From: Ondrej Jirman <megous@xxxxxxxxxx> [ Upstream commit a43c96427e713bea94e9ef50e8be1f493afc0691 ] When adjusting PLL_CPUX on H3, the PLL is temporarily driven too high, and the system becomes unstable (oopses or hangs). Add a notifier to avoid this situation by temporarily switching to a known stable 24 MHz oscillator. Signed-off-by: Ondrej Jirman <megous@xxxxxxxxxx> Tested-by: Lutz Sammer <johns98@xxxxxxx> Acked-by: Chen-Yu Tsai <wens@xxxxxxxx> Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> --- drivers/clk/sunxi-ng/ccu-sun8i-h3.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/clk/sunxi-ng/ccu-sun8i-h3.c b/drivers/clk/sunxi-ng/ccu-sun8i-h3.c index 21c427d86f28..a26c8a19fe93 100644 --- a/drivers/clk/sunxi-ng/ccu-sun8i-h3.c +++ b/drivers/clk/sunxi-ng/ccu-sun8i-h3.c @@ -803,6 +803,13 @@ static const struct sunxi_ccu_desc sun8i_h3_ccu_desc = { .num_resets = ARRAY_SIZE(sun8i_h3_ccu_resets), }; +static struct ccu_mux_nb sun8i_h3_cpu_nb = { + .common = &cpux_clk.common, + .cm = &cpux_clk.mux, + .delay_us = 1, /* > 8 clock cycles at 24 MHz */ + .bypass_index = 1, /* index of 24 MHz oscillator */ +}; + static void __init sun8i_h3_ccu_setup(struct device_node *node) { void __iomem *reg; @@ -821,6 +828,9 @@ static void __init sun8i_h3_ccu_setup(struct device_node *node) writel(val | (3 << 16), reg + SUN8I_H3_PLL_AUDIO_REG); sunxi_ccu_probe(node, reg, &sun8i_h3_ccu_desc); + + ccu_mux_notifier_register(pll_cpux_clk.common.hw.clk, + &sun8i_h3_cpu_nb); } CLK_OF_DECLARE(sun8i_h3_ccu, "allwinner,sun8i-h3-ccu", sun8i_h3_ccu_setup); -- 2.11.0