Re: [PATCH] mfd: syscon: fix syscon probing from dt

[Philipp Zabel <p.zabel@pengutronix.de>]

Hi Heiko,

Am Dienstag, den 06.01.2015, 20:05 +0100 schrieb Heiko Stübner:
> Hi Philipp,
> 
> Am Dienstag, 6. Januar 2015, 16:30:36 schrieb Philipp Zabel:
> > Patch bdb0066df96e ("mfd: syscon: Decouple syscon interface from platform
> > devices") breaks probing pure syscon devices from device tree, such as
> > anatop and iomuxc-gpr on i.MX. This patch adds back the dt id table to
> > match against "syscon" compatible device tree nodes.
> 
> could you elaborate a bit on the problem you're seeing without your patch?
>
> With bdb0066df96e the syscon should be registered by the first call to one of 
> the syscon_regmap_lookup_by_* functions. On my rockchip boards this works 
> without any hickups:

Oh, I didn't understand that is the way it's supposed to work now.

I noticed that after booting v3.19-rc on a nitrogen6x, the
/sys/kernel/debug/regmap/{20c8000.anatop,20e0000.iomuxc-gpr}
directories were missing. The syscon regmap is indeed registered,
but since regmap_init_mmio is called with dev = NULL, regmap_attach_dev,
and thus regmap_debugfs_init, is never called from regmap_init.

Also I want to add child devices to the syscon device since a while ago:
https://lkml.org/lkml/2014/12/15/133
This doesn't work anymore if there is no syscon device.

regards
Philipp