The __get_dwc3_maximum_speed() function returns an enum type which, in
this context here, is basically unsigned int. On error cases, it's
supposed to return USB_SPEED_UNKNOWN, but it was accidentally changed to
return negative error codes in commit f93e96c544 ("usb: dwc3: rtk: use
scoped device node handling to simplify error paths").
There is only one caller and because of the way that the types work out,
returning negative error codes is not a problem. They will be treated
as greater than USB_SPEED_HIGH and ignored as invalid. So this patch
does not affect run time behavior, it's just a clean up.
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/865e56dc-37cc-47b1-8d35-9047ecb1984a@stanley.mountain
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Realtek DHC RTD SoCs integrate dwc3 IP and has some customizations to
support different generations of SoCs.
The RTD1619b subclass SoC only supports USB 2.0 from dwc3. The driver
can set a maximum speed to support this. Add role switching function,
that can switch USB roles through other drivers, or switch USB roles
through user space through set /sys/class/usb_role/.
Signed-off-by: Stanley Chang <stanley_chang@realtek.com>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/20230826031028.1892-1-stanley_chang@realtek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
