Hi Paul:

Thank you for replying.

On 2014/12/6 3:04, Paul Zimmerman wrote:
From: Yunzhi Li [mailto:l...@rock-chips.com]
Sent: Friday, December 05, 2014 4:52 AM

Get PHY parameters from devicetree and power off usb PHY during
system suspend.

Signed-off-by: Yunzhi Li <l...@rock-chips.com>
---

  drivers/usb/dwc2/gadget.c   | 33 ++++++++++++---------------------
  drivers/usb/dwc2/platform.c | 34 ++++++++++++++++++++++++++++++++++
  2 files changed, 46 insertions(+), 21 deletions(-)

diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index 200168e..2601c61 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
[...]

        /*
-        * Attempt to find a generic PHY, then look for an old style
-        * USB PHY, finally fall back to pdata
+        * If platform probe couldn't find a generic PHY or an old style
+        * USB PHY, fall back to pdata
         */
-       phy = devm_phy_get(dev, "usb2-phy");
-       if (IS_ERR(phy)) {
-               uphy = devm_usb_get_phy(dev, USB_PHY_TYPE_USB2);
-               if (IS_ERR(uphy)) {
-                       /* Fallback for pdata */
-                       plat = dev_get_platdata(dev);
-                       if (!plat) {
-                               dev_err(dev,
-                               "no platform data or transceiver defined\n");
-                               return -EPROBE_DEFER;
-                       }
-                       hsotg->plat = plat;
-               } else
-                       hsotg->uphy = uphy;
-       } else {
-               hsotg->phy = phy;
+       if (IS_ERR_OR_NULL(hsotg->phy) && IS_ERR_OR_NULL(hsotg->uphy)) {
+               plat = dev_get_platdata(dev);
+               if (!plat) {
+                       dev_err(dev,
+                       "no platform data or transceiver defined\n");
+                       return -EPROBE_DEFER;
+               }
+               hsotg->plat = plat;
+       } else if (hsotg->phy) {
You have changed the behavior here. Previously, the driver would work
even if there were no phys or pdata defined. Now it will return
-EPROBE_DEFER instead. Are you sure that won't break any existing
platforms?

I don't really catch your meaning. Could you please point out where is the difference? Thanks .

In previous version, if there were no phy or usb_phy defined, devm_phy_get() and devm_usb_get_phy() both failed, then driver falls back to find pdata, if no pdata defined dev_get_platdata() returns NULL, then dwc2_gadget_init returns -EPROBE_DEFER and the dwc2_driver_probe fail. So I think, for the dwc2 driver without my patch, when CONFIG_USB_DWC2_PERIPHERAL or CONFIG_USB_DWC2_DUAL_ROLE selected, if there were no phys or pdata defined, the driver probe will also return -EPROBE_DEFER. And when only CONFIG_USB_DWC2_HOST selected, the previous version driver didn't care any thing about phy, in my patch it will try to find a phy when platform driver probe, but do not fail probe if there isn't a phy node.


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