Hello Pankaj, On Fri, Sep 19, 2014 at 3:06 PM, Pankaj Dubey <pankaj.dubey@xxxxxxxxxxx> wrote: > Currently a syscon entity can be only registered directly through a > platform device that binds to a dedicated syscon driver. However in > certain use cases it is desirable to make a device used with another > driver a syscon interface provider. > > For example, certain SoCs (e.g. Exynos) contain system controller > blocks which perform various functions such as power domain control, > CPU power management, low power mode control, but in addition contain > certain IP integration glue, such as various signal masks, > coprocessor power control, etc. In such case, there is a need to have > a dedicated driver for such system controller but also share registers > with other drivers. The latter is where the syscon interface is helpful. > > In case of DT based platforms, this patch decouples syscon object from > syscon platform driver, and allows to create syscon objects first time > when it is required by calling of syscon_regmap_lookup_by APIs and keep > a list of such syscon objects along with syscon provider device_nodes > and regmap handles. > > For non-DT based platforms, this patch keeps syscon platform driver > structure where is can be probed and such non-DT based drivers can use > syscon_regmap_lookup_by_pdev API and get access to regmap handles. > Once all users of "syscon_regmap_lookup_by_pdev" migrated to DT based, > we can completly remove platform driver of syscon, and keep only helper > functions to get regmap handles. > > Suggested-by: Arnd Bergmann <arnd@xxxxxxxx> > Suggested-by: Tomasz Figa <tomasz.figa@xxxxxxxxx> > Tested-by: Vivek Gautam <gautam.vivek@xxxxxxxxxxx> > Signed-off-by: Pankaj Dubey <pankaj.dubey@xxxxxxxxxxx> > --- > Changes since v3: > - Addressed Arnd's comment for v2. > - Updated of_syscon_register for adding dev pointer in regmap_init_mmio. > - For early users created dummy platform device. > > Changes since v2: > - Added back platform device support from syscon, with one change that > syscon will not be probed for DT based platform. > - Added back syscon_regmap_lookup_by_pdevname API so that non-DT base > users of syscon will not be broken. > - Removed unwanted change in syscon.h. > - Modified Signed-off-by list, added Suggested-by of Tomasz Figa and > Arnd Bergmann. > - Added Tested-by of Vivek Gautam for testing on Exynos platform. > > Changes since v1: > - Removed of_syscon_unregister function. > - Modified of_syscon_register function and it will be used by syscon.c > to create syscon objects whenever required. > - Removed platform device support from syscon. > - Removed syscon_regmap_lookup_by_pdevname API support. > - As there are significant changes w.r.t patchset v1, I am taking over > author for this patchset from Tomasz Figa. > > [1]: https://lkml.org/lkml/2014/9/2/299 > drivers/mfd/syscon.c | 102 ++++++++++++++++++++++++++++++++++++++------------ > 1 file changed, 79 insertions(+), 23 deletions(-) > I tested this patch on an Exynos5420 Peach Pit Chromebook and I see that of_syscon_register() is called for the PMU system controller with compatible string "samsung,exynos5420-pmu", "syscon" which does not have a dedicated platform driver, so: Tested-by: Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx> Best regards, Javier -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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