What I'm trying to do: We have a board with an external watchdog circuit (the kind that is petted by flipping a gpio). The reset output of that is split in two: One gives an immediate interrupt, so software knows that a hard reset is imminent. The other half removes the "reset input" from a ripple counter, causing that to start counting at 32kHz, and after 64ms, the SOC's reset pin then gets pulled. Unfortunately, the board designer overlooked that the 32kHz output from the RTC can be disabled, which (since no other component uses it), is just what happens when clk_disable_unused() gets called. When the watchdog fires, we do get the interrupt, but the board does not get reset as it should, since the counter doesn't count. So I'm thinking that the proper way to handle this is to be able to represent that ripple counter as a clock consumer in DT and have a driver do the clk_prepare_enable(), even if that driver doesn't and can't do anything else. But I'm certainly open to other suggestions. The "clk_ignore_unused" kernel parameter is fine for debugging, but too big a hammer (since it applies to all "unused" clocks). Rasmus Villemoes (2): dt-bindings: misc: add binding for generic ripple counter drivers: misc: add ripple counter driver .../devicetree/bindings/misc/ripple-ctr.txt | 8 +++++ drivers/misc/Kconfig | 7 +++++ drivers/misc/Makefile | 1 + drivers/misc/ripple-ctr.c | 31 +++++++++++++++++++ 4 files changed, 47 insertions(+) create mode 100644 Documentation/devicetree/bindings/misc/ripple-ctr.txt create mode 100644 drivers/misc/ripple-ctr.c -- 2.29.2
