<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/include/linux/usb/ch9.h, branch v3.12-rc7</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>usb: common: introduce usb_state_string()</title>
<updated>2013-03-18T09:17:11+00:00</updated>
<author>
<name>Felipe Balbi</name>
<email>balbi@ti.com</email>
</author>
<published>2013-01-24T20:29:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d1e3d757f7aa91f15db347fc05ffd7ef7f413091'/>
<id>d1e3d757f7aa91f15db347fc05ffd7ef7f413091</id>
<content type='text'>
this function will receive enum usb_device_state
and return a human-readable string from it or,
case an unknown value is passed as argument,
the string "UNKNOWN".

Signed-off-by: Felipe Balbi &lt;balbi@ti.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
this function will receive enum usb_device_state
and return a human-readable string from it or,
case an unknown value is passed as argument,
the string "UNKNOWN".

Signed-off-by: Felipe Balbi &lt;balbi@ti.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>UAPI: (Scripted) Disintegrate include/linux/usb</title>
<updated>2012-10-09T08:49:07+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2012-10-09T08:49:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=5e1ddb481776a487b15b40579a000b279ce527c9'/>
<id>5e1ddb481776a487b15b40579a000b279ce527c9</id>
<content type='text'>
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Acked-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Acked-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Acked-by: Michael Kerrisk &lt;mtk.manpages@gmail.com&gt;
Acked-by: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
Acked-by: Dave Jones &lt;davej@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Acked-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Acked-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Acked-by: Michael Kerrisk &lt;mtk.manpages@gmail.com&gt;
Acked-by: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
Acked-by: Dave Jones &lt;davej@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: Add macros for interrupt endpoint types.</title>
<updated>2012-05-18T22:42:02+00:00</updated>
<author>
<name>Sarah Sharp</name>
<email>sarah.a.sharp@linux.intel.com</email>
</author>
<published>2012-05-08T14:44:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=6538eafc7cb6b2d718d2539bef3158bfaad57468'/>
<id>6538eafc7cb6b2d718d2539bef3158bfaad57468</id>
<content type='text'>
The USB 3.0 spec defines a new way of differentiating interrupt
endpoints.  The idea is that some interrupt endpoints are used for
notifications, i.e. they continually NAK the transfer until something
changes on the device.  Other interrupt endpoints are used as a way to
periodically transfer data.

The USB 3.0 endpoint descriptor uses bits 5:4 of bmAttributes for
interrupt endpoints, to define the endpoint as either a Notification
endpoint, or a Periodic endpoint.  Introduce macros to dig out that
information.

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The USB 3.0 spec defines a new way of differentiating interrupt
endpoints.  The idea is that some interrupt endpoints are used for
notifications, i.e. they continually NAK the transfer until something
changes on the device.  Other interrupt endpoints are used as a way to
periodically transfer data.

The USB 3.0 endpoint descriptor uses bits 5:4 of bmAttributes for
interrupt endpoints, to define the endpoint as either a Notification
endpoint, or a Periodic endpoint.  Introduce macros to dig out that
information.

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: Add support to enable/disable USB3 link states.</title>
<updated>2012-05-18T22:41:58+00:00</updated>
<author>
<name>Sarah Sharp</name>
<email>sarah.a.sharp@linux.intel.com</email>
</author>
<published>2012-04-25T00:21:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=1ea7e0e8e3d0f50901d335ea4178ab2aa8c88201'/>
<id>1ea7e0e8e3d0f50901d335ea4178ab2aa8c88201</id>
<content type='text'>
There are various functions within the USB core that will need to
disable USB 3.0 link power states.  For example, when a USB device
driver is being bound to an interface, we need to disable USB 3.0 LPM
until we know if the driver will allow hub-initiated LPM transitions.
Another example is when the USB core is switching alternate interface
settings.  The USB 3.0 timeout values are dependent on what endpoints
are enabled, so we want to ensure that LPM is disabled until the new alt
setting is fully installed.

Multiple functions need to disable LPM, and those functions can even be
nested.  For example, usb_bind_interface() could disable LPM, and then
call into the driver probe function, which may attempt to switch to a
different alt setting.  Therefore, we need to keep a count of the number
of functions that require LPM to be disabled at any point in time.

Introduce two new USB core API calls, usb_disable_lpm() and
usb_enable_lpm().  These functions increment and decrement a new
variable in the usb_device, lpm_disable_count.  If usb_disable_lpm()
fails, it will call usb_enable_lpm() in order to balance the
lpm_disable_count.

These two new functions must be called with the bandwidth_mutex locked.
If the bandwidth_mutex is not already held by the caller, it should
instead call usb_unlocked_disable_lpm() and usb_enable_lpm(), which take
the bandwidth_mutex before calling usb_disable_lpm() and
usb_enable_lpm(), respectively.

Introduce a new variable (timeout) in the usb3_lpm_params structure to
keep track of the currently enabled U1/U2 timeout values.  When
usb_disable_lpm() is called, and the USB device has the U1 or U2
timeouts set to a non-zero value (meaning either device-initiated or
hub-initiated LPM is enabled), attempt to disable LPM, regardless of the
state of the lpm_disable_count.  We want to ensure that all callers can
be guaranteed that LPM is disabled if usb_disable_lpm() returns zero.

Otherwise the following scenario could occur:

1. Driver A is being bound to interface 1.  usb_probe_interface()
disables LPM.  Driver A doesn't care if hub-initiated LPM is enabled, so
even though usb_disable_lpm() fails, the probe of the driver continues,
and the bandwidth mutex is dropped.

2. Meanwhile, Driver B is being bound to interface 2.
usb_probe_interface() grabs the bandwidth mutex and calls
usb_disable_lpm().  That call should attempt to disable LPM, even
though the lpm_disable_count is set to 1 by Driver A.

For usb_enable_lpm(), we attempt to enable LPM only when the
lpm_disable_count is zero.  If some step in enabling LPM fails, it will
only have a minimal impact on power consumption, and all USB device
drivers should still work properly.  Therefore don't bother to return
any error codes.

Don't enable device-initiated LPM if the device is unconfigured.  The
USB device will only accept the U1/U2_ENABLE control transfers in the
configured state.  Do enable hub-initiated LPM in that case, since
devices are allowed to accept the LGO_Ux link commands in any state.

Don't enable or disable LPM if the device is marked as not being LPM
capable.  This can happen if:
 - the USB device doesn't have a SS BOS descriptor,
 - the device's parent hub has a zeroed bHeaderDecodeLatency value, or
 - the xHCI host doesn't support LPM.

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Cc: Andiry Xu &lt;andiry.xu@amd.com&gt;
Cc: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
There are various functions within the USB core that will need to
disable USB 3.0 link power states.  For example, when a USB device
driver is being bound to an interface, we need to disable USB 3.0 LPM
until we know if the driver will allow hub-initiated LPM transitions.
Another example is when the USB core is switching alternate interface
settings.  The USB 3.0 timeout values are dependent on what endpoints
are enabled, so we want to ensure that LPM is disabled until the new alt
setting is fully installed.

Multiple functions need to disable LPM, and those functions can even be
nested.  For example, usb_bind_interface() could disable LPM, and then
call into the driver probe function, which may attempt to switch to a
different alt setting.  Therefore, we need to keep a count of the number
of functions that require LPM to be disabled at any point in time.

Introduce two new USB core API calls, usb_disable_lpm() and
usb_enable_lpm().  These functions increment and decrement a new
variable in the usb_device, lpm_disable_count.  If usb_disable_lpm()
fails, it will call usb_enable_lpm() in order to balance the
lpm_disable_count.

These two new functions must be called with the bandwidth_mutex locked.
If the bandwidth_mutex is not already held by the caller, it should
instead call usb_unlocked_disable_lpm() and usb_enable_lpm(), which take
the bandwidth_mutex before calling usb_disable_lpm() and
usb_enable_lpm(), respectively.

Introduce a new variable (timeout) in the usb3_lpm_params structure to
keep track of the currently enabled U1/U2 timeout values.  When
usb_disable_lpm() is called, and the USB device has the U1 or U2
timeouts set to a non-zero value (meaning either device-initiated or
hub-initiated LPM is enabled), attempt to disable LPM, regardless of the
state of the lpm_disable_count.  We want to ensure that all callers can
be guaranteed that LPM is disabled if usb_disable_lpm() returns zero.

Otherwise the following scenario could occur:

1. Driver A is being bound to interface 1.  usb_probe_interface()
disables LPM.  Driver A doesn't care if hub-initiated LPM is enabled, so
even though usb_disable_lpm() fails, the probe of the driver continues,
and the bandwidth mutex is dropped.

2. Meanwhile, Driver B is being bound to interface 2.
usb_probe_interface() grabs the bandwidth mutex and calls
usb_disable_lpm().  That call should attempt to disable LPM, even
though the lpm_disable_count is set to 1 by Driver A.

For usb_enable_lpm(), we attempt to enable LPM only when the
lpm_disable_count is zero.  If some step in enabling LPM fails, it will
only have a minimal impact on power consumption, and all USB device
drivers should still work properly.  Therefore don't bother to return
any error codes.

Don't enable device-initiated LPM if the device is unconfigured.  The
USB device will only accept the U1/U2_ENABLE control transfers in the
configured state.  Do enable hub-initiated LPM in that case, since
devices are allowed to accept the LGO_Ux link commands in any state.

Don't enable or disable LPM if the device is marked as not being LPM
capable.  This can happen if:
 - the USB device doesn't have a SS BOS descriptor,
 - the device's parent hub has a zeroed bHeaderDecodeLatency value, or
 - the xHCI host doesn't support LPM.

Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Cc: Andiry Xu &lt;andiry.xu@amd.com&gt;
Cc: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>usb: ch9: define Set SEL and Set Isoch Delay macros</title>
<updated>2012-04-30T08:31:21+00:00</updated>
<author>
<name>Felipe Balbi</name>
<email>balbi@ti.com</email>
</author>
<published>2012-04-24T12:44:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=93c309ded1f6d4d0ff210263e62693825d441819'/>
<id>93c309ded1f6d4d0ff210263e62693825d441819</id>
<content type='text'>
These are new requests introduced by USB 3.0
Specification. Gadget controllers should implement
them.

Signed-off-by: Felipe Balbi &lt;balbi@ti.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
These are new requests introduced by USB 3.0
Specification. Gadget controllers should implement
them.

Signed-off-by: Felipe Balbi &lt;balbi@ti.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>xHCI: BESL calculation based on USB2.0 LPM errata</title>
<updated>2012-03-12T16:31:24+00:00</updated>
<author>
<name>Andiry Xu</name>
<email>andiry.xu@amd.com</email>
</author>
<published>2011-12-12T08:45:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=f99298bfa7c42da8d27c2b42050941471c0866ab'/>
<id>f99298bfa7c42da8d27c2b42050941471c0866ab</id>
<content type='text'>
The latest released errata for USB2.0 ECN LPM adds new fields to USB2.0
extension descriptor, defines two BESL values for device: baseline BESL
and deep BESL. Baseline BESL value communicates a nominal power savings
design point and the deep BESL value communicates a significant power
savings design point.

If device indicates BESL value, driver will use a value count in both
host BESL and device BESL. Use baseline BESL value as default.

Signed-off-by: Andiry Xu &lt;andiry.xu@amd.com&gt;
Tested-by: Jason Fan &lt;jcfan@qca.qualcomm.com&gt;
Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The latest released errata for USB2.0 ECN LPM adds new fields to USB2.0
extension descriptor, defines two BESL values for device: baseline BESL
and deep BESL. Baseline BESL value communicates a nominal power savings
design point and the deep BESL value communicates a significant power
savings design point.

If device indicates BESL value, driver will use a value count in both
host BESL and device BESL. Use baseline BESL value as default.

Signed-off-by: Andiry Xu &lt;andiry.xu@amd.com&gt;
Tested-by: Jason Fan &lt;jcfan@qca.qualcomm.com&gt;
Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>usb: ch9.h: usb_endpoint_maxp() uses __le16_to_cpu()</title>
<updated>2012-02-01T23:56:19+00:00</updated>
<author>
<name>Kuninori Morimoto</name>
<email>kuninori.morimoto.gx@renesas.com</email>
</author>
<published>2012-02-01T00:43:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=504b61630ab65296b6c9113cce834574e8cc01de'/>
<id>504b61630ab65296b6c9113cce834574e8cc01de</id>
<content type='text'>
The usb/ch9.h will be installed to /usr/include/linux,
and be used from user space.
But le16_to_cpu() is only defined for kernel code.
Without this patch, user space compile will be broken.
Special thanks to Stefan Becker

Reported-by: Stefan Becker &lt;chemobejk@gmail.com&gt;
Signed-off-by: Kuninori Morimoto &lt;kuninori.morimoto.gx@renesas.com&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The usb/ch9.h will be installed to /usr/include/linux,
and be used from user space.
But le16_to_cpu() is only defined for kernel code.
Without this patch, user space compile will be broken.
Special thanks to Stefan Becker

Reported-by: Stefan Becker &lt;chemobejk@gmail.com&gt;
Signed-off-by: Kuninori Morimoto &lt;kuninori.morimoto.gx@renesas.com&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>usb: ch9: fix up MaxStreams helper</title>
<updated>2012-01-04T23:52:42+00:00</updated>
<author>
<name>Felipe Balbi</name>
<email>balbi@ti.com</email>
</author>
<published>2012-01-02T11:35:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=18b7ede5f7ee2092aedcb578d3ac30bd5d4fc23c'/>
<id>18b7ede5f7ee2092aedcb578d3ac30bd5d4fc23c</id>
<content type='text'>
According to USB 3.0 Specification Table 9-22, if
bmAttributes [4:0] are set to zero, it means "no
streams supported", but the way this helper was
defined on Linux, we will *always* have one stream
which might cause several problems.

For example on DWC3, we would tell the controller
endpoint has streams enabled and yet start transfers
with Stream ID set to 0, which would goof up the host
side.

While doing that, convert the macro to an inline
function due to the different checks we now need.

Signed-off-by: Felipe Balbi &lt;balbi@ti.com&gt;
Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
According to USB 3.0 Specification Table 9-22, if
bmAttributes [4:0] are set to zero, it means "no
streams supported", but the way this helper was
defined on Linux, we will *always* have one stream
which might cause several problems.

For example on DWC3, we would tell the controller
endpoint has streams enabled and yet start transfers
with Stream ID set to 0, which would goof up the host
side.

While doing that, convert the macro to an inline
function due to the different checks we now need.

Signed-off-by: Felipe Balbi &lt;balbi@ti.com&gt;
Signed-off-by: Sarah Sharp &lt;sarah.a.sharp@linux.intel.com&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound</title>
<updated>2011-10-28T21:25:01+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2011-10-28T21:25:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=68d99b2c8efcb6ed3807a55569300c53b5f88be5'/>
<id>68d99b2c8efcb6ed3807a55569300c53b5f88be5</id>
<content type='text'>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (549 commits)
  ALSA: hda - Fix ADC input-amp handling for Cx20549 codec
  ALSA: hda - Keep EAPD turned on for old Conexant chips
  ALSA: hda/realtek - Fix missing volume controls with ALC260
  ASoC: wm8940: Properly set codec-&gt;dapm.bias_level
  ALSA: hda - Fix pin-config for ASUS W90V
  ALSA: hda - Fix surround/CLFE headphone and speaker pins order
  ALSA: hda - Fix typo
  ALSA: Update the sound git tree URL
  ALSA: HDA: Add new revision for ALC662
  ASoC: max98095: Convert codec-&gt;hw_write to snd_soc_write
  ASoC: keep pointer to resource so it can be freed
  ASoC: sgtl5000: Fix wrong mask in some snd_soc_update_bits calls
  ASoC: wm8996: Fix wrong mask for setting WM8996_AIF_CLOCKING_2
  ASoC: da7210: Add support for line out and DAC
  ASoC: da7210: Add support for DAPM
  ALSA: hda/realtek - Fix DAC assignments of multiple speakers
  ASoC: Use SGTL5000_LINREG_VDDD_MASK instead of hardcoded mask value
  ASoC: Set sgtl5000-&gt;ldo in ldo_regulator_register
  ASoC: wm8996: Use SND_SOC_DAPM_AIF_OUT for AIF2 Capture
  ASoC: wm8994: Use SND_SOC_DAPM_AIF_OUT for AIF3 Capture
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (549 commits)
  ALSA: hda - Fix ADC input-amp handling for Cx20549 codec
  ALSA: hda - Keep EAPD turned on for old Conexant chips
  ALSA: hda/realtek - Fix missing volume controls with ALC260
  ASoC: wm8940: Properly set codec-&gt;dapm.bias_level
  ALSA: hda - Fix pin-config for ASUS W90V
  ALSA: hda - Fix surround/CLFE headphone and speaker pins order
  ALSA: hda - Fix typo
  ALSA: Update the sound git tree URL
  ALSA: HDA: Add new revision for ALC662
  ASoC: max98095: Convert codec-&gt;hw_write to snd_soc_write
  ASoC: keep pointer to resource so it can be freed
  ASoC: sgtl5000: Fix wrong mask in some snd_soc_update_bits calls
  ASoC: wm8996: Fix wrong mask for setting WM8996_AIF_CLOCKING_2
  ASoC: da7210: Add support for line out and DAC
  ASoC: da7210: Add support for DAPM
  ALSA: hda/realtek - Fix DAC assignments of multiple speakers
  ASoC: Use SGTL5000_LINREG_VDDD_MASK instead of hardcoded mask value
  ASoC: Set sgtl5000-&gt;ldo in ldo_regulator_register
  ASoC: wm8996: Use SND_SOC_DAPM_AIF_OUT for AIF2 Capture
  ASoC: wm8994: Use SND_SOC_DAPM_AIF_OUT for AIF3 Capture
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>usb: Provide usb_speed_string() function</title>
<updated>2011-09-18T08:29:04+00:00</updated>
<author>
<name>Michal Nazarewicz</name>
<email>mina86@mina86.com</email>
</author>
<published>2011-08-30T15:11:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=e538dfdae85244fd2c4231725d82cc1f1bc4942c'/>
<id>e538dfdae85244fd2c4231725d82cc1f1bc4942c</id>
<content type='text'>
In a few places in the kernel, the code prints
a human-readable USB device speed (eg. "high speed").
This involves a switch statement sometimes wrapped
around in ({ ... }) block leading to code repetition.

To mitigate this issue, this commit introduces
usb_speed_string() function, which returns
a human-readable name of provided speed.

It also changes a few places switch was used to use
this new function.  This changes a bit the way the
speed is printed in few instances at the same time
standardising it.

Signed-off-by: Michal Nazarewicz &lt;mina86@mina86.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In a few places in the kernel, the code prints
a human-readable USB device speed (eg. "high speed").
This involves a switch statement sometimes wrapped
around in ({ ... }) block leading to code repetition.

To mitigate this issue, this commit introduces
usb_speed_string() function, which returns
a human-readable name of provided speed.

It also changes a few places switch was used to use
this new function.  This changes a bit the way the
speed is printed in few instances at the same time
standardising it.

Signed-off-by: Michal Nazarewicz &lt;mina86@mina86.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;
</pre>
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