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In-Reply-To: <1550561795-31132-7-git-send-email-min.guo@mediatek.com>
From:   Fabien Parent <fparent@baylibre.com>
Date:   Sat, 30 Mar 2019 09:52:36 +0100
Message-ID: <CAOwMV_w5W1d0nXDtm7ui4S9oy5x6kvD+jMthWdQ6tDWYFMjs=A@mail.gmail.com>
Subject: Re: [PATCH v5 6/6] usb: musb: Add support for MediaTek musb controller
To:     min.guo@mediatek.com
Cc:     Bin Liu <b-liu@ti.com>, Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        devicetree@vger.kernel.org, Yonglong Wu <yonglong.wu@mediatek.com>,
        hdegoede@redhat.com, tony@atomide.com,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Alan Stern <stern@rowland.harvard.edu>,
        chunfeng.yun@mediatek.com, linux-mediatek@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi Min Guo,

On Tue, Feb 19, 2019 at 8:39 AM <min.guo@mediatek.com> wrote:
>
> From: Min Guo <min.guo@mediatek.com>
>
> This adds support for MediaTek musb controller in
> host, peripheral and otg mode.
> There are some quirk of MediaTek musb controller, such as:
>  -W1C interrupt status registers
>  -Private data toggle registers
>  -No dedicated DMA interrupt line
>
> Signed-off-by: Min Guo <min.guo@mediatek.com>
> Signed-off-by: Yonglong Wu <yonglong.wu@mediatek.com>
> ---
> changes in v5:
> 1. Replace musb_readb() with musb_clearb() to clear common/tx/rx pending interrupts
> 2. Make musb_clearb/w() return the value of musb_readb/w()
> 3. Add driver to get child nodes of usb connector and extcon device
>
> changes in v4:
> 1. no changes
>
> changes in v3:
> suggested by Bin:
> 1. Remove 'u8/u16 data' parameter in clearb/w() hooks
> 2. Replace musb_readb/w() with musb_clearb/w() to clear interrupts status
>
> changes in v2:
> suggested by Bin:
> 1. Add summarize of MediaTek musb controller differences in the commit log
> 2. Add "|| COMPILE_TEST" in Kconfig
> 3. Move MediaTek's private toggle registers from musb_regs.h to mediatek.c
> 4. Replace musb_readl() with musb_readw() to read 16bit toggle register
> ---
>  drivers/usb/musb/Kconfig    |   8 +-
>  drivers/usb/musb/Makefile   |   1 +
>  drivers/usb/musb/mediatek.c | 629 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 637 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/usb/musb/mediatek.c
>
> diff --git a/drivers/usb/musb/Kconfig b/drivers/usb/musb/Kconfig
> index ad08895..b72b7c1 100644
> --- a/drivers/usb/musb/Kconfig
> +++ b/drivers/usb/musb/Kconfig
> @@ -115,6 +115,12 @@ config USB_MUSB_JZ4740
>         depends on USB_MUSB_GADGET
>         depends on USB_OTG_BLACKLIST_HUB
>
> +config USB_MUSB_MEDIATEK
> +       tristate "MediaTek platforms"
> +       depends on ARCH_MEDIATEK || COMPILE_TEST
> +       depends on NOP_USB_XCEIV
> +       depends on GENERIC_PHY
> +
>  config USB_MUSB_AM335X_CHILD
>         tristate
>
> @@ -141,7 +147,7 @@ config USB_UX500_DMA
>
>  config USB_INVENTRA_DMA
>         bool 'Inventra'
> -       depends on USB_MUSB_OMAP2PLUS
> +       depends on USB_MUSB_OMAP2PLUS || USB_MUSB_MEDIATEK
>         help
>           Enable DMA transfers using Mentor's engine.
>
> diff --git a/drivers/usb/musb/Makefile b/drivers/usb/musb/Makefile
> index 3a88c79..63d82d0 100644
> --- a/drivers/usb/musb/Makefile
> +++ b/drivers/usb/musb/Makefile
> @@ -24,6 +24,7 @@ obj-$(CONFIG_USB_MUSB_DA8XX)                  += da8xx.o
>  obj-$(CONFIG_USB_MUSB_UX500)                   += ux500.o
>  obj-$(CONFIG_USB_MUSB_JZ4740)                  += jz4740.o
>  obj-$(CONFIG_USB_MUSB_SUNXI)                   += sunxi.o
> +obj-$(CONFIG_USB_MUSB_MEDIATEK)                += mediatek.o
>
>
>  obj-$(CONFIG_USB_MUSB_AM335X_CHILD)            += musb_am335x.o
> diff --git a/drivers/usb/musb/mediatek.c b/drivers/usb/musb/mediatek.c
> new file mode 100644
> index 0000000..946b453
> --- /dev/null
> +++ b/drivers/usb/musb/mediatek.c
> @@ -0,0 +1,629 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2018 MediaTek Inc.
> + *
> + * Author:
> + *  Min Guo <min.guo@mediatek.com>
> + *  Yonglong Wu <yonglong.wu@mediatek.com>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/usb/usb_phy_generic.h>
> +#include "musb_core.h"
> +#include "musb_dma.h"
> +
> +#define USB_L1INTS     0x00a0
> +#define USB_L1INTM     0x00a4
> +#define MTK_MUSB_TXFUNCADDR    0x0480
> +
> +/* MediaTek controller toggle enable and status reg */
> +#define MUSB_RXTOG             0x80
> +#define MUSB_RXTOGEN           0x82
> +#define MUSB_TXTOG             0x84
> +#define MUSB_TXTOGEN           0x86
> +
> +#define TX_INT_STATUS          BIT(0)
> +#define RX_INT_STATUS          BIT(1)
> +#define USBCOM_INT_STATUS              BIT(2)
> +#define DMA_INT_STATUS         BIT(3)
> +
> +#define DMA_INTR_STATUS_MSK            GENMASK(7, 0)
> +#define DMA_INTR_UNMASK_SET_MSK        GENMASK(31, 24)
> +
> +enum mtk_vbus_id_state {
> +       MTK_ID_FLOAT = 1,
> +       MTK_ID_GROUND,
> +       MTK_VBUS_OFF,
> +       MTK_VBUS_VALID,
> +};
> +
> +struct mtk_glue {
> +       struct device *dev;
> +       struct musb *musb;
> +       struct platform_device *musb_pdev;
> +       struct platform_device *usb_phy;
> +       struct phy *phy;
> +       struct usb_phy *xceiv;
> +       enum phy_mode phy_mode;
> +       struct clk *main;
> +       struct clk *mcu;
> +       struct clk *univpll;
> +       struct regulator *vbus;
> +       struct extcon_dev *edev;
> +       struct notifier_block vbus_nb;
> +       struct notifier_block id_nb;
> +};
> +
> +static int mtk_musb_clks_get(struct mtk_glue *glue)
> +{
> +       struct device *dev = glue->dev;
> +
> +       glue->main = devm_clk_get(dev, "main");
> +       if (IS_ERR(glue->main)) {
> +               dev_err(dev, "fail to get main clock\n");
> +               return PTR_ERR(glue->main);
> +       }
> +
> +       glue->mcu = devm_clk_get(dev, "mcu");
> +       if (IS_ERR(glue->mcu)) {
> +               dev_err(dev, "fail to get mcu clock\n");
> +               return PTR_ERR(glue->mcu);
> +       }
> +
> +       glue->univpll = devm_clk_get(dev, "univpll");
> +       if (IS_ERR(glue->univpll)) {
> +               dev_err(dev, "fail to get univpll clock\n");
> +               return PTR_ERR(glue->univpll);
> +       }
> +
> +       return 0;
> +}
> +
> +static int mtk_musb_clks_enable(struct mtk_glue *glue)
> +{
> +       int ret;
> +
> +       ret = clk_prepare_enable(glue->main);
> +       if (ret) {
> +               dev_err(glue->dev, "failed to enable main clock\n");
> +               goto err_main_clk;
> +       }
> +
> +       ret = clk_prepare_enable(glue->mcu);
> +       if (ret) {
> +               dev_err(glue->dev, "failed to enable mcu clock\n");
> +               goto err_mcu_clk;
> +       }
> +
> +       ret = clk_prepare_enable(glue->univpll);
> +       if (ret) {
> +               dev_err(glue->dev, "failed to enable univpll clock\n");
> +               goto err_univpll_clk;
> +       }
> +
> +       return 0;
> +
> +err_univpll_clk:
> +       clk_disable_unprepare(glue->mcu);
> +err_mcu_clk:
> +       clk_disable_unprepare(glue->main);
> +err_main_clk:
> +       return ret;
> +}
> +
> +static void mtk_musb_clks_disable(struct mtk_glue *glue)
> +{
> +       clk_disable_unprepare(glue->univpll);
> +       clk_disable_unprepare(glue->mcu);
> +       clk_disable_unprepare(glue->main);
> +}
> +
> +static void mtk_musb_set_vbus(struct musb *musb, int is_on)
> +{
> +       struct device *dev = musb->controller;
> +       struct mtk_glue *glue = dev_get_drvdata(dev->parent);
> +       int ret;
> +
> +       /* vbus is optional */
> +       if (!glue->vbus)
> +               return;
> +
> +       dev_dbg(musb->controller, "%s, is_on=%d\r\n", __func__, is_on);
> +       if (is_on) {
> +               ret = regulator_enable(glue->vbus);
> +               if (ret) {
> +                       dev_err(glue->dev, "fail to enable vbus regulator\n");
> +                       return;
> +               }
> +       } else {
> +               regulator_disable(glue->vbus);
> +       }
> +}
> +
> +/*
> + * switch to host: -> MTK_VBUS_OFF --> MTK_ID_GROUND
> + * switch to device: -> MTK_ID_FLOAT --> MTK_VBUS_VALID
> + */
> +static void mtk_musb_set_mailbox(struct mtk_glue *glue,
> +                                enum mtk_vbus_id_state status)
> +{
> +       struct musb *musb = glue->musb;
> +       u8 devctl = 0;
> +
> +       dev_dbg(glue->dev, "mailbox state(%d)\n", status);
> +       switch (status) {
> +       case MTK_ID_GROUND:
> +               phy_power_on(glue->phy);
> +               devctl = readb(musb->mregs + MUSB_DEVCTL);
> +               musb->xceiv->otg->state = OTG_STATE_A_WAIT_VRISE;
> +               mtk_musb_set_vbus(musb, 1);
> +               glue->phy_mode = PHY_MODE_USB_HOST;
> +               phy_set_mode(glue->phy, glue->phy_mode);
> +               devctl |= MUSB_DEVCTL_SESSION;
> +               musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);
> +               MUSB_HST_MODE(musb);
> +               break;
> +       /*
> +        * MTK_ID_FLOAT process is the same as MTK_VBUS_VALID
> +        * except that turn off VBUS
> +        */
> +       case MTK_ID_FLOAT:
> +               mtk_musb_set_vbus(musb, 0);
> +               /* fall through */
> +       case MTK_VBUS_OFF:
> +               musb->xceiv->otg->state = OTG_STATE_B_IDLE;
> +               devctl &= ~MUSB_DEVCTL_SESSION;
> +               musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);
> +               phy_power_off(glue->phy);
> +               break;
> +       case MTK_VBUS_VALID:
> +               phy_power_on(glue->phy);
> +               glue->phy_mode = PHY_MODE_USB_DEVICE;
> +               phy_set_mode(glue->phy, glue->phy_mode);
> +               MUSB_DEV_MODE(musb);
> +               break;
> +       default:
> +               dev_err(glue->dev, "invalid state\n");
> +       }
> +}
> +
> +static int mtk_musb_id_notifier(struct notifier_block *nb,
> +                               unsigned long event, void *ptr)
> +{
> +       struct mtk_glue *glue = container_of(nb, struct mtk_glue, id_nb);
> +
> +       if (event)
> +               mtk_musb_set_mailbox(glue, MTK_ID_GROUND);
> +       else
> +               mtk_musb_set_mailbox(glue, MTK_ID_FLOAT);
> +
> +       return NOTIFY_DONE;
> +}
> +
> +static int mtk_musb_vbus_notifier(struct notifier_block *nb,
> +                                 unsigned long event, void *ptr)
> +{
> +       struct mtk_glue *glue = container_of(nb, struct mtk_glue, vbus_nb);
> +
> +       if (event)
> +               mtk_musb_set_mailbox(glue, MTK_VBUS_VALID);
> +       else
> +               mtk_musb_set_mailbox(glue, MTK_VBUS_OFF);
> +
> +       return NOTIFY_DONE;
> +}
> +
> +static void mtk_otg_switch_init(struct mtk_glue *glue)
> +{
> +       int ret;
> +
> +       /* extcon is optional */
> +       if (!glue->edev)
> +               return;
> +
> +       glue->vbus_nb.notifier_call = mtk_musb_vbus_notifier;
> +       ret = devm_extcon_register_notifier(glue->dev, glue->edev, EXTCON_USB,
> +                                           &glue->vbus_nb);
> +       if (ret < 0)
> +               dev_err(glue->dev, "failed to register notifier for USB\n");
> +
> +       glue->id_nb.notifier_call = mtk_musb_id_notifier;
> +       ret = devm_extcon_register_notifier(glue->dev, glue->edev,
> +                                           EXTCON_USB_HOST, &glue->id_nb);
> +       if (ret < 0)
> +               dev_err(glue->dev, "failed to register notifier for USB-HOST\n");
> +
> +       dev_dbg(glue->dev, "EXTCON_USB: %d, EXTCON_USB_HOST: %d\n",
> +               extcon_get_state(glue->edev, EXTCON_USB),
> +               extcon_get_state(glue->edev, EXTCON_USB_HOST));
> +
> +       /* default as host, switch to device mode if needed */
> +       if (extcon_get_state(glue->edev, EXTCON_USB_HOST) == false)
> +               mtk_musb_set_mailbox(glue, MTK_ID_FLOAT);
> +       if (extcon_get_state(glue->edev, EXTCON_USB) == true)
> +               mtk_musb_set_mailbox(glue, MTK_VBUS_VALID);
> +}
> +
> +static irqreturn_t generic_interrupt(int irq, void *__hci)
> +{
> +       unsigned long flags;
> +       irqreturn_t retval = IRQ_NONE;
> +       struct musb *musb = __hci;
> +
> +       spin_lock_irqsave(&musb->lock, flags);
> +       musb->int_usb = musb_clearb(musb->mregs, MUSB_INTRUSB);
> +       musb->int_rx = musb_clearw(musb->mregs, MUSB_INTRRX);
> +       musb->int_tx = musb_clearw(musb->mregs, MUSB_INTRTX);
> +
> +       if (musb->int_usb || musb->int_tx || musb->int_rx)
> +               retval = musb_interrupt(musb);
> +
> +       spin_unlock_irqrestore(&musb->lock, flags);
> +
> +       return retval;
> +}
> +
> +static irqreturn_t mtk_musb_interrupt(int irq, void *dev_id)
> +{
> +       irqreturn_t retval = IRQ_NONE;
> +       struct musb *musb = (struct musb *)dev_id;
> +       u32 l1_ints;
> +
> +       l1_ints = musb_readl(musb->mregs, USB_L1INTS) &
> +                       musb_readl(musb->mregs, USB_L1INTM);
> +
> +       if (l1_ints & (TX_INT_STATUS | RX_INT_STATUS | USBCOM_INT_STATUS))
> +               retval = generic_interrupt(irq, musb);
> +
> +#if defined(CONFIG_USB_INVENTRA_DMA)
> +       if (l1_ints & DMA_INT_STATUS)
> +               retval = dma_controller_irq(irq, musb->dma_controller);
> +#endif
> +       return retval;
> +}
> +
> +static u32 mtk_musb_busctl_offset(u8 epnum, u16 offset)
> +{
> +       return MTK_MUSB_TXFUNCADDR + offset + 8 * epnum;
> +}
> +
> +static u8 mtk_musb_clearb(void __iomem *addr, unsigned int offset)
> +{
> +       u8 data;
> +
> +       /* W1C */
> +       data = musb_readb(addr, offset);
> +       musb_writeb(addr, offset, data);
> +       return data;
> +}
> +
> +static u16 mtk_musb_clearw(void __iomem *addr, unsigned int offset)
> +{
> +       u16 data;
> +
> +       /* W1C */
> +       data = musb_readw(addr, offset);
> +       musb_writew(addr, offset, data);
> +       return data;
> +}
> +
> +static int mtk_musb_init(struct musb *musb)
> +{
> +       struct device *dev = musb->controller;
> +       struct mtk_glue *glue = dev_get_drvdata(dev->parent);
> +       int ret;
> +
> +       glue->musb = musb;
> +       musb->phy = glue->phy;
> +       musb->xceiv = glue->xceiv;
> +       musb->is_host = false;
> +       musb->isr = mtk_musb_interrupt;
> +       ret = phy_init(glue->phy);
> +       if (ret)
> +               return ret;
> +
> +       ret = phy_power_on(glue->phy);
> +       if (ret) {
> +               phy_exit(glue->phy);
> +               return ret;
> +       }
> +
> +       phy_set_mode(glue->phy, glue->phy_mode);
> +
> +#if defined(CONFIG_USB_INVENTRA_DMA)
> +       musb_writel(musb->mregs, MUSB_HSDMA_INTR,
> +                   DMA_INTR_STATUS_MSK | DMA_INTR_UNMASK_SET_MSK);
> +#endif
> +       musb_writel(musb->mregs, USB_L1INTM, TX_INT_STATUS | RX_INT_STATUS |
> +                   USBCOM_INT_STATUS | DMA_INT_STATUS);
> +       return 0;
> +}
> +
> +static u16 mtk_musb_get_toggle(struct musb_qh *qh, int is_out)
> +{
> +       struct musb *musb = qh->hw_ep->musb;
> +       u8 epnum = qh->hw_ep->epnum;
> +       u16 toggle;
> +
> +       if (is_out)
> +               toggle = musb_readw(musb->mregs, MUSB_TXTOG);
> +       else
> +               toggle = musb_readw(musb->mregs, MUSB_RXTOG);
> +
> +       return toggle & (1 << epnum);
> +}
> +
> +static u16 mtk_musb_set_toggle(struct musb_qh *qh, int is_out, struct urb *urb)
> +{
> +       struct musb *musb = qh->hw_ep->musb;
> +       u8 epnum = qh->hw_ep->epnum;
> +       u16 toggle;
> +
> +       toggle = usb_gettoggle(urb->dev, qh->epnum, is_out);
> +
> +       if (is_out) {
> +               musb_writew(musb->mregs, MUSB_TXTOGEN, (1 << epnum));
> +               musb_writew(musb->mregs, MUSB_TXTOG, (toggle << epnum));
> +       } else {
> +               musb_writew(musb->mregs, MUSB_RXTOGEN, (1 << epnum));
> +               musb_writew(musb->mregs, MUSB_RXTOG, (toggle << epnum));
> +       }
> +
> +       return 0;
> +}
> +
> +static int mtk_musb_set_mode(struct musb *musb, u8 mode)
> +{
> +       struct device *dev = musb->controller;
> +       struct mtk_glue *glue = dev_get_drvdata(dev->parent);
> +       enum phy_mode new_mode;
> +
> +       switch (mode) {
> +       case MUSB_HOST:
> +               new_mode = PHY_MODE_USB_HOST;
> +               mtk_musb_set_vbus(musb, 1);
> +               break;
> +       case MUSB_PERIPHERAL:
> +               new_mode = PHY_MODE_USB_DEVICE;
> +               break;
> +       case MUSB_OTG:
> +               new_mode = PHY_MODE_USB_HOST;
> +               break;
> +       default:
> +               dev_err(musb->controller->parent,
> +                       "Error requested mode not supported by this kernel\n");
> +               return -EINVAL;
> +       }
> +       if (glue->phy_mode == new_mode)
> +               return 0;
> +
> +       mtk_musb_set_mailbox(glue, MTK_ID_GROUND);
> +       return 0;
> +}
> +
> +static int mtk_musb_exit(struct musb *musb)
> +{
> +       struct device *dev = musb->controller;
> +       struct mtk_glue *glue = dev_get_drvdata(dev->parent);
> +
> +       phy_power_off(glue->phy);
> +       phy_exit(glue->phy);
> +       mtk_musb_clks_disable(glue);
> +
> +       pm_runtime_put_sync(dev);
> +       pm_runtime_disable(dev);
> +       return 0;
> +}
> +
> +static const struct musb_platform_ops mtk_musb_ops = {
> +       .quirks = MUSB_DMA_INVENTRA,
> +       .init = mtk_musb_init,
> +       .get_toggle = mtk_musb_get_toggle,
> +       .set_toggle = mtk_musb_set_toggle,
> +       .exit = mtk_musb_exit,
> +#ifdef CONFIG_USB_INVENTRA_DMA
> +       .dma_init = musbhs_dma_controller_create_noirq,
> +       .dma_exit = musbhs_dma_controller_destroy,
> +#endif
> +       .clearb = mtk_musb_clearb,
> +       .clearw = mtk_musb_clearw,
> +       .busctl_offset = mtk_musb_busctl_offset,
> +       .set_mode = mtk_musb_set_mode,
> +       .set_vbus = mtk_musb_set_vbus,
> +};
> +
> +#define MTK_MUSB_MAX_EP_NUM    8
> +#define MTK_MUSB_RAM_BITS      11
> +
> +static struct musb_fifo_cfg mtk_musb_mode_cfg[] = {
> +       { .hw_ep_num = 1, .style = FIFO_TX, .maxpacket = 512, },
> +       { .hw_ep_num = 1, .style = FIFO_RX, .maxpacket = 512, },
> +       { .hw_ep_num = 2, .style = FIFO_TX, .maxpacket = 512, },
> +       { .hw_ep_num = 2, .style = FIFO_RX, .maxpacket = 512, },
> +       { .hw_ep_num = 3, .style = FIFO_TX, .maxpacket = 512, },
> +       { .hw_ep_num = 3, .style = FIFO_RX, .maxpacket = 512, },
> +       { .hw_ep_num = 4, .style = FIFO_TX, .maxpacket = 512, },
> +       { .hw_ep_num = 4, .style = FIFO_RX, .maxpacket = 512, },
> +       { .hw_ep_num = 5, .style = FIFO_TX, .maxpacket = 512, },
> +       { .hw_ep_num = 5, .style = FIFO_RX, .maxpacket = 512, },
> +       { .hw_ep_num = 6, .style = FIFO_TX, .maxpacket = 1024, },
> +       { .hw_ep_num = 6, .style = FIFO_RX, .maxpacket = 1024, },
> +       { .hw_ep_num = 7, .style = FIFO_TX, .maxpacket = 512, },
> +       { .hw_ep_num = 7, .style = FIFO_RX, .maxpacket = 64, },
> +};
> +
> +static const struct musb_hdrc_config mtk_musb_hdrc_config = {
> +       .fifo_cfg = mtk_musb_mode_cfg,
> +       .fifo_cfg_size = ARRAY_SIZE(mtk_musb_mode_cfg),
> +       .multipoint = true,
> +       .dyn_fifo = true,
> +       .num_eps = MTK_MUSB_MAX_EP_NUM,
> +       .ram_bits = MTK_MUSB_RAM_BITS,
> +};
> +
> +static const struct platform_device_info mtk_dev_info = {
> +       .name = "musb-hdrc",
> +       .id = PLATFORM_DEVID_AUTO,
> +       .dma_mask = DMA_BIT_MASK(32),
> +};
> +
> +static int mtk_musb_probe(struct platform_device *pdev)
> +{
> +       struct musb_hdrc_platform_data *pdata;
> +       struct mtk_glue *glue;
> +       struct platform_device_info pinfo;
> +       struct device *dev = &pdev->dev;
> +       struct device_node *np = dev->of_node;
> +       struct device_node *child, *extcon_node;
> +       int ret = -ENOMEM;
> +
> +       glue = devm_kzalloc(dev, sizeof(*glue), GFP_KERNEL);
> +       if (!glue)
> +               return -ENOMEM;
> +
> +       glue->dev = dev;
> +       pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
> +       if (!pdata)
> +               return -ENOMEM;
> +
> +       ret = mtk_musb_clks_get(glue);
> +       if (ret)
> +               return ret;
> +
> +       pdata->config = &mtk_musb_hdrc_config;
> +       pdata->platform_ops = &mtk_musb_ops;
> +
> +       glue->vbus = devm_regulator_get(dev, "vbus");
> +       if (IS_ERR(glue->vbus)) {
> +               dev_err(dev, "fail to get vbus\n");
> +               return PTR_ERR(glue->vbus);
> +       }
> +
> +       child = of_get_child_by_name(np, "connector");
> +       if (!child) {
> +               dev_err(dev, "failed to find usb connector node\n");
> +               return ERR_PTR(-ENODEV);

The 'probe' function is returning an 'int' and not a pointer. This
line should trigger a warning.

> +       }
> +
> +       extcon_node = of_parse_phandle(child, "extcon", 0);
> +       if (!extcon_node) {
> +               dev_err(dev, "failed to get extcon phandle");
> +               return ERR_PTR(-ENODEV);

Same here

> +       }
> +
> +       glue->edev = extcon_find_edev_by_node(extcon_node);
> +       if (IS_ERR(glue->edev)) {
> +               dev_err(dev, "fail to get extcon\n");
> +               return PTR_ERR(glue->edev);
> +       }
> +
> +       pdata->mode = usb_get_dr_mode(dev);
> +       switch (pdata->mode) {
> +       case USB_DR_MODE_HOST:
> +               glue->phy_mode = PHY_MODE_USB_HOST;
> +               break;
> +       case USB_DR_MODE_PERIPHERAL:
> +               glue->phy_mode = PHY_MODE_USB_DEVICE;
> +               break;
> +       default:
> +               pdata->mode = USB_DR_MODE_OTG;
> +               /* FALL THROUGH */
> +       case USB_DR_MODE_OTG:
> +               glue->phy_mode = PHY_MODE_USB_OTG;
> +               break;
> +       }
> +
> +       glue->phy = devm_of_phy_get_by_index(dev, np, 0);
> +       if (IS_ERR(glue->phy)) {
> +               dev_err(dev, "fail to getting phy %ld\n",
> +                       PTR_ERR(glue->phy));
> +               return PTR_ERR(glue->phy);
> +       }
> +
> +       glue->usb_phy = usb_phy_generic_register();
> +       if (IS_ERR(glue->usb_phy)) {
> +               dev_err(dev, "fail to registering usb-phy %ld\n",
> +                       PTR_ERR(glue->usb_phy));
> +               return PTR_ERR(glue->usb_phy);
> +       }
> +
> +       glue->xceiv = devm_usb_get_phy(dev, USB_PHY_TYPE_USB2);
> +       if (IS_ERR(glue->xceiv)) {
> +               dev_err(dev, "fail to getting usb-phy %d\n", ret);
> +               ret = PTR_ERR(glue->xceiv);
> +               goto err_unregister_usb_phy;
> +       }
> +
> +       platform_set_drvdata(pdev, glue);
> +       pm_runtime_enable(dev);
> +       pm_runtime_get_sync(dev);
> +
> +       ret = mtk_musb_clks_enable(glue);
> +       if (ret)
> +               goto err_enable_clk;
> +
> +       pinfo = mtk_dev_info;
> +       pinfo.parent = dev;
> +       pinfo.res = pdev->resource;
> +       pinfo.num_res = pdev->num_resources;
> +       pinfo.data = pdata;
> +       pinfo.size_data = sizeof(*pdata);
> +
> +       glue->musb_pdev = platform_device_register_full(&pinfo);
> +       if (IS_ERR(glue->musb_pdev)) {
> +               ret = PTR_ERR(glue->musb_pdev);
> +               dev_err(dev, "failed to register musb device: %d\n", ret);
> +               goto err_device_register;
> +       }
> +
> +       if (pdata->mode == USB_DR_MODE_OTG)
> +               mtk_otg_switch_init(glue);
> +
> +       return 0;
> +
> +err_device_register:
> +       mtk_musb_clks_disable(glue);
> +err_enable_clk:
> +       pm_runtime_put_sync(dev);
> +       pm_runtime_disable(dev);
> +err_unregister_usb_phy:
> +       usb_phy_generic_unregister(glue->usb_phy);
> +       return ret;
> +}
> +
> +static int mtk_musb_remove(struct platform_device *pdev)
> +{
> +       struct mtk_glue *glue = platform_get_drvdata(pdev);
> +       struct platform_device *usb_phy = glue->usb_phy;
> +
> +       platform_device_unregister(glue->musb_pdev);
> +       usb_phy_generic_unregister(usb_phy);
> +
> +       return 0;
> +}
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id mtk_musb_match[] = {
> +       {.compatible = "mediatek,mtk-musb",},
> +       {},
> +};
> +MODULE_DEVICE_TABLE(of, mtk_musb_match);
> +#endif
> +
> +static struct platform_driver mtk_musb_driver = {
> +       .probe = mtk_musb_probe,
> +       .remove = mtk_musb_remove,
> +       .driver = {
> +                  .name = "musb-mtk",
> +                  .of_match_table = of_match_ptr(mtk_musb_match),
> +       },
> +};
> +
> +module_platform_driver(mtk_musb_driver);
> +
> +MODULE_DESCRIPTION("MediaTek MUSB Glue Layer");
> +MODULE_AUTHOR("Min Guo <min.guo@mediatek.com>");
> +MODULE_LICENSE("GPL v2");
> --
> 1.9.1
>
>
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