[PATCH V2 RESEND 3/4] PM / devfreq: bail out early if no freq changes in devfreq_set_target

[Dong Aisheng]

It's unnecessary to set the same freq again and run notifier calls.

Signed-off-by: Dong Aisheng <aisheng.d...@nxp.com>
---
 drivers/devfreq/devfreq.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 85927bd7ee76..a6ee91dd17bd 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -352,13 +352,16 @@ static int devfreq_set_target(struct devfreq *devfreq, 
unsigned long new_freq,
 {
        struct devfreq_freqs freqs;
        unsigned long cur_freq;
-       int err = 0;
+       int err;
 
        if (devfreq->profile->get_cur_freq)
                devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
        else
                cur_freq = devfreq->previous_freq;
 
+       if (new_freq == cur_freq)
+               return 0;
+
        freqs.old = cur_freq;
        freqs.new = new_freq;
        devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
@@ -375,7 +378,7 @@ static int devfreq_set_target(struct devfreq *devfreq, 
unsigned long new_freq,
         * and DEVFREQ_POSTCHANGE because for showing the correct frequency
         * change order of between devfreq device and passive devfreq device.
         */
-       if (trace_devfreq_frequency_enabled() && new_freq != cur_freq)
+       if (trace_devfreq_frequency_enabled())
                trace_devfreq_frequency(devfreq, new_freq, cur_freq);
 
        freqs.new = new_freq;
@@ -390,7 +393,7 @@ static int devfreq_set_target(struct devfreq *devfreq, 
unsigned long new_freq,
        if (devfreq->suspend_freq)
                devfreq->resume_freq = new_freq;
 
-       return err;
+       return 0;
 }
 
 /**
-- 
2.25.1