[PATCH] usb: musb: fix dead select of USB_MUSB_DUAL_ROLE

[PATCH] usb: musb: fix dead select of USB_MUSB_DUAL_ROLE

[Julian Braha]

'select' does not work on config options in a 'choice', so currently it is
possible to enable USB_MUSB_POLARFIRE_SOC without USB_MUSB_DUAL_ROLE.

Replace 'select' with 'depends on'.

This dead select was found by kconfirm, a static analysis tool for Kconfig.

Signed-off-by: Julian Braha <julianbraha@gmail.com>
---
 drivers/usb/musb/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/musb/Kconfig b/drivers/usb/musb/Kconfig
index f56929267eaa..f8ff2366f59f 100644
--- a/drivers/usb/musb/Kconfig
+++ b/drivers/usb/musb/Kconfig
@@ -116,7 +116,7 @@ config USB_MUSB_POLARFIRE_SOC
 	tristate "Microchip PolarFire SoC platforms"
 	depends on ARCH_MICROCHIP_POLARFIRE || COMPILE_TEST
 	depends on NOP_USB_XCEIV
-	select USB_MUSB_DUAL_ROLE
+	depends on USB_MUSB_DUAL_ROLE
 	help
 	  Say Y here to enable support for USB on Microchip's PolarFire SoC.
 
-- 
2.54.0

Re: [PATCH] usb: musb: fix dead select of USB_MUSB_DUAL_ROLE

[Arnd Bergmann]

On Sat, Jul 11, 2026, at 15:03, Julian Braha wrote:
> 'select' does not work on config options in a 'choice', so currently it is
> possible to enable USB_MUSB_POLARFIRE_SOC without USB_MUSB_DUAL_ROLE.
>
> Replace 'select' with 'depends on'.
>
> This dead select was found by kconfirm, a static analysis tool for Kconfig.
>
> Signed-off-by: Julian Braha <julianbraha@gmail.com>


Good catch, but I wonder if this is actually a real dependency
at all. What would happen if you just remove the 'select' line
here and build a polarfire kernel that only supports
host or gadget mode but not dual-role?

       Arnd

Re: [PATCH] usb: musb: fix dead select of USB_MUSB_DUAL_ROLE

[Julian Braha]

Hi Arnd,

On 7/11/26 15:39, Arnd Bergmann wrote:
> Good catch, but I wonder if this is actually a real dependency
> at all. What would happen if you just remove the 'select' line
> here and build a polarfire kernel that only supports
> host or gadget mode but not dual-role?

The kernel builds just fine for me with USB_MUSB_POLARFIRE_SOC=y and
USB_MUSB_DUAL_ROLE=n

But I don't have this hardware so I don't know what would happen at
runtime.

I've CC'd more people involved in patches to this config option.

- Julian Braha

Re: [PATCH] usb: musb: fix dead select of USB_MUSB_DUAL_ROLE

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 755 bytes --]

On Sat, Jul 11, 2026 at 04:09:58PM +0100, Julian Braha wrote:
> Hi Arnd,
> 
> On 7/11/26 15:39, Arnd Bergmann wrote:
> > Good catch, but I wonder if this is actually a real dependency
> > at all. What would happen if you just remove the 'select' line
> > here and build a polarfire kernel that only supports
> > host or gadget mode but not dual-role?
> 
> The kernel builds just fine for me with USB_MUSB_POLARFIRE_SOC=y and
> USB_MUSB_DUAL_ROLE=n
> 
> But I don't have this hardware so I don't know what would happen at
> runtime.
> 
> I've CC'd more people involved in patches to this config option.

This is the setup I've been using in my development environment for
(probably) years.

Probably the select should just be deleted.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

Re: [PATCH] usb: musb: fix dead select of USB_MUSB_DUAL_ROLE

[Arnd Bergmann]

On Sun, Jul 12, 2026, at 23:56, Conor Dooley wrote:
> On Sat, Jul 11, 2026 at 04:09:58PM +0100, Julian Braha wrote:
>> On 7/11/26 15:39, Arnd Bergmann wrote:
>> > Good catch, but I wonder if this is actually a real dependency
>> > at all. What would happen if you just remove the 'select' line
>> > here and build a polarfire kernel that only supports
>> > host or gadget mode but not dual-role?
>> 
>> The kernel builds just fine for me with USB_MUSB_POLARFIRE_SOC=y and
>> USB_MUSB_DUAL_ROLE=n
>> 
> This is the setup I've been using in my development environment for
> (probably) years.
>
> Probably the select should just be deleted.

Ok, so it was probably just a misguided attempt to pick the most
useful configuration by default.

Julian, can you send a new patch to just drop the line?

        Arnd