On Mon, Oct 15, 2012 at 10:11:50AM -0600, Stephen Warren wrote: > On 10/13/2012 02:42 PM, Thierry Reding wrote: > > On Fri, Oct 12, 2012 at 03:17:04PM -0600, Stephen Warren wrote: > >> On 10/11/2012 11:09 PM, Thierry Reding wrote: > >>> On Thu, Oct 11, 2012 at 05:36:35PM -0600, Stephen Warren > >>> wrote: > > [...] > >>>> The code in clock.c uses lots of clk_get_sys() calls with > >>>> hard-coded clock names. We really should be using the common > >>>> clock DT bindings for this instead of hard-coding names. This > >>>> is especially true since the names differ on different SoCs, > >>>> so there's a ton of > >>>> of_device_is_compatible(output->dev->of_node, > >>>> "nvidia,tegra30-hdmi") in this code. > >>> > >>> I don't quite see how that is supposed to work. Wouldn't that > >>> mean that we needed to setup various entries in the clock > >>> tables to be able to look the clocks up by generic names? Like > >>> pll_d would need to be the "parent" clock of "tegra-hdmi" or > >>> similar. In that case we could call clk_get(hdmi->dev, > >>> "parent") instead. Is that what you had in mind? > >> > >> There are two ways this could work: > >> > >> 1) > >> > >> All clocks needed could be represented in the node of that device > >> (or perhaps in the DC node?) For example, perhaps hdmi might > >> contain: > >> > >> clocks = <&car TEGRA_CLK_PLL_D> <&car TEGRA_CLK_PLL_D_OUT_0> > >> <&car TEGRA_CLK_HDMI> ...; clock-names = "pll_d", "pll_d_out_0", > >> "hdmi", ...; > >> > >> That should work (I think) with pretty much no modification to > >> the current code, other than calling clk_get(dev, "hdmi") rather > >> than clk_get_sys(NULL, "hdmi"). > > > > I thought DT support didn't work for Tegra yet. If that works we > > should probably get rid of the DRM related entries in the clock > > tables and put the information in the DT regardless of which of the > > alternatives is implemented. > > Certainly, the Tegra clock driver itself doesn't support DT, i.e. > isn't a DT clock provider. So, this won't work completely right now. I > believe Prashant had patches to implement this though. Prashant, > what's the status on those? > > It looks like the core common clock DT support did make it into 3.7, > so any dependencies are probably contained within the Tegra tree. > > Still, perhaps this is something we can clean up later; we'd probably > benefit more from having some form of tegra-drm in place earlier > rather than having it later with perfect clock usage, although DT > binding churn:-( Yes, I agree. Unless of course if we can get the clock DT support ready soon, then we might yet be able to fold support into tegra-drm. Thierry
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