Re: [PATCH v4 1/9] usb: dwc3: add dual-role support

Felipe Balbi
2015-09-02T14:31:59Z

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Hi,

On Wed, Sep 02, 2015 at 05:24:16PM +0300, Roger Quadros wrote:
> 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 | 174 ++++++++++++++++++++++++++++++++++++++-
> drivers/usb/dwc3/core.h | 7 ++
> drivers/usb/dwc3/platform_data.h | 1 +
> 3 files changed, 181 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 064123e..2e36a9b 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -704,6 +704,152 @@ 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);

tracepoint please. We don't want this driver to use dev_(v)?db anymore.
Ditto to all others.

> +
> + dwc->fsm->id = id;
> + dwc->fsm->b_sess_vld = 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);

how about adding a usb_otg_get_drvdata(fsm) ?

> + dev_dbg(dwc->dev, "%s: %d\n", __func__, on);
> + if (on) {
> + dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_HOST);
> + /* start the HCD */
> + usb_otg_start_host(fsm, true);
> + } else {
> + /* stop the HCD */
> + usb_otg_start_host(fsm, false);
> + }

This can be simplified.

if (on)
dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_HOST);

usb_otg_start_host(fsm, on);

> +
> + 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);
> +
> + /* start the UDC */
> + usb_otg_start_gadget(fsm, true);
> + } else {
> + /* stop the UDC */
> + usb_otg_start_gadget(fsm, false);
> + }

likewise:

if (on) {
dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
dwc3_event_buffers_setup(dwc);
}

usb_otg_start_gadget(fsm, on);

> + 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;
> + struct usb_otg_caps *otgcaps = &dwc->otg_config.otg_caps;
> +
> + otgcaps->otg_rev = 0;
> + otgcaps->hnp_support = false;
> + otgcaps->srp_support = false;
> + otgcaps->adp_support = false;
> + dwc->otg_config.fsm_ops = &dwc3_drd_ops;
> +
> + 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, EXTCON_USB, &dwc->otg_nb);
> + if (ret < 0) {
> + dev_err(dwc->dev, "Couldn't register USB cable notifier\n");
> + return -ENODEV;
> + }
> +
> + ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
> + &dwc->otg_nb);
> + if (ret < 0) {
> + dev_err(dwc->dev, "Couldn't register USB-HOST cable notifier\n");
> + ret = -ENODEV;
> + goto extcon_fail;
> + }
> +
> + /* 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 as DRD device with OTG core */
> + dwc->fsm = usb_otg_register(dwc->dev, &dwc->otg_config);
> + if (IS_ERR(dwc->fsm)) {
> + ret = PTR_ERR(dwc->fsm);
> + if (ret == -ENOTSUPP)
> + dev_err(dwc->dev, "CONFIG_USB_OTG needed for dual-role\n");
> + else
> + dev_err(dwc->dev, "Failed to register with OTG core\n");

do you need to cope with EPROBE_DEFER ?

> +
> + goto fail;
> + }
> +
> + dwc3_drd_fsm_sync(dwc);
> +
> + return 0;
> +fail:
> + extcon_unregister_notifier(dwc->edev, EXTCON_USB_HOST, &dwc->otg_nb);
> +extcon_fail:
> + extcon_unregister_notifier(dwc->edev, EXTCON_USB, &dwc->otg_nb);
> +
> + return ret;
> +}
> +
> +static void dwc3_drd_exit(struct dwc3 *dwc)
> +{
> + usb_otg_unregister(dwc->dev);
> + extcon_unregister_notifier(dwc->edev, EXTCON_USB_HOST, &dwc->otg_nb);
> + extcon_unregister_notifier(dwc->edev, EXTCON_USB, &dwc->otg_nb);
> +}
> +
> +/* -------------------------------------------------------------------------- */
> +
> static int dwc3_core_init_mode(struct dwc3 *dwc)
> {
> struct device *dev = dwc->dev;
> @@ -727,13 +873,21 @@ static int dwc3_core_init_mode(struct dwc3 *dwc)
> }
> break;
> case USB_DR_MODE_OTG:
> - dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_OTG);
> + ret = dwc3_drd_init(dwc);
> + if (ret) {
> + dev_err(dev, "limiting to peripheral only\n");
> + dwc->dr_mode = USB_DR_MODE_PERIPHERAL;
> + dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
> + goto gadget_init;
> + }
> +
> ret = dwc3_host_init(dwc);
> if (ret) {
> dev_err(dev, "failed to initialize host\n");
> return ret;
> }
>
> +gadget_init:
> ret = dwc3_gadget_init(dwc);
> if (ret) {
> dev_err(dev, "failed to initialize gadget\n");
> @@ -760,6 +914,7 @@ static void dwc3_core_exit_mode(struct dwc3 *dwc)
> case USB_DR_MODE_OTG:
> dwc3_host_exit(dwc);
> dwc3_gadget_exit(dwc);
> + dwc3_drd_exit(dwc);
> break;
> default:
> /* do nothing */
> @@ -843,6 +998,16 @@ 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);

why do you need to check the parent ? Why isn't that done on the glue
layer ?

> +
> + if (IS_ERR(dwc->edev)) {
> + dev_vdbg(dev, "couldn't get extcon device\n");

dev_err() ??

> + return -EPROBE_DEFER;

this could make us reschedule probe forever.

> + }
> +
> dwc->maximum_speed = of_usb_get_maximum_speed(node);
> dwc->has_lpm_erratum = of_property_read_bool(node,
> "snps,has-lpm-erratum");
> @@ -887,6 +1052,13 @@ static int dwc3_probe(struct platform_device *pdev)
> of_property_read_string(node, "snps,hsphy_interface",
> &dwc->hsphy_interface);
> } 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;

ditto

> + }
> + }
> 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 0447788..5ca2b25 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -31,8 +31,10 @@
> #include <linux/usb/gadget.h>
> #include <linux/usb/otg.h>
> #include <linux/ulpi/interface.h>
> +#include <linux/usb/otg-fsm.h>
>
> #include <linux/phy/phy.h>
> +#include <linux/extcon.h>
>
> #define DWC3_MSG_MAX 500
>
> @@ -753,6 +755,11 @@ struct dwc3 {
>
> struct ulpi *ulpi;
>
> + struct extcon_dev *edev; /* USB cable events ID & VBUS */
> + struct notifier_block otg_nb; /* notifier for USB cable events */
> + struct otg_fsm *fsm;
> + struct usb_otg_config otg_config;
> +
> void __iomem *regs;
> size_t regs_size;
>
> diff --git a/drivers/usb/dwc3/platform_data.h b/drivers/usb/dwc3/platform_data.h
> index d3614ec..b3b245c 100644
> --- a/drivers/usb/dwc3/platform_data.h
> +++ b/drivers/usb/dwc3/platform_data.h
> @@ -47,4 +47,5 @@ struct dwc3_platform_data {
> unsigned tx_de_emphasis:2;
>
> const char *hsphy_interface;
> + const char *extcon; /* extcon name for USB cable events ID/VBUS */
> };
> --
> 2.1.4
>

--
balbi

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