Re: [PATCH] mux: mmio: Fix missing CONFIG_REGMAP_MMIO

[Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>]

On 15/05/2025 16:05, Krzysztof Kozlowski wrote:
> MMIO mux uses now regmap_init_mmio(), so one way or another
> CONFIG_REGMAP_MMIO should be enabled, because there are no stubs for
> !REGMAP_MMIO case:
> 
>   ERROR: modpost: "__regmap_init_mmio_clk" [drivers/mux/mux-mmio.ko] undefined!
> 
> REGMAP_MMIO should be, because it is a non-visible symbol, but this
> causes a circular dependency:
> 
>   error: recursive dependency detected!
>   symbol IRQ_DOMAIN is selected by REGMAP
>   symbol REGMAP default is visible depending on REGMAP_MMIO
>   symbol REGMAP_MMIO is selected by MUX_MMIO
>   symbol MUX_MMIO depends on MULTIPLEXER
>   symbol MULTIPLEXER is selected by MDIO_BUS_MUX_MULTIPLEXER
>   symbol MDIO_BUS_MUX_MULTIPLEXER depends on MDIO_DEVICE
>   symbol MDIO_DEVICE is selected by PHYLIB
>   symbol PHYLIB is selected by ARC_EMAC_CORE
>   symbol ARC_EMAC_CORE is selected by EMAC_ROCKCHIP
>   symbol EMAC_ROCKCHIP depends on OF_IRQ
>   symbol OF_IRQ depends on IRQ_DOMAIN
> 
> ... which we can break by changing dependency in EMAC_ROCKCHIP from
> OF_IRQ to OF.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202505150312.dYbBqUhG-lkp@intel.com/
> Fixes: 61de83fd8256 ("mux: mmio: Do not use syscon helper to build regmap")
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> 
> ---
> 
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Samuel Holland <samuel@sholland.org>
> Cc: Arnd Bergmann <arnd@arndb.de>


Note for netdev folks:

If this looks correct approach, please kindly ack because:
1. The MUX Kconfig part is a fix for a patch in my tree going through
Greg's.
2. Above exposes circular dependency, thus should be fixed in the same
commit.


Best regards,
Krzysztof