opp: Make dev_pm_opp_set_rate() handle freq = 0 to drop performance votes

For devices with performance state, we use dev_pm_opp_set_rate() to set
the appropriate clk rate and the performance state.

We do need a way to remove the performance state vote when we idle the
device and turn the clocks off. Use dev_pm_opp_set_rate() with freq = 0
to achieve this.

Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
[ Viresh: Updated _set_required_opps() to handle the !opp case ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index bae94bf..9fda9a0 100644 (file)
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -711,7 +711,7 @@ static int _set_required_opps(struct device *dev,
 
        /* Single genpd case */
        if (!genpd_virt_devs) {
-               pstate = opp->required_opps[0]->pstate;
+               pstate = likely(opp) ? opp->required_opps[0]->pstate : 0;
                ret = dev_pm_genpd_set_performance_state(dev, pstate);
                if (ret) {
                        dev_err(dev, "Failed to set performance state of %s: %d (%d)\n",
@@ -729,7 +729,7 @@ static int _set_required_opps(struct device *dev,
        mutex_lock(&opp_table->genpd_virt_dev_lock);
 
        for (i = 0; i < opp_table->required_opp_count; i++) {
-               pstate = opp->required_opps[i]->pstate;
+               pstate = likely(opp) ? opp->required_opps[i]->pstate : 0;
 
                if (!genpd_virt_devs[i])
                        continue;
@@ -765,18 +765,23 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
        struct clk *clk;
        int ret;
 
-       if (unlikely(!target_freq)) {
-               dev_err(dev, "%s: Invalid target frequency %lu\n", __func__,
-                       target_freq);
-               return -EINVAL;
-       }
-
        opp_table = _find_opp_table(dev);
        if (IS_ERR(opp_table)) {
                dev_err(dev, "%s: device opp doesn't exist\n", __func__);
                return PTR_ERR(opp_table);
        }
 
+       if (unlikely(!target_freq)) {
+               if (opp_table->required_opp_tables) {
+                       ret = _set_required_opps(dev, opp_table, NULL);
+               } else {
+                       dev_err(dev, "target frequency can't be 0\n");
+                       ret = -EINVAL;
+               }
+
+               goto put_opp_table;
+       }
+
        clk = opp_table->clk;
        if (IS_ERR(clk)) {
                dev_err(dev, "%s: No clock available for the device\n",