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(-) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
