linux-kernel - Re: [PATCH v3 1/2] usb: cdns3: Add quirk flag to enable suspend residency

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Message-ID: <20240517022038.GA3458484@nchen-desktop>
Date: Fri, 17 May 2024 10:20:38 +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, srk@...com
Subject: Re: [PATCH v3 1/2] usb: cdns3: Add quirk flag to enable suspend
 residency

On 24-05-16 10:15:36, 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>
> ---
> Change log:
> ----------
> Changes since v2:
> ----------------
> * Fixed the redundant blank line added in v2
> 
> Changes since v1:
> ----------------
> * Grouped the susp_ctrl register update along with
>   existing CDNS3 snippet as suggested by Peter Chen
> 
> v2: https://lore.kernel.org/all/20240516042845.31211-1-r-gunasekaran@ti.com/
> v1: https://lore.kernel.org/all/20240514092421.20897-1-r-gunasekaran@ti.com/#t
> 
>  drivers/usb/cdns3/core.h |  1 +
>  drivers/usb/cdns3/drd.c  | 10 +++++++++-
>  drivers/usb/cdns3/drd.h  |  3 +++
>  3 files changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/cdns3/core.h b/drivers/usb/cdns3/core.h
> index 81a9c9d6be08..57d47348dc19 100644
> --- a/drivers/usb/cdns3/core.h
> +++ b/drivers/usb/cdns3/core.h
> @@ -44,6 +44,7 @@ struct cdns3_platform_data {
>  			bool suspend, bool wakeup);
>  	unsigned long quirks;
>  #define CDNS3_DEFAULT_PM_RUNTIME_ALLOW	BIT(0)
> +#define CDNS3_DRD_SUSPEND_RESIDENCY_ENABLE	BIT(1)
>  };
>  
>  /**
> diff --git a/drivers/usb/cdns3/drd.c b/drivers/usb/cdns3/drd.c
> index 8b936a2e93a0..84fb38a5723a 100644
> --- a/drivers/usb/cdns3/drd.c
> +++ b/drivers/usb/cdns3/drd.c
> @@ -389,7 +389,7 @@ static irqreturn_t cdns_drd_irq(int irq, void *data)
>  int cdns_drd_init(struct cdns *cdns)
>  {
>  	void __iomem *regs;
> -	u32 state;
> +	u32 state, reg;
>  	int ret;
>  
>  	regs = devm_ioremap_resource(cdns->dev, &cdns->otg_res);
> @@ -433,6 +433,14 @@ int cdns_drd_init(struct cdns *cdns)
>  			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);
> +			}
> +
>  			cdns->version  = CDNS3_CONTROLLER_V1;

Acked-by: Peter Chen <peter.chen@...nel.org>

Peter
>  		} else {
>  			dev_err(cdns->dev, "not supported DID=0x%08x\n", state);
> 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
> 

-- 

Thanks,
Peter Chen