from WHERE platform driver's probe is called?

from WHERE platform driver's probe is called?

[Sunil Shahu]

Hello,
I am looking into platform driver and devices and understood HOW platform driver's probe is called from kernel doc and following forum.http://comments.gmane.org/gmane.linux.kernel.kernelnewbies/37050

For further information I went through code in platform_driver_register() and got lost. I looked web but could not find substantiation information.

I am still not able to locate from WHERE this probe function is called and WHO calls it?Can someone please point to source code or some other document related to this?
Thanks,Sunil.
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from WHERE platform driver's probe is called?

[Sudip Mukherjee]

On Fri, Nov 21, 2014 at 6:46 PM, Sunil Shahu <sunil.rockon@yahoo.in> wrote:
> Hello,
>
> I am looking into platform driver and devices and understood HOW platform
> driver's probe is called from kernel doc and following forum.
> http://comments.gmane.org/gmane.linux.kernel.kernelnewbies/37050
>
> For further information I went through code in platform_driver_register()
> and got lost. I looked web but could not find substantiation information.
>
> I am still not able to locate from WHERE this probe function is called and
> WHO calls it?
> Can someone please point to source code or some other document related to
> this?

i am also not exactly sure, but i think the individual drivers probe
function is called from platform_drv_probe() of platform.c

thanks
sudip

>
> Thanks,
> Sunil.
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>

from WHERE platform driver's probe is called?

[Daniel Baluta]

On Fri, Nov 21, 2014 at 3:16 PM, Sunil Shahu <sunil.rockon@yahoo.in> wrote:
> Hello,
>
> I am looking into platform driver and devices and understood HOW platform
> driver's probe is called from kernel doc and following forum.
> http://comments.gmane.org/gmane.linux.kernel.kernelnewbies/37050
>
> For further information I went through code in platform_driver_register()
> and got lost. I looked web but could not find substantiation information.
>
> I am still not able to locate from WHERE this probe function is called and
> WHO calls it?
> Can someone please point to source code or some other document related to
> this?

Does dump_stack() help?

Daniel.

from WHERE platform driver's probe is called?

[Varka Bhadram]

This link can answer your ques:
http://stackoverflow.com/questions/22722520/who-calls-probe-function-in-driver-code

Thanks.

On Fri, Nov 21, 2014 at 6:46 PM, Sunil Shahu <sunil.rockon@yahoo.in> wrote:

> Hello,
>
> I am looking into platform driver and devices and understood HOW platform
> driver's probe is called from kernel doc and following forum.
> http://comments.gmane.org/gmane.linux.kernel.kernelnewbies/37050
>
> For further information I went through code in platform_driver_register()
> and got lost. I looked web but could not find substantiation information.
>
> I am still not able to locate from WHERE this probe function is called and
> WHO calls it?
> Can someone please point to source code or some other document related to
> this?
>
> Thanks,
> Sunil.
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
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from WHERE platform driver's probe is called?

[Greg KH]

On Fri, Nov 21, 2014 at 01:16:21PM +0000, Sunil Shahu wrote:
> Hello,
> 
> I am looking into platform driver and devices and understood HOW platform
> driver's probe is called from kernel doc and following forum.
> http://comments.gmane.org/gmane.linux.kernel.kernelnewbies/37050
> 
> For further information I went through code in platform_driver_register() and
> got lost. I looked web but could not find substantiation information.
> 
> I am still not able to locate from WHERE this probe function is called and WHO
> calls it?

It all starts by your own driver, you end up calling it yourself,
through the driver core callbacks.

> Can someone please point to source code or some other document related to this?

Can you please provide a specific example of what you are wanting to see
the callback chain for?  What driver are you asking about?  Have you
read the platform code in drivers/base/ ?

thanks,

greg k-h

from WHERE platform driver's probe is called?

[subin gangadharan]

Hi Sunil,

>>I am still not able to locate from WHERE this probe function is called and WHO calls it?

I can try to give you a snapshot of the function call trace. But if
you really want to get in depth detail, as Greg said look at the code
driver/base.

driver_register
->bus_add_driver->driver_attach->__driver_attach->driver_probe_device->really_probe->drv->probe

Basically when you register your platform driver, the platform
bus(platform_bus_type) will scan for the matching device. If you look
at the platform_bus_type structure you can find the match function
which does the matching of driver and device. Once it's found the
right device, it will attach the driver to the device.Look at the
function driver_attach. And if you look at the
platform_driver_register function, you can see that
"platform_drv_probe" function is assigned to driver.probe function.
And this probe function will finally call your registered platform
driver probe function.

Hope this helps.

from WHERE platform driver's probe is called?

[Aruna Hewapathirane]

>>I am looking into platform driver and devices and understood HOW platform
driver's probe is called from kernel doc and >>following forum.
>>>>http://comments.gmane.org/gmane.linux.kernel.kernelnewbies/37050
<http://comments.gmane.org/gmane.linux.kernel.kernelnewbies/37050>

I would ask *what* is platform device driver ? and what is the *difference*
between a platform device driver and a normal device driver ?

The answer here explains it extremely well :
http://stackoverflow.com/questions/15610570/what-is-the-difference-between-platform-driver-and-normal-device-driver

>>For further information I went through code in platform_driver_register()
and got lost. I looked web but could not find
>>substantiation information.

This will help:
http://code.woboq.org/linux/linux/drivers/base/platform.c.html#platform_driver_probe

>>I am still not able to locate from WHERE this probe function is called
and WHO calls it?
>>Can someone please point to source code or some other document related to
this?

Review this article carefully:
https://coherentmusings.wordpress.com/2013/12/13/how-to-write-a-platform-devicedriver-adc-driver-using-wm97xx-codec/

Have fun :)

Aruna




On Fri, Nov 21, 2014 at 8:16 AM, Sunil Shahu <sunil.rockon@yahoo.in> wrote:

> Hello,
>
> I am looking into platform driver and devices and understood HOW platform
> driver's probe is called from kernel doc and following forum.
> http://comments.gmane.org/gmane.linux.kernel.kernelnewbies/37050
>
> For further information I went through code in platform_driver_register()
> and got lost. I looked web but could not find substantiation information.
>
> I am still not able to locate from WHERE this probe function is called and
> WHO calls it?
> Can someone please point to source code or some other document related to
> this?
>
> Thanks,
> Sunil.
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
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from WHERE platform driver's probe is called?

[subin gangadharan]

On Thu, Nov 27, 2014 at 1:00 AM, Sunil Shahu <sunil.rockon@yahoo.in> wrote:
> Hi Daniel,
> Thanks, dump_stack() is what I needed.
>
> Hi Subin,
> Thanks for the snapshot.
>
> Also, I am attaching a graph for what I understood after following
> dump_stack().
>
> Please let me know if there is any issue with the flow.
>
> Thanks,
> Sunil.
>
>
>
> On Saturday, 22 November 2014 9:04 AM, subin gangadharan
> <subingangadharan@gmail.com> wrote:
>
>
> Hi Sunil,
>
>>>I am still not able to locate from WHERE this probe function is called and
>>> WHO calls it?
>
> I can try to give you a snapshot of the function call trace. But if
> you really want to get in depth detail, as Greg said look at the code
> driver/base.
>
> driver_register
> ->bus_add_driver->driver_attach->__driver_attach->driver_probe_device->really_probe->drv->probe
>
> Basically when you register your platform driver, the platform
> bus(platform_bus_type) will scan for the matching device. If you look
> at the platform_bus_type structure you can find the match function
> which does the matching of driver and device. Once it's found the
> right device, it will attach the driver to the device.Look at the
> function driver_attach. And if you look at the
> platform_driver_register function, you can see that
> "platform_drv_probe" function is assigned to driver.probe function.
> And this probe function will finally call your registered platform
> driver probe function.
>
> Hope this helps.
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>


Hi Sunil,

Thanks for the nice detailed snap shot.

Subin