Re: [RFC PATCH] clk: add extension API

From: Peter De Schrijver
Date: Thu May 31 2012 - 05:06:02 EST


>
> What if a module needs two clocks and you drive the reset on both of the
> clocks ? What would happen ?
>

Only 'leave clocks' have this reset method and a module can only have 1 of
them.

> > but then we would have the keep a list of IDs (1 per module) which the drivers
> > can use to call some tegra reset function which would in the end use registers
> > in the same memory area to cause a reset. (the registers controlling
> > modulereset are interleaved with those controlling the enable/disable of the
> > main moduleclock and bitpositions are identical)
>
> Well, under a generic device-level API, you could just call an internal
> clk_reset() function because you know which clocks feed into which
> devices anyway. It could look something like:
>
> on Tegra:
>
> device_reset(dev)
> -> dev_pm_domain->reset()
> -> tegra_periph_reset()
>

These methods are also needed internally by the powergating code.

> on OMAP:
>
> device_reset(dev)
> -> dev_pm_domain->reset()
> -> omap_hwmod_reset()
>
>
> btw:
>
> tegra_periph_reset(....)
> {
> tegra_periph_reset_assert(...);
> udelay(2);
> tegra_periph_reset_deassert(...);
> }

which uses the clockframework currently.

Cheers,

Peter.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/