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Date: Wed, 15 May 2024 09:38:38 +0800
From: Peter Chen <peter.chen@kernel.org>
To: Ravi Gunasekaran <r-gunasekaran@ti.com>
Cc: pawell@cadence.com, rogerq@kernel.org, gregkh@linuxfoundation.org,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] usb: cdns3: Add quirk flag to enable suspend
 residency
Message-ID: <20240515013838.GA3279984@nchen-desktop>
References: <20240514092421.20897-1-r-gunasekaran@ti.com>
 <20240514092421.20897-2-r-gunasekaran@ti.com>
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In-Reply-To: <20240514092421.20897-2-r-gunasekaran@ti.com>

On 24-05-14 14:54:20, Ravi Gunasekaran wrote:
> From: Roger Quadros <rogerq@kernel.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@kernel.org>
> Signed-off-by: Ravi Gunasekaran <r-gunasekaran@ti.com>
> ---
>  drivers/usb/cdns3/core.h | 1 +
>  drivers/usb/cdns3/drd.c  | 9 ++++++++-
>  drivers/usb/cdns3/drd.h  | 3 +++
>  3 files changed, 12 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..de0d25a072b4 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);
> @@ -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;)

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
> 

-- 

Thanks,
Peter Chen