As of the patch ("PM / Domains: Mark "name" const in
genpd_dev_pm_attach_by_name()") it's clear that the name in
dev_pm_domain_attach_by_name() can be const.  Mark it as so.  This
allows drivers to pass in a name that was declared "const" in a
driver.

Fixes: 27dceb81f445 ("PM / Domains: Introduce dev_pm_domain_attach_by_name()")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The genpd_dev_pm_attach_by_name() simply takes the name and passes it
to of_property_match_string() where the argument is "const char *".
Adding a const here allows a later patch to add a const to
dev_pm_domain_attach_by_name() which allows drivers to pass in a name
that was declared "const" in a driver.

Fixes: 5d6be70add65 ("PM / Domains: Introduce option to attach a device by name to genpd")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Currently a genpd only handles the performance state requirements from
the devices under its control. This commit extends that to also handle
the performance state requirement(s) put on the master genpd by its
sub-domains. There is a separate value required for each master that
the genpd has and so a new field is added to the struct gpd_link
(link->performance_state), which represents the link between a genpd and
its master. The struct gpd_link also got another field
prev_performance_state, which is used by genpd core as a temporary
variable during transitions.

On a call to dev_pm_genpd_set_performance_state(), the genpd core first
updates the performance state of the masters of the device's genpd and
then updates the performance state of the genpd. The masters do the same
and propagate performance state updates to their masters before updating
their own. The performance state transition from genpd to its master is
done with the help of dev_pm_opp_xlate_performance_state(), which looks
at the OPP tables of both the domains to translate the state.

Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

dev_pm_genpd_set_performance_state() will be required to call
dev_pm_opp_xlate_performance_state() going forward to translate from
performance state of a sub-domain to performance state of its master.
And dev_pm_opp_xlate_performance_state() needs pointers to the OPP
tables of both genpd and its master.

Lets fetch and save them while the OPP tables are added. Fetching the
OPP tables should never fail as we just added the OPP tables and so add
a WARN_ON() for such a bug instead of full error paths.

Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

The OPP core already has the performance state values for each of the
genpd's OPPs and there is no need to call the genpd callback again to
get the performance state for the case where the end device doesn't have
an OPP table and has the "required-opps" property directly in its node.

This commit renames of_genpd_opp_to_performance_state() as
of_get_required_opp_performance_state() and moves it to the OPP core, as
it is all about OPP stuff now.

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

The OPP core currently stores the performance state in the consumer
device's OPP table, but that is going to change going forward and
performance state will rather be set directly in the genpd's OPP table.

For that we need to get the performance state for genpd's device
structure (genpd->dev) instead of the consumer device's structure. Add a
new helper to do that.

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

The current documented description of the GENPD_FLAG_* flags, are too
simplified, so let's extend them.

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

For the multiple PM domain case, let's introduce a new API called
dev_pm_domain_attach_by_name(). This allows a consumer driver to associate
its device with one of its PM domains, by using a name based lookup.

Do note that, currently it's only genpd that supports multiple PM domains
per device, but dev_pm_domain_attach_by_name() can easily by extended to
cover other PM domain types, if/when needed.

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

For the multiple PM domain case, let's introduce a new function called
genpd_dev_pm_attach_by_name(). This allows a device to be associated with
its PM domain through genpd, by using a name based lookup.

Note that, genpd_dev_pm_attach_by_name() shall only be called by the driver
core / PM core, similar to how the existing dev_pm_domain_attach_by_id()
makes use of genpd_dev_pm_attach_by_id(). However, this is implemented by
following changes on top.

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

The DT node passed here isn't necessarily an OPP node, as this routine
can also be used for cases where the "required-opps" property is present
directly in the device's node. Rename it.

This also removes a stale comment.

Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>