Subject: Re: [PATCH -next] power: fix bq27x00_battery kconfig

From: Lars-Peter Clausen <[email-masked]>
Date: Fri, 03 May 2013 12:06:54 +0200

On 05/03/2013 11:56 AM, Xiong Zhou wrote:
> From: Xiong Zhou <[email-masked]>
> 
> This patch fixes build failure(randconfig) of next-20130501.
> When config I2C as m, BATTERY_BQ27x00 as y, here comes the failure.
> BATTERY_BQ27x00 depends on I2C according to the code.
> 

> Failure message:
> drivers/built-in.o: In function `bq27x00_read_i2c':
> bq27x00_battery.c:(.text+0x1082a7): undefined reference to `i2c_transfer'
> drivers/built-in.o: In function `bq27x00_battery_init':
> bq27x00_battery.c:(.init.text+0x6085): undefined reference to `i2c_register_driver'
> bq27x00_battery.c:(.init.text+0x60c7): undefined reference to `i2c_del_driver'
> drivers/built-in.o: In function `bq27x00_battery_exit':
> bq27x00_battery.c:(.exit.text+0xbf0): undefined reference to `i2c_del_driver'
> make: *** [vmlinux] Error 1
> 
> Signed-off-by: Xiong Zhou <[email-masked]>

It's actually a bit more tricky. The driver can be built without I2C
support, so it does not depend on I2C, but if I2C is built as a module the
driver should also only be built as a module.

I think the best solution is to put the platform code and the i2c code of
the bq27x00 driver each in their on module, but if you want a quick solution

depends on I2C || I2C=n

should work.

> ---
> drivers/power/Kconfig |    1 +
> 1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
> index 0d0b5d7..89e5ebd 100644
> --- a/drivers/power/Kconfig
> +++ b/drivers/power/Kconfig
> @@ -152,6 +152,7 @@ config BATTERY_SBS
>  
>  config BATTERY_BQ27x00
>  	tristate "BQ27x00 battery driver"
> +	depends on I2C
>  	help
>  	  Say Y here to enable support for batteries with BQ27x00 (I2C/HDQ) chips.
>  
> --
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