NVIDIA: VR: SAUCE: cpufreq: Use policy->min/max init as QoS request

Consider policy->min/max being set in the driver .init()
callback as a QoS request. Impacted driver are:
- gx-suspmod.c (min)
- cppc-cpufreq.c (min)
- longrun.c (min/max)

Update the documentation accordingly.

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
(cherry picked from https://lore.kernel.org/lkml/20260511135538.522653-5-pierre.gondois@arm.com/)
Signed-off-by: Seth Forshee <sforshee@nvidia.com>

Author: pierregondois

Documentation/cpu-freq/cpu-drivers.rst

@@ -114,8 +114,14 @@ Then, the driver must fill in the following values:
 |policy->cur			    | The current operating frequency of   |
 |				    | this CPU (if appropriate)		   |
 +-----------------------------------+--------------------------------------+
-|policy->min,			    |					   |
-|policy->max,			    |					   |
+|policy->min			    | If set by the driver in ->init(),    |
+|				    | used as initial minimum frequency	   |
+|				    | QoS request.			   |
++-----------------------------------+--------------------------------------+
+|policy->max			    | If set by the driver in ->init(),    |
+|				    | used as initial maximum frequency	   |
+|				    | QoS request.			   |
++-----------------------------------+--------------------------------------+
 |policy->policy and, if necessary,  |					   |
 |policy->governor		    | must contain the "default policy" for|
 |				    | this CPU. A few moments later,       |

drivers/cpufreq/cpufreq.c

@@ -1393,8 +1393,16 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy)
 
 static int cpufreq_policy_init_qos(struct cpufreq_policy *policy)
 {
+	unsigned int min_freq, max_freq;
 	int ret;
 
+	/* Use policy->min/max set by the driver as QoS requests. */
+	min_freq = max(FREQ_QOS_MIN_DEFAULT_VALUE, policy->min);
+	if (policy->max)
+		max_freq = min(FREQ_QOS_MAX_DEFAULT_VALUE, policy->max);
+	else
+		max_freq = FREQ_QOS_MAX_DEFAULT_VALUE;
+
 	/*
 	 * If the driver didn't set policy->min/max, set them as
 	 * they are used to clamp frequency requests.
@@ -1412,12 +1420,12 @@ static int cpufreq_policy_init_qos(struct cpufreq_policy *policy)
 	}
 
 	ret = freq_qos_add_request(&policy->constraints, &policy->min_freq_req,
-				   FREQ_QOS_MIN, FREQ_QOS_MIN_DEFAULT_VALUE);
+				   FREQ_QOS_MIN, min_freq);
 	if (ret < 0)
 		return ret;
 
 	ret = freq_qos_add_request(&policy->constraints, &policy->max_freq_req,
-				   FREQ_QOS_MAX, FREQ_QOS_MAX_DEFAULT_VALUE);
+				   FREQ_QOS_MAX, max_freq);
 	if (ret < 0)
 		return ret;