linux-kernel - Re: [PATCH] rtc: bd70528: fix BD71815 watchdog dependency

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Message-ID: <82120164-c12a-bf12-0838-c3d926fe4eaf@roeck-us.net>
Date:   Thu, 22 Apr 2021 07:22:37 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Arnd Bergmann <arnd@...nel.org>,
        Alessandro Zummo <a.zummo@...ertech.it>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Lee Jones <lee.jones@...aro.org>,
        Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-rtc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] rtc: bd70528: fix BD71815 watchdog dependency

On 4/22/21 6:32 AM, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@...db.de>
> 
> The added Kconfig dependency is slightly incorrect, which can
> lead to a link failure when the watchdog is a loadable module:
> 
> arm-linux-gnueabi-ld: drivers/rtc/rtc-bd70528.o: in function `bd70528_set_rtc_based_timers':
> rtc-bd70528.c:(.text+0x6cc): undefined reference to `bd70528_wdt_set'
> arm-linux-gnueabi-ld: drivers/rtc/rtc-bd70528.o: in function `bd70528_set_time':
> rtc-bd70528.c:(.text+0xaa0): undefined reference to `bd70528_wdt_lock'
> arm-linux-gnueabi-ld: rtc-bd70528.c:(.text+0xab8): undefined reference to `bd70528_wdt_unlock'
> arm-linux-gnueabi-ld: drivers/rtc/rtc-bd70528.o: in function `bd70528_alm_enable':
> rtc-bd70528.c:(.text+0xfc0): undefined reference to `bd70528_wdt_lock'
> arm-linux-gnueabi-ld: rtc-bd70528.c:(.text+0x1030): undefined reference to `bd70528_wdt_unlock'
> 
> The problem is that it allows to be built-in if any of the other
> drivers are built-in, even when the watchdog is a loadable module.
> 
> Rework this so that having the watchdog as a loadable module always
> forces the rtc to be a module as well instead of built-in, regardless
> of the other ones.
> 
> Fixes: c56dc069f268 ("rtc: bd70528: Support RTC on ROHM BD71815")
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
>  drivers/rtc/Kconfig | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index d8c13fded164..91cc106e2bf6 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -502,7 +502,8 @@ config RTC_DRV_M41T80_WDT
>  
>  config RTC_DRV_BD70528
>  	tristate "ROHM BD70528, BD71815 and BD71828 PMIC RTC"
> -	depends on MFD_ROHM_BD71828 || MFD_ROHM_BD70528 && (BD70528_WATCHDOG || !BD70528_WATCHDOG)
> +	depends on MFD_ROHM_BD71828 || MFD_ROHM_BD70528 || BD70528_WATCHDOG

Is the "|| BD70528_WATCHDOG" above correct ? Seems odd to me, since
it makes the depend statement true even if neither MFD_ROHM_BD71828
nor MFD_ROHM_BD70528 is enabled.

I think the condition needs to be something like
	depends on (MFD_ROHM_BD71828 || MFD_ROHM_BD70528) && (BD70528_WATCHDOG || !BD70528_WATCHDOG)
or, in two lines,
	depends on MFD_ROHM_BD71828 || MFD_ROHM_BD70528
	depends on BD70528_WATCHDOG || !BD70528_WATCHDOG

Thanks,
Guenter

> +	depends on BD70528_WATCHDOG || !BD70528_WATCHDOG
>  	help
>  	  If you say Y here you will get support for the RTC
>  	  block on ROHM BD70528, BD71815 and BD71828 Power Management IC.
>