soc/tegra: Enable runtime PM during OPP state-syncing

GENPD core now can set up domain's performance state properly while device
is RPM-suspended. Runtime PM of a device must be enabled during setup
because GENPD checks whether device is suspended and check doesn't work
while RPM is disabled. Instead of replicating the boilerplate RPM-enable
code around OPP helper for each driver, let's make OPP helper to take care
of enabling it.

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

diff --git a/drivers/soc/tegra/common.c b/drivers/soc/tegra/common.c
index cd33e99..35c882d 100644 (file)
--- a/drivers/soc/tegra/common.c
+++ b/drivers/soc/tegra/common.c
@@ -10,6 +10,7 @@
 #include <linux/export.h>
 #include <linux/of.h>
 #include <linux/pm_opp.h>
+#include <linux/pm_runtime.h>
 
 #include <soc/tegra/common.h>
 #include <soc/tegra/fuse.h>
@@ -43,6 +44,7 @@ static int tegra_core_dev_init_opp_state(struct device *dev)
 {
        unsigned long rate;
        struct clk *clk;
+       bool rpm_enabled;
        int err;
 
        clk = devm_clk_get(dev, NULL);
@@ -57,8 +59,31 @@ static int tegra_core_dev_init_opp_state(struct device *dev)
                return -EINVAL;
        }
 
+       /*
+        * Runtime PM of the device must be enabled in order to set up
+        * GENPD's performance properly because GENPD core checks whether
+        * device is suspended and this check doesn't work while RPM is
+        * disabled. This makes sure the OPP vote below gets cached in
+        * GENPD for the device. Instead, the vote is done the next time
+        * the device gets runtime resumed.
+        */
+       rpm_enabled = pm_runtime_enabled(dev);
+       if (!rpm_enabled)
+               pm_runtime_enable(dev);
+
+       /* should never happen in practice */
+       if (!pm_runtime_enabled(dev)) {
+               dev_WARN(dev, "failed to enable runtime PM\n");
+               pm_runtime_disable(dev);
+               return -EINVAL;
+       }
+
        /* first dummy rate-setting initializes voltage vote */
        err = dev_pm_opp_set_rate(dev, rate);
+
+       if (!rpm_enabled)
+               pm_runtime_disable(dev);
+
        if (err) {
                dev_err(dev, "failed to initialize OPP clock: %d\n", err);
                return err;