Quoting Kishon Vijay Abraham I (2017-01-22 00:46:21)

Hi,

On Saturday 21 January 2017 12:20 AM, Stephen Boyd wrote:

quoted

Some USB PHYs need to be told about vbus changing state
explicitly. For example the qcom USB HS PHY needs to toggle a bit
when vbus goes from low to high (VBUSVLDEXT) to cause the
"session valid" signal to toggle. This signal will pull up D+
when the phy starts running. If the vbus signal isn't routed to
the PHY this "session valid" signal won't ever toggle, so we have
to toggle it explicitly. This callback is used to do that.

Cc: Peter Chen <redacted>
Signed-off-by: Stephen Boyd <redacted>
---

New patch

 drivers/phy/phy-core.c  | 15 +++++++++++++++
 include/linux/phy/phy.h | 10 ++++++++++
 2 files changed, 25 insertions(+)

diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index a268f4d6f3e9..8b1a6bfa5133 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c

@@ -357,6 +357,21 @@ int phy_set_mode(struct phy *phy, enum phy_mode mode)
 }
 EXPORT_SYMBOL_GPL(phy_set_mode);
 
+int phy_set_vbus(struct phy *phy, int on)
+{
+     int ret;
+
+     if (!phy || !phy->ops->set_vbus)
+             return 0;
+
+     mutex_lock(&phy->mutex);
+     ret = phy->ops->set_vbus(phy, on);
+     mutex_unlock(&phy->mutex);
+
+     return ret;
+}
+EXPORT_SYMBOL_GPL(phy_set_vbus);
+
 int phy_reset(struct phy *phy)
 {
      int ret;

diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
index 78bb0d7f6b11..4d1ebde7fb14 100644
--- a/include/linux/phy/phy.h
+++ b/include/linux/phy/phy.h

@@ -36,6 +36,7 @@ enum phy_mode {
  * @power_on: powering on the phy
  * @power_off: powering off the phy
  * @set_mode: set the mode of the phy
+ * @set_vbus: enable/disable vbus in the phy (USB)
  * @reset: resetting the phy
  * @owner: the module owner containing the ops
  */

@@ -45,6 +46,7 @@ struct phy_ops {
      int     (*power_on)(struct phy *phy);
      int     (*power_off)(struct phy *phy);
      int     (*set_mode)(struct phy *phy, enum phy_mode mode);
+     int     (*set_vbus)(struct phy *phy, int on);

please avoid adding usb specific ops in generic phy ops.

Is there any alternative? Something has to happen here.

The only other thing I can think of is putting back the vbus extcon in
the phy driver so it can be notified when vbus is present or not. I can
rely on phy_set_mode() being called so that we don't need to figure out
if we're in host mode or not like was being done before.