From ac30d90f33674e49b4428b66f7dd9949f054b6c4 Mon Sep 17 00:00:00 2001 From: Miquel Raynal Date: Thu, 3 Apr 2025 09:39:06 +0200 Subject: [PATCH] clk: Ensure the parent clocks are enabled while reparenting Reparenting a clock C with a new parent P means that C will only continue clocking if P is already clocking when the mux is updated. In case the parent is currently disabled, failures (stalls) are likely to happen. This is exactly what happens on i.MX8 when enabling the video pipeline. We tell LCDIF clocks to use the VIDEO PLL as input, while the VIDEO PLL is currently off. This all happens as part of the assigned-clocks handling procedure, where the reparenting happens before the enable() calls. Enabling the parents as part of the reparenting procedure seems sane and also matches the logic applied in other parts of the CCM. Signed-off-by: Miquel Raynal --- drivers/clk/clk-uclass.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c index 90b70529a47..4b3d812f9c6 100644 --- a/drivers/clk/clk-uclass.c +++ b/drivers/clk/clk-uclass.c @@ -623,14 +623,27 @@ int clk_set_parent(struct clk *clk, struct clk *parent) if (!ops->set_parent) return -ENOSYS; + ret = clk_enable(parent); + if (ret) { + printf("Cannot enable parent %s\n", parent->dev->name); + return ret; + } + ret = ops->set_parent(clk, parent); - if (ret) + if (ret) { + clk_disable(parent); return ret; + } - if (CONFIG_IS_ENABLED(CLK_CCF)) + if (CONFIG_IS_ENABLED(CLK_CCF)) { ret = device_reparent(clk->dev, parent->dev); + if (ret) { + clk_disable(parent); + return ret; + } + } - return ret; + return 0; } int clk_enable(struct clk *clk) -- 2.39.5