linux-kernel - [PATCH 2/3] pmdomain: core: Show latency/residency for domain idle states in debugfs

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Message-ID: <20260119143121.161583-3-ulf.hansson@linaro.org>
Date: Mon, 19 Jan 2026 15:31:14 +0100
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Ulf Hansson <ulf.hansson@...aro.org>,
	Dhruva Gole <d-gole@...com>,
	linux-pm@...r.kernel.org
Cc: "Rafael J . Wysocki" <rafael@...nel.org>,
	Kevin Hilman <khilman@...libre.com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] pmdomain: core: Show latency/residency for domain idle states in debugfs

Similar to how cpuidle provides the values for latency and residency for
CPU's idle states through sysfs, let's make the corresponding data for PM
domain's idle states available for user space, via genpd's debugfs support.

Suggested-by: Dhruva Gole <d-gole@...com>
Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
---
 drivers/pmdomain/core.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/pmdomain/core.c b/drivers/pmdomain/core.c
index 919dff2081d6..bf512ff0857d 100644
--- a/drivers/pmdomain/core.c
+++ b/drivers/pmdomain/core.c
@@ -3809,15 +3809,24 @@ static int idle_states_desc_show(struct seq_file *s, void *data)
 	if (ret)
 		return -ERESTARTSYS;
 
-	seq_puts(s, "State  Name\n");
+	seq_puts(s, "State  Latency(us)  Residency(us)  Name\n");
 
 	for (i = 0; i < genpd->state_count; i++) {
 		struct genpd_power_state *state = &genpd->states[i];
+		u64 latency, residency;
 		char state_name[7];
 
+		latency = state->power_off_latency_ns +
+			state->power_on_latency_ns;
+		do_div(latency, NSEC_PER_USEC);
+
+		residency = state->residency_ns;
+		do_div(residency, NSEC_PER_USEC);
+
 		snprintf(state_name, ARRAY_SIZE(state_name), "S%-5d", i);
-		seq_printf(s, "%-6s %s\n",
-			   state_name, state->name ?: "N/A");
+		seq_printf(s, "%-6s %-12llu %-14llu %s\n",
+			   state_name, latency, residency,
+			   state->name ?: "N/A");
 	}
 
 	genpd_unlock(genpd);
-- 
2.43.0