linux-kernel - Re: [PATCH 1/8] watchdog: bcm2835: Move the driver to the soc/ directory.

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Date:   Tue, 20 Nov 2018 09:29:55 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Eric Anholt <eric@...olt.net>
Cc:     Florian Fainelli <f.fainelli@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        linux-watchdog@...r.kernel.org,
        linux-rpi-kernel@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Stefan Wahren <stefan.wahren@...e.com>,
        bcm-kernel-feedback-list@...adcom.com
Subject: Re: [PATCH 1/8] watchdog: bcm2835: Move the driver to the soc/
 directory.

On Tue, Nov 20, 2018 at 09:19:53AM -0800, Eric Anholt wrote:
> The binding for the bcm2835 "wdt" actually covers a large range of the
> PM block's register space.  The WDT is not a separate HW block from
> the rest of power domain management, so move the driver to the soc/
> directory in preparation for expanding its role to cover power
> domains.
> 
> This move does result in the driver being made mandatory for the
> BCM2835 platform, which is probably actually reasonable given that
> it's necessary for reboot/halt support.
> 
> Signed-off-by: Eric Anholt <eric@...olt.net>

Keeping drivers out of their domain tends to have the effect of maintainers
not being aware of changes, which in turn tends to result in bad code.
I have seen that happen a lot with hwmon drivers, and  I am not in favor
of it. It would be better to keep the watchdog code where it is and have
it instantiated from a soc parent, which could pass, for example, regmap
information to the driver for register accesses.

If the new SoC approach is to move everything into SoC, you'll be on 
your own. I won't NACK this, but I won't ACK it either.

Guenter

> ---
>  drivers/soc/bcm/Makefile                              |  1 +
>  .../{watchdog/bcm2835_wdt.c => soc/bcm/bcm2835-pm.c}  |  0
>  drivers/watchdog/Kconfig                              | 11 -----------
>  drivers/watchdog/Makefile                             |  1 -
>  4 files changed, 1 insertion(+), 12 deletions(-)
>  rename drivers/{watchdog/bcm2835_wdt.c => soc/bcm/bcm2835-pm.c} (100%)
> 
> diff --git a/drivers/soc/bcm/Makefile b/drivers/soc/bcm/Makefile
> index dc4fced72d21..16504eb694b1 100644
> --- a/drivers/soc/bcm/Makefile
> +++ b/drivers/soc/bcm/Makefile
> @@ -1,2 +1,3 @@
> +obj-$(CONFIG_ARCH_BCM2835)      += bcm2835-pm.o
>  obj-$(CONFIG_RASPBERRYPI_POWER)	+= raspberrypi-power.o
>  obj-$(CONFIG_SOC_BRCMSTB)	+= brcmstb/
> diff --git a/drivers/watchdog/bcm2835_wdt.c b/drivers/soc/bcm/bcm2835-pm.c
> similarity index 100%
> rename from drivers/watchdog/bcm2835_wdt.c
> rename to drivers/soc/bcm/bcm2835-pm.c
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 2d64333f4782..796e2a593056 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -1573,17 +1573,6 @@ config BCM63XX_WDT
>  	  To compile this driver as a loadable module, choose M here.
>  	  The module will be called bcm63xx_wdt.
>  
> -config BCM2835_WDT
> -	tristate "Broadcom BCM2835 hardware watchdog"
> -	depends on ARCH_BCM2835 || (OF && COMPILE_TEST)
> -	select WATCHDOG_CORE
> -	help
> -	  Watchdog driver for the built in watchdog hardware in Broadcom
> -	  BCM2835 SoC.
> -
> -	  To compile this driver as a loadable module, choose M here.
> -	  The module will be called bcm2835_wdt.
> -
>  config BCM_KONA_WDT
>  	tristate "BCM Kona Watchdog"
>  	depends on ARCH_BCM_MOBILE || COMPILE_TEST
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index f69cdff5ad7f..1788537e85af 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -70,7 +70,6 @@ obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
>  obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
>  obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
>  obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
> -obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o
>  obj-$(CONFIG_MOXART_WDT) += moxart_wdt.o
>  obj-$(CONFIG_SIRFSOC_WATCHDOG) += sirfsoc_wdt.o
>  obj-$(CONFIG_ST_LPC_WATCHDOG) += st_lpc_wdt.o
> -- 
> 2.19.1
>