[PATCH v5 02/14] ARM: OMAP2+: gpmc: Adapt to HWMOD

Tony Lindgren tony at atomide.com
Wed Jun 13 08:02:09 EDT 2012

* Mohammed, Afzal <afzal at ti.com> [120612 22:24]:
> Hi Jon,
> On Tue, Jun 12, 2012 at 23:10:01, Hunter, Jon wrote:
> > On 06/12/2012 01:53 AM, Mohammed, Afzal wrote:
> > > On Tue, Jun 12, 2012 at 01:26:29, Hunter, Jon wrote:
> > >> My preference would be to store gpmc_l3_clk in the pdata and pass to
> > >> probe via the pdata. The aim would be to remove the global gpmc_l3_clk
> > >> altogether.
> > > 
> > > For timing calculation by platform outside of driver, we need clk rate
> > 
> > Right but potentially, this could be done by the driver.
> I do not think it is practically possible. Please see timing calculations
> in arch/arm/mach-omap2/gpmc-*, the way it is done for different
> peripherals are different, and we cannot expect gpmc driver to do those as
> that would require gpmc driver being aware of type of peripheral connected.
> And all those gpmc-* timing calculation needs to be done before driver
> is ready, they rely on functions like gpmc_get_fclk_rate(), which in turn
> requires the clk rate to be available before driver is probed.

Yeah I also think the GPMC code should handle the L3 timings, and dynamically
calculate them for DVFS when L3 frequency changes. Does the GPMC have enough
information now to do that?

Additionally GPMC should add constraints to DVFS if not enough data is know
to scale L3.


More information about the linux-arm-kernel mailing list