Quoting Rajendra Nayak (2021-07-16 03:00:57) > Some devics within power domains with performance states do not devices > 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. > Also drop/set as part of runtime suspend/resume callbacks. > > Signed-off-by: Rajendra Nayak <rnayak@xxxxxxxxxxxxxx> > --- > drivers/base/power/domain.c | 37 ++++++++++++++++++++++++++++++++++--- > include/linux/pm_domain.h | 1 + > 2 files changed, 35 insertions(+), 3 deletions(-) > > diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c > index a934c67..dcc0b71 100644 > --- a/drivers/base/power/domain.c > +++ b/drivers/base/power/domain.c > @@ -1000,6 +1008,8 @@ static int genpd_runtime_resume(struct device *dev) > genpd_stop_dev(genpd, dev); > err_poweroff: > if (!pm_runtime_is_irq_safe(dev) || genpd_is_irq_safe(genpd)) { > + if (default_pstate) > + dev_pm_genpd_set_performance_state(dev, 0); > genpd_lock(genpd); > gpd_data->rpm_pstate = genpd_drop_performance_state(dev); Maybe this should be prev_state = genpd_drop_performance_state(dev); if (!default_pstate) gdp_data->rpm_pstate = prev_state; so we don't call dev_pm_genpd_set_performance_state() effectively twice? Also it would make sure we call dev_pm_genpd_set_performance_state() underneath the genpd_lock() if that is important. Similarly do that on suspend path. > genpd_power_off(genpd, true, 0); > @@ -2598,6 +2608,12 @@ 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) > @@ -2675,10 +2692,24 @@ 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; > + } > + > + /* Set the default performance state */ > + np = base_dev->of_node; > + if (of_parse_phandle(np, "required-opps", index)) { > + pstate = of_get_required_opp_performance_state(np, index); > + if (pstate < 0) { > + dev_err(dev, "failed to set pstate:%d", pstate); Missing newline on printk. Also can we spell out pstate as "failed to set required performance state %d for power-domain %d"? > + ret = pstate; > + } > + dev_pm_genpd_set_performance_state(dev, pstate); > + dev_gpd_data(dev)->default_pstate = pstate; > + } > > - return ret ? -EPROBE_DEFER : 1; > + return ret ? ret : 1; > } > > /**