From: Leonard Crestez leonard.crestez@nxp.com
[ Upstream commit b234fe9558615098d8d62516e7041ad7f99ebcea ]
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: ba5625c3e272 ("clk: imx: Add clock driver support for imx8mm") Fixes: 96d6392b54db ("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/f5d2b9c53f1ed5ccb1dd3c6624f56759d92e1689.157177177... Acked-by: Shawn Guo shawnguo@kernel.org Signed-off-by: Stephen Boyd sboyd@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/clk/imx/clk-imx8mm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/clk/imx/clk-imx8mm.c b/drivers/clk/imx/clk-imx8mm.c index 6f46bcb1d6432..59ce93691e970 100644 --- a/drivers/clk/imx/clk-imx8mm.c +++ b/drivers/clk/imx/clk-imx8mm.c @@ -666,7 +666,7 @@ static int __init imx8mm_clocks_init(struct device_node *ccm_node) 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));