[PATCH v4 3/4] usb: dwc3: imx8mp: Add support for setting SOC specific flags

[Jun Li]

> -----Original Message-----
> From: Alexander Stein <alexander.stein at ew.tq-group.com>
> Sent: Wednesday, January 26, 2022 10:14 PM
> To: Greg Kroah-Hartman <gregkh at linuxfoundation.org>; Rob Herring
> <robh+dt at kernel.org>; Shawn Guo <shawnguo at kernel.org>; Sascha Hauer
> <s.hauer at pengutronix.de>; Fabio Estevam <festevam at gmail.com>
> Cc: Alexander Stein <alexander.stein at ew.tq-group.com>; dl-linux-imx
> <linux-imx at nxp.com>; linux-usb at vger.kernel.org;
> devicetree at vger.kernel.org; linux-arm-kernel at lists.infradead.org; Jun Li
> <jun.li at nxp.com>
> Subject: [PATCH v4 3/4] usb: dwc3: imx8mp: Add support for setting SOC
> specific flags
> 
> The i.MX8MP glue layer has support for the following flags:
> * over-current polarity
> * PWR pad polarity
> * controlling PPC flag in HCCPARAMS register
> * permanent port attach for usb2 & usb3 port
> 
> Allow setting these flags by supporting specific flags in the glue node.
> In order to get this to work an additional IORESOURCE_MEM and clock is
> necessary. For backward compatibility this is purely optional.
> 
> Signed-off-by: Alexander Stein <alexander.stein at ew.tq-group.com>
> ---
>  drivers/usb/dwc3/dwc3-imx8mp.c | 62 ++++++++++++++++++++++++++++++++++
>  1 file changed, 62 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/dwc3-imx8mp.c
> b/drivers/usb/dwc3/dwc3-imx8mp.c
> index 1c8fe657b3a9..5a96b66bf237 100644
> --- a/drivers/usb/dwc3/dwc3-imx8mp.c
> +++ b/drivers/usb/dwc3/dwc3-imx8mp.c
> @@ -36,10 +36,22 @@
> 
>  #define USB_WAKEUP_EN_MASK		GENMASK(5, 0)
> 
> +/* USB glue registers */
> +#define USB_CTRL0		0x00
> +#define USB_CTRL1		0x04
> +
> +#define USB_CTRL0_PORTPWR_EN	BIT(12) /* 1 - PPC enabled (default) */
> +#define USB_CTRL0_USB3_FIXED	BIT(22) /* 1 - USB3 permanent attached */
> +#define USB_CTRL0_USB2_FIXED	BIT(23) /* 1 - USB2 permanent attached */
> +
> +#define USB_CTRL1_OC_POLARITY	BIT(16) /* 0 - HIGH / 1 - LOW */
> +#define USB_CTRL1_PWR_POLARITY	BIT(17) /* 0 - HIGH / 1 - LOW */
> +
>  struct dwc3_imx8mp {
>  	struct device			*dev;
>  	struct platform_device		*dwc3;
>  	void __iomem			*hsio_blk_base;
> +	void __iomem			*glue_base;
>  	struct clk			*hsio_clk;
>  	struct clk			*suspend_clk;
>  	int				irq;
> @@ -47,6 +59,42 @@ struct dwc3_imx8mp {
>  	bool				wakeup_pending;
>  };
> 
> +static void imx8mp_configure_glue(struct dwc3_imx8mp *dwc3_imx)
> +{
> +	struct device *dev = dwc3_imx->dev;
> +	u32 value;
> +
> +	if (!dwc3_imx->glue_base)
> +		return;
> +
> +	value = readl(dwc3_imx->glue_base + USB_CTRL0);
> +
> +	if (device_property_read_bool(dev, "fsl,permanently-attached"))
> +		value |= (USB_CTRL0_USB2_FIXED | USB_CTRL0_USB3_FIXED);
> +	else
> +		value &= ~(USB_CTRL0_USB2_FIXED | USB_CTRL0_USB3_FIXED);
> +
> +	if (device_property_read_bool(dev,
> "fsl,disable-port-power-control"))
> +		value &= ~(USB_CTRL0_PORTPWR_EN);
> +	else
> +		value |= USB_CTRL0_PORTPWR_EN;
> +
> +	writel(value, dwc3_imx->glue_base + USB_CTRL0);
> +
> +	value = readl(dwc3_imx->glue_base + USB_CTRL1);
> +	if (device_property_read_bool(dev, "fsl,over-current-active-low"))
> +		value |= USB_CTRL1_OC_POLARITY;
> +	else
> +		value &= ~USB_CTRL1_OC_POLARITY;
> +
> +	if (device_property_read_bool(dev, "fsl,power-active-low"))
> +		value |= USB_CTRL1_PWR_POLARITY;
> +	else
> +		value &= ~USB_CTRL1_PWR_POLARITY;

I think you don't need a value update&write if property is not present.

> +
> +	writel(value, dwc3_imx->glue_base + USB_CTRL1);
> +}
> +
>  static void dwc3_imx8mp_wakeup_enable(struct dwc3_imx8mp *dwc3_imx)
>  {
>  	struct dwc3	*dwc3 = platform_get_drvdata(dwc3_imx->dwc3);
> @@ -100,6 +148,7 @@ static int dwc3_imx8mp_probe(struct platform_device
> *pdev)
>  	struct device		*dev = &pdev->dev;
>  	struct device_node	*dwc3_np, *node = dev->of_node;
>  	struct dwc3_imx8mp	*dwc3_imx;
> +	struct resource		*res;

Looks like this is not used anywhere, remove it.

>  	int			err, irq;
> 
>  	if (!node) {
> @@ -119,6 +168,15 @@ static int dwc3_imx8mp_probe(struct platform_device
> *pdev)
>  	if (IS_ERR(dwc3_imx->hsio_blk_base))
>  		return PTR_ERR(dwc3_imx->hsio_blk_base);
> 
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> +	if (!res) {
> +		dev_warn(dev, "Base address for glue layer missing. Continuing
> without, some features are missing though.");
> +	} else {
> +		dwc3_imx->glue_base = devm_ioremap_resource(dev, res);
> +		if (IS_ERR(dwc3_imx->glue_base))
> +			return PTR_ERR(dwc3_imx->glue_base);
> +	}
> +
>  	dwc3_imx->hsio_clk = devm_clk_get(dev, "hsio");
>  	if (IS_ERR(dwc3_imx->hsio_clk)) {
>  		err = PTR_ERR(dwc3_imx->hsio_clk);
> @@ -152,6 +210,8 @@ static int dwc3_imx8mp_probe(struct platform_device
> *pdev)
>  	}
>  	dwc3_imx->irq = irq;
> 
> +	imx8mp_configure_glue(dwc3_imx);
> +
>  	pm_runtime_set_active(dev);
>  	pm_runtime_enable(dev);
>  	err = pm_runtime_get_sync(dev);
> @@ -252,6 +312,8 @@ static int __maybe_unused dwc3_imx8mp_resume(struct
> dwc3_imx8mp *dwc3_imx,
>  	dwc3_imx8mp_wakeup_disable(dwc3_imx);
>  	dwc3_imx->pm_suspended = false;
> 
> +	imx8mp_configure_glue(dwc3_imx);
> +

I guess this is to restore the settings if we experienced a power lost,
Please add some comments.

thanks
Li Jun

>  	if (dwc3_imx->wakeup_pending) {
>  		dwc3_imx->wakeup_pending = false;
>  		if (dwc->current_dr_role == DWC3_GCTL_PRTCAP_DEVICE) {
> --
> 2.25.1