usb: mtu3: mtu3_debug: remove an unused struct member

The "nregs" member is not used. The code uses the "regset.nregs"
struct member instead.

Acked-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/X8ikv1QA3Do50D+R@mwanda
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: mtu3: mtu3_debug: Add forward declaration of 'struct ssusb_mtk'

Without it, the build system complains that it was declared inside
the parameter list.

Fixes the following W=1 kernel build warning(s):

In file included from drivers/usb/mtu3/mtu3_trace.c:11:
drivers/usb/mtu3/mtu3_debug.h:29:36: warning: ‘struct ssusb_mtk’ declared inside parameter list will not be visible outside of this definition or declaration
29 | void ssusb_dev_debugfs_init(struct ssusb_mtk *ssusb);
| ^~~~~~~~~
drivers/usb/mtu3/mtu3_debug.h:30:35: warning: ‘struct ssusb_mtk’ declared inside parameter list will not be visible outside of this definition or declaration
30 | void ssusb_dr_debugfs_init(struct ssusb_mtk *ssusb);
| ^~~~~~~~~
drivers/usb/mtu3/mtu3_debug.h:31:39: warning: ‘struct ssusb_mtk’ declared inside parameter list will not be visible outside of this definition or declaration
31 | void ssusb_debugfs_create_root(struct ssusb_mtk *ssusb);
| ^~~~~~~~~
drivers/usb/mtu3/mtu3_debug.h:32:39: warning: ‘struct ssusb_mtk’ declared inside parameter list will not be visible outside of this definition or declaration
32 | void ssusb_debugfs_remove_root(struct ssusb_mtk *ssusb);
| ^~~~~~~~~

Cc: Chunfeng Yun <chunfeng.yun@mediatek.com>
Cc: linux-mediatek@lists.infradead.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20200703174148.2749969-2-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: mtu3: Use the correct style for SPDX License Identifier

This patch corrects the SPDX License Identifier style in
header files related to MediaTek USB3 Dual Role controller.
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.

Reviewed-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

USB: mtu3: Use the correct style for SPDX License Identifier

This patch corrects the SPDX License Identifier style in
header files related to MediaTek USB3 Dual Role controller.
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>
Reviewed-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20200404103728.GA6011@nishad
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: mtu3: add tracepoints to help debug

This patch implements a few initial tracepoints for the
mtu3 driver. More traces can be added as necessary in order
to ease the task of debugging.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: mtu3: move vbus and mode debugfs interfaces into mtu3_debugfs.c

Due to the separated debugfs files are added, move vbus and mode
debugfs interfaces related with dual-role switch from mtu3_dr.c
into mtu3_debugfs.c

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: mtu3: add debugfs interface files

This adds more debugfs consumers. The debugfs entries read some
important registers, fifo status, QMU ring, endpoint status, and
IPPC probe interface to get internal status.
With these entries, users can check the registers, endpoint and
GPD used during run time.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>