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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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