From: Sakari Ailus <sakari.ailus@linux.intel.com>
To: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: Jacopo Mondi <jacopo@jmondi.org>,
Linux Media Mailing List <linux-media@vger.kernel.org>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Jacopo Mondi <jacopo+renesas@jmondi.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
linux-next@vger.kernel.org
Subject: Re: [PATCH] media: i2c: fix max9271 build dependencies
Date: Mon, 8 Feb 2021 11:24:25 +0200 [thread overview]
Message-ID: <20210208092424.GP32460@paasikivi.fi.intel.com> (raw)
In-Reply-To: <20210208100822.76ca0c2e@coco.lan>
On Mon, Feb 08, 2021 at 10:08:22AM +0100, Mauro Carvalho Chehab wrote:
> Em Mon, 8 Feb 2021 10:41:47 +0200
> Sakari Ailus <sakari.ailus@linux.intel.com> escreveu:
>
> > Hi Jacopo,
> >
> > On Mon, Feb 08, 2021 at 09:36:16AM +0100, Jacopo Mondi wrote:
> > > Hello everyone,
> > >
> > > On Mon, Feb 08, 2021 at 09:27:01AM +0200, Sakari Ailus wrote:
> > > > Hi Mauro,
> > > >
> > > > Thanks for the patch.
> > >
> > > Sorry, that's cleary an oversight from my side.
> > > Thanks for tackling it.
> > >
> > > >
> > > > 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 <sfr@canb.auug.org.au>
> > > > > Fixes: a59f853b3b4b ("media: i2c: Add driver for RDACM21 camera module")
> > > > > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> > > > > ---
> > > > > 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.
>
> While such solution is technically OK, it will make harder for the ones
> wanting to use the RDACM drivers, because those two drivers will be
> ridden at the config menu, until MAX9271 got selected.
>
> With the above solution, this driver will be auto-selected if either
> RDACM20 or RDACM21 is needed.
>
> Btw, this is exactly the same strategy we use for tuner I2C modules:
> the user doesn't need to know that his board uses tuner "foo" or "bar".
> All it needs is to know that it will require, for instance, the em28xx
> driver.
>
> > > >
> > >
> > > OTOH I it makes sense to have MAX9271 depend on the camera modules, as
> > > selecting the serializer alone is not that useful.
> > >
> > > Could the two camera modules symbols instead select the MAX9271 one ?
> >
> > MAX9271 could be used elsewhere than in RDACM* devices.
>
> Sure, but then it is just a matter of adding the other driver there:
>
> depends on VIDEO_RDACM20 || VIDEO_RDACM21 || VIDEO_FOO
>
> To be frank, I doubt that we'll end having dozens of boards with this.
> If we end having lots of drivers, we can work on a different
> solution.
Also note that there will be combinations of something compiled as a module
and another driver linked directly to the kernel.
So each of the RDACM drivers would likely also need:
depends on VIDEO_MAX9271_SERIALIZER || !VIDEO_MAX9271_SERIALIZER
>
> >
> > Also, as select does not handle dependencies, all drivers that need MAX9271
> > would have to include the dependencies of MAX9271.
>
> Yes. "Depends on" handles any dependencies that are required for building
> MAX9271. In this specific case, the dependencies are the same, so select
> could equally work.
Sure.
--
Kind regards,
Sakari Ailus
next prev parent reply other threads:[~2021-02-08 9:29 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-08 0:32 linux-next: build warning after merge of the v4l-dvb tree Stephen Rothwell
2021-02-08 6:30 ` Mauro Carvalho Chehab
2021-02-08 8:33 ` Geert Uytterhoeven
2021-02-08 8:49 ` Mauro Carvalho Chehab
2021-02-08 8:52 ` Geert Uytterhoeven
2021-02-08 9:14 ` Mauro Carvalho Chehab
2021-02-08 6:53 ` [PATCH] media: i2c: fix max9271 build dependencies Mauro Carvalho Chehab
2021-02-08 7:27 ` Sakari Ailus
2021-02-08 8:36 ` Jacopo Mondi
2021-02-08 8:41 ` Sakari Ailus
2021-02-08 8:59 ` Jacopo Mondi
2021-02-08 9:03 ` Sakari Ailus
2021-02-08 9:08 ` Mauro Carvalho Chehab
2021-02-08 9:24 ` Sakari Ailus [this message]
2021-02-08 10:07 ` Mauro Carvalho Chehab
2021-02-08 11:32 ` Laurent Pinchart
2021-02-08 11:41 ` Jacopo Mondi
2021-02-08 13:11 ` Mauro Carvalho Chehab
2021-02-08 13:31 ` Mauro Carvalho Chehab
2021-02-08 13:40 ` Laurent Pinchart
2021-02-08 14:23 ` Mauro Carvalho Chehab
2021-02-08 14:31 ` Laurent Pinchart
2021-02-08 15:01 ` Mauro Carvalho Chehab
2021-02-08 13:55 ` Jacopo Mondi
2021-02-08 14:14 ` Mauro Carvalho Chehab
2021-02-08 14:49 ` Jacopo Mondi
2021-02-08 15:42 ` Mauro Carvalho Chehab
2021-02-08 16:26 ` Laurent Pinchart
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