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    Subject[RFC][PATCH v2 12/13] usb: dwc3: add dual-role support
    Date
    Register with the USB OTG core. Since we don't support
    OTG yet we just work as a dual-role device even
    if device tree says "otg".

    Use extcon framework to get VBUS/ID cable events and
    kick the OTG state machine.

    Signed-off-by: Roger Quadros <rogerq@ti.com>
    ---
    drivers/usb/dwc3/core.c | 146 ++++++++++++++++++++++++++++++++++++++-
    drivers/usb/dwc3/core.h | 6 ++
    drivers/usb/dwc3/platform_data.h | 1 +
    3 files changed, 151 insertions(+), 2 deletions(-)

    diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
    index 9f0e209..3e04b96 100644
    --- a/drivers/usb/dwc3/core.c
    +++ b/drivers/usb/dwc3/core.c
    @@ -39,6 +39,7 @@
    #include <linux/usb/gadget.h>
    #include <linux/usb/of.h>
    #include <linux/usb/otg.h>
    +#include <linux/usb/usb-otg.h>

    #include "platform_data.h"
    #include "core.h"
    @@ -504,7 +505,8 @@ static int dwc3_core_init(struct dwc3 *dwc)
    * SOF/ITP Mode Used
    */
    if ((dwc->dr_mode == USB_DR_MODE_HOST ||
    - dwc->dr_mode == USB_DR_MODE_OTG) &&
    + dwc->dr_mode == USB_DR_MODE_OTG ||
    + dwc->dr_mode == USB_DR_MODE_DRD) &&
    (dwc->revision >= DWC3_REVISION_210A &&
    dwc->revision <= DWC3_REVISION_250A))
    reg |= DWC3_GCTL_DSBLCLKGTNG | DWC3_GCTL_SOFITPSYNC;
    @@ -656,6 +658,119 @@ static int dwc3_core_get_phy(struct dwc3 *dwc)
    return 0;
    }

    +/* --------------------- Dual-Role management ------------------------------- */
    +
    +static void dwc3_drd_fsm_sync(struct dwc3 *dwc)
    +{
    + int id, vbus;
    +
    + /* get ID */
    + id = extcon_get_cable_state(dwc->edev, "USB-HOST");
    + /* Host means ID == 0 */
    + id = !id;
    +
    + /* get VBUS */
    + vbus = extcon_get_cable_state(dwc->edev, "USB");
    + dev_dbg(dwc->dev, "id %d vbus %d\n", id, vbus);
    +
    + dwc->fsm->id = id;
    + dwc->fsm->vbus = vbus;
    + usb_otg_sync_inputs(dwc->fsm);
    +}
    +
    +static int dwc3_drd_start_host(struct otg_fsm *fsm, int on)
    +{
    + struct device *dev = usb_otg_fsm_to_dev(fsm);
    + struct dwc3 *dwc = dev_get_drvdata(dev);
    +
    + dev_dbg(dwc->dev, "%s: %d\n", __func__, on);
    + if (on)
    + dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_HOST);
    +
    + return 0;
    +}
    +
    +static int dwc3_drd_start_gadget(struct otg_fsm *fsm, int on)
    +{
    + struct device *dev = usb_otg_fsm_to_dev(fsm);
    + struct dwc3 *dwc = dev_get_drvdata(dev);
    +
    + dev_dbg(dwc->dev, "%s: %d\n", __func__, on);
    + if (on) {
    + dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
    + dwc3_event_buffers_setup(dwc);
    + }
    +
    + return 0;
    +}
    +
    +static struct otg_fsm_ops dwc3_drd_ops = {
    + .start_host = dwc3_drd_start_host,
    + .start_gadget = dwc3_drd_start_gadget,
    +};
    +
    +static int dwc3_drd_notifier(struct notifier_block *nb,
    + unsigned long event, void *ptr)
    +{
    + struct dwc3 *dwc = container_of(nb, struct dwc3, otg_nb);
    +
    + dwc3_drd_fsm_sync(dwc);
    +
    + return NOTIFY_DONE;
    +}
    +
    +static int dwc3_drd_init(struct dwc3 *dwc)
    +{
    + int ret, id, vbus;
    +
    + if (!dwc->edev) {
    + dev_err(dwc->dev, "No extcon device found for OTG mode\n");
    + return -ENODEV;
    + }
    +
    + dwc->otg_nb.notifier_call = dwc3_drd_notifier;
    + ret = extcon_register_notifier(dwc->edev, &dwc->otg_nb);
    + if (ret < 0) {
    + dev_err(dwc->dev, "Couldn't register USB cable notifier\n");
    + return -ENODEV;
    + }
    +
    + /* sanity check id & vbus states */
    + id = extcon_get_cable_state(dwc->edev, "USB-HOST");
    + vbus = extcon_get_cable_state(dwc->edev, "USB");
    + if (id < 0 || vbus < 0) {
    + dev_err(dwc->dev, "Invalid USB cable state. id %d, vbus %d\n",
    + id, vbus);
    + ret = -ENODEV;
    + goto fail;
    + }
    +
    + /* register parent as OTG device with USB core */
    + dwc->fsm = usb_otg_register(dwc->dev, &dwc3_drd_ops, true);
    + if (IS_ERR(dwc->fsm)) {
    + dev_err(dwc->dev, "Failed to register with OTG core\n");
    + ret = -ENODEV;
    + goto fail;
    + }
    +
    + dwc3_drd_fsm_sync(dwc);
    +
    + return 0;
    +
    +fail:
    + extcon_unregister_notifier(dwc->edev, &dwc->otg_nb);
    +
    + return ret;
    +}
    +
    +static void dwc3_drd_exit(struct dwc3 *dwc)
    +{
    + usb_otg_unregister(dwc->dev);
    + extcon_unregister_notifier(dwc->edev, &dwc->otg_nb);
    +}
    +
    +/* -------------------------------------------------------------------------- */
    +
    static int dwc3_core_init_mode(struct dwc3 *dwc)
    {
    struct device *dev = dwc->dev;
    @@ -679,7 +794,15 @@ static int dwc3_core_init_mode(struct dwc3 *dwc)
    }
    break;
    case USB_DR_MODE_OTG:
    - dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_OTG);
    + dev_info(dev, "otg not implemented, we'll work as dual-role\n");
    + /* fall through */
    + case USB_DR_MODE_DRD:
    + ret = dwc3_drd_init(dwc);
    + if (ret) {
    + dev_err(dev, "failed to initialize drd\n");
    + return ret;
    + }
    +
    ret = dwc3_host_init(dwc);
    if (ret) {
    dev_err(dev, "failed to initialize host\n");
    @@ -710,8 +833,10 @@ static void dwc3_core_exit_mode(struct dwc3 *dwc)
    dwc3_host_exit(dwc);
    break;
    case USB_DR_MODE_OTG:
    + case USB_DR_MODE_DRD:
    dwc3_host_exit(dwc);
    dwc3_gadget_exit(dwc);
    + dwc3_drd_exit(dwc);
    break;
    default:
    /* do nothing */
    @@ -799,6 +924,16 @@ static int dwc3_probe(struct platform_device *pdev)
    hird_threshold = 12;

    if (node) {
    + if (of_property_read_bool(node, "extcon"))
    + dwc->edev = extcon_get_edev_by_phandle(dev, 0);
    + else if (of_property_read_bool(dev->parent->of_node, "extcon"))
    + dwc->edev = extcon_get_edev_by_phandle(dev->parent, 0);
    +
    + if (IS_ERR(dwc->edev)) {
    + dev_vdbg(dev, "couldn't get extcon device\n");
    + return -EPROBE_DEFER;
    + }
    +
    dwc->maximum_speed = of_usb_get_maximum_speed(node);
    dwc->has_lpm_erratum = of_property_read_bool(node,
    "snps,has-lpm-erratum");
    @@ -839,6 +974,13 @@ static int dwc3_probe(struct platform_device *pdev)
    of_property_read_u8(node, "snps,tx_de_emphasis",
    &tx_de_emphasis);
    } else if (pdata) {
    + if (pdata->extcon) {
    + dwc->edev = extcon_get_extcon_dev(pdata->extcon);
    + if (!dwc->edev) {
    + dev_vdbg(dev, "couldn't get extcon device\n");
    + return -EPROBE_DEFER;
    + }
    + }
    dwc->maximum_speed = pdata->maximum_speed;
    dwc->has_lpm_erratum = pdata->has_lpm_erratum;
    if (pdata->lpm_nyet_threshold)
    diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
    index d201910..2ece013 100644
    --- a/drivers/usb/dwc3/core.h
    +++ b/drivers/usb/dwc3/core.h
    @@ -30,8 +30,10 @@
    #include <linux/usb/ch9.h>
    #include <linux/usb/gadget.h>
    #include <linux/usb/otg.h>
    +#include <linux/usb/otg-fsm.h>

    #include <linux/phy/phy.h>
    +#include <linux/extcon.h>

    #define DWC3_MSG_MAX 500

    @@ -738,6 +740,10 @@ struct dwc3 {
    struct phy *usb2_generic_phy;
    struct phy *usb3_generic_phy;

    + struct extcon_dev *edev; /* USB cable events ID & VBUS */
    + struct notifier_block otg_nb; /* notifier for USB cable events */
    + struct otg_fsm *fsm;
    +
    void __iomem *regs;
    size_t regs_size;

    diff --git a/drivers/usb/dwc3/platform_data.h b/drivers/usb/dwc3/platform_data.h
    index a3a3b6d5..9552601 100644
    --- a/drivers/usb/dwc3/platform_data.h
    +++ b/drivers/usb/dwc3/platform_data.h
    @@ -24,6 +24,7 @@ struct dwc3_platform_data {
    enum usb_device_speed maximum_speed;
    enum usb_dr_mode dr_mode;
    bool tx_fifo_resize;
    + const char *extcon; /* extcon name for USB cable events ID/VBUS */

    unsigned is_utmi_l1_suspend:1;
    u8 hird_threshold;
    --
    2.1.0


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