clk: check for disabled clock-provider in of_clk_get_hw_from_clkspec
From: Heiko Stuebner <heiko@...> Date: Thu, 20 Feb 2025 23:32:58 +0100
Commit-Message
of_clk_get_hw_from_clkspec checks all available clock-providers by compairing their of-nodes to the one from the clkspec. If no matching clock-provider is found, the function returns EPROBE_DEFER to cause a re-check at a later date. If a matching clock-provider is found, a authoritative answer can be retrieved from it whether the clock exists or not. This does not take into account that the clock-provider may never appear, because it's node is disabled. This can happen for example when a clock is optional, provided by a separate block which just never gets enabled. One example of this happening is the rk3588's VOP, which has optional additional display-clock-supplies coming from PLLs inside the hdmiphy blocks. These can be used for better rates, but the system will also work without them. The problem around that is described in the followups to: https://lore.kernel.org/dri-devel/20250215-vop2-hdmi1-disp-modes-v1-3-81962a7151d6@collabora.com/ As we already know the of-node of the presumed clock-provider, just add a check via of_device_is_available whether this is a "valid" device node. This prevents ethernal defer-loops. Signed-off-by: Heiko Stuebner <heiko@...>
Patch-Comment
drivers/clk/clk.c | 4 ++++ 1 file changed, 4 insertions(+)
Statistics
- 4 lines added
- 0 lines removed