[PATCH v12 10/13] usb: chipidea: add wait vbus lower than OTGSC_BSV before role starts

Peter Chen
2013-07-11T06:27:18Z

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 (500 jiffies currently), which is obvious not correct.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
---
drivers/usb/chipidea/ci.h | 3 +++
drivers/usb/chipidea/core.c | 32 ++++++++++++++++++++++++++++++++
drivers/usb/chipidea/otg.c | 4 ++++
3 files changed, 39 insertions(+), 0 deletions(-)

diff --git a/drivers/usb/chipidea/ci.h b/drivers/usb/chipidea/ci.h
index 3160363..df27696 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 long timeout);
+
#endif /* __DRIVERS_USB_CHIPIDEA_CI_H */
diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
index 7a07300..1c39541 100644
--- a/drivers/usb/chipidea/core.c
+++ b/drivers/usb/chipidea/core.c
@@ -295,6 +295,38 @@ 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: timeout to indicate an error
+ *
+ * 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 long timeout)
+{
+ unsigned long elapse = jiffies + timeout;
+
+ 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 c74194d..8aa0241 100644
--- a/drivers/usb/chipidea/otg.c
+++ b/drivers/usb/chipidea/otg.c
@@ -67,6 +67,7 @@ void ci_handle_vbus_change(struct ci_hdrc *ci)
usb_gadget_vbus_disconnect(&ci->gadget);
}

+#define CI_VBUS_STABLE_TIMEOUT 500
static void ci_handle_id_switch(struct ci_hdrc *ci)
{
enum ci_role role = ci_otg_role(ci);
@@ -76,6 +77,9 @@ 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);
ci_role_start(ci, role);
}
}
--
1.7.0.4