This helper peforms the same function as devfreq_recommended_opp().
However, it works on devices without OPPs by iterating over freq_table.
Since freq_table is assumed to be sorted in ascending order, the
algorithm is relatively simple.
Devices with OPPs should continue using devfreq_recommended_opp(), as
that function respects disabled OPPs.
Signed-off-by: Samuel Holland <samuel@xxxxxxxxxxxx>
---
drivers/devfreq/devfreq.c | 27 +++++++++++++++++++++++++++
include/linux/devfreq.h | 2 ++
2 files changed, 29 insertions(+)
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index f5d27f5285db..fd46792297ad 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -1984,6 +1984,33 @@ subsys_initcall(devfreq_init);
* OPP framework.
*/
+/**
+ * devfreq_recommended_freq() - Helper function to get the proper frequency from
+ * freq_table for the value given to target callback.
+ * @devfreq: The devfreq device.
+ * @freq: The frequency given to target function.
+ * @flags: Flags handed from devfreq framework.
+ */
+void devfreq_recommended_freq(struct devfreq *devfreq,
+ unsigned long *freq, u32 flags)
+{
+ const unsigned long *min = devfreq->profile->freq_table;
+ const unsigned long *max = min + devfreq->profile->max_state - 1;
+ const unsigned long *f;
+
+ if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
+ /* Find the first item lower than freq, or else min. */
+ for (f = max; f > min && *f > *freq; --f)
+ ;
+ } else {
+ /* Find the first item higher than freq, or else max. */
+ for (f = min; f < max && *f < *freq; ++f)
+ ;
+ }
+ *freq = *f;
+}
+EXPORT_SYMBOL(devfreq_recommended_freq);
+
/**
* devfreq_recommended_opp() - Helper function to get proper OPP for the
* freq value given to target callback.
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 142474b4af96..4d324fea8a78 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -239,6 +239,8 @@ void devfreq_resume(void);
int update_devfreq(struct devfreq *devfreq);
/* Helper functions for devfreq user device driver with OPP. */
+void devfreq_recommended_freq(struct devfreq *devfreq,
+ unsigned long *freq, u32 flags);
struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
unsigned long *freq, u32 flags);
int devfreq_register_opp_notifier(struct device *dev,
--
2.31.1
