[RFC V6 3/8] PM / devfreq: Add new target_freq attribute flag for governors
From: Sibi Sankar
Date: Thu May 07 2026 - 02:25:14 EST
Introduce the target_freq attribute flag as a pre-cursor to adding support
for devfreq governors who do not explicitly allow for a method to get/set
target frequency.
Signed-off-by: Sibi Sankar <sibi.sankar@xxxxxxxxxxxxxxxx>
---
drivers/devfreq/devfreq.c | 4 ++++
drivers/devfreq/governor_passive.c | 1 +
drivers/devfreq/governor_performance.c | 1 +
drivers/devfreq/governor_powersave.c | 1 +
drivers/devfreq/governor_simpleondemand.c | 1 +
drivers/devfreq/governor_userspace.c | 1 +
drivers/devfreq/hisi_uncore_freq.c | 1 +
drivers/devfreq/tegra30-devfreq.c | 3 ++-
include/linux/devfreq-governor.h | 3 +++
9 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index e5d3f9cf94dc..85e937e321e8 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -1526,6 +1526,10 @@ static ssize_t target_freq_show(struct device *dev,
{
struct devfreq *df = to_devfreq(dev);
+ if (!df->profile || !df->governor ||
+ !IS_SUPPORTED_ATTR(df->governor->attrs, TARGET_FREQ))
+ return -EINVAL;
+
return sprintf(buf, "%lu\n", df->previous_freq);
}
static DEVICE_ATTR_RO(target_freq);
diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
index d7feecd900f1..b75e4bbee4b1 100644
--- a/drivers/devfreq/governor_passive.c
+++ b/drivers/devfreq/governor_passive.c
@@ -448,6 +448,7 @@ static int devfreq_passive_event_handler(struct devfreq *devfreq,
static struct devfreq_governor devfreq_passive = {
.name = DEVFREQ_GOV_PASSIVE,
+ .attrs = DEVFREQ_GOV_ATTR_TARGET_FREQ,
.flags = DEVFREQ_GOV_FLAG_IMMUTABLE,
.get_target_freq = devfreq_passive_get_target_freq,
.event_handler = devfreq_passive_event_handler,
diff --git a/drivers/devfreq/governor_performance.c b/drivers/devfreq/governor_performance.c
index fdb22bf512cf..b9ec587f582c 100644
--- a/drivers/devfreq/governor_performance.c
+++ b/drivers/devfreq/governor_performance.c
@@ -37,6 +37,7 @@ static int devfreq_performance_handler(struct devfreq *devfreq,
static struct devfreq_governor devfreq_performance = {
.name = DEVFREQ_GOV_PERFORMANCE,
+ .attrs = DEVFREQ_GOV_ATTR_TARGET_FREQ,
.get_target_freq = devfreq_performance_func,
.event_handler = devfreq_performance_handler,
};
diff --git a/drivers/devfreq/governor_powersave.c b/drivers/devfreq/governor_powersave.c
index ee2d6ec8a512..69eab1d0a7fc 100644
--- a/drivers/devfreq/governor_powersave.c
+++ b/drivers/devfreq/governor_powersave.c
@@ -37,6 +37,7 @@ static int devfreq_powersave_handler(struct devfreq *devfreq,
static struct devfreq_governor devfreq_powersave = {
.name = DEVFREQ_GOV_POWERSAVE,
+ .attrs = DEVFREQ_GOV_ATTR_TARGET_FREQ,
.get_target_freq = devfreq_powersave_func,
.event_handler = devfreq_powersave_handler,
};
diff --git a/drivers/devfreq/governor_simpleondemand.c b/drivers/devfreq/governor_simpleondemand.c
index ac9c5e9e51a4..65ff9d912ef9 100644
--- a/drivers/devfreq/governor_simpleondemand.c
+++ b/drivers/devfreq/governor_simpleondemand.c
@@ -118,6 +118,7 @@ static int devfreq_simple_ondemand_handler(struct devfreq *devfreq,
static struct devfreq_governor devfreq_simple_ondemand = {
.name = DEVFREQ_GOV_SIMPLE_ONDEMAND,
.attrs = DEVFREQ_GOV_ATTR_POLLING_INTERVAL
+ | DEVFREQ_GOV_ATTR_TARGET_FREQ
| DEVFREQ_GOV_ATTR_TIMER,
.get_target_freq = devfreq_simple_ondemand_func,
.event_handler = devfreq_simple_ondemand_handler,
diff --git a/drivers/devfreq/governor_userspace.c b/drivers/devfreq/governor_userspace.c
index 3906ebedbae8..d1b765a7b8e5 100644
--- a/drivers/devfreq/governor_userspace.c
+++ b/drivers/devfreq/governor_userspace.c
@@ -135,6 +135,7 @@ static int devfreq_userspace_handler(struct devfreq *devfreq,
static struct devfreq_governor devfreq_userspace = {
.name = DEVFREQ_GOV_USERSPACE,
+ .attrs = DEVFREQ_GOV_ATTR_TARGET_FREQ,
.get_target_freq = devfreq_userspace_func,
.event_handler = devfreq_userspace_handler,
};
diff --git a/drivers/devfreq/hisi_uncore_freq.c b/drivers/devfreq/hisi_uncore_freq.c
index 4d00d813c8ac..0800116e3334 100644
--- a/drivers/devfreq/hisi_uncore_freq.c
+++ b/drivers/devfreq/hisi_uncore_freq.c
@@ -399,6 +399,7 @@ static struct devfreq_governor hisi_platform_governor = {
* Set interrupt_driven to skip the devfreq monitor mechanism, though
* this governor is not interrupt-driven.
*/
+ .attrs = DEVFREQ_GOV_ATTR_TARGET_FREQ,
.flags = DEVFREQ_GOV_FLAG_IRQ_DRIVEN,
.get_target_freq = hisi_platform_gov_func,
.event_handler = hisi_platform_gov_handler,
diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
index 401aac6a9f07..fcb278c4a74c 100644
--- a/drivers/devfreq/tegra30-devfreq.c
+++ b/drivers/devfreq/tegra30-devfreq.c
@@ -776,7 +776,8 @@ static int tegra_governor_event_handler(struct devfreq *devfreq,
static struct devfreq_governor tegra_devfreq_governor = {
.name = "tegra_actmon",
- .attrs = DEVFREQ_GOV_ATTR_POLLING_INTERVAL,
+ .attrs = DEVFREQ_GOV_ATTR_POLLING_INTERVAL
+ | DEVFREQ_GOV_ATTR_TARGET_FREQ,
.flags = DEVFREQ_GOV_FLAG_IMMUTABLE
| DEVFREQ_GOV_FLAG_IRQ_DRIVEN,
.get_target_freq = tegra_governor_get_target,
diff --git a/include/linux/devfreq-governor.h b/include/linux/devfreq-governor.h
index dfdd0160a29f..2853f571dfdf 100644
--- a/include/linux/devfreq-governor.h
+++ b/include/linux/devfreq-governor.h
@@ -43,9 +43,12 @@
* : Indicate polling_interval sysfs attribute
* - DEVFREQ_GOV_ATTR_TIMER
* : Indicate timer sysfs attribute
+ * - DEVFREQ_GOV_ATTR_TARGET_FREQ
+ * : Indicate the target freq sysfs attribute
*/
#define DEVFREQ_GOV_ATTR_POLLING_INTERVAL BIT(0)
#define DEVFREQ_GOV_ATTR_TIMER BIT(1)
+#define DEVFREQ_GOV_ATTR_TARGET_FREQ BIT(2)
/**
* struct devfreq_governor - Devfreq policy governor
--
2.34.1