[PATCH v5 07/11] cpufreq: CPPC: Add sysfs for min/max_perf and perf_limited

[Sumit Gupta]

Add sysfs interfaces for Minimum Performance, Maximum Performance
and Performance Limited Register in the cppc_cpufreq driver.

Reviewed-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Signed-off-by: Sumit Gupta <sumitg@xxxxxxxxxx>
---
 .../ABI/testing/sysfs-devices-system-cpu      | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 3a05604c21bf..b022cbf46adc 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -327,6 +327,48 @@ Description:	Energy performance preference
 
 		This file is only present if the cppc-cpufreq driver is in use.
 
+What:		/sys/devices/system/cpu/cpuX/cpufreq/min_perf
+Date:		February 2026
+Contact:	linux-pm@xxxxxxxxxxxxxxx
+Description:	Minimum Performance Frequency
+
+		Read/write a frequency value in kHz from/to this file. This
+		file sets the minimum performance level (as frequency) at
+		which the platform may run. The frequency value is internally
+		converted to a performance value and must be in the range
+		[cpuinfo_min_freq, cpuinfo_max_freq], inclusive.
+
+		This file is only present if the cppc-cpufreq driver is in use.
+
+What:		/sys/devices/system/cpu/cpuX/cpufreq/max_perf
+Date:		February 2026
+Contact:	linux-pm@xxxxxxxxxxxxxxx
+Description:	Maximum Performance Frequency
+
+		Read/write a frequency value in kHz from/to this file. This
+		file sets the maximum performance level (as frequency) at
+		which the platform may run. The frequency value is internally
+		converted to a performance value and must be in the range
+		[cpuinfo_min_freq, cpuinfo_max_freq], inclusive.
+
+		This file is only present if the cppc-cpufreq driver is in use.
+
+What:		/sys/devices/system/cpu/cpuX/cpufreq/perf_limited
+Date:		February 2026
+Contact:	linux-pm@xxxxxxxxxxxxxxx
+Description:	Performance Limited
+
+		Read to check if platform throttling (thermal/power/current
+		limits) caused delivered performance to fall below the
+		requested level. A non-zero value indicates throttling occurred.
+
+		Write the bitmask of bits to clear:
+		  1 = clear bit 0 (desired performance excursion)
+		  2 = clear bit 1 (minimum performance excursion)
+		  3 = clear both bits
+		The platform sets these bits; OSPM can only clear them.
+
+		This file is only present if the cppc-cpufreq driver is in use.
 
 What:		/sys/devices/system/cpu/cpu*/cache/index3/cache_disable_{0,1}
 Date:		August 2008
-- 
2.34.1