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usb: chipidea: add wait vbus lower than OTGSC_BSV before role starts
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@denx.de> Signed-off-by: Peter Chen <peter.chen@freescale.com> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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3 changed files with 39 additions and 0 deletions
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@ -308,4 +308,7 @@ int hw_port_test_set(struct ci_hdrc *ci, u8 mode);
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u8 hw_port_test_get(struct ci_hdrc *ci);
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int hw_wait_reg(struct ci_hdrc *ci, enum ci_hw_regs reg, u32 mask,
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u32 value, unsigned int timeout_ms);
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#endif /* __DRIVERS_USB_CHIPIDEA_CI_H */
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@ -294,6 +294,38 @@ int hw_device_reset(struct ci_hdrc *ci, u32 mode)
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return 0;
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}
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/**
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* hw_wait_reg: wait the register value
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*
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* Sometimes, it needs to wait register value before going on.
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* Eg, when switch to device mode, the vbus value should be lower
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* than OTGSC_BSV before connects to host.
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*
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* @ci: the controller
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* @reg: register index
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* @mask: mast bit
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* @value: the bit value to wait
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* @timeout_ms: timeout in millisecond
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*
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* This function returns an error code if timeout
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*/
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int hw_wait_reg(struct ci_hdrc *ci, enum ci_hw_regs reg, u32 mask,
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u32 value, unsigned int timeout_ms)
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{
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unsigned long elapse = jiffies + msecs_to_jiffies(timeout_ms);
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while (hw_read(ci, reg, mask) != value) {
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if (time_after(jiffies, elapse)) {
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dev_err(ci->dev, "timeout waiting for %08x in %d\n",
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mask, reg);
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return -ETIMEDOUT;
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}
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msleep(20);
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}
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return 0;
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}
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static irqreturn_t ci_irq(int irq, void *data)
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{
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struct ci_hdrc *ci = data;
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@ -52,6 +52,7 @@ void ci_handle_vbus_change(struct ci_hdrc *ci)
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usb_gadget_vbus_disconnect(&ci->gadget);
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}
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#define CI_VBUS_STABLE_TIMEOUT_MS 5000
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static void ci_handle_id_switch(struct ci_hdrc *ci)
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{
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enum ci_role role = ci_otg_role(ci);
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@ -61,6 +62,9 @@ static void ci_handle_id_switch(struct ci_hdrc *ci)
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ci_role(ci)->name, ci->roles[role]->name);
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ci_role_stop(ci);
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/* wait vbus lower than OTGSC_BSV */
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hw_wait_reg(ci, OP_OTGSC, OTGSC_BSV, 0,
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CI_VBUS_STABLE_TIMEOUT_MS);
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ci_role_start(ci, role);
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}
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}
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