Re: [PATCH v8 05/26] clocksource: Add driver for the Ingenic JZ47xx OST

[Paul Cercueil]

Le jeu. 24 janv. 2019 à 19:46, Stephen Boyd <sboyd@xxxxxxxxxx> a 
écrit :
> Quoting Paul Cercueil (2019-01-24 12:46:28)
> >  Le jeu. 24 janv. 2019 à 16:28, Stephen Boyd <sboyd@xxxxxxxxxx> a
> >  écrit :
> >  > Quoting Guenter Roeck (2019-01-23 10:01:55)
> >  >>  On Wed, Jan 23, 2019 at 02:25:53PM -0300, Paul Cercueil wrote:
> >  >>  > Hi,
> >  >>  >
> >  >>  > Le mer. 23 janv. 2019 Ã  11:31, Guenter Roeck
> >  >> <linux@xxxxxxxxxxxx> a écrit :
> >  >>  > >On 1/23/19 4:58 AM, Mathieu Malaterre wrote:
> >  >>  > >>On Wed, Dec 12, 2018 at 11:09 PM Paul Cercueil
> >  >> <paul@xxxxxxxxxxxxxxx>
> >  >>  > >>wrote:
> >  >>  > >>>
> >  >>  > >>>From: Maarten ter Huurne <maarten@xxxxxxxxxxxxxx>
> >  >>  > >>>
> >  >>  > >>>OST is the OS Timer, a 64-bit timer/counter with buffered
> >  >> reading.
> >  >>  > >>>
> >  >>  > >>>SoCs before the JZ4770 had (if any) a 32-bit OST; the 
> > JZ4770
> >  >> and
> >  >>  > >>>JZ4780 have a 64-bit OST.
> >  >>  > >>>
> >  >>  > >>>This driver will register both a clocksource and a 
> > sched_clock
> >  >> to the
> >  >>  > >>>system.
> >  >>  > >>>
> >  >>  > >>>Signed-off-by: Maarten ter Huurne <maarten@xxxxxxxxxxxxxx>
> >  >>  > >>>Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> >  >>  > >>>---
> >  >>  > >>>
> >  >>  > >>>Notes:
> >  >>  > >>>      v5: New patch
> >  >>  > >>>
> >  >>  > >>>      v6: - Get rid of SoC IDs; pass pointer to
> >  >> ingenic_ost_soc_info
> >  >>  > >>>as
> >  >>  > >>>            devicetree match data instead.
> >  >>  > >>>          - Use device_get_match_data() instead of the of_*
> >  >> variant
> >  >>  > >>>          - Handle error of dev_get_regmap() properly
> >  >>  > >>>
> >  >>  > >>>      v7: Fix section mismatch by using
> >  >>  > >>>builtin_platform_driver_probe()
> >  >>  > >>>
> >  >>  > >>>      v8: builtin_platform_driver_probe() does not work
> >  >> anymore in
> >  >>  > >>>          4.20-rc6? The probe function won't be called. 
> > Work
> >  >> around
> >  >>  > >>>this
> >  >>  > >>>          for now by using late_initcall.
> >  >>  > >>>
> >  >>  > >
> >  >>  > >Did anyone notice this ? Either something is wrong with the
> >  >> driver, or
> >  >>  > >with the kernel core. Hacking around it seems like the worst
> >  >> possible
> >  >>  > >"solution".
> >  >>  >
> >  >>  > I can confirm it still happens on 5.0-rc3.
> >  >>  >
> >  >>  > Just to explain what I'm doing:
> >  >>  >
> >  >>  > My ingenic-timer driver probes with 
> > builtin_platform_driver_probe
> >  >> (this
> >  >>  > works),
> >  >>  > and then calls of_platform_populate to probe its children. 
> > This
> >  >> driver,
> >  >>  > ingenic-ost, is one of them, and will fail to probe with
> >  >>  > builtin_platform_driver_probe.
> >  >>  >
> >  >>
> >  >>  The big question is _why_ it fails to probe.
> >  >>
> >  >
> >  > Are you sharing the device tree node between a 'normal' platform
> >  > device
> >  > driver and something more low level DT that marks the device's 
> > backing
> >  > DT node as OF_POPULATED early on? That's my only guess why it's 
> > not
> >  > working.
> >
> >  I do, but I clear the OF_POPULATED flag so that it is then probed 
> > as a
> >  normal platform device, and it's not on this driver's node but its
> >  parent.
>
> Where do you clear the OF_POPULATED flag?

In the ingenic-timer driver introduced in patch [04/26], inside the 
probe function.