On 11/22/2013 09:58 AM, Rob Herring wrote: > On Thu, Nov 21, 2013 at 7:56 PM, Joel Fernandes <joelf@xxxxxx> wrote: >> This work is a migration effort of OMAP system timers to the >> clocksource/clockevent framework. Consider this as a first-pass in this effort. >> There are few cleanups that need to be done first. The HWMOD code is >> intertwined with the timer code. HWMOD code cleanups in the future will >> hopefully make most of this code go away, so till then we separate out the >> power/clocks portion of the code from the actual timer bits. This will >> facilitate near-future work of adapting the system timer as a clocksource. >> >> New functions for OF-only boot are introduced, and we can soon delete the old >> versions once we migrate all platforms. Currently only AM335x is migrated and >> testedA new omap_generic_timer_init function is introduced for DT platforms. >> Code required earlier for non-DT platforms such as setup of timer IDs and timer >> parent clock is not required. parent clocks are automatically setup by the mux >> clock driver through DT so they no longer need to be hardcoded. >> >> The init code will try to pick the best timer for clocksource and clockevent >> however bindings are added to force a particular timer as clocksource or >> clockevent through DT. >> >> Signed-off-by: Joel Fernandes <joelf@xxxxxx> >> --- >> .../devicetree/bindings/arm/omap/timer.txt | 12 ++ >> arch/arm/mach-omap2/common.h | 1 + >> arch/arm/mach-omap2/timer.c | 235 +++++++++++++++++++++ >> 3 files changed, 248 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/arm/omap/timer.txt b/Documentation/devicetree/bindings/arm/omap/timer.txt >> index d02e27c..6cf7a75 100644 >> --- a/Documentation/devicetree/bindings/arm/omap/timer.txt >> +++ b/Documentation/devicetree/bindings/arm/omap/timer.txt >> @@ -32,6 +32,18 @@ Optional properties: >> - ti,timer-secure: Indicates the timer is reserved on a secure OMAP device >> and therefore cannot be used by the kernel. >> >> +- ti,timer-clockevent, >> + ti,timer-clocksource These properties force the system timer code to choose >> + the particular timer as a clockevent or clocksource. >> + If these properties are not specified, the timer code >> + picks up a "ti,timer-alwon" as the clocksource and a >> + timer containing one of the following properties as >> + the clockevent in the following order: >> + ti,timer-alwon >> + ti,timer-dsp >> + ti,timer-pwm >> + ti,timer-secure > > These properties were added specifically for the reason of avoiding > linux specific properties like these. When is this not sufficient? Some platforms cannot use certain timers as clockevents and clocksource, to keep this code functionally equivalent and working, I added these properties so that its possible to select specific timers as clockevents/sources as was being done in the non-DT case. I'm open to suggestions for doing this in a better way for DT. > > And I agree with the comment to use OF_CLKSRC. > There are difficulties I mentioned in a previous post [1] stating why it may not be possible to use OF_CLKSRC macros, and still keep the code functionally equivalent to when it was non-DT. thanks, -Joel [1] http://marc.info/?l=linux-arm-kernel&m=138513299917850&w=2 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
