Re: [PATCH v4 1/2] dt-bindings: qcom,snps-dwc3: Add property indicating presence of eUSB2 phy

[Peter Chen]

On 26-07-16 00:09:47, Thinh Nguyen wrote:
> > 
> > Only the new user for adding phy_type="eusb2" at dts needs to check the
> > controller logic, and this is what the user needs to do that check the
> > new added device tree property logic at the driver.
> 
> To clarify, are you suggesting to introduce a new phy_type property to
> indicate phy type? If so, that sounds similar to qcom,has-eusb2-phy but
> more generic. Also, where do you plan to define it (dwc3 or phy node)?
> 

No, I meant just adding new entry at below usbphy_modes array, that's the
easier way. At the current code at of.c, it indeed mixes description of
the phy interface (between controller and phy) and phy type, the array
names phy interface, and dt property names "phy_type".

diff --git a/drivers/usb/phy/of.c b/drivers/usb/phy/of.c
index 1ab134f45d67..5cbf17d493ad 100644
--- a/drivers/usb/phy/of.c
+++ b/drivers/usb/phy/of.c
@@ -16,6 +16,7 @@ static const char *const usbphy_modes[] = {
 	[USBPHY_INTERFACE_MODE_ULPI]	= "ulpi",
 	[USBPHY_INTERFACE_MODE_SERIAL]	= "serial",
 	[USBPHY_INTERFACE_MODE_HSIC]	= "hsic",
+	[USBPHY_INTERFACE_MODE_EUSB2]	= "eusb2",
 };

line34: err = of_property_read_string(np, "phy_type", &phy_type);

In fact, HSIC is not the interface between controller and PHY, it is
after UTMI(+) or ULPI, and similar with eUSB2.

The API of_usb_get_phy_mode is mainly used by controller driver
to know what kinds of PHY it is connected, and do corresponding
configuration, the configuration may not limit to interface between
controller and PHY. Do you agree we just take "phy mode" and
"phy type" are same thing, and delete "INTERFACE" in this file
and add "eusb2" as a new "phy_type"?
	
> 
> If you mean defining a new PHY_TYPE_EUSB2 constant in
> include/dt-bindings/phy/phy.h, the glue driver needs to parse the
> phandle args, and the eusb2 bindings would also need to change the
> number of #phy-cells. That's a bigger change.
> 

No. Like you said, it is a bigger change.

-- 

Thanks,
Peter Chen