Re: [PATCH 0/3] Implement role-switch notifications from dwc3-drd to dwc3-qcom

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 08/07/2021 04:54, Bjorn Andersson wrote:
Bryan had a previous patch where the glue layer was notified about role
switching (iirc) and as soon as we hit a probe deferal in the core
driver we'd dereference some pointer in the glue layer. I don't find the
patch right now, but I suspect it might have been caused by the same
platform_get_drvdata() as we see in qcom_dwc3_resume_irq().

Here

https://lore.kernel.org/linux-usb/20200311191501.8165-7-bryan.odonoghue@xxxxxxxxxx/

and here

https://lore.kernel.org/linux-usb/20200311191501.8165-8-bryan.odonoghue@xxxxxxxxxx/

one thing about that I don't think is right now in retrospect is having to find a DT connector in the core, meaning it incorrectly assumes you have a node named "connector" as a child of dwc3-core

https://lore.kernel.org/linux-usb/158463604559.152100.9219030962819234620@xxxxxxxxxxxxxxxxxxxxxxxxxx/

Having done some work with TCPM on pm8150b silicon I see what Stephen was saying about that

That's one solid reason I like the USB role-switch API - because it gets you out of the business of trying to discern from dwc3-qcom if dwc3-core has role-switching turned on by iterating through its range of DT nodes and looking for a special one named "connector"

The initial and imperfect solution I had for that looked like this

if (dwc3_qcom_find_gpio_usb_connector(qcom->dwc3)) {}

Wesley had another iteration on that that was a little better

https://lore.kernel.org/linux-usb/20201009082843.28503-4-wcheng@xxxxxxxxxxxxxx/

+static int dwc3_qcom_connector_check(struct fwnode_handle *fwnode)
+{
+	if (fwnode && (!fwnode_property_match_string(fwnode, "compatible",
+						     "gpio-usb-b-connector") ||
+	    !fwnode_property_match_string(fwnode, "compatible",
+					  "usb-c-connector")))
+		return 1;
+
+	return 0;
+}

All we are really doing there is replicating functionality that the role-switch API already provides


---
bod



[Index of Archives]     [Linux Media]     [Linux Input]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Old Linux USB Devel Archive]

  Powered by Linux