linux-kernel - Re: [PATCH 1/2] usb: cdns3: Add quirk flag to enable suspend residency

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Message-ID: <20240516013924.GA3283751@nchen-desktop>
Date: Thu, 16 May 2024 09:39:24 +0800
From: Peter Chen <peter.chen@...nel.org>
To: Ravi Gunasekaran <r-gunasekaran@...com>
Cc: pawell@...ence.com, rogerq@...nel.org, gregkh@...uxfoundation.org,
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] usb: cdns3: Add quirk flag to enable suspend
 residency

On 24-05-15 09:52:57, Ravi Gunasekaran wrote:
> 
> 
> On 5/15/24 7:08 AM, Peter Chen wrote:
> > On 24-05-14 14:54:20, Ravi Gunasekaran wrote:
> >> From: Roger Quadros <rogerq@...nel.org>
> >>
> >> Some platforms (e.g. ti,j721e-usb, ti,am64-usb) require
> >> this bit to be set to workaround a lockup issue with PHY
> >> short suspend intervals [1]. Add a platform quirk flag
> >> to indicate if Suspend Residency should be enabled.
> >>
> >> [1] - https://www.ti.com/lit/er/sprz457h/sprz457h.pdf
> >> i2409 - USB: USB2 PHY locks up due to short suspend
> >>
> >> Signed-off-by: Roger Quadros <rogerq@...nel.org>
> >> Signed-off-by: Ravi Gunasekaran <r-gunasekaran@...com>
> >> ---
> 
> [...]
> 
> >>  	regs = devm_ioremap_resource(cdns->dev, &cdns->otg_res);
> >> @@ -439,6 +439,13 @@ int cdns_drd_init(struct cdns *cdns)
> >>  			return -EINVAL;
> >>  		}
> >>  
> >> +		if (cdns->pdata &&
> >> +		    (cdns->pdata->quirks & CDNS3_DRD_SUSPEND_RESIDENCY_ENABLE)) {
> >> +			reg = readl(&cdns->otg_v1_regs->susp_ctrl);
> >> +			reg |= SUSP_CTRL_SUSPEND_RESIDENCY_ENABLE;
> >> +			writel(reg, &cdns->otg_v1_regs->susp_ctrl);
> >> +		}
> >> +
> > 
> > It is better put this above (just above code cdns->version  =
> > CDNS3_CONTROLLER_V1;)
> > 
> 
> You mean here, to group it with CDNS3 v1?
> 
> else if (OTG_CDNS3_CHECK_DID(state)) {                                               
>       cdns->otg_irq_regs = (struct cdns_otg_irq_regs __iomem *)
>                             &cdns->otg_v1_regs->ien;
>       writel(1, &cdns->otg_v1_regs->simulate);
> 
> +     if (cdns->pdata &&
> +	  (cdns->pdata->quirks & CDNS3_DRD_SUSPEND_RESIDENCY_ENABLE)) {
> +	      reg = readl(&cdns->otg_v1_regs->susp_ctrl);
> +	      reg |= SUSP_CTRL_SUSPEND_RESIDENCY_ENABLE;
> +	      writel(reg, &cdns->otg_v1_regs->susp_ctrl);
> +     }
>       dns->version  = CDNS3_CONTROLLER_V1;

Yes.

Peter

> } else
> 
> > Peter
> >>  		dev_dbg(cdns->dev, "DRD version v1 (ID: %08x, rev: %08x)\n",
> >>  			 readl(&cdns->otg_v1_regs->did),
> >>  			 readl(&cdns->otg_v1_regs->rid));
> >> diff --git a/drivers/usb/cdns3/drd.h b/drivers/usb/cdns3/drd.h
> >> index d72370c321d3..1e2aee14d629 100644
> >> --- a/drivers/usb/cdns3/drd.h
> >> +++ b/drivers/usb/cdns3/drd.h
> >> @@ -193,6 +193,9 @@ struct cdns_otg_irq_regs {
> >>  /* OTGREFCLK - bitmasks */
> >>  #define OTGREFCLK_STB_CLK_SWITCH_EN	BIT(31)
> >>  
> >> +/* SUPS_CTRL - bitmasks */
> >> +#define SUSP_CTRL_SUSPEND_RESIDENCY_ENABLE	BIT(17)
> >> +
> >>  /* OVERRIDE - bitmasks */
> >>  #define OVERRIDE_IDPULLUP		BIT(0)
> >>  /* Only for CDNS3_CONTROLLER_V0 version */
> >> -- 
> >> 2.17.1
> >>
> > 
> 
> -- 
> Regards,
> Ravi

-- 

Thanks,
Peter Chen