* Balaji T K <balajitk@xxxxxx> [131011 08:51]: > On Friday 11 October 2013 09:06 PM, Tony Lindgren wrote: > >>>What the pin control driver should do is control the pins. Whether the registers > >>>are spread out in the entire IO-memory does not matter. We did have one system > >>>which placed the IO-muxing together with each peripheral (!) and I did > >>>still want > >>>that to be handled by a single pinctrl driver picking out windows to all these > >>>IO-ranges. > >>> > >>>Things like the PRM which has (my guess) a gazillion registers related to its > >>>deep-core SoC stuff should be handled by things like > >>>drivers/mfd/syscon.c, which means it is dead simple for some other driver > >>>using "just this one register" in that range to get a handle at it and poke it > >>>using syscon_node_to_regmap() (just derference an ampersand ref) > >>>syscon_regmap_lookup_by_compatible() (use a compatible string) > >>>all returning a regmap * that you can use to poke these registers. > >> > >>The register handling is fine. But how do we deal with resource handling? > >>e.g. the block that has the deep-core registers might need to be clocked or powered > >>before the registers can be accessed. > > > >Right, that's the key issue here. The register access would have to be conditional > >based on the hardware modules PM state. Otherwise we'll have hard to trace hangs > >and oopses. > > > Hi Tony, > > How are the clocks/power state currently handled in case of omap4_pmx_core, > omap4_pmx_wkup register access via pinctrl-single ? It's currently always on during runtime and managed in for the whole SCM by mach-omap2/control.c. Then there's a separate SCM register that triggers the save and restore of the padconf registers in hardware for off-idle along with other SCM related things, see the *_control_save/restore_context() functions. Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
