phy-sun4i-usb: Add sun4i_usb_phy_force_session_end() function

PATCH New Hans de Goede 3 participants 8 messages Sep 18, 2016 – Sep 22, 2016

Subsystems (4)

USB Arm/Allwinner sunXi SoC support Generic PHY framework MUSB multipoint high speed dual-role controller

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Hans de Goede

author

2016-09-18 16:50 UTC #0 lore raw

PATCH 1/2 phy-sun4i-usb: Add sun4i_usb_phy_force_session_end() function

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 <[email protected]>

---
 drivers/phy/phy-sun4i-usb.c       | 11 +++++++++++
 include/linux/phy/phy-sun4i-usb.h |  7 +++++++
 2 files changed, 18 insertions(+)

drivers/phy/phy-sun4i-usb.c +11 -0

index 43c0d98..06f4e11a 100644
@@ -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);
+
 static const struct phy_ops sun4i_usb_phy_ops = {
 	.init		= sun4i_usb_phy_init,
 	.exit		= sun4i_usb_phy_exit,

include/linux/phy/phy-sun4i-usb.h +7 -0

index 50aed92..3bb773f 100644
@@ -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);
+
 #endif

Signature · 1 line

2.9.3

Hans de Goede

author

2016-09-18 16:50 UTC #1 lore raw

PATCH 2/2 musb: sunxi: Force session end on babble errors in host-mode

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).

This commit calls sun4i_usb_phy_force_session_end() on babble errors in host-mode, fixing the musb controller being stuck in this state on systems without Vbus control; and also fixes the need to unplug the usb-b -> usb-a cable to get out of this state on systems with Vbus control.

Signed-off-by Hans de Goede <[email protected]>

---
 drivers/usb/musb/sunxi.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

drivers/usb/musb/sunxi.c +10 -0

index 1408245..5079d90 100644
@@ -192,8 +192,18 @@ static irqreturn_t sunxi_musb_interrupt(int irq, void *__hci)
 	 * normally babble never happens treat it as disconnect.
 	 */
 	if ((musb->int_usb & MUSB_INTR_BABBLE) && is_host_active(musb)) {
+		struct sunxi_glue *glue =
+				dev_get_drvdata(musb->controller->parent);
+
+		dev_warn(musb->controller->parent, "babble, treating as disconnect\n");
+
 		musb->int_usb &= ~MUSB_INTR_BABBLE;
 		musb->int_usb |= MUSB_INTR_DISCONNECT;
+		/*
+		 * Fix the musb controller sometimes getting stuck in
+		 * bdevice state after a babble error.
+		 */
+		sun4i_usb_phy_force_session_end(glue->phy);
 	}
 
 	if ((musb->int_usb & MUSB_INTR_RESET) && !is_host_active(musb)) {

Signature · 1 line

2.9.3

Bin Liu

maintainer

2016-09-22 02:33 UTC #2 lore raw

PATCH 2/2 musb: sunxi: Force session end on babble errors in host-mode

Hi,

Quoted 26 lines · Hans de Goede

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).
This commit calls sun4i_usb_phy_force_session_end() on babble errors in host-mode, fixing the musb controller being stuck in this state on systems without Vbus control; and also fixes the need to unplug the usb-b -> usb-a cable to get out of this state on systems with Vbus control.
Signed-off-by Hans de Goede <[email protected]>
---
 drivers/usb/musb/sunxi.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
drivers/usb/musb/sunxi.c +0 -0
index 1408245..5079d90 100644

drivers/usb/musb/sunxi.c static irqreturn_t sunxi_musb_interrupt(int irq, void *__hci) · line 194

Quoted 3 lines

drivers/usb/musb/sunxi.c +0 -0

@@ -192,8 +192,18 @@ static irqreturn_t sunxi_musb_interrupt(int irq, void *__hci)
 	 * normally babble never happens treat it as disconnect.
 	 */
 	if ((musb->int_usb & MUSB_INTR_BABBLE) && is_host_active(musb)) {

musb_interrupt() handle BABBLE in host mode, and has a glue hook musb_platform_recover() in musb_recover_from_babble().

Maybe you can use it?

drivers/usb/musb/sunxi.c static irqreturn_t sunxi_musb_interrupt(int irq, void *__hci) · line 206

Quoted 12 lines

drivers/usb/musb/sunxi.c +10 -0

+		struct sunxi_glue *glue =
+				dev_get_drvdata(musb->controller->parent);
+
+		dev_warn(musb->controller->parent, "babble, treating as disconnect\n");
+
 		musb->int_usb &= ~MUSB_INTR_BABBLE;
 		musb->int_usb |= MUSB_INTR_DISCONNECT;
+		/*
+		 * Fix the musb controller sometimes getting stuck in
+		 * bdevice state after a babble error.
+		 */
+		sun4i_usb_phy_force_session_end(glue->phy);

As I commented in PATCH 1/2, can you somehow reuse sun4i_usb_phy_set_mode() instead?

Quoted 5 lines

drivers/usb/musb/sunxi.c +0 -0
 	}
 
 	if ((musb->int_usb & MUSB_INTR_RESET) && !is_host_active(musb)) {
Signature · 1 line
2.9.3

Regards,
-Bin.

Hans de Goede

author

2016-09-22 08:05 UTC #3 lore raw

PATCH 2/2 musb: sunxi: Force session end on babble errors in host-mode

Hi,

Quoted 36 lines · Bin Liu

Hi,
Quoted 26 lines · Hans de Goede
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).
This commit calls sun4i_usb_phy_force_session_end() on babble errors in host-mode, fixing the musb controller being stuck in this state on systems without Vbus control; and also fixes the need to unplug the usb-b -> usb-a cable to get out of this state on systems with Vbus control.
Signed-off-by Hans de Goede <[email protected]>
---
 drivers/usb/musb/sunxi.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
drivers/usb/musb/sunxi.c +0 -0
index 1408245..5079d90 100644
drivers/usb/musb/sunxi.c static irqreturn_t sunxi_musb_interrupt(int irq, void *__hci) · line 194
Quoted 3 lines
drivers/usb/musb/sunxi.c +0 -0
@@ -192,8 +192,18 @@ static irqreturn_t sunxi_musb_interrupt(int irq, void *__hci)
 	 * normally babble never happens treat it as disconnect.
 	 */
 	if ((musb->int_usb & MUSB_INTR_BABBLE) && is_host_active(musb)) {
musb_interrupt() handle BABBLE in host mode, and has a glue hook musb_platform_recover() in musb_recover_from_babble().

Quoted 1 line

Maybe you can use it?

Ah yes, I looked at this at the past, but that was before the babble recover rework by Felipe Balbi which got commited on 2015-03-10.

With this rework the sunxi code should indeed be able to use the core recovery, and we can use the musb_platform_recover() to force a session end.

And thinking more about you're other remark, I do think I can actually modify the sun4i phy_set_mode callback so that it can be used for this.

I'll post a v2 with these changes soon-ish.

Regards,

Hans

Quoted 25 lines

drivers/usb/musb/sunxi.c static irqreturn_t sunxi_musb_interrupt(int irq, void *__hci) · line 206
Quoted 12 lines
drivers/usb/musb/sunxi.c +10 -0
+		struct sunxi_glue *glue =
+				dev_get_drvdata(musb->controller->parent);
+
+		dev_warn(musb->controller->parent, "babble, treating as disconnect\n");
+
 		musb->int_usb &= ~MUSB_INTR_BABBLE;
 		musb->int_usb |= MUSB_INTR_DISCONNECT;
+		/*
+		 * Fix the musb controller sometimes getting stuck in
+		 * bdevice state after a babble error.
+		 */
+		sun4i_usb_phy_force_session_end(glue->phy);
As I commented in PATCH 1/2, can you somehow reuse sun4i_usb_phy_set_mode() instead?
Quoted 5 lines
drivers/usb/musb/sunxi.c +0 -1
 	}
 
 	if ((musb->int_usb & MUSB_INTR_RESET) && !is_host_active(musb)) {
--
2.9.3
Regards,
-Bin.

Kishon Vijay Abraham I

2016-09-20 04:45 UTC #4 lore raw

PATCH 1/2 phy-sun4i-usb: Add sun4i_usb_phy_force_session_end() function

In reply to Hans de Goede

Hi,

Quoted 29 lines · Hans de Goede

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 <[email protected]>
---
 drivers/phy/phy-sun4i-usb.c       | 11 +++++++++++
 include/linux/phy/phy-sun4i-usb.h |  7 +++++++
 2 files changed, 18 insertions(+)
drivers/phy/phy-sun4i-usb.c +0 -0
index 43c0d98..06f4e11a 100644
@@ -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);
 

drivers/phy/phy-sun4i-usb.c void sun4i_usb_phy_set_squelch_detect(struct phy *_phy, bool enabled) · line 482

Quoted 10 lines

drivers/phy/phy-sun4i-usb.c +10 -0

+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 :-(

Quoted 9 lines

drivers/phy/phy-sun4i-usb.c +1 -0

+
 static const struct phy_ops sun4i_usb_phy_ops = {
 	.init		= sun4i_usb_phy_init,
 	.exit		= sun4i_usb_phy_exit,

include/linux/phy/phy-sun4i-usb.h +0 -0

index 50aed92..3bb773f 100644

include/linux/phy/phy-sun4i-usb.h line 31

Quoted 9 lines

include/linux/phy/phy-sun4i-usb.h +6 -0

@@ -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?

Thanks
Kishon

Hans de Goede

author

2016-09-21 08:05 UTC #5 lore raw

PATCH 1/2 phy-sun4i-usb: Add sun4i_usb_phy_force_session_end() function

Hi,

Quoted 32 lines · Kishon Vijay Abraham I

Hi,
Quoted 29 lines · Hans de Goede
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 <[email protected]>
---
 drivers/phy/phy-sun4i-usb.c       | 11 +++++++++++
 include/linux/phy/phy-sun4i-usb.h |  7 +++++++
 2 files changed, 18 insertions(+)
drivers/phy/phy-sun4i-usb.c +0 -0
index 43c0d98..06f4e11a 100644
@@ -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);
 

Quoted 12 lines

drivers/phy/phy-sun4i-usb.c void sun4i_usb_phy_set_squelch_detect(struct phy *_phy, bool enabled) · line 482
Quoted 10 lines
drivers/phy/phy-sun4i-usb.c +10 -0
+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.

Quoted 12 lines

drivers/phy/phy-sun4i-usb.c +1 -0

+
 static const struct phy_ops sun4i_usb_phy_ops = {
 	.init		= sun4i_usb_phy_init,
 	.exit		= sun4i_usb_phy_exit,

include/linux/phy/phy-sun4i-usb.h +0 -0

index 50aed92..3bb773f 100644
@@ -23,4 +23,11 @@
  */
 void sun4i_usb_phy_set_squelch_detect(struct phy *phy, bool enabled);

Quoted 8 lines

include/linux/phy/phy-sun4i-usb.h line 31
Quoted 6 lines
include/linux/phy/phy-sun4i-usb.h +6 -0
+/**
+ * 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

Bin Liu

maintainer

2016-09-22 02:28 UTC #6 lore raw

PATCH 1/2 phy-sun4i-usb: Add sun4i_usb_phy_force_session_end() function

Hi,

Quoted 48 lines · Hans de Goede

Hi,
Quoted 32 lines · Kishon Vijay Abraham I
Hi,
Quoted 29 lines · Hans de Goede
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 <[email protected]>
---
drivers/phy/phy-sun4i-usb.c | 11 +++++++++++
include/linux/phy/phy-sun4i-usb.h | 7 +++++++
2 files changed, 18 insertions(+)
drivers/phy/phy-sun4i-usb.c +0 -0
index 43c0d98..06f4e11a 100644
@@ -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);
 
Quoted 12 lines
drivers/phy/phy-sun4i-usb.c void sun4i_usb_phy_set_squelch_detect(struct phy *_phy, bool enabled) · line 482
Quoted 10 lines
drivers/phy/phy-sun4i-usb.c +10 -0
+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 :-(

Quoted 1 line

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

Instead, can you somehow reuse sun4i_usb_phy_set_mode()?

Regards,
-Bin.

Quoted 35 lines

Quoted 13 lines
Quoted 13 lines
drivers/phy/phy-sun4i-usb.c +1 -0
+
 static const struct phy_ops sun4i_usb_phy_ops = {
 	.init		= sun4i_usb_phy_init,
 	.exit		= sun4i_usb_phy_exit,
include/linux/phy/phy-sun4i-usb.h +0 -0
index 50aed92..3bb773f 100644
@@ -23,4 +23,11 @@
 */
 void sun4i_usb_phy_set_squelch_detect(struct phy *phy, bool enabled);
 
Quoted 8 lines
include/linux/phy/phy-sun4i-usb.h line 31
Quoted 6 lines
include/linux/phy/phy-sun4i-usb.h +6 -0
+/**
+ * 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

Hans de Goede

author

2016-09-22 07:31 UTC #7 lore raw

PATCH 1/2 phy-sun4i-usb: Add sun4i_usb_phy_force_session_end() function

Hi,

Quoted 51 lines · Bin Liu

Hi,
Quoted 48 lines · Hans de Goede
Hi,
Quoted 44 lines · Kishon Vijay Abraham I
Hi,
Quoted 29 lines · Hans de Goede
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 <[email protected]>
---
drivers/phy/phy-sun4i-usb.c | 11 +++++++++++
include/linux/phy/phy-sun4i-usb.h | 7 +++++++
2 files changed, 18 insertions(+)
drivers/phy/phy-sun4i-usb.c +0 -0
index 43c0d98..06f4e11a 100644
@@ -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);
 
drivers/phy/phy-sun4i-usb.c void sun4i_usb_phy_set_squelch_detect(struct phy *_phy, bool enabled) · line 482
Quoted 10 lines
drivers/phy/phy-sun4i-usb.c +10 -0
+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 :-(

Quoted 3 lines

Quoted 1 line
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

Quoted 39 lines

Regards,
-Bin.
Quoted 35 lines
Quoted 13 lines
Quoted 13 lines
drivers/phy/phy-sun4i-usb.c +1 -0
+
 static const struct phy_ops sun4i_usb_phy_ops = {
 	.init		= sun4i_usb_phy_init,
 	.exit		= sun4i_usb_phy_exit,
include/linux/phy/phy-sun4i-usb.h +0 -0
index 50aed92..3bb773f 100644
@@ -23,4 +23,11 @@
 */
 void sun4i_usb_phy_set_squelch_detect(struct phy *phy, bool enabled);
 
Quoted 8 lines
include/linux/phy/phy-sun4i-usb.h line 31
Quoted 6 lines
include/linux/phy/phy-sun4i-usb.h +6 -0
+/**
+ * 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