This patchset introduces support for Tegra's microsecond counter as the udelay() timer. This is useful on Tegra SoCs which do not have an arch timer such as Tegra20 and Tegra30. Using the microsecond counter instead of a delay based loop avoids potential problems during cpu frequency changes. The set consists of 3 patches: Patch 1 introduces a new call which is used by the ARM architecture delay timer code to prevent changing the delay timer after calibration is finished and thus can be in use. Patch 2 adds logic to choose the delay timer with the highest resolution. This allows the same registration code to be used on all Tegra SoCs and yet use the higher resolution arch timer when available (eg on Tegra114 or Tegra124). Patch 3 adds the actual delay timer code. Patch set has been verified on ventana (Tegra20), beaver (Tegra30), dalmore (Tegra114) and jetson TK1 (Tegra124). Changes since v1: * Address review comments What needs to be done to make progress on this one? I think it's really useful to have this when CPU DVFS is available. Peter De Schrijver (3): kernel: add calibration_delay_done() ARM: choose highest resolution delay timer clocksource: tegra: Use us counter as delay timer arch/arm/lib/delay.c | 26 ++++++++++++++++++++++---- drivers/clocksource/tegra20_timer.c | 13 +++++++++++++ init/calibrate.c | 11 +++++++++++ 3 files changed, 46 insertions(+), 4 deletions(-) -- 1.7.7.rc0.72.g4b5ea.dirty -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
