Hi,

On 09/22/2016 05:28 AM, Bin Liu wrote:
Hi,

On Wed, Sep 21, 2016 at 11:05:33AM +0300, Hans de Goede wrote:
Hi,

On 09/20/2016 07:45 AM, Kishon Vijay Abraham I wrote:
Hi,

On Sunday 18 September 2016 10:20 PM, Hans de Goede wrote:
The sunxi musb has a bug where sometimes it will generate a babble
error on device disconnect instead of a disconnect irq. When this
happens the musb-controller switches from host mode to device mode
(it clears MUSB_DEVCTL_SESSION and sets MUSB_DEVCTL_BDEVICE) and
gets stuck in this state.

Clearing this requires reporting Vbus low for 200 or more ms, but
on some devices Vbus is simply always high (host-only mode, no Vbus
control). The phy-sun4i-usb code already has code to force a session
end for devices without Vbus control.

This commit adds a sun4i_usb_phy_force_session_end() function exporting
this functionality to the sunxi-musb glue, so that it can force a session
end to fixup the stuck state after a babble error.

Signed-off-by: Hans de Goede <hdego...@redhat.com>
---
drivers/phy/phy-sun4i-usb.c       | 11 +++++++++++
include/linux/phy/phy-sun4i-usb.h |  7 +++++++
2 files changed, 18 insertions(+)

diff --git a/drivers/phy/phy-sun4i-usb.c b/drivers/phy/phy-sun4i-usb.c
index 43c0d98..06f4e11a 100644
--- a/drivers/phy/phy-sun4i-usb.c
+++ b/drivers/phy/phy-sun4i-usb.c
@@ -470,6 +470,17 @@ void sun4i_usb_phy_set_squelch_detect(struct phy *_phy, 
bool enabled)
}
EXPORT_SYMBOL_GPL(sun4i_usb_phy_set_squelch_detect);

+void sun4i_usb_phy_force_session_end(struct phy *_phy)
+{
+       struct sun4i_usb_phy *phy = phy_get_drvdata(_phy);
+       struct sun4i_usb_phy_data *data = to_sun4i_usb_phy_data(phy);
+
+       data->id_det = -1;
+       data->force_session_end = true;
+       queue_delayed_work(system_wq, &data->detect, 0);
+}
+EXPORT_SYMBOL_GPL(sun4i_usb_phy_force_session_end);

Er.. one more export symbol :-(

Yes unfortunately we need one more to work around sunxi musb / phy bugs.

Instead, can you somehow reuse sun4i_usb_phy_set_mode()?

That was my first thought too, and I looked into this, but it did not
work out.

Regards,

Hans


Regards,
-Bin.


+
static const struct phy_ops sun4i_usb_phy_ops = {
        .init           = sun4i_usb_phy_init,
        .exit           = sun4i_usb_phy_exit,
diff --git a/include/linux/phy/phy-sun4i-usb.h 
b/include/linux/phy/phy-sun4i-usb.h
index 50aed92..3bb773f 100644
--- a/include/linux/phy/phy-sun4i-usb.h
+++ b/include/linux/phy/phy-sun4i-usb.h
@@ -23,4 +23,11 @@
 */
void sun4i_usb_phy_set_squelch_detect(struct phy *phy, bool enabled);

+/**
+ * sun4i_usb_force_session_end() - Force the current session to end
+ *                                by reporting VBus low for 200+ ms
+ * @phy: reference to a sun4i usb phy
+ */
+void sun4i_usb_phy_force_session_end(struct phy *phy);

Should we include a static inline function if sun4i phy is not defined?

No, we're also not doing that for the already exported
sun4i_usb_phy_set_squelch_detect()

And it is not necessary since the only caller is drivers/usb/musb/sunxi.c,
and drivers/usb/musb/Kconfig has:

config USB_MUSB_SUNXI
        tristate "Allwinner (sunxi)"
        depends on PHY_SUN4I_USB

Regards,

Hans
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