On Tue, Sep 02, 2014 at 10:15:15AM +0200, Gregory CLEMENT wrote: > Hi Mike, Jason, Andrew and Sebastian, > > Few users reported a timer drift on the Armada 370 based board such as > the mirabox or the Netgear ReadyNAS 102. This is the second series > with few improvements after the review of the 1st version. > > The reason is that when the SSCG (Spread Spectrum Clock Generator) is > enabled, it shifts the frequency of the clock. The percentage is no > more than 1% but when the clock is used for a timer it leads to a > clock drift. > > This series allows to correct the affected clock when the SSCG is > enabled. This drift can happen on all the mvebu SoC on the cpu clock > block (ie cpu, ddr and l2 cache). Currently the only notable effect is > for the Armada 370 because this SoC use the l2cache clock as source > for the timer. That's why even if the series allow any of the mvebu > SoC to benefit to this correction, Armada 370 is the only user of it. > > The first 2 patches should go through the clk subsystem, whereas the > third one should go to the arm-soc through the mvebu tree. > > The last one is just to fix a typo I found while I was reading the clk > code. > > Thanks, > > Gregory > > Changelog: > > v1 -> v2: > - made the function a370_is_sscg_enabled() a static one > - reword the comment to make clear that the formula in datasheet is > erroneous > - added a fix_sscg_deviation() callback in order to be able to deal > with the Dove case which is different from the other mvebu SoCs > > > Gregory CLEMENT (4): > clk: mvebu: Fix clk frequency value if SSCG is enabled > clk: mvebu: armada-370: Fix timer drift caused by the SSCG deviation > ARM: mvebu: add SSCG to Armada 370 Device Tree > clk: mvebu: armada-375: Fix the description of the SAR in the comment > > arch/arm/boot/dts/armada-370.dtsi | 4 ++ > drivers/clk/mvebu/armada-370.c | 8 ++++ > drivers/clk/mvebu/armada-375.c | 4 +- > drivers/clk/mvebu/common.c | 82 > +++++++++++++++++++++++++++++++++++++++ > drivers/clk/mvebu/common.h | 7 ++++ > 5 files changed, 103 insertions(+), 2 deletions(-)
Patches 1, 2, and 4 applied to mvebu/drivers-clk with Leigh's Tested-by. #3 applied to mvebu/dt with same Tested-by. thx, Jason. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
