bcma,ssb: simplify dependency handling for bcma and ssb drivers

The files, drivers/bcma/Kconfig and drivers/ssb/Kconfig, define two helper
config options BCMA_POSSIBLE and SSB_POSSIBLE. Both options are defined
identical:

config {BCMA_POSSIBLE,SSB_POSSIBLE}
	bool
	depends on HAS_IOMEM && HAS_DMA
	default y

While this kind of duplication might still be acceptable in order to have
both sections work independently of each other, it really gets strange when
looking how they are then used in expression where both of those configs
appear. E.g., config B43's dependency is:

  (BCMA_POSSIBLE || SSB_POSSIBLE) && MAC80211 && HAS_DMA

Note that BCMA_POSSIBLE and SSB_POSSIBLE identical and already have HAS_DMA
as condition, so that is then also another duplication.

Another example is the choice Supported bus types in B43, which already
depends on B43 and hence, we know that HAS_IOMEM && HAS_DMA holds, so all
stated dependencies in the choice are true in all cases.

Given this whole confusion around the use of these two symbols, just remove
them and replace them with the expression they intend to abbreviate.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
---
 drivers/bcma/Kconfig                            | 7 +------
 drivers/net/ethernet/broadcom/Kconfig           | 4 ++--
 drivers/net/wireless/broadcom/b43/Kconfig       | 5 +----
 drivers/net/wireless/broadcom/b43legacy/Kconfig | 2 +-
 drivers/net/wireless/broadcom/brcm80211/Kconfig | 3 +--
 drivers/ssb/Kconfig                             | 7 +------
 6 files changed, 7 insertions(+), 21 deletions(-)

On Mon, 2023-12-18 at 12:58 +0100, Lukas Bulwahn wrote:

Dunno, I'm not super involved with this but ...

> +++ b/drivers/bcma/Kconfig
> @@ -1,12 +1,7 @@
>  # SPDX-License-Identifier: GPL-2.0
> -config BCMA_POSSIBLE
> -	bool
> -	depends on HAS_IOMEM && HAS_DMA
> -	default y
> -
>  menuconfig BCMA
>  	tristate "Broadcom specific AMBA"
> -	depends on BCMA_POSSIBLE
> +	depends on HAS_IOMEM && HAS_DMA

[...]
>  config BRCMSMAC
>  	tristate "Broadcom IEEE802.11n PCIe SoftMAC WLAN driver"
> -	depends on MAC80211
> -	depends on BCMA_POSSIBLE
> +	depends on HAS_IOMEM && HAS_DMA && MAC80211
>  	select BCMA

to me it kind of seems more obvious for example in this case to say
"depend on BCMA_POSSIBLE and select BCMA" rather than open-coding the
BCMA dependencies both here and in BCMA? Now granted, they're rather
unlikely to _change_, but it still seems more obvious?

johannes

Johannes Berg <johannes@sipsolutions.net> writes:

> On Mon, 2023-12-18 at 12:58 +0100, Lukas Bulwahn wrote:
>
> Dunno, I'm not super involved with this but ...
>
>> +++ b/drivers/bcma/Kconfig
>> @@ -1,12 +1,7 @@
>>  # SPDX-License-Identifier: GPL-2.0
>> -config BCMA_POSSIBLE
>> -	bool
>> -	depends on HAS_IOMEM && HAS_DMA
>> -	default y
>> -
>>  menuconfig BCMA
>>  	tristate "Broadcom specific AMBA"
>> -	depends on BCMA_POSSIBLE
>> +	depends on HAS_IOMEM && HAS_DMA
>
> [...]
>>  config BRCMSMAC
>>  	tristate "Broadcom IEEE802.11n PCIe SoftMAC WLAN driver"
>> -	depends on MAC80211
>> -	depends on BCMA_POSSIBLE
>> +	depends on HAS_IOMEM && HAS_DMA && MAC80211
>>  	select BCMA
>
> to me it kind of seems more obvious for example in this case to say
> "depend on BCMA_POSSIBLE and select BCMA" rather than open-coding the
> BCMA dependencies both here and in BCMA? Now granted, they're rather
> unlikely to _change_, but it still seems more obvious?

I was thinking the same. Lukas, is there a specific reason why you want
to change this or this just something you noticed by chance?

On Mon, Dec 18, 2023 at 3:59 PM Kalle Valo <kvalo@kernel.org> wrote:
>
> Johannes Berg <johannes@sipsolutions.net> writes:
>
> > On Mon, 2023-12-18 at 12:58 +0100, Lukas Bulwahn wrote:
> >
> > Dunno, I'm not super involved with this but ...
> >
> >> +++ b/drivers/bcma/Kconfig
> >> @@ -1,12 +1,7 @@
> >>  # SPDX-License-Identifier: GPL-2.0
> >> -config BCMA_POSSIBLE
> >> -    bool
> >> -    depends on HAS_IOMEM && HAS_DMA
> >> -    default y
> >> -
> >>  menuconfig BCMA
> >>      tristate "Broadcom specific AMBA"
> >> -    depends on BCMA_POSSIBLE
> >> +    depends on HAS_IOMEM && HAS_DMA
> >
> > [...]
> >>  config BRCMSMAC
> >>      tristate "Broadcom IEEE802.11n PCIe SoftMAC WLAN driver"
> >> -    depends on MAC80211
> >> -    depends on BCMA_POSSIBLE
> >> +    depends on HAS_IOMEM && HAS_DMA && MAC80211
> >>      select BCMA
> >
> > to me it kind of seems more obvious for example in this case to say
> > "depend on BCMA_POSSIBLE and select BCMA" rather than open-coding the
> > BCMA dependencies both here and in BCMA? Now granted, they're rather
> > unlikely to _change_, but it still seems more obvious?
>
> I was thinking the same. Lukas, is there a specific reason why you want
> to change this or this just something you noticed by chance?
>

I just noticed this by chance---well, I was wondering what these
config symbols were doing in my kernel build configuration (they are
actually in every config). While reading through the code, I was
confused on what the dependencies were trying to tell me, as the
config symbols and conditions seemed to repeat over and over in
different places.

I thought it was worth a clean up and this was the patch I came up
with in the end.

Lukas