Re: [PATCH 2/3] usb: dwc3: xilinx: use reset_control_reset() in versal init

[Pandey, Radhey Shyam]

On 5/14/2026 7:04 AM, Thinh Nguyen wrote:
> On Mon, May 11, 2026, Radhey Shyam Pandey wrote:
> > Replace separate reset_control_assert() and reset_control_deassert() calls
> > with reset_control_reset(), which pulses the reset in one step. Report
> > failures with dev_err_probe() and a single message. No functional change.
>
> The behavior of reset_control_reset() is a little different. I wouldn't
> call this "No functional change". However, I assumed this was tested.
> Please provide a proper reason for this change in the change log.

In the dwc3-xilinx case, reset_control_reset() routes through the
zynqmp reset driver and invokes PM_RESET_ACTION_PULSE. This triggers
the Xilinx firmware reset implementation, which performs both assert
and deassert. Effectively, reset() issues a single SMC call for a
reset pulse instead of separate assert and deassert calls and moves
IP out of reset.

Yes this new reset sequence is validated on HW. I will include
above description and respin v2..

> > Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxx>
> > ---
> >   drivers/usb/dwc3/dwc3-xilinx.c | 16 ++++------------
> >   1 file changed, 4 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/usb/dwc3/dwc3-xilinx.c b/drivers/usb/dwc3/dwc3-xilinx.c
> > index a3c7dc258c7d..94458b3da1a0 100644
> > --- a/drivers/usb/dwc3/dwc3-xilinx.c
> > +++ b/drivers/usb/dwc3/dwc3-xilinx.c
> > @@ -98,18 +98,10 @@ static int dwc3_xlnx_init_versal(struct dwc3_xlnx *priv_data)
> >   
> >   	dwc3_xlnx_mask_phy_rst(priv_data, false);
> >   
> > -	/* Assert and De-assert reset */
> > -	ret = reset_control_assert(crst);
> > -	if (ret < 0) {
> > -		dev_err_probe(dev, ret, "failed to assert Reset\n");
> > -		return ret;
> > -	}
> > -
> > -	ret = reset_control_deassert(crst);
> > -	if (ret < 0) {
> > -		dev_err_probe(dev, ret, "failed to De-assert Reset\n");
> > -		return ret;
> > -	}
> > +	/* assert and deassert reset */
> > +	ret = reset_control_reset(crst);
> > +	if (ret)
> > +		return dev_err_probe(dev, ret, "failed to assert and deassert reset\n");
> >   
> >   	dwc3_xlnx_mask_phy_rst(priv_data, true);
> >   	dwc3_xlnx_set_coherency(priv_data, XLNX_USB2_TRAFFIC_ROUTE_CONFIG);
> > --
> > 2.44.4