+Thinh Hi Peter, On Fri, Feb 25, 2022 at 09:54:27AM -0500, Peter Geis wrote: > From: Bin Yang <yangbin@xxxxxxxxxxxxxx> > > In the 3.0 device core, if the core is programmed to operate in > 2.0 only, then setting the GUCTL1.DEV_FORCE_20_CLK_FOR_30_CLK makes > the internal 2.0(utmi/ulpi) clock to be routed as the 3.0 (pipe) > clock. Enabling this feature allows the pipe3 clock to be not-running > when forcibly operating in 2.0 device mode. > > Signed-off-by: Bin Yang <yangbin@xxxxxxxxxxxxxx> > Signed-off-by: Peter Geis <pgwipeout@xxxxxxxxx> > --- > drivers/usb/dwc3/core.c | 4 ++++ > drivers/usb/dwc3/core.h | 1 + > 2 files changed, 5 insertions(+) > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c > index 18adddfba3da..032d40794fae 100644 > --- a/drivers/usb/dwc3/core.c > +++ b/drivers/usb/dwc3/core.c > @@ -1167,6 +1167,10 @@ static int dwc3_core_init(struct dwc3 *dwc) > if (dwc->parkmode_disable_ss_quirk) > reg |= DWC3_GUCTL1_PARKMODE_DISABLE_SS; > > + if (dwc->maximum_speed == USB_SPEED_HIGH || > + dwc->maximum_speed == USB_SPEED_FULL) > + reg |= DWC3_GUCTL1_DEV_FORCE_20_CLK_FOR_30_CLK; > + I doubt this is applicable to all revisions of the DWC_usb3x IP cores? For instance in the programming guide for DWC_usb31 1.90a bit 26 of GUCTL1 is 'Reserved'. While I do see it in the DWC_usb3 databook, table 4-8 entry "Remove pipe_clk mux for 2.0 mode?" mentions this feature was only added in v2.90a. So this setting at least needs a revision check to make sure we're not causing unexpected behavior. Something like DWC3_VER_IS_WITHIN(DWC3, 290A, ANY) Jack > dwc3_writel(dwc->regs, DWC3_GUCTL1, reg); > } > > diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h > index eb9c1efced05..ea3ca04406bb 100644 > --- a/drivers/usb/dwc3/core.h > +++ b/drivers/usb/dwc3/core.h > @@ -259,6 +259,7 @@ > /* Global User Control 1 Register */ > #define DWC3_GUCTL1_DEV_DECOUPLE_L1L2_EVT BIT(31) > #define DWC3_GUCTL1_TX_IPGAP_LINECHECK_DIS BIT(28) > +#define DWC3_GUCTL1_DEV_FORCE_20_CLK_FOR_30_CLK BIT(26) > #define DWC3_GUCTL1_DEV_L1_EXIT_BY_HW BIT(24) > #define DWC3_GUCTL1_PARKMODE_DISABLE_SS BIT(17) > > -- > 2.25.1 >
