/r/20200404104952.GA6575@nishad
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: musb: clean up debugfs file and directory creation

When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.

Because of this, lots of init functions do not need to have return
values, so this cleans up a lot of unused error handling code that never
could have triggered in the past.

Cc: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: musb: Remove redundant license text

Now that the SPDX tag is in all USB files, that identifies the license
in a specific and legally-defined manner. So the extra GPL text wording
can be removed as it is no longer needed at all.

This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text. And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.

No copyright headers or other non-license-description text was removed.

Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Acked-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: add SPDX identifiers to all remaining files in drivers/usb/

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the drivers/usb/ and include/linux/usb* files with the correct
SPDX license identifier based on the license text in the file itself.
The SPDX identifier is a legally binding shorthand, which can be used
instead of the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: musb: add tracepoints support for debugging

To avoid printk() overhead while debugging, this patch implements the
foundation of tracepoints logging for musb driver to make debug
easier.

Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: musb: remove extern qualifier from musb_debug.h header

This change removes confusing extern qualifier, which doesn't have any practical
sense there.

Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@nokia.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: drop unneeded musb_debug trickery

We have a generic way of enabling/disabling
different debug messages on a driver called
DYNAMIC_PRINTK. Anyone interested in enabling
just part of the debug messages, please read
the documentation under:

Documentation/dynamic-debug-howto.txt

for information on how to use that great
infrastructure.

Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: fix building musb drivers

Commit 3dacdf11 "usb: factor out state_string() on otg drivers"
broke building musb drivers since there is already another
otg_state_string() function in musb drivers, but with different
prototype. Fix musb drivers to use common otg_state_string(), too.

Also provide a nop for otg_state_string() if CONFIG_USB_OTG_UTILS
is not defined.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

USB: musb: make DBG() calls actually depend on CONFIG_USB_MUSB_DEBUG

Enabling CONFIG_USB_MUSB_DEBUG option causes -DDEBUG to be added to gcc's
command line, however the DBG() macro doesn't depend on DEBUG, so that the
debugging messages get printed regardless of the option, and I don't think
that this was intended. Get rid of otherwise unused xprintk() macro and make
DBG() macro directly call pr_debug() which only results in the actual code
generated if DEBUG is defined.

This change makes musb_hdrc.o ~30% less in size with CONFIG_USB_MUSB_DEBUG
disabled (in host mode).

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

usb: musb: add debugfs support

for now only a simple register dump entry (which can
be rather useful on debugging) and a way to start
test modes.

Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

usb: musb: fix debug global variable name

In order to avoid namespace conflicts, add a prefix
to our kernel-wise symbol.

Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

usb: musb: get rid of MUSB_LOGLEVEL and use parameter

We can change debugging level on the fly via
/sys/module/musb_hdrc/parameters/debug.

We can also get rid of the LOGLEVEL facility in Kconfig
and rely only in module parameter.

Cc: Anand Gadiyar <gadiyar@ti.com>
Cc: Bryan Wu <bryan.wu@analog.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

USB: Add MUSB and TUSB support

This patch adds support for MUSB and TUSB controllers
integrated into omap2430 and davinci. It also adds support
for external tusb6010 controller.

Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>