linux-kernel - [RFC PATCH 1/3] PM / Domains: Add helper functions for finding and attaching PM domains

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Date:   Tue, 20 Sep 2016 11:28:05 +0100
From:   Jon Hunter <jonathanh@...dia.com>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Kevin Hilman <khilman@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>
CC:     <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-tegra@...r.kernel.org>, Jon Hunter <jonathanh@...dia.com>
Subject: [RFC PATCH 1/3] PM / Domains: Add helper functions for finding and attaching PM domains

In preparation for supporting devices that require more than one PM
domain, move the code for finding and attaching PM domains into local
helper functions.

Signed-off-by: Jon Hunter <jonathanh@...dia.com>
---
 drivers/base/power/domain.c | 121 ++++++++++++++++++++++++++------------------
 1 file changed, 73 insertions(+), 48 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index b0cf46dcae73..382735949591 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1779,6 +1779,41 @@ struct generic_pm_domain *of_genpd_remove_last(struct device_node *np)
 }
 EXPORT_SYMBOL_GPL(of_genpd_remove_last);
 
+static struct generic_pm_domain *genpd_dev_pm_lookup(struct device *dev,
+						     unsigned int index)
+{
+	struct of_phandle_args pd_args;
+	struct generic_pm_domain *pd;
+	int ret;
+
+	ret = of_parse_phandle_with_args(dev->of_node, "power-domains",
+					 "#power-domain-cells", index, &pd_args);
+	if (ret < 0) {
+		if (ret != -ENOENT)
+			return ERR_PTR(ret);
+
+		/*
+		 * Try legacy Samsung-specific bindings
+		 * (for backwards compatibility of DT ABI)
+		 */
+		pd_args.args_count = 0;
+		pd_args.np = of_parse_phandle(dev->of_node,
+					      "samsung,power-domain", 0);
+		if (!pd_args.np)
+			return ERR_PTR(-ENOENT);
+	}
+
+	pd = genpd_get_from_provider(&pd_args);
+	of_node_put(pd_args.np);
+	if (IS_ERR(pd)) {
+		dev_dbg(dev, "%s() failed to find PM domain: %ld\n",
+			__func__, PTR_ERR(pd));
+		return ERR_PTR(-EPROBE_DEFER);
+	}
+
+	return pd;
+}
+
 /**
  * genpd_dev_pm_detach - Detach a device from its PM domain.
  * @dev: Device to detach.
@@ -1829,6 +1864,40 @@ static void genpd_dev_pm_sync(struct device *dev)
 	genpd_queue_power_off_work(pd);
 }
 
+static int genpd_dev_pm_attach_device(struct device *dev,
+				      struct generic_pm_domain *pd)
+{
+	unsigned int i;
+	int ret;
+
+	dev_dbg(dev, "adding to PM domain %s\n", pd->name);
+
+	for (i = 1; i < GENPD_RETRY_MAX_MS; i <<= 1) {
+		ret = genpd_add_device(pd, dev, NULL);
+		if (ret != -EAGAIN)
+			break;
+
+		mdelay(i);
+		cond_resched();
+	}
+
+	if (ret < 0) {
+		dev_err(dev, "failed to add to PM domain %s: %d",
+			pd->name, ret);
+		goto out;
+	}
+
+	dev->pm_domain->detach = genpd_dev_pm_detach;
+	dev->pm_domain->sync = genpd_dev_pm_sync;
+
+	mutex_lock(&pd->lock);
+	ret = genpd_poweron(pd, 0);
+	mutex_unlock(&pd->lock);
+out:
+	return ret ? -EPROBE_DEFER : 0;
+
+}
+
 /**
  * genpd_dev_pm_attach - Attach a device to its PM domain using DT.
  * @dev: Device to attach.
@@ -1846,9 +1915,7 @@ static void genpd_dev_pm_sync(struct device *dev)
  */
 int genpd_dev_pm_attach(struct device *dev)
 {
-	struct of_phandle_args pd_args;
 	struct generic_pm_domain *pd;
-	unsigned int i;
 	int ret;
 
 	if (!dev->of_node)
@@ -1857,59 +1924,17 @@ int genpd_dev_pm_attach(struct device *dev)
 	if (dev->pm_domain)
 		return -EEXIST;
 
-	ret = of_parse_phandle_with_args(dev->of_node, "power-domains",
-					"#power-domain-cells", 0, &pd_args);
-	if (ret < 0) {
-		if (ret != -ENOENT)
-			return ret;
-
-		/*
-		 * Try legacy Samsung-specific bindings
-		 * (for backwards compatibility of DT ABI)
-		 */
-		pd_args.args_count = 0;
-		pd_args.np = of_parse_phandle(dev->of_node,
-						"samsung,power-domain", 0);
-		if (!pd_args.np)
-			return -ENOENT;
-	}
-
 	mutex_lock(&gpd_list_lock);
-	pd = genpd_get_from_provider(&pd_args);
-	of_node_put(pd_args.np);
+	pd = genpd_dev_pm_lookup(dev, 0);
 	if (IS_ERR(pd)) {
 		mutex_unlock(&gpd_list_lock);
-		dev_dbg(dev, "%s() failed to find PM domain: %ld\n",
-			__func__, PTR_ERR(pd));
 		return -EPROBE_DEFER;
 	}
 
-	dev_dbg(dev, "adding to PM domain %s\n", pd->name);
-
-	for (i = 1; i < GENPD_RETRY_MAX_MS; i <<= 1) {
-		ret = genpd_add_device(pd, dev, NULL);
-		if (ret != -EAGAIN)
-			break;
-
-		mdelay(i);
-		cond_resched();
-	}
-	mutex_unlock(&gpd_list_lock);
-
-	if (ret < 0) {
-		dev_err(dev, "failed to add to PM domain %s: %d",
-			pd->name, ret);
-		goto out;
-	}
-
-	dev->pm_domain->detach = genpd_dev_pm_detach;
-	dev->pm_domain->sync = genpd_dev_pm_sync;
+	ret = genpd_dev_pm_attach_device(dev, pd);
+	mutex_lock(&gpd_list_lock);
 
-	mutex_lock(&pd->lock);
-	ret = genpd_poweron(pd, 0);
-	mutex_unlock(&pd->lock);
-out:
-	return ret ? -EPROBE_DEFER : 0;
+	return ret;
 }
 EXPORT_SYMBOL_GPL(genpd_dev_pm_attach);
 #endif /* CONFIG_PM_GENERIC_DOMAINS_OF */
-- 
2.1.4