[PATCH v4 2/3] ARM: omap: hwmod: get rid of all omap_clk_get_by_name usage

Tomi Valkeinen tomi.valkeinen at ti.com
Fri Aug 31 03:15:09 EDT 2012

On Fri, 2012-08-31 at 11:53 +0530, Archit Taneja wrote:

> The only little problem was that during bootup, when hwmods are setup, 
> only the 'parent' hwmod was able to get reset properly, all the other 
> 'child' hwmods don't have modulemode bits tied to them, and hence 
> weren't able to reset. So we got some error prints.
> Once DSS driver kicks in, the driver ensures the parent is enabled for 
> any child to be enabled, so we don't face the issue again.
> So, if DSS driver is not built in, and if the bootloader left DSS in a 
> bad state, the DSS clocks might remain messed up all the time since 
> hwmod fwk wasn't able to reset them.
> I think this is why we didn't proceed with remove "dss_fck" as a slave 
> clock. If this issue is minor, we could go ahead and remove it.

I wonder if we could handle this with a custom reset function. We
already have a reset func for dss core. If I remember right, the main
point for that is the fact that omap4 doesn't have a softreset for dss
core, so we manually write the default values to registers.

For omap2/3 this would be simple: skip the resets for all other dss
submodules, and dss core's reset would enable all the clocks and set the
softreset bit. This would reset all the submodules also.

Omap4 is more tricky. I guess we'd need to enable all the clocks, clear
manually dss core's registers, and then set softreset bits in all the
submodules. So in this case dss core would need to have information
about the other submodules.


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