Re: [PATCH RFC] iio: dac: Fix build error when CONFIG_SPI_MASTER=y && CONFIG_I2C=m

[Axel Lin <axel.lin@ingics.com>]

於 三，2013-05-08 於 16:36 +0800，Axel Lin 提到：
> This patch fixes below build error when CONFIG_SPI_MASTER=y && CONFIG_I2C=m:
> 
> drivers/built-in.o: In function `ad5064_i2c_write':
> drivers/iio/dac/ad5064.c:608: undefined reference to `i2c_master_send'
> drivers/built-in.o: In function `ad5064_i2c_register_driver':
> drivers/iio/dac/ad5064.c:646: undefined reference to `i2c_register_driver'
> drivers/built-in.o: In function `ad5064_i2c_unregister_driver':
> drivers/iio/dac/ad5064.c:651: undefined reference to `i2c_del_driver'
> make: *** [vmlinux] Error 1
> 
> Add config IIO_DAC_I2C_AND_SPI helper to handle such case:
> When CONFIG_I2C=m, meaning we can't build the drivers in with I2C support.
> Thus don't allow the drivers to be compiled as built-in.
> 
> Signed-off-by: Axel Lin <axel.lin@ingics.com>

I should add 
Reported-by: Wu Fengguang <fengguang.wu@intel.com>
And also Cc Fengguang now.
I look into this issue because it is reported by Fengguang's kbuild test
robot.

> ---
>  drivers/iio/dac/Kconfig | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
> index f4a6f08..34bc1d7 100644
> --- a/drivers/iio/dac/Kconfig
> +++ b/drivers/iio/dac/Kconfig
> @@ -1,11 +1,22 @@
>  #
>  # DAC drivers
>  #
> +
> +# Helper to resolve issues with configs that have SPI enabled but I2C
> +# modular, meaning we can't build the drivers in with I2C support.
> +# We use an ordered list of conditional defaults to pick the appropriate
> +# setting - SPI can't be modular so that case doesn't need to be covered.
> +config IIO_DAC_I2C_AND_SPI
> +	tristate
> +	default m if I2C=m
> +	default y if I2C=y
> +	default y if SPI_MASTER=y
> +
>  menu "Digital to analog converters"
>  
>  config AD5064
>  	tristate "Analog Devices AD5064 and similar multi-channel DAC driver"
> -	depends on (SPI_MASTER || I2C)
> +	depends on IIO_DAC_I2C_AND_SPI
>  	help
>  	  Say yes here to build support for Analog Devices AD5024, AD5025, AD5044,
>  	  AD5045, AD5064, AD5064-1, AD5065, AD5628, AD5629R, AD5648, AD5666, AD5668,
> @@ -27,7 +38,7 @@ config AD5360
>  
>  config AD5380
>  	tristate "Analog Devices AD5380/81/82/83/84/90/91/92 DAC driver"
> -	depends on (SPI_MASTER || I2C)
> +	depends on IIO_DAC_I2C_AND_SPI
>  	select REGMAP_I2C if I2C
>  	select REGMAP_SPI if SPI_MASTER
>  	help
> @@ -57,7 +68,7 @@ config AD5624R_SPI
>  
>  config AD5446
>  	tristate "Analog Devices AD5446 and similar single channel DACs driver"
> -	depends on (SPI_MASTER || I2C)
> +	depends on IIO_DAC_I2C_AND_SPI
>  	help
>  	  Say yes here to build support for Analog Devices AD5300, AD5301, AD5310,
>  	  AD5311, AD5320, AD5321, AD5444, AD5446, AD5450, AD5451, AD5452, AD5453,