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authorAdam Wallis <awallis@codeaurora.org>2017-12-08 17:59:13 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-12-08 17:43:52 +0100
commitab725cbec3e83dc29cc00b733bd26063b588fa98 (patch)
tree9466ec276003810875ae7e896031c038ed8a8fff /drivers/usb/host/xhci-plat.c
parent3054ea45fb8758b7c1a4849001e213e1267452fa (diff)
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 'drivers/usb/host/xhci-plat.c')
-rw-r--r--drivers/usb/host/xhci-plat.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index 09f164f8cf8c..6f038306c14d 100644
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -269,6 +269,11 @@ static int xhci_plat_probe(struct platform_device *pdev)
if (device_property_read_bool(&pdev->dev, "quirk-broken-port-ped"))
xhci->quirks |= XHCI_BROKEN_PORT_PED;
+ /* imod_interval is the interrupt moderation value in nanoseconds. */
+ xhci->imod_interval = 40000;
+ device_property_read_u32(sysdev, "imod-interval-ns",
+ &xhci->imod_interval);
+
hcd->usb_phy = devm_usb_get_phy_by_phandle(sysdev, "usb-phy", 0);
if (IS_ERR(hcd->usb_phy)) {
ret = PTR_ERR(hcd->usb_phy);