PM: domains: Add support for 'required-opps' to set default perf state

Some devices within power domains with performance states do not
support DVFS, but still need to vote on a default/static state
while they are active. They can express this using the 'required-opps'
property in device tree, which points to the phandle of the OPP
supported by the corresponding power-domains.

Add support to parse this information from DT and then set the
specified performance state during attach and drop it on detach.
runtime suspend/resume callbacks already have logic to drop/set
the vote as needed and should take care of dropping the default
perf state vote on runtime suspend and restore it back on runtime
resume.

Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index a934c67..e1c8994 100644 (file)
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -2598,6 +2598,12 @@ static void genpd_dev_pm_detach(struct device *dev, bool power_off)
 
        dev_dbg(dev, "removing from PM domain %s\n", pd->name);
 
+       /* Drop the default performance state */
+       if (dev_gpd_data(dev)->default_pstate) {
+               dev_pm_genpd_set_performance_state(dev, 0);
+               dev_gpd_data(dev)->default_pstate = 0;
+       }
+
        for (i = 1; i < GENPD_RETRY_MAX_MS; i <<= 1) {
                ret = genpd_remove_device(pd, dev);
                if (ret != -EAGAIN)
@@ -2637,6 +2643,7 @@ static int __genpd_dev_pm_attach(struct device *dev, struct device *base_dev,
 {
        struct of_phandle_args pd_args;
        struct generic_pm_domain *pd;
+       int pstate;
        int ret;
 
        ret = of_parse_phandle_with_args(dev->of_node, "power-domains",
@@ -2675,10 +2682,29 @@ static int __genpd_dev_pm_attach(struct device *dev, struct device *base_dev,
                genpd_unlock(pd);
        }
 
-       if (ret)
+       if (ret) {
                genpd_remove_device(pd, dev);
+               return -EPROBE_DEFER;
+       }
 
-       return ret ? -EPROBE_DEFER : 1;
+       /* Set the default performance state */
+       pstate = of_get_required_opp_performance_state(dev->of_node, index);
+       if (pstate < 0 && pstate != -ENODEV) {
+               ret = pstate;
+               goto err;
+       } else if (pstate > 0) {
+               ret = dev_pm_genpd_set_performance_state(dev, pstate);
+               if (ret)
+                       goto err;
+               dev_gpd_data(dev)->default_pstate = pstate;
+       }
+       return 1;
+
+err:
+       dev_err(dev, "failed to set required performance state for power-domain %s: %d\n",
+               pd->name, ret);
+       genpd_remove_device(pd, dev);
+       return ret;
 }
 
 /**

diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 21a0577..67017c9 100644 (file)
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -198,6 +198,7 @@ struct generic_pm_domain_data {
        struct notifier_block *power_nb;
        int cpu;
        unsigned int performance_state;
+       unsigned int default_pstate;
        unsigned int rpm_pstate;
        ktime_t next_wakeup;
        void *data;