Re: [PATCH v4] usb: xhci: allow imod-interval to be configurable

2017-12-06 Thread Rob Herring
On Mon, Dec 04, 2017 at 09:27:51AM -0500, Adam Wallis wrote:
> The xHCI driver currently has the IMOD set to 160, which
> translates to an IMOD interval of 40,000ns (160 * 250)ns
> 
> Commit 0cbd4b34cda9 ("xhci: mediatek: support MTK xHCI host controller")
> introduced a QUIRK for the MTK platform to adjust this interval to 20,
> which translates to an IMOD interval of 5,000ns (20 * 250)ns. This is
> due to the fact that the MTK controller IMOD interval is 8 times
> as much as defined in xHCI spec.
> 
> Instead of adding more quirk bits for additional platforms, this patch
> introduces the ability for vendors to set the IMOD_INTERVAL as is
> optimal for their platform. By using device_property_read_u32() on
> "imod-interval-ns", the IMOD INTERVAL can be specified in nano seconds.
> If no interval is specified, the default of 40,000ns (IMOD=160) will be
> used.
> 
> No bounds checking has been implemented due to the fact that a vendor
> may have violated the spec and would need to specify a value outside of
> the max 8,000 IRQs/second limit specified in the xHCI spec.
> 
> Tested-by: Chunfeng Yun 
> Signed-off-by: Adam Wallis 
> ---
> changes from v3:
>   * Changed imod-interval to imod-interval-ns [Rob Herring/Chunfeng]
>   * Changed "modulation" to "moderation" throughout patch [Mathias]
> changes from v2:
>   * Added PCI default value [Mathias]
>   * Removed xhci-mtk.h from xhci-plat.c [Chunfeng Yun]
>   * Removed MTK quirk from xhci-plat and moved logic to xhci-mtk [Chunfeng]
>   * Updated bindings Documentation to use proper units [Rob Herring]
>   * Added imod-interval description and example to MTK binding documentation
> changes from v1:
>   * Removed device_property_read_u32() per suggestion from greg k-h
>   * Used ER_IRQ_INTERVAL_MASK in place of (u16) cast
> 
>  Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt | 2 ++
>  Documentation/devicetree/bindings/usb/usb-xhci.txt  | 1 +
>  drivers/usb/host/xhci-mtk.c | 9 +
>  drivers/usb/host/xhci-pci.c | 3 +++
>  drivers/usb/host/xhci-plat.c| 5 +
>  drivers/usb/host/xhci.c | 7 ++-
>  drivers/usb/host/xhci.h | 2 ++
>  7 files changed, 24 insertions(+), 5 deletions(-)

Reviewed-by: Rob Herring 

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Re: [PATCH v4] usb: xhci: allow imod-interval to be configurable

2017-12-05 Thread Adam Wallis
Rob,

On 12/5/2017 3:48 AM, Mathias Nyman wrote:
> On 05.12.2017 04:54, Adam Wallis wrote:
>> On 12/4/2017 9:15 PM, Chunfeng Yun wrote:
>>> On Mon, 2017-12-04 at 09:27 -0500, Adam Wallis wrote:
 The xHCI driver currently has the IMOD set to 160, which
[..]
> 
> If Rob Acks this version I'll apply it and remove that blank line.
> 
> -Mathias
> 

Let me know if you have any other issues with this patch, otherwise with your
ACK, we are done.

Thanks

Adam

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> linux-arm-ker...@lists.infradead.org
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Re: [PATCH v4] usb: xhci: allow imod-interval to be configurable

2017-12-05 Thread Mathias Nyman

On 05.12.2017 04:54, Adam Wallis wrote:

On 12/4/2017 9:15 PM, Chunfeng Yun wrote:

On Mon, 2017-12-04 at 09:27 -0500, Adam Wallis wrote:

The xHCI driver currently has the IMOD set to 160, which
translates to an IMOD interval of 40,000ns (160 * 250)ns

Commit 0cbd4b34cda9 ("xhci: mediatek: support MTK xHCI host controller")
introduced a QUIRK for the MTK platform to adjust this interval to 20,
which translates to an IMOD interval of 5,000ns (20 * 250)ns. This is
due to the fact that the MTK controller IMOD interval is 8 times
as much as defined in xHCI spec.

Instead of adding more quirk bits for additional platforms, this patch
introduces the ability for vendors to set the IMOD_INTERVAL as is
optimal for their platform. By using device_property_read_u32() on
"imod-interval-ns", the IMOD INTERVAL can be specified in nano seconds.
If no interval is specified, the default of 40,000ns (IMOD=160) will be
used.

No bounds checking has been implemented due to the fact that a vendor
may have violated the spec and would need to specify a value outside of
the max 8,000 IRQs/second limit specified in the xHCI spec.

Tested-by: Chunfeng Yun 
Signed-off-by: Adam Wallis 
---
changes from v3:
   * Changed imod-interval to imod-interval-ns [Rob Herring/Chunfeng]
   * Changed "modulation" to "moderation" throughout patch [Mathias]
changes from v2:
   * Added PCI default value [Mathias]
   * Removed xhci-mtk.h from xhci-plat.c [Chunfeng Yun]
   * Removed MTK quirk from xhci-plat and moved logic to xhci-mtk [Chunfeng]
   * Updated bindings Documentation to use proper units [Rob Herring]
   * Added imod-interval description and example to MTK binding documentation
changes from v1:
   * Removed device_property_read_u32() per suggestion from greg k-h
   * Used ER_IRQ_INTERVAL_MASK in place of (u16) cast

  Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt | 2 ++
  Documentation/devicetree/bindings/usb/usb-xhci.txt  | 1 +
  drivers/usb/host/xhci-mtk.c | 9 +
  drivers/usb/host/xhci-pci.c | 3 +++
  drivers/usb/host/xhci-plat.c| 5 +
  drivers/usb/host/xhci.c | 7 ++-
  drivers/usb/host/xhci.h | 2 ++
  7 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt 
b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt
index 3059596..9ff5602 100644
--- a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt
+++ b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt
@@ -46,6 +46,7 @@ Optional properties:
   - pinctrl-names : a pinctrl state named "default" must be defined
   - pinctrl-0 : pin control group
See: Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
+ - imod-interval-ns: default interrupt moderation interval is 5000ns
  
  Example:

  usb30: usb@1127 {
@@ -66,6 +67,7 @@ usb30: usb@1127 {
usb3-lpm-capable;
mediatek,syscon-wakeup = <>;
mediatek,wakeup-src = <1>;
+   imod-interval-ns = <1>;
  };
  
  2nd: dual-role mode with xHCI driver

diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt 
b/Documentation/devicetree/bindings/usb/usb-xhci.txt
index ae6e484..969908d 100644
--- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
+++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
@@ -29,6 +29,7 @@ Optional properties:
- usb2-lpm-disable: indicate if we don't want to enable USB2 HW LPM
- usb3-lpm-capable: determines if platform is USB3 LPM capable
- quirk-broken-port-ped: set if the controller has broken port disable 
mechanism
+  - imod-interval-ns: default interrupt moderation interval is 5000ns
  
  Example:

usb@f0931000 {
diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c
index b62a1d2..1cb2a8b 100644
--- a/drivers/usb/host/xhci-mtk.c
+++ b/drivers/usb/host/xhci-mtk.c
@@ -674,6 +674,15 @@ static int xhci_mtk_probe(struct platform_device *pdev)
  
  	xhci = hcd_to_xhci(hcd);

xhci->main_hcd = hcd;
+
+   /*
+* imod_interval is the interrupt moderation value in nanoseconds.
+* The increment interval is 8 times as much as that defined in
+* the xHCI spec on MTK's controller.
+*/
+   xhci->imod_interval = 5000;
+   device_property_read_u32(dev, "imod-interval-ns", >imod_interval);
+
xhci->shared_hcd = usb_create_shared_hcd(driver, dev,
dev_name(dev), hcd);
if (!xhci->shared_hcd) {
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 7ef1274..4bcddd4 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -234,6 +234,9 @@ static int xhci_pci_setup(struct usb_hcd *hcd)
if (!xhci->sbrn)
pci_read_config_byte(pdev, 

Re: [PATCH v4] usb: xhci: allow imod-interval to be configurable

2017-12-04 Thread Adam Wallis
On 12/4/2017 9:15 PM, Chunfeng Yun wrote:
> On Mon, 2017-12-04 at 09:27 -0500, Adam Wallis wrote:
>> The xHCI driver currently has the IMOD set to 160, which
>> translates to an IMOD interval of 40,000ns (160 * 250)ns
>>
>> Commit 0cbd4b34cda9 ("xhci: mediatek: support MTK xHCI host controller")
>> introduced a QUIRK for the MTK platform to adjust this interval to 20,
>> which translates to an IMOD interval of 5,000ns (20 * 250)ns. This is
>> due to the fact that the MTK controller IMOD interval is 8 times
>> as much as defined in xHCI spec.
>>
>> Instead of adding more quirk bits for additional platforms, this patch
>> introduces the ability for vendors to set the IMOD_INTERVAL as is
>> optimal for their platform. By using device_property_read_u32() on
>> "imod-interval-ns", the IMOD INTERVAL can be specified in nano seconds.
>> If no interval is specified, the default of 40,000ns (IMOD=160) will be
>> used.
>>
>> No bounds checking has been implemented due to the fact that a vendor
>> may have violated the spec and would need to specify a value outside of
>> the max 8,000 IRQs/second limit specified in the xHCI spec.
>>
>> Tested-by: Chunfeng Yun 
>> Signed-off-by: Adam Wallis 
>> ---
>> changes from v3:
>>   * Changed imod-interval to imod-interval-ns [Rob Herring/Chunfeng]
>>   * Changed "modulation" to "moderation" throughout patch [Mathias]
>> changes from v2:
>>   * Added PCI default value [Mathias]
>>   * Removed xhci-mtk.h from xhci-plat.c [Chunfeng Yun]
>>   * Removed MTK quirk from xhci-plat and moved logic to xhci-mtk [Chunfeng]
>>   * Updated bindings Documentation to use proper units [Rob Herring]
>>   * Added imod-interval description and example to MTK binding documentation
>> changes from v1:
>>   * Removed device_property_read_u32() per suggestion from greg k-h
>>   * Used ER_IRQ_INTERVAL_MASK in place of (u16) cast
>>
>>  Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt | 2 ++
>>  Documentation/devicetree/bindings/usb/usb-xhci.txt  | 1 +
>>  drivers/usb/host/xhci-mtk.c | 9 +
>>  drivers/usb/host/xhci-pci.c | 3 +++
>>  drivers/usb/host/xhci-plat.c| 5 +
>>  drivers/usb/host/xhci.c | 7 ++-
>>  drivers/usb/host/xhci.h | 2 ++
>>  7 files changed, 24 insertions(+), 5 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt 
>> b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt
>> index 3059596..9ff5602 100644
>> --- a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt
>> +++ b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt
>> @@ -46,6 +46,7 @@ Optional properties:
>>   - pinctrl-names : a pinctrl state named "default" must be defined
>>   - pinctrl-0 : pin control group
>>  See: Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
>> + - imod-interval-ns: default interrupt moderation interval is 5000ns
>>  
>>  Example:
>>  usb30: usb@1127 {
>> @@ -66,6 +67,7 @@ usb30: usb@1127 {
>>  usb3-lpm-capable;
>>  mediatek,syscon-wakeup = <>;
>>  mediatek,wakeup-src = <1>;
>> +imod-interval-ns = <1>;
>>  };
>>  
>>  2nd: dual-role mode with xHCI driver
>> diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt 
>> b/Documentation/devicetree/bindings/usb/usb-xhci.txt
>> index ae6e484..969908d 100644
>> --- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
>> +++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
>> @@ -29,6 +29,7 @@ Optional properties:
>>- usb2-lpm-disable: indicate if we don't want to enable USB2 HW LPM
>>- usb3-lpm-capable: determines if platform is USB3 LPM capable
>>- quirk-broken-port-ped: set if the controller has broken port disable 
>> mechanism
>> +  - imod-interval-ns: default interrupt moderation interval is 5000ns
>>  
>>  Example:
>>  usb@f0931000 {
>> diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c
>> index b62a1d2..1cb2a8b 100644
>> --- a/drivers/usb/host/xhci-mtk.c
>> +++ b/drivers/usb/host/xhci-mtk.c
>> @@ -674,6 +674,15 @@ static int xhci_mtk_probe(struct platform_device *pdev)
>>  
>>  xhci = hcd_to_xhci(hcd);
>>  xhci->main_hcd = hcd;
>> +
>> +/*
>> + * imod_interval is the interrupt moderation value in nanoseconds.
>> + * The increment interval is 8 times as much as that defined in
>> + * the xHCI spec on MTK's controller.
>> + */
>> +xhci->imod_interval = 5000;
>> +device_property_read_u32(dev, "imod-interval-ns", >imod_interval);
>> +
>>  xhci->shared_hcd = usb_create_shared_hcd(driver, dev,
>>  dev_name(dev), hcd);
>>  if (!xhci->shared_hcd) {
>> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
>> index 7ef1274..4bcddd4 100644
>> --- a/drivers/usb/host/xhci-pci.c
>> 

Re: [PATCH v4] usb: xhci: allow imod-interval to be configurable

2017-12-04 Thread Chunfeng Yun
On Mon, 2017-12-04 at 09:27 -0500, Adam Wallis wrote:
> The xHCI driver currently has the IMOD set to 160, which
> translates to an IMOD interval of 40,000ns (160 * 250)ns
> 
> Commit 0cbd4b34cda9 ("xhci: mediatek: support MTK xHCI host controller")
> introduced a QUIRK for the MTK platform to adjust this interval to 20,
> which translates to an IMOD interval of 5,000ns (20 * 250)ns. This is
> due to the fact that the MTK controller IMOD interval is 8 times
> as much as defined in xHCI spec.
> 
> Instead of adding more quirk bits for additional platforms, this patch
> introduces the ability for vendors to set the IMOD_INTERVAL as is
> optimal for their platform. By using device_property_read_u32() on
> "imod-interval-ns", the IMOD INTERVAL can be specified in nano seconds.
> If no interval is specified, the default of 40,000ns (IMOD=160) will be
> used.
> 
> No bounds checking has been implemented due to the fact that a vendor
> may have violated the spec and would need to specify a value outside of
> the max 8,000 IRQs/second limit specified in the xHCI spec.
> 
> Tested-by: Chunfeng Yun 
> Signed-off-by: Adam Wallis 
> ---
> changes from v3:
>   * Changed imod-interval to imod-interval-ns [Rob Herring/Chunfeng]
>   * Changed "modulation" to "moderation" throughout patch [Mathias]
> changes from v2:
>   * Added PCI default value [Mathias]
>   * Removed xhci-mtk.h from xhci-plat.c [Chunfeng Yun]
>   * Removed MTK quirk from xhci-plat and moved logic to xhci-mtk [Chunfeng]
>   * Updated bindings Documentation to use proper units [Rob Herring]
>   * Added imod-interval description and example to MTK binding documentation
> changes from v1:
>   * Removed device_property_read_u32() per suggestion from greg k-h
>   * Used ER_IRQ_INTERVAL_MASK in place of (u16) cast
> 
>  Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt | 2 ++
>  Documentation/devicetree/bindings/usb/usb-xhci.txt  | 1 +
>  drivers/usb/host/xhci-mtk.c | 9 +
>  drivers/usb/host/xhci-pci.c | 3 +++
>  drivers/usb/host/xhci-plat.c| 5 +
>  drivers/usb/host/xhci.c | 7 ++-
>  drivers/usb/host/xhci.h | 2 ++
>  7 files changed, 24 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt 
> b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt
> index 3059596..9ff5602 100644
> --- a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt
> +++ b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt
> @@ -46,6 +46,7 @@ Optional properties:
>   - pinctrl-names : a pinctrl state named "default" must be defined
>   - pinctrl-0 : pin control group
>   See: Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
> + - imod-interval-ns: default interrupt moderation interval is 5000ns
>  
>  Example:
>  usb30: usb@1127 {
> @@ -66,6 +67,7 @@ usb30: usb@1127 {
>   usb3-lpm-capable;
>   mediatek,syscon-wakeup = <>;
>   mediatek,wakeup-src = <1>;
> + imod-interval-ns = <1>;
>  };
>  
>  2nd: dual-role mode with xHCI driver
> diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt 
> b/Documentation/devicetree/bindings/usb/usb-xhci.txt
> index ae6e484..969908d 100644
> --- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
> +++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
> @@ -29,6 +29,7 @@ Optional properties:
>- usb2-lpm-disable: indicate if we don't want to enable USB2 HW LPM
>- usb3-lpm-capable: determines if platform is USB3 LPM capable
>- quirk-broken-port-ped: set if the controller has broken port disable 
> mechanism
> +  - imod-interval-ns: default interrupt moderation interval is 5000ns
>  
>  Example:
>   usb@f0931000 {
> diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c
> index b62a1d2..1cb2a8b 100644
> --- a/drivers/usb/host/xhci-mtk.c
> +++ b/drivers/usb/host/xhci-mtk.c
> @@ -674,6 +674,15 @@ static int xhci_mtk_probe(struct platform_device *pdev)
>  
>   xhci = hcd_to_xhci(hcd);
>   xhci->main_hcd = hcd;
> +
> + /*
> +  * imod_interval is the interrupt moderation value in nanoseconds.
> +  * The increment interval is 8 times as much as that defined in
> +  * the xHCI spec on MTK's controller.
> +  */
> + xhci->imod_interval = 5000;
> + device_property_read_u32(dev, "imod-interval-ns", >imod_interval);
> +
>   xhci->shared_hcd = usb_create_shared_hcd(driver, dev,
>   dev_name(dev), hcd);
>   if (!xhci->shared_hcd) {
> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
> index 7ef1274..4bcddd4 100644
> --- a/drivers/usb/host/xhci-pci.c
> +++ b/drivers/usb/host/xhci-pci.c
> @@ -234,6 +234,9 @@ static int xhci_pci_setup(struct usb_hcd *hcd)
>   if 

Re: [PATCH v4] usb: xhci: allow imod-interval to be configurable

2017-12-04 Thread Timur Tabi

On 12/04/2017 09:48 AM, Adam Wallis wrote:

As noted in the patch description, xhci-plat devices will use a default of
40,000, while MTK devices will use a default of 5,000. This is also documented
in the probe for each relevant driver. This is further confirmed in the
description for each driver's binding TXT file.


Serves me right for reviewing patches before I've had my morning coffee.

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Re: [PATCH v4] usb: xhci: allow imod-interval to be configurable

2017-12-04 Thread Adam Wallis
Timur

On 12/4/2017 9:58 AM, Timur Tabi wrote:
> On 12/4/17 8:27 AM, Adam Wallis wrote:
>> If no interval is specified, the default of 40,000ns (IMOD=160) will be
>> used.
> 
> ...
> 
>> + - imod-interval-ns: default interrupt moderation interval is 5000ns
> 
> ...
> 
>> +  - imod-interval-ns: default interrupt moderation interval is 5000ns
> 
> ...
> 
>> +    xhci->imod_interval = 5000;
> 
> ...
> 
>> +    xhci->imod_interval = 4;
> 
> ...
> 
>> +    xhci->imod_interval = 4;
> 
> Is the default 5,000 or 40,000?  I can't tell.
> 
As noted in the patch description, xhci-plat devices will use a default of
40,000, while MTK devices will use a default of 5,000. This is also documented
in the probe for each relevant driver. This is further confirmed in the
description for each driver's binding TXT file.

Adam

-- 
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Re: [PATCH v4] usb: xhci: allow imod-interval to be configurable

2017-12-04 Thread Timur Tabi

On 12/4/17 8:27 AM, Adam Wallis wrote:

If no interval is specified, the default of 40,000ns (IMOD=160) will be
used.


...


+ - imod-interval-ns: default interrupt moderation interval is 5000ns


...


+  - imod-interval-ns: default interrupt moderation interval is 5000ns


...


+   xhci->imod_interval = 5000;


...


+   xhci->imod_interval = 4;


...


+   xhci->imod_interval = 4;


Is the default 5,000 or 40,000?  I can't tell.

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[PATCH v4] usb: xhci: allow imod-interval to be configurable

2017-12-04 Thread Adam Wallis
The xHCI driver currently has the IMOD set to 160, which
translates to an IMOD interval of 40,000ns (160 * 250)ns

Commit 0cbd4b34cda9 ("xhci: mediatek: support MTK xHCI host controller")
introduced a QUIRK for the MTK platform to adjust this interval to 20,
which translates to an IMOD interval of 5,000ns (20 * 250)ns. This is
due to the fact that the MTK controller IMOD interval is 8 times
as much as defined in xHCI spec.

Instead of adding more quirk bits for additional platforms, this patch
introduces the ability for vendors to set the IMOD_INTERVAL as is
optimal for their platform. By using device_property_read_u32() on
"imod-interval-ns", the IMOD INTERVAL can be specified in nano seconds.
If no interval is specified, the default of 40,000ns (IMOD=160) will be
used.

No bounds checking has been implemented due to the fact that a vendor
may have violated the spec and would need to specify a value outside of
the max 8,000 IRQs/second limit specified in the xHCI spec.

Tested-by: Chunfeng Yun 
Signed-off-by: Adam Wallis 
---
changes from v3:
  * Changed imod-interval to imod-interval-ns [Rob Herring/Chunfeng]
  * Changed "modulation" to "moderation" throughout patch [Mathias]
changes from v2:
  * Added PCI default value [Mathias]
  * Removed xhci-mtk.h from xhci-plat.c [Chunfeng Yun]
  * Removed MTK quirk from xhci-plat and moved logic to xhci-mtk [Chunfeng]
  * Updated bindings Documentation to use proper units [Rob Herring]
  * Added imod-interval description and example to MTK binding documentation
changes from v1:
  * Removed device_property_read_u32() per suggestion from greg k-h
  * Used ER_IRQ_INTERVAL_MASK in place of (u16) cast

 Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt | 2 ++
 Documentation/devicetree/bindings/usb/usb-xhci.txt  | 1 +
 drivers/usb/host/xhci-mtk.c | 9 +
 drivers/usb/host/xhci-pci.c | 3 +++
 drivers/usb/host/xhci-plat.c| 5 +
 drivers/usb/host/xhci.c | 7 ++-
 drivers/usb/host/xhci.h | 2 ++
 7 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt 
b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt
index 3059596..9ff5602 100644
--- a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt
+++ b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt
@@ -46,6 +46,7 @@ Optional properties:
  - pinctrl-names : a pinctrl state named "default" must be defined
  - pinctrl-0 : pin control group
See: Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
+ - imod-interval-ns: default interrupt moderation interval is 5000ns
 
 Example:
 usb30: usb@1127 {
@@ -66,6 +67,7 @@ usb30: usb@1127 {
usb3-lpm-capable;
mediatek,syscon-wakeup = <>;
mediatek,wakeup-src = <1>;
+   imod-interval-ns = <1>;
 };
 
 2nd: dual-role mode with xHCI driver
diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt 
b/Documentation/devicetree/bindings/usb/usb-xhci.txt
index ae6e484..969908d 100644
--- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
+++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
@@ -29,6 +29,7 @@ Optional properties:
   - usb2-lpm-disable: indicate if we don't want to enable USB2 HW LPM
   - usb3-lpm-capable: determines if platform is USB3 LPM capable
   - quirk-broken-port-ped: set if the controller has broken port disable 
mechanism
+  - imod-interval-ns: default interrupt moderation interval is 5000ns
 
 Example:
usb@f0931000 {
diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c
index b62a1d2..1cb2a8b 100644
--- a/drivers/usb/host/xhci-mtk.c
+++ b/drivers/usb/host/xhci-mtk.c
@@ -674,6 +674,15 @@ static int xhci_mtk_probe(struct platform_device *pdev)
 
xhci = hcd_to_xhci(hcd);
xhci->main_hcd = hcd;
+
+   /*
+* imod_interval is the interrupt moderation value in nanoseconds.
+* The increment interval is 8 times as much as that defined in
+* the xHCI spec on MTK's controller.
+*/
+   xhci->imod_interval = 5000;
+   device_property_read_u32(dev, "imod-interval-ns", >imod_interval);
+
xhci->shared_hcd = usb_create_shared_hcd(driver, dev,
dev_name(dev), hcd);
if (!xhci->shared_hcd) {
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 7ef1274..4bcddd4 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -234,6 +234,9 @@ static int xhci_pci_setup(struct usb_hcd *hcd)
if (!xhci->sbrn)
pci_read_config_byte(pdev, XHCI_SBRN_OFFSET, >sbrn);
 
+   /* imod_interval is the interrupt moderation value in nanoseconds. */
+   xhci->imod_interval = 4;
+
retval = xhci_gen_setup(hcd,