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[RFC PATCH 0/3] PM / Domains: Add support for devices that require multiple domains

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  [RFC PATCH 0/3] PM / Domains: Add support for devices that require multiple domains Jon Hunter <jonathanh@nvidia.com> - 2016-09-20 12:30 +0200
    [RFC PATCH 3/3] dt-bindings: Add support for devices with multiple PM domains Jon Hunter <jonathanh@nvidia.com> - 2016-09-20 12:30 +0200
    [RFC PATCH 1/3] PM / Domains: Add helper functions for finding and attaching PM domains Jon Hunter <jonathanh@nvidia.com> - 2016-09-20 12:30 +0200

#1487213 — [RFC PATCH 0/3] PM / Domains: Add support for devices that require multiple domains

The Tegra124/210 XUSB subsystem (that consists of both host and device
controllers) is partitioned across 3 PM domains which are:
- XUSBA: Superspeed logic (for USB 3.0)
- XUSBB: Device controller
- XUSBC: Host controller

These power domains are not nested and can be powered-up and down
independently of one another. In practice different scenarios require
different combinations of the power domains, for example:
- Superspeed host: XUSBA and XUSBC
- Superspeed device: XUSBA and XUSBB

Although it could be possible to logically nest both the XUSBB and XUSBC
domains under the XUSBA, superspeed may not always be used/required and
so this would keep it on unnecessarily.

Given that Tegra uses device-tree for describing the hardware, it would
be ideal that the device-tree 'power-domains' property for generic PM
domains could be extended to allow more than one PM domain to be
specified. For example, define the following the Tegra210 xHCI device ...

	usb@70090000 {
		compatible = "nvidia,tegra210-xusb";
		...
		power-domains = <&pd_xusbhost>, <&pd_xusbss>;
	};

This RFC extends the generic PM domain framework to allow a device to
define more than one PM domain in the device-tree 'power-domains'
property.

Jon Hunter (3):
  PM / Domains: Add helper functions for finding and attaching PM
    domains
  PM / Domains: Add support for devices with multiple domains
  dt-bindings: Add support for devices with multiple PM domains

 .../devicetree/bindings/power/power_domain.txt     |   5 +-
 drivers/base/power/domain.c                        | 205 +++++++++++++++------
 2 files changed, 155 insertions(+), 55 deletions(-)

-- 
2.1.4

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#1487216 — [RFC PATCH 3/3] dt-bindings: Add support for devices with multiple PM domains

Now that the generic PM domain framework supports devices that require
multiple PM domains, update the device-tree binding for generic PM
domains to state that one or more PM domain is permitted for a device.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
---
 Documentation/devicetree/bindings/power/power_domain.txt | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
index 025b5e7df61c..12131159b605 100644
--- a/Documentation/devicetree/bindings/power/power_domain.txt
+++ b/Documentation/devicetree/bindings/power/power_domain.txt
@@ -20,8 +20,9 @@ Required properties:
    as specified by device tree binding documentation of particular provider.
 
 Optional properties:
- - power-domains : A phandle and PM domain specifier as defined by bindings of
-                   the power controller specified by phandle.
+ - power-domains : An array of one or more PM domain specifiers (defined by the
+		   bindings of the PM domain provider) for each PM domain that
+		   is required by the device.
    Some power domains might be powered from another power domain (or have
    other hardware specific dependencies). For representing such dependency
    a standard PM domain consumer binding is used. When provided, all domains
-- 
2.1.4

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#1487217 — [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@nvidia.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

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