Re: [PATCH] usb: phy: mxs: manually reset phy regs after a warm reset

[Xu Yang]

On Mon, Mar 30, 2026 at 10:33:53AM -0400, Frank Li wrote:
> On Mon, Mar 30, 2026 at 05:31:33PM +0800, Xu Yang wrote:
> > The usb phy registers are not fully reset on warm reset under stress
> > conditions. We need to manually reset those (CTRL, PWD, DEBUG, PLL_SIC)
> 
> Avoid the words "we ..."
> 
> So need manually reset CTRL, PWD, DEBUG, PLL_SIC ...

OK.

> 
> > regs after a warm reset. This will reset DEBUG and PLL_SIC registers.
> > CTRL and PWD register are handled by "SFT" bit in stmp_reset_block().
> >
> > ERR051269: USB PHY registers not fully resetting on warm reset under
> >            stress conditions
> >
> > The following USB PHY registers must be written by SW to restore the reset
> > value after a warm reset:
> >
> > Reg: ctrl Addr: 0x29910030 Data: 0xc000_0000
> > Reg: pwd Addr: 0x29910000 Data: 0x001e_1c00
> > Reg: debug0 Addr: 0x29910050 Data: 0x7f18_0000
> > Reg: pll_sic Addr: 0x299100a0 Data: 0x00d1_2000
> >
> > Signed-off-by: Xu Yang <xu.yang_2@xxxxxxx>
> > ---
> >  drivers/usb/phy/phy-mxs-usb.c | 32 +++++++++++++++++++++++++++++---
> >  1 file changed, 29 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/usb/phy/phy-mxs-usb.c b/drivers/usb/phy/phy-mxs-usb.c
> > index 7069dd3f4d0d..dd42db8a0829 100644
> > --- a/drivers/usb/phy/phy-mxs-usb.c
> > +++ b/drivers/usb/phy/phy-mxs-usb.c
> > @@ -209,6 +209,9 @@ static const struct mxs_phy_data imx6ul_phy_data = {
> >  static const struct mxs_phy_data imx7ulp_phy_data = {
> >  };
> >
> > +static const struct mxs_phy_data imx8ulp_phy_data = {
> > +};
> > +
> >  static const struct of_device_id mxs_phy_dt_ids[] = {
> >  	{ .compatible = "fsl,imx6sx-usbphy", .data = &imx6sx_phy_data, },
> >  	{ .compatible = "fsl,imx6sl-usbphy", .data = &imx6sl_phy_data, },
> > @@ -217,6 +220,7 @@ static const struct of_device_id mxs_phy_dt_ids[] = {
> >  	{ .compatible = "fsl,vf610-usbphy", .data = &vf610_phy_data, },
> >  	{ .compatible = "fsl,imx6ul-usbphy", .data = &imx6ul_phy_data, },
> >  	{ .compatible = "fsl,imx7ulp-usbphy", .data = &imx7ulp_phy_data, },
> > +	{ .compatible = "fsl,imx8ulp-usbphy", .data = &imx8ulp_phy_data, },
> >  	{ /* sentinel */ }
> >  };
> >  MODULE_DEVICE_TABLE(of, mxs_phy_dt_ids);
> > @@ -248,6 +252,11 @@ static inline bool is_imx7ulp_phy(struct mxs_phy *mxs_phy)
> >  	return mxs_phy->data == &imx7ulp_phy_data;
> >  }
> >
> > +static inline bool is_imx8ulp_phy(struct mxs_phy *mxs_phy)
> > +{
> > +	return mxs_phy->data == &imx8ulp_phy_data;
> 
> don't use this kind check.
> 
> Add field 'need_reset_reg' in mxs_phy_data
> 
> imx8ulp_phy_data = {
> 	.need_reset_reg = true;
> }
> 
> if (mxs->data->need_reset_reg)
> 	...
> 
> The same logic for
> 	if (is_imx7ulp_phy(mxs_phy) || is_imx8ulp_phy(mxs_phy))
> 		mxs_phy_pll_enable(phy->io_priv, false);
> 
> add 'need_phy_pull_enable' in mxs_phy_data. (new patch for it)
>     set it true at both imx7ulp_phy_data and imx8ulp_phy_data.

OK.

Thanks,
Xu Yang