Messages in this thread Patch in this message | | | Date | Mon, 9 Nov 2020 12:41:25 +0100 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH RESEND] driver core: export device_is_bound() to fix build failure |
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On Mon, Nov 09, 2020 at 10:57:05AM +0000, Aisheng Dong wrote: > Hi Greg, > > > From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > Sent: Monday, November 9, 2020 6:37 PM > > Subject: Re: [PATCH RESEND] driver core: export device_is_bound() to fix build > > failure > > > > On Mon, Nov 09, 2020 at 10:14:46AM +0000, Sudip Mukherjee wrote: > > > Hi Greg, > > > > > > On Sun, Nov 8, 2020 at 8:23 AM Greg Kroah-Hartman > > > <gregkh@linuxfoundation.org> wrote: > > > > > > > > On Sat, Nov 07, 2020 at 10:47:27PM +0000, Sudip Mukherjee wrote: > > > > > When CONFIG_MXC_CLK_SCU is configured as 'm' the build fails as it > > > > > is unable to find device_is_bound(). The error being: > > > > > ERROR: modpost: "device_is_bound" [drivers/clk/imx/clk-imx-scu.ko] > > > > > undefined! > > > > > > > > > > Export the symbol so that the module finds it. > > > > > > > > > > Fixes: 77d8f3068c63 ("clk: imx: scu: add two cells binding > > > > > support") > > > > > Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> > > > > > --- > > > > > > > > > > resending with the Fixes: tag. > > > > > > > > > > drivers/base/dd.c | 1 + > > > > > 1 file changed, 1 insertion(+) > > > > > > > > > > diff --git a/drivers/base/dd.c b/drivers/base/dd.c index > > > > > 148e81969e04..a796a57e5efb 100644 > > > > > --- a/drivers/base/dd.c > > > > > +++ b/drivers/base/dd.c > > > > > @@ -353,6 +353,7 @@ bool device_is_bound(struct device *dev) { > > > > > return dev->p && klist_node_attached(&dev->p->knode_driver); > > > > > } > > > > > +EXPORT_SYMBOL(device_is_bound); > > > > > > > > EXPORT_SYMBOL_GPL() please, like all the other exports in this file. > > > > > > > > Also, wait, no, don't call this, are you sure you are calling it in > > > > a race-free way? And what branch/tree is the above commit in? > > > > > > I have not checked fully but since it is being called from probe() I > > > assume the lock will be held at that time. > > > > probe() should never call this function as it makes no sense at all at that point in > > time. The driver should be fixed. > > Would you suggest if any other API we can use to allow the driver to know whether > another device has been probed?
There is none, sorry, as that just opens up way too many problems.
> For imx scu driver in question, it has a special requirement that it depends on scu power domain > driver. However, there're a huge number (200+) of power domains for each device clock, we can't define > them all in DT for a single clock controller node. > > That's why we wanted to use device_is_bound() before to check if scu power domain is ready or not to > support defer probe.
Use the device link functionality for this type of thing, that is what it was created for.
thanks,
greg k-h
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