RE: [PATCH v2 2/3] usb: chipidea: imx: support disabling runtime-pm

[Jun Li <jun.li@nxp.com>]

> -----Original Message-----
> From: Francesco Dolcini <francesco@dolcini.it>
> Sent: Friday, May 5, 2023 12:50 AM
> To: Luca Ceresoli <luca.ceresoli@bootlin.com>
> Cc: devicetree@vger.kernel.org; festevam@gmail.com;
> gregkh@linuxfoundation.org; Jun Li <jun.li@nxp.com>;
> kernel@pengutronix.de; linux-arm-kernel@lists.infradead.org;
> dl-linux-imx <linux-imx@nxp.com>; linux-kernel@vger.kernel.org;
> linux-usb@vger.kernel.org; peter.chen@nxp.com; robh+dt@kernel.org;
> s.hauer@pengutronix.de; shawnguo@kernel.org; Krzysztof Kozlowski
> <krzysztof.kozlowski@linaro.org>; Francesco Dolcini
> <francesco.dolcini@toradex.com>
> Subject: Re: [PATCH v2 2/3] usb: chipidea: imx: support disabling runtime-pm
>
> Hello Luca,
> I guess your mail to Philippe bounced, let me try to answer since I am aware
> of the issue here.
>
> On Thu, May 04, 2023 at 06:23:12PM +0200, Luca Ceresoli wrote:
> > I found this thread after several hours spent in debugging why USB host
> is
> > not detecting new devices on a custom board using the iMX6ULL Colibri
> > SoM.
> >
> > My best workaround at the moment is:
> We have the same workaround in our BSP since quite some time, see
> https://git.t/
> oradex.com%2Fcgit%2Fmeta-toradex-bsp-common.git%2Ftree%2Frecipes-kernel
> %2Flinux%2Flinux-toradex-mainline-git%2F0002-drivers-chipidea-disable-r
> untime-pm-for-imx6ul.patch&data=05%7C01%7Cjun.li%40nxp.com%7C776dc1e71a
> 554ee20ed908db4cbfa5aa%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C638
> 188158228795706%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2l
> uMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=3cFsUurgKBfic
> LNfRxMOErukGiMczhJREFGvaFYTH34%3D&reserved=0
>
> > I haven't found any follow-up patches from you, so I'm wondering whether
> > you have made any progress on this issue.
> You can find the latest discussion on that regard here
> https://lore/.
> kernel.org%2Fall%2FY1vLpaxpc5WBCuGD%40francesco-nb.int.toradex.com%2F&d
> ata=05%7C01%7Cjun.li%40nxp.com%7C776dc1e71a554ee20ed908db4cbfa5aa%7C686
> ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C638188158228795706%7CUnknown%7C
> TWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI
> 6Mn0%3D%7C3000%7C%7C%7C&sdata=xgIAlY5Az9zQgOBaUTHeGJDXNIyNRmEBlcR49JOVB
> sI%3D&reserved=0
>
> > As I see it, a quirk in the driver would make sense.
> I am not sure.
>
> The reason this is not working is that the VBUS is not directly
> connected to the SOC and the USB IP is powered in a different way (all
> of that was reviewed/acked by NXP when the board was designed).

Hi Luca,

Is your board design similar like Francesco's as below?

"VDD_USB_CAP in our design is connected to a 3.0V external LDO,
 voltage on both VBUS pads is 0V"

I am going to fix this by update the PHY power supply check to cover
Francesco's case(PHY is powered by VDD_USB_CAP).

Thanks
Li Jun

>
> The issue is in drivers/usb/phy/phy-mxs-usb.c:mxs_phy_disconnect_line(),
> however:
>  1 - checking for the VBUS when in host mode is not correct.
>  2 - checking for the VBUS when in OTG/dual-role mode should be done using
>  extcon or equivalent. In this case on the colibri-imx6ull you would get
>  the correct behavior.
>
> The NXP downstream kernel has some improvements on that regard, for
> instance 1 would work, 2 I am not 100% sure.
>
> Here the related patches:
>
> From 60422d8301fc354e69ec0184831468c3b65cc26a Mon Sep 17 00:00:00 2001
> From: Li Jun <jun.li@nxp.com>
> Date: Wed, 12 Apr 2017 05:31:17 +0800
> Subject: [PATCH 1/3] MLK-14285-1 usb: phy: add usb mode for usb_phy
>
> USB phy driver may need to know the current working mode of
> the controller, and does some different settings according to
> host mode or device mode.
>
> Signed-off-by: Li Jun <jun.li@nxp.com>
> (cherry picked from commit 2286cb30feedd6f4a5cb82a0f0af5aa3a04ab698)
> Signed-off-by: Vipul Kumar <vipul_kumar@mentor.com>
> Signed-off-by: Srikanth Krishnakar <Srikanth_Krishnakar@mentor.com>
> ---
>  include/linux/usb/phy.h | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
>
> diff --git a/include/linux/usb/phy.h b/include/linux/usb/phy.h
> index e4de6bc1f69b..93963a018a13 100644
> --- a/include/linux/usb/phy.h
> +++ b/include/linux/usb/phy.h
> @@ -63,6 +63,13 @@ enum usb_otg_state {
>       OTG_STATE_A_VBUS_ERR,
>  };
>
> +/* The usb role of phy to be working with */
> +enum usb_current_mode {
> +     CUR_USB_MODE_NONE,
> +     CUR_USB_MODE_HOST,
> +     CUR_USB_MODE_DEVICE,
> +};
> +
>  struct usb_phy;
>  struct usb_otg;
>
> @@ -155,6 +162,10 @@ struct usb_phy {
>        * manually detect the charger type.
>        */
>       enum usb_charger_type (*charger_detect)(struct usb_phy *x);
> +
> +     int     (*set_mode)(struct usb_phy *x,
> +                     enum usb_current_mode mode);
> +
>  };
>
>  /* for board-specific init logic */
> @@ -213,6 +224,15 @@ usb_phy_vbus_off(struct usb_phy *x)
>       return x->set_vbus(x, false);
>  }
>
> +static inline int
> +usb_phy_set_mode(struct usb_phy *x, enum usb_current_mode mode)
> +{
> +     if (!x || !x->set_mode)
> +             return 0;
> +
> +     return x->set_mode(x, mode);
> +}
> +
>  /* for usb host and peripheral controller drivers */
>  #if IS_ENABLED(CONFIG_USB_PHY)
>  extern struct usb_phy *usb_get_phy(enum usb_phy_type type);
>
>
> From cf3f741f4b7ab5d139938c4c0cd65d4547d386ff Mon Sep 17 00:00:00 2001
> From: Li Jun <jun.li@nxp.com>
> Date: Wed, 12 Apr 2017 05:41:21 +0800
> Subject: [PATCH 2/3] MLK-14285-3 usb: phy: mxs: optimize disconnect line
>  condition
>
> We only have below cases to disconnect line when suspend:
> 1. Device mode without connection to any host/charger(no vbus).
> 2. Device mode connect to a charger(w/ vbus), usb suspend when
>    system is entering suspend.
> This patch can fix usb phy wrongly does disconnect line in case
> some usb host enters suspend but vbus is off.
>
> Signed-off-by: Li Jun <jun.li@nxp.com>
> (cherry picked from commit 2af48913f77cec3658f5863b13f63619d8101279)
> ---
>  drivers/usb/phy/phy-mxs-usb.c | 32 ++++++++++++++++++--------------
>  1 file changed, 18 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/usb/phy/phy-mxs-usb.c
> b/drivers/usb/phy/phy-mxs-usb.c
> index 8a262c5a0408..31f40dbb71c0 100644
> --- a/drivers/usb/phy/phy-mxs-usb.c
> +++ b/drivers/usb/phy/phy-mxs-usb.c
> @@ -1,6 +1,7 @@
>  // SPDX-License-Identifier: GPL-2.0+
>  /*
> - * Copyright 2012-2014 Freescale Semiconductor, Inc.
> + * Copyright 2012-2016 Freescale Semiconductor, Inc.
> + * Copyright 2017 NXP
>   * Copyright (C) 2012 Marek Vasut <marex@denx.de>
>   * on behalf of DENX Software Engineering GmbH
>   */
> @@ -204,6 +205,7 @@ struct mxs_phy {
>       int port_id;
>       u32 tx_reg_set;
>       u32 tx_reg_mask;
> +     enum usb_current_mode mode;
>  };
>
>  static inline bool is_imx6q_phy(struct mxs_phy *mxs_phy)
> @@ -386,18 +388,6 @@ static void __mxs_phy_disconnect_line(struct mxs_phy
> *mxs_phy, bool disconnect)
>               usleep_range(500, 1000);
>  }
>
> -static bool mxs_phy_is_otg_host(struct mxs_phy *mxs_phy)
> -{
> -     void __iomem *base = mxs_phy->phy.io_priv;
> -     u32 phyctrl = readl(base + HW_USBPHY_CTRL);
> -
> -     if (IS_ENABLED(CONFIG_USB_OTG) &&
> -                     !(phyctrl & BM_USBPHY_CTRL_OTG_ID_VALUE))
> -             return true;
> -
> -     return false;
> -}
> -
>  static void mxs_phy_disconnect_line(struct mxs_phy *mxs_phy, bool on)
>  {
>       bool vbus_is_on = false;
> @@ -412,7 +402,7 @@ static void mxs_phy_disconnect_line(struct mxs_phy
> *mxs_phy, bool on)
>
>       vbus_is_on = mxs_phy_get_vbus_status(mxs_phy);
>
> -     if (on && !vbus_is_on && !mxs_phy_is_otg_host(mxs_phy))
> +     if (on && ((!vbus_is_on && mxs_phy->mode != CUR_USB_MODE_HOST)))
>               __mxs_phy_disconnect_line(mxs_phy, true);
>       else
>               __mxs_phy_disconnect_line(mxs_phy, false);
> @@ -708,6 +698,19 @@ static enum usb_charger_type
> mxs_phy_charger_detect(struct usb_phy *phy)
>       return chgr_type;
>  }
>
> +/*
> + * Set the usb current role for phy.
> + */
> +static int mxs_phy_set_mode(struct usb_phy *phy,
> +             enum usb_current_mode mode)
> +{
> +     struct mxs_phy *mxs_phy = to_mxs_phy(phy);
> +
> +     mxs_phy->mode = mode;
> +
> +     return 0;
> +}
> +
>  static int mxs_phy_probe(struct platform_device *pdev)
>  {
>       void __iomem *base;
> @@ -793,6 +796,7 @@ static int mxs_phy_probe(struct platform_device *pdev)
>
>       mxs_phy->clk = clk;
>       mxs_phy->data = of_device_get_match_data(&pdev->dev);
> +     mxs_phy->phy.set_mode           = mxs_phy_set_mode;
>
>       platform_set_drvdata(pdev, mxs_phy);
>
>
> From d4c4385b997f32b081e859d491f25f5beb738ae9 Mon Sep 17 00:00:00 2001
> From: Li Jun <jun.li@nxp.com>
> Date: Wed, 12 Apr 2017 05:38:48 +0800
> Subject: [PATCH 3/3] MLK-14285-2 usb: chipidea: set mode for usb phy driver
>
> After enters one specific role, notify usb phy driver.
>
> Signed-off-by: Li Jun <jun.li@nxp.com>
> (cherry picked from commit d3aa2a13f4e47bc7fae7f2eee1e86291d7513312)
> ---
>  drivers/usb/chipidea/ci.h | 21 ++++++++++++++++++---
>  1 file changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/chipidea/ci.h b/drivers/usb/chipidea/ci.h
> index 99440baa6458..9d7ba902246d 100644
> --- a/drivers/usb/chipidea/ci.h
> +++ b/drivers/usb/chipidea/ci.h
> @@ -274,9 +274,21 @@ static inline int ci_role_start(struct ci_hdrc *ci,
> enum ci_role role)
>               return -ENXIO;
>
>       ret = ci->roles[role]->start(ci);
> -     if (!ret)
> -             ci->role = role;
> -     return ret;
> +     if (ret)
> +             return ret;
> +
> +     ci->role = role;
> +
> +     if (ci->usb_phy) {
> +             if (role == CI_ROLE_HOST)
> +                     usb_phy_set_mode(ci->usb_phy,
> +                                     CUR_USB_MODE_HOST);
> +             else
> +                     usb_phy_set_mode(ci->usb_phy,
> +                                     CUR_USB_MODE_DEVICE);
> +     }
> +
> +     return 0;
>  }
>
>  static inline void ci_role_stop(struct ci_hdrc *ci)
> @@ -289,6 +301,9 @@ static inline void ci_role_stop(struct ci_hdrc *ci)
>       ci->role = CI_ROLE_END;
>
>       ci->roles[role]->stop(ci);
> +
> +     if (ci->usb_phy)
> +             usb_phy_set_mode(ci->usb_phy, CUR_USB_MODE_NONE);
>  }
>
>  static inline enum usb_role ci_role_to_usb_role(struct ci_hdrc *ci)
>
>
> Francesco