This patch adds support for making one power domain a sub-domain of
other domain. This is useful for modeling power dependences,
which needs to have more than one power domain enabled to be operational.

Signed-off-by: Elaine Zhang <redacted>
---
  drivers/soc/rockchip/pm_domains.c | 51 +++++++++++++++++++++++++++++++++++++++
  1 file changed, 51 insertions(+)

diff --git a/drivers/soc/rockchip/pm_domains.c b/drivers/soc/rockchip/pm_domains.c
index 350527b..c4c2aea 100644
--- a/drivers/soc/rockchip/pm_domains.c
+++ b/drivers/soc/rockchip/pm_domains.c

@@ -372,6 +372,51 @@ static void rockchip_configure_pd_cnt(struct rockchip_pmu *pmu,
  	regmap_write(pmu->regmap, domain_reg_offset + 4, count);
  }

+static int rockchip_pm_add_subdomain(struct rockchip_pmu *pmu,
+				     struct device_node *parent)
+{
+	struct device_node *np;
+	int error;
+
+	for_each_child_of_node(parent, np) {
+		struct generic_pm_domain *child_domain, *parent_domain;
+		u32 idx = ~0;
+
+		if (of_property_read_u32(parent, "reg", &idx)) {
+			dev_err(pmu->dev,
+				"%s: failed to retrieve domain id (reg)\n",
+				parent->name);
+			return -EINVAL;

+		}
+		child_domain = pmu->genpd_data.domains[idx];
+
+		if (pm_genpd_add_subdomain(parent_domain, child_domain))
+			pr_warn("%s failed to add subdomain: %s\n",
+				parent_domain->name, child_domain->name);
+		else
+			pr_warn("%s add subdomain: %s\n",
+				parent_domain->name, child_domain->name);
+
+		rockchip_pm_add_subdomain(pmu, np);
+	}
+	return 0;
+}
+
  static int rockchip_pm_domain_probe(struct platform_device *pdev)
  {
  	struct device *dev = &pdev->dev;

@@ -437,6 +482,12 @@ static int rockchip_pm_domain_probe(struct platform_device *pdev)
  				node->name, error);
  			goto err_out;
  		}
+		error = rockchip_pm_add_subdomain(pmu, node);
+		if (error < 0) {
+			dev_err(dev, "failed to handle subdomain node %s: %d\n",
+				node->name, error);
+			goto err_out;
+		}
  	}

  	if (error) {