[RESEND PATCH 1/1] ARM: exynos_defconfig: Enable SBS battery support

[Doug Anderson]

Bartlomiej,

On Mon, Aug 11, 2014 at 8:42 AM, Bartlomiej Zolnierkiewicz
<b.zolnierkie at samsung.com> wrote:
>
> Hi,
>
> On Monday, August 11, 2014 02:52:27 PM Javier Martinez Canillas wrote:
>> Hello Bartlomiej,
>>
>> On 08/11/2014 02:40 PM, Bartlomiej Zolnierkiewicz wrote:
>> >> index fc7d168..c390bb9 100644
>> >> --- a/arch/arm/configs/exynos_defconfig
>> >> +++ b/arch/arm/configs/exynos_defconfig
>> >> @@ -77,6 +77,7 @@ CONFIG_SPI_S3C64XX=y
>> >>  CONFIG_I2C_S3C2410=y
>> >>  CONFIG_DEBUG_GPIO=y
>> >>  CONFIG_POWER_SUPPLY=y
>> >> +CONFIG_BATTERY_SBS=m
>> >
>> > Why not make it "=y"?
>> >
>> > Rationale:
>> > - currently no hardware related option uses "=m" in exynos_defconfig
>> > - it would match the SBS option usage in multi_v7_defconfig
>> >
>> >>  CONFIG_CHARGER_TPS65090=y
>> >>  # CONFIG_HWMON is not set
>> >>  CONFIG_THERMAL=y
>> >
>>
>> I know but personally I think this should be changed. The idea of having a multi
>> platform kernel is to build a single kernel image that can be used to boot
>> different platforms. Not all platforms have a SBS-compliant battery so this
>> support shouldn't be built in the kernel image IMHO.
>>
>> This also matches to what real users will do since distributions most likely
>> will have a minimal kernel and every possible hardware support will be enabled
>> as a loadable kernel module. This is what distros do for other platforms too.
>>
>> If someone has a different use case and wants a kernel image that is optimized
>> for a particular platform then she has to create its own defconfig anyways.
>
> Distributions usually use their own configs anyway and the current most
> popular use case for exynos_defconfig (not multi_v7_defconfig) seems to
> be to build kernel image alone and use it without any modules:
>
> $ grep "=m" arch/arm/configs/exynos_defconfig
> CONFIG_DM_CRYPT=m
>
> $ grep "=m" .config
> CONFIG_NET_IP_TUNNEL=m
> CONFIG_INET_TUNNEL=m
> CONFIG_IPV6=m
> CONFIG_INET6_XFRM_MODE_TRANSPORT=m
> CONFIG_INET6_XFRM_MODE_TUNNEL=m
> CONFIG_INET6_XFRM_MODE_BEET=m
> CONFIG_IPV6_SIT=m
> CONFIG_DM_CRYPT=m
> CONFIG_CRYPTO_RNG=m
> CONFIG_CRYPTO_ANSI_CPRNG=m
>
> What I'm trying to say is that there is a high probability that people
> will continue to use just the kernel image for exynos_defconfig and
> will therefore miss SBS battery support altogether (which is only 3.6
> kB of code more in the kernel image so there is no much gain in making
> it modular currently).

I'm not against making it =y for exynos_defconfig.  I do pretty
strongly agree that the multi_v7 version should be =m eventually,
though.  We'd need to do everything we can to make that kernel
smaller.

-Doug