From: Peter Chen <peter.chen@xxxxxxxxxxxxx>
When the gadget role starts, we need to make sure the vbus is lower
than OTGSC_BSV, or there will be an vbus interrupt since we use
B_SESSION_VALID as vbus interrupt to indicate connect and disconnect.
When the host role starts, it may not be useful to wait vbus to lower
than OTGSC_BSV, but it can indicate some hardware problems like the
vbus is still higher than OTGSC_BSV after we disconnect to host some
time later (5000 milliseconds currently), which is obvious not correct.
Tested-by: Marek Vasut <marex@xxxxxxx>
Signed-off-by: Peter Chen <peter.chen@xxxxxxxxxxxxx>
Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
---
drivers/usb/chipidea/ci.h | 3 +++
drivers/usb/chipidea/core.c | 32 ++++++++++++++++++++++++++++++++
drivers/usb/chipidea/otg.c | 4 ++++
3 files changed, 39 insertions(+)
diff --git a/drivers/usb/chipidea/ci.h b/drivers/usb/chipidea/ci.h
index 3160363..1c94fc5 100644
--- a/drivers/usb/chipidea/ci.h
+++ b/drivers/usb/chipidea/ci.h
@@ -308,4 +308,7 @@ int hw_port_test_set(struct ci_hdrc *ci, u8 mode);
u8 hw_port_test_get(struct ci_hdrc *ci);
+int hw_wait_reg(struct ci_hdrc *ci, enum ci_hw_regs reg, u32 mask,
+ u32 value, unsigned int timeout_ms);
+
#endif /* __DRIVERS_USB_CHIPIDEA_CI_H */
diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
index c95e098..9462640 100644
--- a/drivers/usb/chipidea/core.c
+++ b/drivers/usb/chipidea/core.c
@@ -294,6 +294,38 @@ int hw_device_reset(struct ci_hdrc *ci, u32 mode)
return 0;
}
+/**
+ * hw_wait_reg: wait the register value
+ *
+ * Sometimes, it needs to wait register value before going on.
+ * Eg, when switch to device mode, the vbus value should be lower
+ * than OTGSC_BSV before connects to host.
+ *
+ * @ci: the controller
+ * @reg: register index
+ * @mask: mast bit
+ * @value: the bit value to wait
+ * @timeout_ms: timeout in millisecond
+ *
+ * This function returns an error code if timeout
+ */
+int hw_wait_reg(struct ci_hdrc *ci, enum ci_hw_regs reg, u32 mask,
+ u32 value, unsigned int timeout_ms)
+{
+ unsigned long elapse = jiffies + msecs_to_jiffies(timeout_ms);
+
+ while (hw_read(ci, reg, mask) != value) {
+ if (time_after(jiffies, elapse)) {
+ dev_err(ci->dev, "timeout waiting for %08x in %d\n",
+ mask, reg);
+ return -ETIMEDOUT;
+ }
+ msleep(20);
+ }
+
+ return 0;
+}
+
static irqreturn_t ci_irq(int irq, void *data)
{
struct ci_hdrc *ci = data;
diff --git a/drivers/usb/chipidea/otg.c b/drivers/usb/chipidea/otg.c
index 7f37484..39bd7ec 100644
--- a/drivers/usb/chipidea/otg.c
+++ b/drivers/usb/chipidea/otg.c
@@ -52,6 +52,7 @@ void ci_handle_vbus_change(struct ci_hdrc *ci)
usb_gadget_vbus_disconnect(&ci->gadget);
}
+#define CI_VBUS_STABLE_TIMEOUT_MS 5000
static void ci_handle_id_switch(struct ci_hdrc *ci)
{
enum ci_role role = ci_otg_role(ci);
@@ -61,6 +62,9 @@ static void ci_handle_id_switch(struct ci_hdrc *ci)
ci_role(ci)->name, ci->roles[role]->name);
ci_role_stop(ci);
+ /* wait vbus lower than OTGSC_BSV */
+ hw_wait_reg(ci, OP_OTGSC, OTGSC_BSV, 0,
+ CI_VBUS_STABLE_TIMEOUT_MS);
ci_role_start(ci, role);
}
}
--
1.8.4.rc2
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