clk: imx8m: Use SYS_PLL1_800M as intermediate parent of CLK_ARM

During cpu frequency switching the main "CLK_ARM" is reparented to an intermediate "step" clock. On imx8mm and imx8mn the 24M oscillator is used for this purpose but it is extremely slow, increasing wakeup latencies to the point that i2c transactions can timeout and system becomes unresponsive. Fix by switching the "step" clk to SYS_PLL1_800M, matching the behavior of imx8m cpufreq drivers in imx vendor tree. This bug was not immediately apparent because upstream arm64 defconfig uses the "performance" governor by default so no cpufreq transitions happen. Fixes: ba5625c ("clk: imx: Add clock driver support for imx8mm") Fixes: 96d6392 ("clk: imx: Add support for i.MX8MN clock driver") Cc: stable@vger.kernel.org Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> Link: https://lkml.kernel.org/r/f5d2b9c53f1ed5ccb1dd3c6624f56759d92e1689.1571771777.git.leonard.crestez@nxp.com Acked-by: Shawn Guo <shawnguo@kernel.org> Signed-off-by: Stephen Boyd <sboyd@kernel.org>
mariux64 · Oct 28, 2019 · b234fe9 · b234fe9
1 parent 3d883e8
commit b234fe9
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Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/drivers/clk/imx/clk-imx8mm.c b/drivers/clk/imx/clk-imx8mm.c
@@ -638,7 +638,7 @@ static int imx8mm_clocks_probe(struct platform_device *pdev)
 					   clks[IMX8MM_CLK_A53_DIV],
 					   clks[IMX8MM_CLK_A53_SRC],
 					   clks[IMX8MM_ARM_PLL_OUT],
-					   clks[IMX8MM_CLK_24M]);
+					   clks[IMX8MM_SYS_PLL1_800M]);
 
 	imx_check_clocks(clks, ARRAY_SIZE(clks));
 

diff --git a/drivers/clk/imx/clk-imx8mn.c b/drivers/clk/imx/clk-imx8mn.c
@@ -610,7 +610,7 @@ static int imx8mn_clocks_probe(struct platform_device *pdev)
 					   clks[IMX8MN_CLK_A53_DIV],
 					   clks[IMX8MN_CLK_A53_SRC],
 					   clks[IMX8MN_ARM_PLL_OUT],
-					   clks[IMX8MN_CLK_24M]);
+					   clks[IMX8MN_SYS_PLL1_800M]);
 
 	imx_check_clocks(clks, ARRAY_SIZE(clks));