diff options
| author | Roger Quadros <rogerq@ti.com> | 2017-10-31 15:11:55 +0200 |
|---|---|---|
| committer | Felipe Balbi <felipe.balbi@linux.intel.com> | 2017-12-11 12:36:53 +0200 |
| commit | 42bf02ec6e420e541af9a47437d0bdf961ca2972 (patch) | |
| tree | d26f219a5d67aad75da1ec0db2e7a71fe0164352 /drivers/usb/dwc3/gadget.c | |
| parent | d855e08cf623835bc3208209cd9ab32d6c710162 (diff) | |
| download | linux-42bf02ec6e420e541af9a47437d0bdf961ca2972.tar.bz2 | |
usb: dwc3: Allow disabling of metastability workaround
Some platforms (e.g. TI's DRA7 USB2 instance) have more trouble
with the metastability workaround as it supports only
a High-Speed PHY and the PHY can enter into an Erratic state [1]
when the controller is set in SuperSpeed mode as part of
the metastability workaround.
This causes upto 2 seconds delay in enumeration on DRA7's USB2
instance in gadget mode.
If these platforms can be better off without the workaround,
provide a device tree property to suggest that so the workaround
is avoided.
[1] Device mode enumeration trace showing PHY Erratic Error.
irq/90-dwc3-969 [000] d... 52.323145: dwc3_event: event (00000901): Erratic Error [U0]
irq/90-dwc3-969 [000] d... 52.560646: dwc3_event: event (00000901): Erratic Error [U0]
irq/90-dwc3-969 [000] d... 52.798144: dwc3_event: event (00000901): Erratic Error [U0]
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Diffstat (limited to 'drivers/usb/dwc3/gadget.c')
| -rw-r--r-- | drivers/usb/dwc3/gadget.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 981fd986cf82..2168ba4951a9 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -2005,7 +2005,8 @@ static void dwc3_gadget_set_speed(struct usb_gadget *g, * STAR#9000525659: Clock Domain Crossing on DCTL in * USB 2.0 Mode */ - if (dwc->revision < DWC3_REVISION_220A) { + if (dwc->revision < DWC3_REVISION_220A && + !dwc->dis_metastability_quirk) { reg |= DWC3_DCFG_SUPERSPEED; } else { switch (speed) { @@ -3224,7 +3225,8 @@ int dwc3_gadget_init(struct dwc3 *dwc) * is less than super speed because we don't have means, yet, to tell * composite.c that we are USB 2.0 + LPM ECN. */ - if (dwc->revision < DWC3_REVISION_220A) + if (dwc->revision < DWC3_REVISION_220A && + !dwc->dis_metastability_quirk) dev_info(dwc->dev, "changing max_speed on rev %08x\n", dwc->revision); |