From: Yoshihiro Shimoda <yoshihiro.shimoda...@renesas.com>

Since some host controller (e.g. EHCI) needs a companion host controller
(e.g. OHCI), this patch adds such a configuration to use it in the OTG
core.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda...@renesas.com>
Signed-off-by: Roger Quadros <rog...@ti.com>
Acked-by: Peter Chen <peter.c...@nxp.com>
Acked-by: Rob Herring <r...@kernel.org>
---
 Documentation/devicetree/bindings/usb/generic.txt |  3 +++
 drivers/usb/common/usb-otg.c                      | 32 ++++++++++++++++-------
 include/linux/usb/otg.h                           |  7 ++++-
 3 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/Documentation/devicetree/bindings/usb/generic.txt 
b/Documentation/devicetree/bindings/usb/generic.txt
index f6866c1..1db1c33 100644
--- a/Documentation/devicetree/bindings/usb/generic.txt
+++ b/Documentation/devicetree/bindings/usb/generic.txt
@@ -27,6 +27,9 @@ Optional properties:
  - otg-controller: phandle to otg controller. Host or gadget controllers can
                        contain this property to link it to a particular OTG
                        controller.
+ - hcd-needs-companion: must be present if otg controller is dealing with
+                       EHCI host controller that needs a companion OHCI host
+                       controller.
 
 This is an attribute to a USB controller such as:
 
diff --git a/drivers/usb/common/usb-otg.c b/drivers/usb/common/usb-otg.c
index b5bdf62..98fcfa2 100644
--- a/drivers/usb/common/usb-otg.c
+++ b/drivers/usb/common/usb-otg.c
@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
+#include <linux/usb/of.h>
 #include <linux/usb/otg.h>
 #include <linux/usb/gadget.h>
 #include <linux/workqueue.h>
@@ -348,6 +349,10 @@ struct usb_otg *usb_otg_register(struct device *dev,
        else
                INIT_WORK(&otg->work, usb_drd_work);
 
+       if (of_find_property(dev->of_node, "hcd-needs-companion", NULL) ||
+           config->hcd_needs_companion)        /* needs companion ? */
+               otg->flags |= OTG_FLAG_HCD_NEEDS_COMPANION;
+
        otg->wq = create_freezable_workqueue("usb_otg");
        if (!otg->wq) {
                dev_err(dev, "otg: %s: can't create workqueue\n",
@@ -562,15 +567,18 @@ int usb_otg_register_hcd(struct usb_hcd *hcd, unsigned 
int irqnum,
        /* HCD will be started by OTG fsm when needed */
        mutex_lock(&otg->fsm.lock);
        if (otg->primary_hcd.hcd) {
-               /* probably a shared HCD ? */
-               if (usb_otg_hcd_is_primary_hcd(hcd)) {
+               /* probably a shared HCD or a companion OHCI HCD ? */
+               if (!(otg->flags & OTG_FLAG_HCD_NEEDS_COMPANION) &&
+                   usb_otg_hcd_is_primary_hcd(hcd)) {
                        dev_err(otg_dev, "otg: primary host already 
registered\n");
                        goto err;
                }
 
-               if (hcd->shared_hcd == otg->primary_hcd.hcd) {
+               if (otg->flags & OTG_FLAG_HCD_NEEDS_COMPANION ||
+                   (hcd->shared_hcd == otg->primary_hcd.hcd)) {
                        if (otg->shared_hcd.hcd) {
-                               dev_err(otg_dev, "otg: shared host already 
registered\n");
+                               dev_err(otg_dev,
+                                       "otg: shared/companion host already 
registered\n");
                                goto err;
                        }
 
@@ -578,10 +586,12 @@ int usb_otg_register_hcd(struct usb_hcd *hcd, unsigned 
int irqnum,
                        otg->shared_hcd.irqnum = irqnum;
                        otg->shared_hcd.irqflags = irqflags;
                        otg->shared_hcd.ops = ops;
-                       dev_info(otg_dev, "otg: shared host %s registered\n",
+                       dev_info(otg_dev,
+                                "otg: shared/companion host %s registered\n",
                                 dev_name(hcd->self.controller));
                } else {
-                       dev_err(otg_dev, "otg: invalid shared host %s\n",
+                       dev_err(otg_dev,
+                               "otg: invalid shared/companion host %s\n",
                                dev_name(hcd->self.controller));
                        goto err;
                }
@@ -604,14 +614,17 @@ int usb_otg_register_hcd(struct usb_hcd *hcd, unsigned 
int irqnum,
         * we're ready only if we have shared HCD
         * or we don't need shared HCD.
         */
-       if (otg->shared_hcd.hcd || !otg->primary_hcd.hcd->shared_hcd) {
+       if (otg->shared_hcd.hcd ||
+           (!(otg->flags & OTG_FLAG_HCD_NEEDS_COMPANION) &&
+            !otg->primary_hcd.hcd->shared_hcd)) {
                otg->host = hcd_to_bus(hcd);
                /* FIXME: set bus->otg_port if this is true OTG port with HNP */
 
                /* start FSM */
                usb_otg_start_fsm(otg);
        } else {
-               dev_dbg(otg_dev, "otg: can't start till shared host 
registers\n");
+               dev_dbg(otg_dev,
+                       "otg: can't start till shared/companion host 
registers\n");
        }
 
        mutex_unlock(&otg->fsm.lock);
@@ -659,7 +672,8 @@ int usb_otg_unregister_hcd(struct usb_hcd *hcd)
                         dev_name(hcd_dev));
        } else if (hcd == otg->shared_hcd.hcd) {
                otg->shared_hcd.hcd = NULL;
-               dev_info(otg_dev, "otg: shared host %s unregistered\n",
+               dev_info(otg_dev,
+                        "otg: shared/companion host %s unregistered\n",
                         dev_name(hcd_dev));
        } else {
                mutex_unlock(&otg->fsm.lock);
diff --git a/include/linux/usb/otg.h b/include/linux/usb/otg.h
index cc58a2d..4c585ec 100644
--- a/include/linux/usb/otg.h
+++ b/include/linux/usb/otg.h
@@ -72,7 +72,8 @@ struct usb_otg_caps {
  * @list: list of otg controllers
  * @work: otg state machine work
  * @wq: otg state machine work queue
- * @flags: to track if host/gadget is running
+ * @flags: to track if host/gadget is running, or to indicate if hcd needs
+ *        companion
  */
 struct usb_otg {
        u8                      default_a;
@@ -100,6 +101,7 @@ struct usb_otg {
        u32 flags;
 #define OTG_FLAG_GADGET_RUNNING (1 << 0)
 #define OTG_FLAG_HOST_RUNNING (1 << 1)
+#define OTG_FLAG_HCD_NEEDS_COMPANION (1 << 2)
        /* use otg->fsm.lock for serializing access */
 
 /*------------- deprecated interface -----------------------------*/
@@ -126,11 +128,14 @@ struct usb_otg {
  * @caps: otg capabilities of the controller
  * @ops: otg fsm operations
  * @otg_work: optional custom otg state machine work function
+ * @hcd_needs_companion: Indicates if host controller needs a companion
+ *                      controller
  */
 struct usb_otg_config {
        struct usb_otg_caps *otg_caps;
        struct otg_fsm_ops *fsm_ops;
        void (*otg_work)(struct work_struct *work);
+       bool hcd_needs_companion;
 };
 
 extern const char *usb_otg_state_string(enum usb_otg_state state);
-- 
2.7.4

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