From: Gregory CLEMENT Date: Tue, 2 Sep 2014 08:15:17 +0000 (+0200) Subject: clk: mvebu: armada-370: Fix timer drift caused by the SSCG deviation X-Git-Tag: firefly_0821_release~176^2~3030^2~1^2~2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=5e1a63f5f548bb8a3967f00be2f0e1e04290c613;p=firefly-linux-kernel-4.4.55.git clk: mvebu: armada-370: Fix timer drift caused by the SSCG deviation This commit activates the SSCG deviation correction for the Armada 370. It uses the optional function introduced by the commit "clk: mvebu: Fix clk frequency value if SSCG is enabled". Without this fix the deviation measured on a Mirabox was of a few second each hour, whereas with this fix it was reduced at around 50ppm (around 4s per day). Signed-off-by: Gregory CLEMENT Tested-by: Leigh Brown Link: https://lkml.kernel.org/r/1409645719-20003-3-git-send-email-gregory.clement@free-electrons.com Signed-off-by: Jason Cooper --- diff --git a/drivers/clk/mvebu/armada-370.c b/drivers/clk/mvebu/armada-370.c index bef198a83863..756f0f39d6a3 100644 --- a/drivers/clk/mvebu/armada-370.c +++ b/drivers/clk/mvebu/armada-370.c @@ -23,6 +23,7 @@ */ #define SARL 0 /* Low part [0:31] */ +#define SARL_A370_SSCG_ENABLE BIT(10) #define SARL_A370_PCLK_FREQ_OPT 11 #define SARL_A370_PCLK_FREQ_OPT_MASK 0xF #define SARL_A370_FAB_FREQ_OPT 15 @@ -133,10 +134,17 @@ static void __init a370_get_clk_ratio( } } +static bool a370_is_sscg_enabled(void __iomem *sar) +{ + return !(readl(sar) & SARL_A370_SSCG_ENABLE); +} + static const struct coreclk_soc_desc a370_coreclks = { .get_tclk_freq = a370_get_tclk_freq, .get_cpu_freq = a370_get_cpu_freq, .get_clk_ratio = a370_get_clk_ratio, + .is_sscg_enabled = a370_is_sscg_enabled, + .fix_sscg_deviation = kirkwood_fix_sscg_deviation, .ratios = a370_coreclk_ratios, .num_ratios = ARRAY_SIZE(a370_coreclk_ratios), };