[PATCH v6 3/3] PM / devfreq: Add required OPPs support to passive governor

[Hsin-Yi Wang]

From: Saravana Kannan <sarava...@google.com>

Look at the required OPPs of the "parent" device to determine the OPP that
is required from the slave device managed by the passive governor. This
allows having mappings between a parent device and a slave device even when
they don't have the same number of OPPs.

Signed-off-by: Saravana Kannan <sarava...@google.com>
Acked-by: MyungJoo Ham <myungjoo....@samsung.com>
Acked-by: Chanwoo Choi <cw00.c...@samsung.com>
Signed-off-by: Hsin-Yi Wang <hsi...@chromium.org>
---
 drivers/devfreq/governor_passive.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/drivers/devfreq/governor_passive.c 
b/drivers/devfreq/governor_passive.c
index 63332e4a65ae8..8fd51cc9b991a 100644
--- a/drivers/devfreq/governor_passive.c
+++ b/drivers/devfreq/governor_passive.c
@@ -19,7 +19,7 @@ static int devfreq_passive_get_target_freq(struct devfreq 
*devfreq,
                        = (struct devfreq_passive_data *)devfreq->data;
        struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
        unsigned long child_freq = ULONG_MAX;
-       struct dev_pm_opp *opp;
+       struct dev_pm_opp *opp, *p_opp = ERR_PTR(-ENODEV);
        int i, count, ret = 0;
 
        /*
@@ -29,7 +29,7 @@ static int devfreq_passive_get_target_freq(struct devfreq 
*devfreq,
         */
        if (p_data->get_target_freq) {
                ret = p_data->get_target_freq(devfreq, freq);
-               goto out;
+               return ret;
        }
 
        /*
@@ -56,13 +56,22 @@ static int devfreq_passive_get_target_freq(struct devfreq 
*devfreq,
         * list of parent device. Because in this case, *freq is temporary
         * value which is decided by ondemand governor.
         */
-       opp = devfreq_recommended_opp(parent_devfreq->dev.parent, freq, 0);
-       if (IS_ERR(opp)) {
-               ret = PTR_ERR(opp);
-               goto out;
+       p_opp = devfreq_recommended_opp(parent_devfreq->dev.parent, freq, 0);
+       if (IS_ERR(p_opp)) {
+               ret = PTR_ERR(p_opp);
+               return ret;
        }
 
-       dev_pm_opp_put(opp);
+       if (devfreq->opp_table && parent_devfreq->opp_table) {
+               opp = dev_pm_opp_xlate_required_opp(parent_devfreq->opp_table,
+                                                   devfreq->opp_table, p_opp);
+               if (!IS_ERR(opp)) {
+                       *freq = dev_pm_opp_get_freq(opp);
+                       dev_pm_opp_put(opp);
+               } else
+                       ret = PTR_ERR(opp);
+               goto out;
+       }
 
        /*
         * Get the OPP table's index of decided freqeuncy by governor
@@ -89,6 +98,8 @@ static int devfreq_passive_get_target_freq(struct devfreq 
*devfreq,
        *freq = child_freq;
 
 out:
+       dev_pm_opp_put(p_opp);
+
        return ret;
 }
 
-- 
2.30.0.365.g02bc693789-goog