Subject: Re: [PATCH] media: i2c: fix max9271 build dependencies

From: Sakari Ailus <[email-masked]>
Date: Mon, 8 Feb 2021 09:27:01 +0200

Hi Mauro,

Thanks for the patch.

On Mon, Feb 08, 2021 at 07:53:15AM +0100, Mauro Carvalho Chehab wrote:
> As described on its c file, the Maxim MAX9271 GMSL serializer isn't a
> self-contained driver, as MAX9271 is usually embedded in camera modules
> with at least one image sensor and optional additional components,
> such as uController units or ISPs/DSPs.
> 
> After chanseset a59f853b3b4b ("media: i2c: Add driver for RDACM21 camera module"),
> there are now two drivers currently needing it: rdacm20 and rdacm21.
> 
> Building with allmodconfig is now causing those warnings:
> 
> 	WARNING: modpost: drivers/media/i2c/rdacm21-camera_module: 'max9271_set_serial_link' exported twice. Previous export was in drivers/media/i2c/rdacm20-camera_module.ko
> 	WARNING: modpost: drivers/media/i2c/rdacm21-camera_module: 'max9271_configure_i2c' exported twice. Previous export was in drivers/media/i2c/rdacm20-camera_module.ko
> 	WARNING: modpost: drivers/media/i2c/rdacm21-camera_module: 'max9271_set_high_threshold' exported twice. Previous export was in drivers/media/i2c/rdacm20-camera_module.ko
> 	WARNING: modpost: drivers/media/i2c/rdacm21-camera_module: 'max9271_configure_gmsl_link' exported twice. Previous export was in drivers/media/i2c/rdacm20-camera_module.ko
> 	WARNING: modpost: drivers/media/i2c/rdacm21-camera_module: 'max9271_set_gpios' exported twice. Previous export was in drivers/media/i2c/rdacm20-camera_module.ko
> 	WARNING: modpost: drivers/media/i2c/rdacm21-camera_module: 'max9271_clear_gpios' exported twice. Previous export was in drivers/media/i2c/rdacm20-camera_module.ko
> 	WARNING: modpost: drivers/media/i2c/rdacm21-camera_module: 'max9271_enable_gpios' exported twice. Previous export was in drivers/media/i2c/rdacm20-camera_module.ko
> 	WARNING: modpost: drivers/media/i2c/rdacm21-camera_module: 'max9271_disable_gpios' exported twice. Previous export was in drivers/media/i2c/rdacm20-camera_module.ko
> 	WARNING: modpost: drivers/media/i2c/rdacm21-camera_module: 'max9271_verify_id' exported twice. Previous export was in drivers/media/i2c/rdacm20-camera_module.ko
> 	WARNING: modpost: drivers/media/i2c/rdacm21-camera_module: 'max9271_set_address' exported twice. Previous export was in drivers/media/i2c/rdacm20-camera_module.ko
> 	WARNING: modpost: drivers/media/i2c/rdacm21-camera_module: 'max9271_set_deserializer_address' exported twice. Previous export was in drivers/media/i2c/rdacm20-camera_module.ko
> 	WARNING: modpost: drivers/media/i2c/rdacm21-camera_module: 'max9271_set_translation' exported twice. Previous export was in drivers/media/i2c/rdacm20-camera_module.ko
> 
> Address the issue by adding a Kconfig item for it, that it is
> seleced if either one of the modules that need max9271 is used.
> 
> Reported-by: Stephen Rothwell <[email-masked]>
> Fixes: a59f853b3b4b ("media: i2c: Add driver for RDACM21 camera module")
> Signed-off-by: Mauro Carvalho Chehab <[email-masked]>
> ---
>  drivers/media/i2c/Kconfig  | 10 ++++++++++
>  drivers/media/i2c/Makefile |  8 ++++----
>  2 files changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index 2d3dc0d82f9e..a6802195d583 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -712,6 +712,16 @@ config VIDEO_ST_MIPID02
>  	  module will be called st-mipid02.
>  endmenu
>  
> +#
> +# Camera ancillary chips
> +#
> +
> +# MAX9271 is usually embedded in camera modules
> +config VIDEO_MAX9271_SERIALIZER
> +	tristate
> +	default y
> +	depends on VIDEO_RDACM20 || VIDEO_RDACM21
> +

I'd instead make the RDACM drivers depend on this one instead. The RDACM20
driver directly depends on the symbols in the MAX9271 driver.

>  #
>  # V4L2 I2C drivers that are related with Camera support
>  #
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> index 6bd22d63e1a7..63bb16e51876 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -125,10 +125,10 @@ obj-$(CONFIG_VIDEO_IMX319)	+= imx319.o
>  obj-$(CONFIG_VIDEO_IMX334)	+= imx334.o
>  obj-$(CONFIG_VIDEO_IMX355)	+= imx355.o
>  obj-$(CONFIG_VIDEO_MAX9286)	+= max9286.o
> -rdacm20-camera_module-objs	:= rdacm20.o max9271.o
> -obj-$(CONFIG_VIDEO_RDACM20)	+= rdacm20-camera_module.o
> -rdacm21-camera_module-objs	:= rdacm21.o max9271.o
> -obj-$(CONFIG_VIDEO_RDACM21)	+= rdacm21-camera_module.o
> +obj-$(CONFIG_VIDEO_RDACM20)	+= rdacm20.o
> +obj-$(CONFIG_VIDEO_RDACM21)	+= rdacm21.o
>  obj-$(CONFIG_VIDEO_ST_MIPID02) += st-mipid02.o
>  
> +obj-$(CONFIG_VIDEO_MAX9271_SERIALIZER) += max9271.o
> +
>  obj-$(CONFIG_SDR_MAX2175) += max2175.o

-- 
Kind regards,

Sakari Ailus