On 2019/11/4 18:04, Thierry Reding wrote:
> On Mon, Nov 04, 2019 at 10:59:45AM +0800, Mao Wenan wrote:
>> If CONFIG_USB_TEGRA_XUDC=y and CONFIG_USB_ROLE_SWITCH=m,
>> below erros can be seen:
>> drivers/usb/gadget/udc/tegra-xudc.o: In function `tegra_xudc_remove':
>> tegra-xudc.c:(.text+0x6b0): undefined reference to `usb_role_switch_unregister'
>> drivers/usb/gadget/udc/tegra-xudc.o: In function `tegra_xudc_probe':
>> tegra-xudc.c:(.text+0x1b88): undefined reference to `usb_role_switch_register'
>> drivers/usb/gadget/udc/tegra-xudc.o: In function `tegra_xudc_usb_role_sw_work':
>> tegra-xudc.c:(.text+0x5ecc): undefined reference to `usb_role_switch_get_role'
>>
>> This patch add dependency USB_ROLE_SWITCH for UDC driver.
>>
>> Fixes: 49db427232fe ("usb: gadget: Add UDC driver for tegra XUSB device mode controller")
>> Signed-off-by: Mao Wenan <maowenan@xxxxxxxxxx>
>> ---
>> drivers/usb/gadget/udc/Kconfig | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/usb/gadget/udc/Kconfig b/drivers/usb/gadget/udc/Kconfig
>> index acaec3a..d103154 100644
>> --- a/drivers/usb/gadget/udc/Kconfig
>> +++ b/drivers/usb/gadget/udc/Kconfig
>> @@ -445,6 +445,7 @@ config USB_TEGRA_XUDC
>> tristate "NVIDIA Tegra Superspeed USB 3.0 Device Controller"
>> depends on ARCH_TEGRA || COMPILE_TEST
>> depends on PHY_TEGRA_XUSB
>> + depends on USB_ROLE_SWITCH
>
> It looks like most other drivers that use the USB role switch class do
> "select" here. Now, that's suboptimal because USB_ROLE_SWITCH is a user-
> visible symbol, which can lead to conflicts, so it should be avoided. I
> think that in this case it might make sense to hide USB_ROLE_SWITCH and
> then convert all "depends on USB_ROLE_SWITCH" occurrences to "select
> USB_ROLE_SWITCH". The USB role switch class is, after all, not useful by
> itself. It always needs a host and/or gadget driver to make use of it.
>
Thanks, I send v2 and change 'depends on' to 'select' for this patch.
> Thierry
>
