linux-kernel - Re: [PATCH 3/3] usb: dwc3: keystone: Turn on USB3 PHY before controller

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Message-ID: <1589420265.5899.0.camel@mhfsdcap03>
Date:   Thu, 14 May 2020 09:37:45 +0800
From:   Chunfeng Yun <chunfeng.yun@...iatek.com>
To:     Roger Quadros <rogerq@...com>
CC:     <balbi@...nel.org>, <robh+dt@...nel.org>, <vigneshr@...com>,
        <linux-usb@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] usb: dwc3: keystone: Turn on USB3 PHY before
 controller

On Wed, 2020-05-13 at 16:07 +0300, Roger Quadros wrote:
> The Local Power Sleep Controller (LPSC) dependency on AM65
> requires SERDES0 to be powered on before USB.
> 
> We need to power up SERDES0 power domain and hold it on
> throughout the reset, init, power on sequence.
> 
> Signed-off-by: Roger Quadros <rogerq@...com>
> ---
>  drivers/usb/dwc3/dwc3-keystone.c | 47 +++++++++++++++++++++++++++++++-
>  1 file changed, 46 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/dwc3/dwc3-keystone.c b/drivers/usb/dwc3/dwc3-keystone.c
> index 1e14a6f4884b..46d46f3507fc 100644
> --- a/drivers/usb/dwc3/dwc3-keystone.c
> +++ b/drivers/usb/dwc3/dwc3-keystone.c
> @@ -14,6 +14,7 @@
>  #include <linux/dma-mapping.h>
>  #include <linux/io.h>
>  #include <linux/of_platform.h>
> +#include <linux/phy/phy.h>
>  #include <linux/pm_runtime.h>
>  
>  /* USBSS register offsets */
> @@ -34,6 +35,7 @@
>  struct dwc3_keystone {
>  	struct device			*dev;
>  	void __iomem			*usbss;
> +	struct phy			*usb3_phy;
>  };
>  
>  static inline u32 kdwc3_readl(void __iomem *base, u32 offset)
> @@ -95,8 +97,44 @@ static int kdwc3_probe(struct platform_device *pdev)
>  	if (IS_ERR(kdwc->usbss))
>  		return PTR_ERR(kdwc->usbss);
>  
> -	pm_runtime_enable(kdwc->dev);
> +	/* PSC dependency on AM65 needs SERDES0 to be powered before USB0 */
> +	kdwc->usb3_phy = devm_phy_get(dev, "usb3-phy");
Use devm_phy_optional_get() instead?

> +	if (IS_ERR(kdwc->usb3_phy)) {
> +		error = PTR_ERR(kdwc->usb3_phy);
> +		if (error == -ENOSYS || error == -ENODEV) {
> +			kdwc->usb3_phy = NULL;
> +		} else {
> +			if (error != -EPROBE_DEFER) {
> +				dev_err(dev, "couldn't get usb3 phy: %d\n",
> +					error);
> +			}
> +
> +			return error;
> +		}
> +	}
> +
> +	phy_pm_runtime_get_sync(kdwc->usb3_phy);
> +
> +	error = phy_reset(kdwc->usb3_phy);
> +	if (error < 0) {
> +		dev_err(dev, "usb3 phy reset failed: %d\n", error);
> +		return error;
> +	}
> +
> +	error = phy_init(kdwc->usb3_phy);
> +	if (error < 0) {
> +		dev_err(dev, "usb3 phy init failed: %d\n", error);
> +		return error;
> +	}
>  
> +	error = phy_power_on(kdwc->usb3_phy);
> +	if (error < 0) {
> +		dev_err(dev, "usb3 phy power on failed: %d\n", error);
> +		phy_exit(kdwc->usb3_phy);
> +		return error;
> +	}
> +
> +	pm_runtime_enable(kdwc->dev);
>  	error = pm_runtime_get_sync(kdwc->dev);
>  	if (error < 0) {
>  		dev_err(kdwc->dev, "pm_runtime_get_sync failed, error %d\n",
> @@ -138,6 +176,9 @@ static int kdwc3_probe(struct platform_device *pdev)
>  err_irq:
>  	pm_runtime_put_sync(kdwc->dev);
>  	pm_runtime_disable(kdwc->dev);
> +	phy_power_off(kdwc->usb3_phy);
> +	phy_exit(kdwc->usb3_phy);
> +	phy_pm_runtime_put_sync(kdwc->usb3_phy);
>  
>  	return error;
>  }
> @@ -163,6 +204,10 @@ static int kdwc3_remove(struct platform_device *pdev)
>  	pm_runtime_put_sync(kdwc->dev);
>  	pm_runtime_disable(kdwc->dev);
>  
> +	phy_power_off(kdwc->usb3_phy);
> +	phy_exit(kdwc->usb3_phy);
> +	phy_pm_runtime_put_sync(kdwc->usb3_phy);
> +
>  	platform_set_drvdata(pdev, NULL);
>  
>  	return 0;