From 5836ebeb4a2b7e25305fab9170060d5f3de1ff30 Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Fri, 2 May 2025 15:01:19 +0100 Subject: [PATCH] cpuidle: psci: Avoid initializing faux device if no DT idle states are present Commit af5376a77e87 ("cpuidle: psci: Transition to the faux device interface") transitioned the PSCI cpuidle driver from using a platform device to the faux device framework. However, unlike platform devices, the faux device infrastructure logs an error when the probe function fails, even if the failure is intentional or expected. To prevent unnecessary error logs, we can skip creating the faux device entirely if there are no PSCI idle states defined in the device tree. Introduce a check for DT idle states during initialization and avoid setting up the device if none are found. This ensures cleaner logs and avoids misleading probe failure messages when PSCI idle support is intentionally not described in DT. Fixes: af5376a77e87 ("cpuidle: psci: Transition to the faux device interface") Reported-by: Jon Hunter Closes: https://lore.kernel.org/r/cf4e70e4-9fe5-4697-8744-8c12c41b5ff9@nvidia.com Signed-off-by: Sudeep Holla Reviewed-by: Ulf Hansson Link: https://patch.msgid.link/20250502140119.2578909-1-sudeep.holla@arm.com Signed-off-by: Rafael J. Wysocki --- drivers/cpuidle/cpuidle-psci.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c index ee35ac816321..40f378c1dc9f 100644 --- a/drivers/cpuidle/cpuidle-psci.c +++ b/drivers/cpuidle/cpuidle-psci.c @@ -438,10 +438,29 @@ static struct faux_device_ops psci_cpuidle_ops = { .probe = psci_cpuidle_probe, }; +static bool __init dt_idle_state_present(void) +{ + struct device_node *cpu_node __free(device_node); + struct device_node *state_node __free(device_node); + + cpu_node = of_cpu_device_node_get(cpumask_first(cpu_possible_mask)); + if (!cpu_node) + return false; + + state_node = of_get_cpu_state_node(cpu_node, 0); + if (!state_node) + return false; + + return !!of_match_node(psci_idle_state_match, state_node); +} + static int __init psci_idle_init(void) { struct faux_device *fdev; + if (!dt_idle_state_present()) + return 0; + fdev = faux_device_create("psci-cpuidle", NULL, &psci_cpuidle_ops); if (!fdev) { pr_err("Failed to create psci-cpuidle device\n"); -- 2.25.1