(EXT) RE: [PATCH v3 3/4] usb: dwc3: imx8mp: Add support for setting SOC specific flags
Alexander Stein
alexander.stein at ew.tq-group.com
Wed Jan 26 04:49:46 PST 2022
Am Mittwoch, 19. Januar 2022, 15:14:05 CET schrieb Jun Li:
> > -----Original Message-----
> > From: Alexander Stein <alexander.stein at ew.tq-group.com>
> > Sent: Tuesday, January 18, 2022 9:16 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 v3 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 | 81 ++++++++++++++++++++++++++++++++++
> > 1 file changed, 81 insertions(+)
> >
> > diff --git a/drivers/usb/dwc3/dwc3-imx8mp.c
> > b/drivers/usb/dwc3/dwc3-imx8mp.c index 1c8fe657b3a9..3df4313b3740 100644
> > --- a/drivers/usb/dwc3/dwc3-imx8mp.c
> > +++ b/drivers/usb/dwc3/dwc3-imx8mp.c
> > @@ -36,17 +36,66 @@
> >
> > #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;
> >
> > + struct clk *phy_clk;
> >
> > int irq;
> > bool pm_suspended;
> > 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) || (!dwc3_imx->phy_clk))
> > + 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;
> > +
> > + 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 +149,7 @@ 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;
> >
> > int err, irq;
> >
> > if (!node) {
> >
> > @@ -119,6 +169,15 @@ 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);
> >
> > @@ -145,6 +204,24 @@ static int dwc3_imx8mp_probe(struct platform_device
> > *pdev)
> >
> > goto disable_hsio_clk;
> >
> > }
> >
> > + dwc3_imx->phy_clk = devm_clk_get(dev, "phy");
> > + if (PTR_ERR(dwc3_imx->phy_clk) == -ENOENT) {
> > + dev_warn(dev, "PHY clock missing. Continuing without,
some features
> > are missing though.");
Hi,
> What feature needs phy clock turned on here, why phy driver turns on
> this clock is not enough for you?
I have to admit that the clock name 'phy' might be misleading. In this case
the actual clock is IMX8MP_CLK_USB_PHY_ROOT. Apparently this clock (or a
dependent) is necessary to access the USB3_GLUE block in imx8mp. This block
contains the USB3_CTRL0/USB3_CTRL1, we want to access in this case, as well as
the PHY registers, hence the name I guess.
While it is true that phy-fsl-imx8mq-usb enables this clock as well, there is
no guarantee this lock is enabled when we want to access the GLUE registers.
Depending on the probe order it is actually possible the clock is disabled
while dwc3-imx8mp being probed, resulting in a system lockup.
This happens especially if there is only one USB host enabled and the drivers
are built as modules.
Meanwhile I noticed [1] landed last week. So I gave it a try. With that in
place there is no need to use IMX8MP_CLK_USB_PHY_ROOT in this driver anymore.
As it turns out IMX8MP_CLK_USB_ROOT is the required clock (used by imx8mp-blk-
ctrl for USB power domain).
With that, I'll send a new version based on Lucas' patchset.
Thanks for the feedback
Alexander
[1] https://patchwork.kernel.org/project/linux-arm-kernel/cover/
20220119134027.2931945-1-l.stach at pengutronix.de/
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