diff options
| author | Adam Wallis <awallis@codeaurora.org> | 2017-12-08 17:59:13 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-12-08 17:43:52 +0100 |
| commit | ab725cbec3e83dc29cc00b733bd26063b588fa98 (patch) | |
| tree | 9466ec276003810875ae7e896031c038ed8a8fff /Documentation | |
| parent | 3054ea45fb8758b7c1a4849001e213e1267452fa (diff) | |
| download | linux-ab725cbec3e83dc29cc00b733bd26063b588fa98.tar.gz | |
usb: xhci: allow imod-interval to be configurable
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 <chunfeng.yun@mediatek.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Adam Wallis <awallis@codeaurora.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt | 2 | ||||
| -rw-r--r-- | Documentation/devicetree/bindings/usb/usb-xhci.txt | 1 |
2 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.txt index 30595964876a..9ff560298498 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@11270000 { @@ -66,6 +67,7 @@ usb30: usb@11270000 { usb3-lpm-capable; mediatek,syscon-wakeup = <&pericfg>; mediatek,wakeup-src = <1>; + imod-interval-ns = <10000>; }; 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 a53107132cc3..e2ea59bbca93 100644 --- a/Documentation/devicetree/bindings/usb/usb-xhci.txt +++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt @@ -31,6 +31,7 @@ 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 { |