usb: ehci: Fix db410c usb reset not working

[JianfengA.Zhu at sony.com]

usb reset not working error log
====================================================================
dragonboard410c => usb reset
resetting USB...
Bus usb at 78d9000: Port not available.
dragonboard410c =>
====================================================================

After commit ed8fbd2889fc ("dts: msm8916: replace with upstream DTS")
msm8916_usbphy will be defined as a child device of usb at 78d9000. usb reset
will first call usb_stop, and msm8916_usbphy as child dev will be unbind
in usb_stop, and there is no bind operation in do_usb_start afterwards, so
the msm8916_usbphy uclass cannot be found. This causes ehci_msm probe to
fail.

Detailed calling process
====================================================================
usb reset:
|-> usb_stop (drivers/usb/host/usb-uclass.c)
.|-> device_find_first_child
. |-> device_unbind(rh); <== (unbind msm8916_usbphy)
|-> do_usb_start
 |-> usb_init (drivers/usb/host/usb-uclass.c)
  |-> device_probe(bus);
   |-> ehci_usb_probe
    |-> generic_setup_phy <== err couldn't find msm8916_usbphy
====================================================================

Fix: rebind the msm8916_usbphy driver during ehci_usb_probe if the
msm8916_usbphy uclass has been removed.

Signed-off-by: Jianfeng Zhu <JianfengA.Zhu at sony.com>
Reviewed-by: Jacky Cao <Jacky.Cao at sony.com>
Reviewed-by: Toyama, Yoshihiro <Yoshihiro.Toyama at sony.com>
---
 drivers/usb/host/ehci-msm.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/usb/host/ehci-msm.c b/drivers/usb/host/ehci-msm.c
index ff336082e3..7cb3ae0849 100644
--- a/drivers/usb/host/ehci-msm.c
+++ b/drivers/usb/host/ehci-msm.c
@@ -47,6 +47,8 @@ static const struct ehci_ops msm_ehci_ops = {
 	.init_after_reset = msm_init_after_reset
 };
 
+static int ehci_usb_of_bind(struct udevice *dev);
+
 static int ehci_usb_probe(struct udevice *dev)
 {
 	struct msm_ehci_priv *p = dev_get_priv(dev);
@@ -54,6 +56,7 @@ static int ehci_usb_probe(struct udevice *dev)
 	struct usb_plat *plat = dev_get_plat(dev);
 	struct ehci_hccr *hccr;
 	struct ehci_hcor *hcor;
+	struct udevice *phydev;
 	int ret;
 
 	ret = clk_get_by_name(dev, "core", &p->core_clk);
@@ -80,6 +83,10 @@ static int ehci_usb_probe(struct udevice *dev)
 	hcor = (struct ehci_hcor *)((phys_addr_t)hccr +
 			HC_LENGTH(ehci_readl(&(hccr)->cr_capbase)));
 
+	ret = uclass_get_device_by_name(UCLASS_PHY, "msm8916_usbphy", &phydev);
+	if (ret)
+		ehci_usb_of_bind(dev);
+
 	ret = generic_setup_phy(dev, &p->phy, 0);
 	if (ret)
 		goto cleanup_iface;
-- 
2.25.1