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Date:   Mon, 8 Feb 2021 13:37:48 +0200
From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Hans Verkuil <hverkuil@xs4all.nl>
Cc:     Jacopo Mondi <jacopo+renesas@jmondi.org>,
        kieran.bingham+renesas@ideasonboard.com,
        niklas.soderlund+renesas@ragnatech.se, geert@linux-m68k.org,
        linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
        linux-kernel@vger.kernel.org, Hyun Kwon <hyunk@xilinx.com>,
        Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
        sergei.shtylyov@gmail.com
Subject: Re: [PATCH v8 1/5] media: i2c: Add driver for RDACM21 camera module
Message-ID: <YCEijDCVxBkc0Cq7@pendragon.ideasonboard.com>
References: <20210114170429.139762-1-jacopo+renesas@jmondi.org>
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Hi Hans,

On Mon, Feb 08, 2021 at 12:34:55PM +0100, Hans Verkuil wrote:
> On 08/02/2021 12:28, Laurent Pinchart wrote:
> > On Mon, Feb 08, 2021 at 12:21:01PM +0100, Hans Verkuil wrote:
> >> On 14/01/2021 18:04, Jacopo Mondi wrote:
> >>> The RDACM21 is a GMSL camera supporting 1280x1080 resolution images
> >>> developed by IMI based on an Omnivision OV10640 sensor, an Omnivision
> >>> OV490 ISP and a Maxim MAX9271 GMSL serializer.
> >>>
> >>> The driver uses the max9271 library module, to maximize code reuse with
> >>> other camera module drivers using the same serializer, such as rdacm20.
> >>>
> >>> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> >>> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> >>> ---
> >>>  MAINTAINERS                 |  12 +
> >>>  drivers/media/i2c/Kconfig   |  13 +
> >>>  drivers/media/i2c/Makefile  |   2 +
> >>>  drivers/media/i2c/rdacm21.c | 623 ++++++++++++++++++++++++++++++++++++
> >>>  4 files changed, 650 insertions(+)
> >>>  create mode 100644 drivers/media/i2c/rdacm21.c
> >>>
> >>> diff --git a/MAINTAINERS b/MAINTAINERS
> >>> index 14adf87d90c7..1822d73ed615 100644
> >>> --- a/MAINTAINERS
> >>> +++ b/MAINTAINERS
> >>> @@ -14967,6 +14967,18 @@ F:	drivers/media/i2c/max9271.c
> >>>  F:	drivers/media/i2c/max9271.h
> >>>  F:	drivers/media/i2c/rdacm20.c
> >>>
> >>> +RDACM21 Camera Sensor
> >>> +M:	Jacopo Mondi <jacopo+renesas@jmondi.org>
> >>> +M:	Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> >>> +M:	Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> >>> +M:	Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> >>> +L:	linux-media@vger.kernel.org
> >>> +S:	Maintained
> >>> +F:	Documentation/devicetree/bindings/media/i2c/rdacm2x-gmsl.yaml
> >>> +F:	drivers/media/i2c/max9271.c
> >>> +F:	drivers/media/i2c/max9271.h
> >>> +F:	drivers/media/i2c/rdacm21.c
> >>> +
> >>>  RDC R-321X SoC
> >>>  M:	Florian Fainelli <florian@openwrt.org>
> >>>  S:	Maintained
> >>> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> >>> index 2b9d81e4794a..d500edb8638b 100644
> >>> --- a/drivers/media/i2c/Kconfig
> >>> +++ b/drivers/media/i2c/Kconfig
> >>> @@ -1212,6 +1212,19 @@ config VIDEO_RDACM20
> >>>  	  This camera should be used in conjunction with a GMSL
> >>>  	  deserialiser such as the MAX9286.
> >>>
> >>> +config VIDEO_RDACM21
> >>> +	tristate "IMI RDACM21 camera support"
> >>> +	depends on I2C
> >>> +	select V4L2_FWNODE
> >>> +	select VIDEO_V4L2_SUBDEV_API
> >>> +	select MEDIA_CONTROLLER
> >>> +	help
> >>> +	  This driver supports the IMI RDACM21 GMSL camera, used in
> >>> +	  ADAS systems.
> >>> +
> >>> +	  This camera should be used in conjunction with a GMSL
> >>> +	  deserialiser such as the MAX9286.
> >>> +
> >>>  config VIDEO_RJ54N1
> >>>  	tristate "Sharp RJ54N1CB0C sensor support"
> >>>  	depends on I2C && VIDEO_V4L2
> >>> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> >>> index a3149dce21bb..85b1edc62508 100644
> >>> --- a/drivers/media/i2c/Makefile
> >>> +++ b/drivers/media/i2c/Makefile
> >>> @@ -124,6 +124,8 @@ 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_ST_MIPID02) += st-mipid02.o
> >>
> >> This isn't right. The max9271 code exports various functions, but since it is
> >> included with *two* modules (rdacm20/1-camera_module.ko) it is exported twice.
> >>
> >> Since max9271 is not a self-contained driver it should not export symbols.
> > 
> > Shouldn't we instead make max9271 a stand-alone module ?
> 
> If that makes sense, then that's the alternative option. I don't know if it
> can be used with anything else but rdacm20/21.
> 
> Either way, this needs to be fixed.

I've just noticed that Mauro has submitted a patch for this.

> >> Can you provide a patch fixing that?

-- 
Regards,

Laurent Pinchart