On Mon, Feb 08, 2021 at 01:32:38PM +0200, Laurent Pinchart wrote: > Hi Mauro, > > On Mon, Feb 08, 2021 at 11:07:23AM +0100, Mauro Carvalho Chehab wrote: > > Em Mon, 8 Feb 2021 11:24:25 +0200 Sakari Ailus escreveu: > > > 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 escreveu: > > > > > On Mon, Feb 08, 2021 at 09:36:16AM +0100, Jacopo Mondi wrote: > > > > > > 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@xxxxxxxxxxxxxxxx> > > > > > > > > Fixes: a59f853b3b4b ("media: i2c: Add driver for RDACM21 camera module") > > > > > > > > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> > > > > > > > > --- > > > > > > > > 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 > > > > No. I fail to see where this would work, as MAX9271 is a mandatory > > dependency of those drivers. See: > > > > static int rdacm20_s_stream(struct v4l2_subdev *sd, int enable) > > { > > struct rdacm20_device *dev = sd_to_rdacm20(sd); > > > > return max9271_set_serial_link(dev->serializer, enable); > > } > > > > > > Without compiling max9271, the device won't stream ;-) > > > > - > > > > Yet, assuming that this could be an optional feature, if you use this: > > > > config VIDEO_MAX9271_SERIALIZER > > tristate > > default y > > depends on VIDEO_RDACM20 || VIDEO_RDACM21 > > > > You should *not* never do: > > > > depends on VIDEO_MAX9271_SERIALIZER || !VIDEO_MAX9271_SERIALIZER > > > > for VIDEO_RDACM20 or VIDEO_RDACM21, as it would cause a dependency > > loop. > > > > - > > > > If you do, instead: > > > > if VIDEO_V4L2 && I2C > > config VIDEO_MAX9271_SERIALIZER > > tristate > > > > config VIDEO_RDACM20 > > select VIDEO_MAX9271_SERIALIZER > > ... > > > > config VIDEO_RDACM21 > > select VIDEO_MAX9271_SERIALIZER > > ... > > endif > > > > Then you also won't need: > > depends on VIDEO_MAX9271_SERIALIZER || !VIDEO_MAX9271_SERIALIZER > > > > As select should do the right thing in this case, ensuring that MAX9271 > > will be builtin either if RDACM20 or RDACM21 is builtin. > > I also vote for usage of "select". > I would prefer that too, I was concerned about possible un-met dependencies, as Sakari pointed out, but the current situation is no better, as the only Kconfig symbols where those can be listed are the camera modules one. > > - > > > > This should also work: > > > > config VIDEO_MAX9271_SERIALIZER > > tristate > > ... > > > > if VIDEO_MAX9271_SERIALIZER > > > > config VIDEO_RDACM20 > > tristate > > ... > > > > config VIDEO_RDACM21 > > tristate > > ... > > > > endif > > > > without needing a "depend on FOO || !FOO" logic, but, as I said before, this > > case will force the user that want to build the RDACM20/RDACM21 drivers to > > be aware that a MAX9271 driver is required. > > > > - > > > > You would only need a "depend on FOO || !FOO" if the driver FOO is > > optional and if you try do something like: > > > > config FOO > > tristate > > ... > > > > config VIDEO_RDACM20 > > tristate > > depends on FOO > > ... > > > > config VIDEO_RDACM21 > > tristate > > depends on FOO > > ... > > > > as, on such case, it would allow the vars to be: > > > > FOO="m" > > VIDEO_RDACM20="y" > > VIDEO_RDACM21="m" > > > > which would cause build errors. > > -- > Regards, > > Laurent Pinchart