[PATCH v2 0/9] PM / Domains: Generic OF-based support

Changes in v2:
	- Fix the ACPI patch, it didn't even compile for CONFIG_ACPI.
	- Updated some comments in code and in commit messages.
	- Fixed the dev_pm_domain_attach API to handle EPROBE_DEFER properly.
	- Rebased the ARM Exynos patch.
	- Added some Tested-by tags.


This patchset has a bit of a history and some parts of it has been posted
earlier.

http://lists.infradead.org/pipermail/linux-arm-kernel/2014-June/262725.html

In the first revision I intentially didn't increase version number of the
patches, since I think it would have cause more confusion than clarity.

A summary of changes in V1 and since the last patchset, from the link above:
	- Instead of letting driver core handling the device to power domain
	binding/unbinding, follow the behavior of how the ACPI power domain
	is handled.


This is a summary of what these patches are intended to do:

1)
Add generic power domain OF-based support which also includes APIs to handle
attach/detach of generic power domains to devices.

2)
Adding a common API to attach/detach power domains and include support for the
ACPI and the generic power domain in there.

3)

From subsystem level code, at probe/remove, convert from invoking the ACPI

specific power domain attach/detach functions to the new common attach/detach
APIs.

4)
Add support for the AMBA bus to attach/detach power domains, using the new
common APIs.

5)
Convert Exynos to use the new generic power domain OF support.

Obviously, there are dependencies througout this patchset, which means if they
get accepted the all need to go together. It might also be convenient to share
them through an immutable branch.


Tomasz Figa (2):
  PM / Domains: Add generic OF-based power domain look-up
  ARM: exynos: Move to generic power domain bindings

Ulf Hansson (7):
  ACPI / PM: Let acpi_dev_pm_detach() return an error code
  PM / Domains: Add APIs to attach/detach a PM domain for a device
  drivercore / platform: Convert to dev_pm_domain_attach|detach()
  i2c: core: Convert to dev_pm_domain_attach|detach()
  mmc: sdio: Convert to dev_pm_domain_attach|detach()
  spi: core: Convert to dev_pm_domain_attach|detach()
  amba: Add support for attach/detach of power domains

 .../bindings/arm/exynos/power_domain.txt           |  13 +-
 .../devicetree/bindings/power/power_domain.txt     |  51 ++++
 arch/arm/mach-exynos/pm_domains.c                  |  78 +-----
 drivers/acpi/device_pm.c                           |   8 +-
 drivers/amba/bus.c                                 |  10 +-
 drivers/base/platform.c                            |  15 +-
 drivers/base/power/common.c                        |  56 ++++
 drivers/base/power/domain.c                        | 291 +++++++++++++++++++++
 drivers/i2c/i2c-core.c                             |  13 +-
 drivers/mmc/core/sdio_bus.c                        |   4 +-
 drivers/spi/spi.c                                  |  12 +-
 include/linux/acpi.h                               |   7 +-
 include/linux/pm.h                                 |  14 +
 include/linux/pm_domain.h                          |  46 ++++
 kernel/power/Kconfig                               |   4 +
 15 files changed, 515 insertions(+), 107 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/power/power_domain.txt

-- 
1.9.1

To give callers the option of acting on a errors while removing the
pm_domain ops for the device in the ACPI PM domain, let
acpi_dev_pm_detach() return an int to provide the error code.

Signed-off-by: Ulf Hansson <redacted>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
---
 drivers/acpi/device_pm.c | 8 +++++++-
 include/linux/acpi.h     | 7 +++++--
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index 67075f8..0d52ce1 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c

@@ -1055,6 +1055,8 @@ static struct dev_pm_domain acpi_general_pm_domain = {
  *
  * Callers must ensure proper synchronization of this function with power
  * management callbacks.
+ *
+ * Returns 0 on successfully attached PM domain or negative error code.
  */
 int acpi_dev_pm_attach(struct device *dev, bool power_on)
 {

@@ -1087,8 +1089,10 @@ EXPORT_SYMBOL_GPL(acpi_dev_pm_attach);
  *
  * Callers must ensure proper synchronization of this function with power
  * management callbacks.
+ *
+ * Returns 0 on successfully detached PM domain or negative error code.
  */
-void acpi_dev_pm_detach(struct device *dev, bool power_off)
+int acpi_dev_pm_detach(struct device *dev, bool power_off)
 {
 	struct acpi_device *adev = ACPI_COMPANION(dev);
 

@@ -1107,7 +1111,9 @@ void acpi_dev_pm_detach(struct device *dev, bool power_off)
 			acpi_device_wakeup(adev, ACPI_STATE_S0, false);
 			acpi_dev_pm_low_power(dev, adev, ACPI_STATE_S0);
 		}
+		return 0;
 	}
+	return -EINVAL;
 }
 EXPORT_SYMBOL_GPL(acpi_dev_pm_detach);
 #endif /* CONFIG_PM */

diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 807cbc4..c83cca5 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h

@@ -587,7 +587,7 @@ static inline int acpi_subsys_freeze(struct device *dev) { return 0; }
 #if defined(CONFIG_ACPI) && defined(CONFIG_PM)
 struct acpi_device *acpi_dev_pm_get_node(struct device *dev);
 int acpi_dev_pm_attach(struct device *dev, bool power_on);
-void acpi_dev_pm_detach(struct device *dev, bool power_off);
+int acpi_dev_pm_detach(struct device *dev, bool power_off);
 #else
 static inline struct acpi_device *acpi_dev_pm_get_node(struct device *dev)
 {

@@ -597,7 +597,10 @@ static inline int acpi_dev_pm_attach(struct device *dev, bool power_on)
 {
 	return -ENODEV;
 }
-static inline void acpi_dev_pm_detach(struct device *dev, bool power_off) {}
+static inline int acpi_dev_pm_detach(struct device *dev, bool power_off)
+{
+	return -ENODEV;
+}
 #endif
 
 #ifdef CONFIG_ACPI

-- 
1.9.1

From: Tomasz Figa <redacted>

This patch introduces generic code to perform power domain look-up using
device tree and automatically bind devices to their power domains.
Generic device tree binding is introduced to specify power domains of
devices in their device tree nodes.

Backwards compatibility with legacy Samsung-specific power domain
bindings is provided, but for now the new code is not compiled when
CONFIG_ARCH_EXYNOS is selected to avoid collision with legacy code. This
will change as soon as Exynos power domain code gets converted to use
the generic framework in further patch.

Signed-off-by: Tomasz Figa <redacted>
Signed-off-by: Ulf Hansson <redacted>
[Ulf:Add attach|detach functions]
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
---
 .../devicetree/bindings/power/power_domain.txt     |  51 ++++
 drivers/base/power/domain.c                        | 291 +++++++++++++++++++++
 include/linux/pm_domain.h                          |  46 ++++
 kernel/power/Kconfig                               |   4 +
 4 files changed, 392 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/power/power_domain.txt

diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
new file mode 100644
index 0000000..303d0a9
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/power_domain.txt

@@ -0,0 +1,51 @@
+* Generic power domains
+
+System on chip designs are often divided into multiple power domains that
+can be used for power gating of selected IP blocks for power saving by
+reduced leakage current.
+
+This device tree binding can be used to bind power domain consumer devices
+with their power domains provided by power domain providers. A power domain
+provider can be represented by any node in the device tree and can provide
+one or more power domains. A consumer node can refer to the provider by
+a phandle and a set of phandle arguments (so called power domain specifier)
+of length specified by #power-domain-cells property in the power domain
+provider node.
+
+==Power domain providers==
+
+Required properties:
+ - #power-domain-cells : Number of cells in a power domain specifier;
+   Typically 0 for nodes representing a single power domain and 1 for nodes
+   providing multiple power domains (e.g. power controllers), but can be
+   any value as specified by device tree binding documentation of particular
+   provider.
+
+Example:
+
+	power: power-controller at 12340000 {
+		compatible = "foo,power-controller";
+		reg = <0x12340000 0x1000>;
+		#power-domain-cells = <1>;
+	};
+
+The node above defines a power controller that is a power domain provider
+and expects one cell as its phandle argument.
+
+==Power domain consumers==
+
+Required properties:
+ - power-domains : A phandle and power domain specifier as defined by bindings
+                   of power controller specified by phandle.
+
+Example:
+
+	leaky-device at 12350000 {
+		compatible = "foo,i-leak-current";
+		reg = <0x12350000 0x1000>;
+		power-domains = <&power 0>;
+	};
+
+The node above defines a typical power domain consumer device, which is located
+inside power domain with index 0 of power controller represented by node with
+label "power".

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index eee55c1..0fb26e5 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c

@@ -8,6 +8,7 @@
 
 #include <linux/kernel.h>
 #include <linux/io.h>
+#include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/pm_domain.h>
 #include <linux/pm_qos.h>

@@ -2189,3 +2190,293 @@ void pm_genpd_init(struct generic_pm_domain *genpd,
 	list_add(&genpd->gpd_list_node, &gpd_list);
 	mutex_unlock(&gpd_list_lock);
 }
+
+#ifdef CONFIG_PM_GENERIC_DOMAINS_OF
+/*
+ * Device Tree based power domain providers.
+ *
+ * The code below implements generic device tree based power domain providers
+ * that bind device tree nodes with generic power domains registered in the
+ * system.
+ *
+ * Any driver that registers generic power domains and need to support binding
+ * of devices to these domains is supposed to register a power domain provider,
+ * which maps a power domain specifier retrieved from device tree to a power
+ * domain.
+ *
+ * Two simple mapping functions have been provided for convenience:
+ *  - of_genpd_xlate_simple() for 1:1 device tree node to domain mapping,
+ *  - of_genpd_xlate_onecell() for mapping of multiple domains per node
+ *    by index.
+ */
+
+/**
+ * struct of_genpd_provider - Power domain provider registration structure
+ * @link: Entry in global list of domain providers
+ * @node: Pointer to device tree node of domain provider
+ * @xlate: Provider-specific xlate callback mapping a set of specifier cells
+ *         into a power domain.
+ * @data: context pointer to be passed into @xlate callback
+ */
+struct of_genpd_provider {
+	struct list_head link;
+	struct device_node *node;
+	genpd_xlate_t xlate;
+	void *data;
+};
+
+/* List of registered power domain providers. */
+static LIST_HEAD(of_genpd_providers);
+/* Mutex to protect the list above. */
+static DEFINE_MUTEX(of_genpd_mutex);
+
+/**
+ * of_genpd_xlate_simple() - Xlate function for direct node-domain mapping
+ * @genpdspec: OF phandle args to map into a power domain
+ * @data: xlate function private data - pointer to struct generic_pm_domain
+ *
+ * This is a generic xlate function that can be used to model power domains
+ * that have their own device tree nodes. The private data of xlate function
+ * needs to be a valid pointer to struct generic_pm_domain.
+ */
+struct generic_pm_domain *of_genpd_xlate_simple(
+					struct of_phandle_args *genpdspec,
+					void *data)
+{
+	if (genpdspec->args_count != 0)
+		return ERR_PTR(-EINVAL);
+	return data;
+}
+EXPORT_SYMBOL_GPL(of_genpd_xlate_simple);
+
+/**
+ * of_genpd_xlate_onecell() - Xlate function for providers using single index.
+ * @genpdspec: OF phandle args to map into a power domain
+ * @data: xlate function private data - pointer to struct genpd_onecell_data
+ *
+ * This is a generic xlate function that can be used to model simple power
+ * domain controllers that have one device tree node and provide multiple
+ * power domains. A single cell is used as an index to an array of power
+ * domains specified in genpd_onecell_data struct when registering the
+ * provider.
+ */
+struct generic_pm_domain *of_genpd_xlate_onecell(
+					struct of_phandle_args *genpdspec,
+					void *data)
+{
+	struct genpd_onecell_data *genpd_data = data;
+	unsigned int idx = genpdspec->args[0];
+
+	if (genpdspec->args_count != 1)
+		return ERR_PTR(-EINVAL);
+
+	if (idx >= genpd_data->domain_num) {
+		pr_err("%s: invalid domain index %d\n", __func__, idx);
+		return ERR_PTR(-EINVAL);
+	}
+
+	return genpd_data->domains[idx];
+}
+EXPORT_SYMBOL_GPL(of_genpd_xlate_onecell);
+
+/**
+ * of_genpd_add_provider() - Register a domain provider for a node
+ * @np: Device node pointer associated with domain provider.
+ * @xlate: Callback for decoding domain from phandle arguments.
+ * @data: Context pointer for @genpd_src_get callback.
+ */
+int of_genpd_add_provider(struct device_node *np, genpd_xlate_t xlate,
+			  void *data)
+{
+	struct of_genpd_provider *cp;
+
+	cp = kzalloc(sizeof(*cp), GFP_KERNEL);
+	if (!cp)
+		return -ENOMEM;
+
+	cp->node = of_node_get(np);
+	cp->data = data;
+	cp->xlate = xlate;
+
+	mutex_lock(&of_genpd_mutex);
+	list_add(&cp->link, &of_genpd_providers);
+	mutex_unlock(&of_genpd_mutex);
+	pr_debug("Added domain provider from %s\n", np->full_name);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(of_genpd_add_provider);
+
+/**
+ * of_genpd_del_provider() - Remove a previously registered domain provider
+ * @np: Device node pointer associated with domain provider
+ */
+void of_genpd_del_provider(struct device_node *np)
+{
+	struct of_genpd_provider *cp;
+
+	mutex_lock(&of_genpd_mutex);
+	list_for_each_entry(cp, &of_genpd_providers, link) {
+		if (cp->node == np) {
+			list_del(&cp->link);
+			of_node_put(cp->node);
+			kfree(cp);
+			break;
+		}
+	}
+	mutex_unlock(&of_genpd_mutex);
+}
+EXPORT_SYMBOL_GPL(of_genpd_del_provider);
+
+/**
+ * of_genpd_get_from_provider() - Look-up power domain
+ * @genpdspec: OF phandle args to use for look-up
+ *
+ * Looks for domain provider under node specified by @genpdspec and if found
+ * uses xlate function of the provider to map phandle args to a power domain.
+ *
+ * Returns a valid pointer to struct generic_pm_domain on success or ERR_PTR()
+ * on failure.
+ */
+static struct generic_pm_domain *of_genpd_get_from_provider(
+					struct of_phandle_args *genpdspec)
+{
+	struct generic_pm_domain *genpd = ERR_PTR(-ENOENT);
+	struct of_genpd_provider *provider;
+
+	mutex_lock(&of_genpd_mutex);
+
+	/* Check if we have such a provider in our array */
+	list_for_each_entry(provider, &of_genpd_providers, link) {
+		if (provider->node == genpdspec->np)
+			genpd = provider->xlate(genpdspec, provider->data);
+		if (!IS_ERR(genpd))
+			break;
+	}
+
+	mutex_unlock(&of_genpd_mutex);
+
+	return genpd;
+}
+
+/**
+ * genpd_dev_pm_attach - Attach a device to it's power domain using DT.
+ * @dev: Device to attach.
+ *
+ * Parse device's OF node to find a power domain specifier. If such is found,
+ * attaches the device to retrieved pm_domain ops.
+ *
+ * Both generic and legacy Samsung-specific DT bindings are supported to
+ * keep backwards compatibility with existing DTBs.
+ *
+ * Returns 0 on successfully attached power domain or negative error code.
+ */
+int genpd_dev_pm_attach(struct device *dev)
+{
+	struct of_phandle_args pd_args;
+	struct generic_pm_domain *pd;
+	int ret;
+
+	if (!dev->of_node)
+		return -ENODEV;
+
+	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;
+	}
+
+	pd = of_genpd_get_from_provider(&pd_args);
+	if (IS_ERR(pd)) {
+		dev_dbg(dev, "%s() failed to find power domain: %ld\n",
+			__func__, PTR_ERR(pd));
+		of_node_put(dev->of_node);
+		return PTR_ERR(pd);
+	}
+
+	dev_dbg(dev, "adding to power domain %s\n", pd->name);
+
+	while (1) {
+		ret = pm_genpd_add_device(pd, dev);
+		if (ret != -EAGAIN)
+			break;
+		cond_resched();
+	}
+
+	if (ret < 0) {
+		dev_err(dev, "failed to add to power domain %s: %d",
+			pd->name, ret);
+		of_node_put(dev->of_node);
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(genpd_dev_pm_attach);
+
+/**
+ * genpd_dev_pm_detach - Detach a device from it's power domain.
+ * @dev: Device to attach.
+ *
+ * Try to locate a corresponding generic power domain, which the device
+ * then previously were attached to. If found the device is detached from
+ * the power domain.
+ *
+ * Returns 0 on successfully detached power domain or negative error code.
+ */
+int genpd_dev_pm_detach(struct device *dev)
+{
+	struct generic_pm_domain *pd = NULL, *gpd;
+	int ret = 0;
+
+	if (!dev->pm_domain)
+		return -ENODEV;
+
+	mutex_lock(&gpd_list_lock);
+	list_for_each_entry(gpd, &gpd_list, gpd_list_node) {
+		if (&gpd->domain == dev->pm_domain) {
+			pd = gpd;
+			break;
+		}
+	}
+	mutex_unlock(&gpd_list_lock);
+
+	if (!pd)
+		return -ENOENT;
+
+	dev_dbg(dev, "removing from power domain %s\n", pd->name);
+
+	while (1) {
+		ret = pm_genpd_remove_device(pd, dev);
+		if (ret != -EAGAIN)
+			break;
+		cond_resched();
+	}
+
+	if (ret < 0) {
+		dev_err(dev, "failed to remove from power domain %s: %d",
+			pd->name, ret);
+		return ret;
+	}
+
+	/* Check if domain can be powered off after removing this device. */
+	genpd_queue_power_off_work(pd);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(genpd_dev_pm_detach);
+#endif

diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 7c1d252..5989758 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h

@@ -310,4 +310,50 @@ static inline void pm_genpd_syscore_poweron(struct device *dev)
 	pm_genpd_syscore_switch(dev, false);
 }
 
+/* OF power domain providers */
+struct of_device_id;
+
+struct genpd_onecell_data {
+	struct generic_pm_domain **domains;
+	unsigned int domain_num;
+};
+
+typedef struct generic_pm_domain *(*genpd_xlate_t)(struct of_phandle_args *args,
+						   void *data);
+
+#ifdef CONFIG_PM_GENERIC_DOMAINS_OF
+int of_genpd_add_provider(struct device_node *np, genpd_xlate_t xlate,
+			  void *data);
+void of_genpd_del_provider(struct device_node *np);
+
+struct generic_pm_domain *of_genpd_xlate_simple(
+					struct of_phandle_args *genpdspec,
+					void *data);
+struct generic_pm_domain *of_genpd_xlate_onecell(
+					struct of_phandle_args *genpdspec,
+					void *data);
+
+int genpd_dev_pm_attach(struct device *dev);
+int genpd_dev_pm_detach(struct device *dev);
+#else /* !CONFIG_PM_GENERIC_DOMAINS_OF */
+static inline int of_genpd_add_provider(struct device_node *np,
+					genpd_xlate_t xlate, void *data)
+{
+	return 0;
+}
+static inline void of_genpd_del_provider(struct device_node *np) {}
+
+#define of_genpd_xlate_simple		NULL
+#define of_genpd_xlate_onecell		NULL
+
+static inline int genpd_dev_pm_attach(struct device *dev)
+{
+	return -ENODEV;
+}
+static inline int genpd_dev_pm_detach(struct device *dev)
+{
+	return -ENODEV;
+}
+#endif /* CONFIG_PM_GENERIC_DOMAINS_OF */
+
 #endif /* _LINUX_PM_DOMAIN_H */

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index e4e4121..897619b 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig

@@ -302,6 +302,10 @@ config PM_GENERIC_DOMAINS_RUNTIME
 	def_bool y
 	depends on PM_RUNTIME && PM_GENERIC_DOMAINS
 
+config PM_GENERIC_DOMAINS_OF
+	def_bool y
+	depends on PM_GENERIC_DOMAINS && OF && !ARCH_EXYNOS
+
 config CPU_PM
 	bool
 	depends on SUSPEND || CPU_IDLE

-- 
1.9.1

To maintain scalability let's add common methods to attach and detach
a PM domain for a device, dev_pm_domain_attach|detach().

Typically dev_pm_domain_attach() shall be invoked from subsystem level
code at the probe phase to try to attach a device to it's PM domain.
The reversed actions may be done a the remove phase and then by invoking
dev_pm_domain_detach().

The supported PM domains at this point are the ACPI and the generic
PM domains.

Signed-off-by: Ulf Hansson <redacted>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
---
 drivers/base/power/common.c | 56 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/pm.h          | 14 ++++++++++++
 2 files changed, 70 insertions(+)

diff --git a/drivers/base/power/common.c b/drivers/base/power/common.c
index df2e5ee..c143d20 100644
--- a/drivers/base/power/common.c
+++ b/drivers/base/power/common.c

@@ -11,6 +11,8 @@
 #include <linux/export.h>
 #include <linux/slab.h>
 #include <linux/pm_clock.h>
+#include <linux/acpi.h>
+#include <linux/pm_domain.h>
 
 /**
  * dev_pm_get_subsys_data - Create or refcount power.subsys_data for device.

@@ -82,3 +84,57 @@ int dev_pm_put_subsys_data(struct device *dev)
 	return ret;
 }
 EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);
+
+/**
+ * dev_pm_domain_attach - Attach a device to it's PM domain.
+ * @dev: Device to attach.
+ * @power_on: Used to indicate whether we should power on the device.
+ *
+ * The @dev may only be attached to a single PM domain. By iterating through
+ * the available alternatives we try to find a valid PM domain for the device.
+ *
+ * This function should typically be invoked from subsystem level code during
+ * the probe phase. Especially for those that's hold devices which requires
+ * power management through PM domains.
+ *
+ * Callers must ensure proper synchronization of this function with power
+ * management callbacks.
+ *
+ * Returns 0 on successfully attached PM domain or negative error code.
+ */
+int dev_pm_domain_attach(struct device *dev, bool power_on)
+{
+	int ret;
+
+	ret = acpi_dev_pm_attach(dev, power_on);
+	if (!ret || ret == -EPROBE_DEFER)
+		return ret;
+
+	return genpd_dev_pm_attach(dev);
+}
+EXPORT_SYMBOL_GPL(dev_pm_domain_attach);
+
+/**
+ * dev_pm_domain_detach - Detach a device from it's PM domain.
+ * @dev: Device to attach.
+ * @power_off: Used to indicate whether we should power off the device.
+ *
+ * The @dev may be attached to a PM domain. By iterating through the available
+ * alternatives we detach it from it's PM domain.
+ *
+ * This functions will reverse the actions from dev_pm_domain_attach() and thus
+ * detach the @dev from it's PM domain. Typically it should be invoked from
+ * subsystem level code during the remove phase.
+ *
+ * Callers must ensure proper synchronization of this function with power
+ * management callbacks.
+ *
+ * Returns 0 on successfully detached PM domain or negative error code.
+ */
+int dev_pm_domain_detach(struct device *dev, bool power_off)
+{
+	if (acpi_dev_pm_detach(dev, power_off))
+		return genpd_dev_pm_detach(dev);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dev_pm_domain_detach);

diff --git a/include/linux/pm.h b/include/linux/pm.h
index 72c0fe0..8176b07 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h

@@ -621,6 +621,20 @@ struct dev_pm_domain {
 	struct dev_pm_ops	ops;
 };
 
+#ifdef CONFIG_PM
+extern int dev_pm_domain_attach(struct device *dev, bool power_on);
+extern int dev_pm_domain_detach(struct device *dev, bool power_off);
+#else
+static inline int dev_pm_domain_attach(struct device *dev, bool power_on)
+{
+	return -ENODEV;
+}
+static inline int dev_pm_domain_detach(struct device *dev, bool power_off)
+{
+	return -ENODEV;
+}
+#endif
+
 /*
  * The PM_EVENT_ messages are also used by drivers implementing the legacy
  * suspend framework, based on the ->suspend() and ->resume() callbacks common

-- 
1.9.1

Previously only the ACPI power domain was supported by the platform
bus.

Let's convert to the common attach/detach functions for power domains,
which currently means we are extending the support to include the
generic power domain as well.

Signed-off-by: Ulf Hansson <redacted>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
---
 drivers/base/platform.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index ab4f4ce..904be3d 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c

@@ -506,11 +506,12 @@ static int platform_drv_probe(struct device *_dev)
 	if (ret < 0)
 		return ret;
 
-	acpi_dev_pm_attach(_dev, true);
-
-	ret = drv->probe(dev);
-	if (ret)
-		acpi_dev_pm_detach(_dev, true);
+	ret = dev_pm_domain_attach(_dev, true);
+	if (ret != -EPROBE_DEFER) {
+		ret = drv->probe(dev);
+		if (ret)
+			dev_pm_domain_detach(_dev, true);
+	}
 
 	if (drv->prevent_deferred_probe && ret == -EPROBE_DEFER) {
 		dev_warn(_dev, "probe deferral not supported\n");

@@ -532,7 +533,7 @@ static int platform_drv_remove(struct device *_dev)
 	int ret;
 
 	ret = drv->remove(dev);
-	acpi_dev_pm_detach(_dev, true);
+	dev_pm_domain_detach(_dev, true);
 
 	return ret;
 }

@@ -543,7 +544,7 @@ static void platform_drv_shutdown(struct device *_dev)
 	struct platform_device *dev = to_platform_device(_dev);
 
 	drv->shutdown(dev);
-	acpi_dev_pm_detach(_dev, true);
+	dev_pm_domain_detach(_dev, true);
 }
 
 /**

-- 
1.9.1

Previously only the ACPI power domain was supported by the sdio bus.

Let's convert to the common attach/detach functions for power domains,
which currently means we are extending the support to include the
generic power domain as well.

Cc: linux-mmc at vger.kernel.org
Signed-off-by: Ulf Hansson <redacted>
---
 drivers/mmc/core/sdio_bus.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/core/sdio_bus.c b/drivers/mmc/core/sdio_bus.c
index 4fa8fef9..1df0fc6 100644
--- a/drivers/mmc/core/sdio_bus.c
+++ b/drivers/mmc/core/sdio_bus.c

@@ -315,7 +315,7 @@ int sdio_add_func(struct sdio_func *func)
 	ret = device_add(&func->dev);
 	if (ret == 0) {
 		sdio_func_set_present(func);
-		acpi_dev_pm_attach(&func->dev, false);
+		dev_pm_domain_attach(&func->dev, false);
 	}
 
 	return ret;

@@ -332,7 +332,7 @@ void sdio_remove_func(struct sdio_func *func)
 	if (!sdio_func_present(func))
 		return;
 
-	acpi_dev_pm_detach(&func->dev, false);
+	dev_pm_domain_detach(&func->dev, false);
 	device_del(&func->dev);
 	put_device(&func->dev);
 }

-- 
1.9.1

Previously only the ACPI power domain was supported by the spi bus.

Let's convert to the common attach/detach functions for power domains,
which currently means we are extending the support to include the
generic power domain as well.

Cc: linux-spi at vger.kernel.org
Signed-off-by: Ulf Hansson <redacted>
---
 drivers/spi/spi.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index e0531ba..6a7b0cc 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c

@@ -264,10 +264,12 @@ static int spi_drv_probe(struct device *dev)
 	if (ret)
 		return ret;
 
-	acpi_dev_pm_attach(dev, true);
-	ret = sdrv->probe(to_spi_device(dev));
-	if (ret)
-		acpi_dev_pm_detach(dev, true);
+	ret = dev_pm_domain_attach(dev, true);
+	if (ret != -EPROBE_DEFER) {
+		ret = sdrv->probe(to_spi_device(dev));
+		if (ret)
+			dev_pm_domain_detach(dev, true);
+	}
 
 	return ret;
 }

@@ -278,7 +280,7 @@ static int spi_drv_remove(struct device *dev)
 	int ret;
 
 	ret = sdrv->remove(to_spi_device(dev));
-	acpi_dev_pm_detach(dev, true);
+	dev_pm_domain_detach(dev, true);
 
 	return ret;
 }

-- 
1.9.1

AMBA devices may on some SoCs resides in power domains. To be able to
manage these devices from there, let's try to attach devices to their
corresponding power domain during the probe phase.

To reverse these actions at the remove phase, we try to detach the
device from it's power domain.

Signed-off-by: Ulf Hansson <redacted>
---
 drivers/amba/bus.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index 3cf61a1..8f52393 100644
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c

@@ -182,9 +182,15 @@ static int amba_probe(struct device *dev)
 	int ret;
 
 	do {
+		ret = dev_pm_domain_attach(dev, true);
+		if (ret == -EPROBE_DEFER)
+			break;
+
 		ret = amba_get_enable_pclk(pcdev);
-		if (ret)
+		if (ret) {
+			dev_pm_domain_detach(dev, true);
 			break;
+		}
 
 		pm_runtime_get_noresume(dev);
 		pm_runtime_set_active(dev);

@@ -199,6 +205,7 @@ static int amba_probe(struct device *dev)
 		pm_runtime_put_noidle(dev);
 
 		amba_put_disable_pclk(pcdev);
+		dev_pm_domain_detach(dev, true);
 	} while (0);
 
 	return ret;

@@ -220,6 +227,7 @@ static int amba_remove(struct device *dev)
 	pm_runtime_put_noidle(dev);
 
 	amba_put_disable_pclk(pcdev);
+	dev_pm_domain_detach(dev, true);
 
 	return ret;
 }

-- 
1.9.1

From: Tomasz Figa <redacted>

This patch moves Exynos power domain code to use the new generic power
domain look-up framework introduced in previous patches, thus also
allowing the new code to be compiled with CONFIG_ARCH_EXYNOS as well.

Signed-off-by: Tomasz Figa <redacted>
Cc: linux-samsung-soc at vger.kernel.org
Signed-off-by: Ulf Hansson <redacted>
[Ulf:Rebased and resolved conflicts]
---
 .../bindings/arm/exynos/power_domain.txt           | 13 ++--
 arch/arm/mach-exynos/pm_domains.c                  | 78 +---------------------
 kernel/power/Kconfig                               |  2 +-
 3 files changed, 8 insertions(+), 85 deletions(-)

diff --git a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt
index 8b4f7b7f..abde1ea 100644
--- a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt
+++ b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt

@@ -8,6 +8,8 @@ Required Properties:
     * samsung,exynos4210-pd - for exynos4210 type power domain.
 - reg: physical base address of the controller and length of memory mapped
     region.
+- #power-domain-cells: number of cells in power domain specifier;
+    must be 0.
 
 Optional Properties:
 - clocks: List of clock handles. The parent clocks of the input clocks to the

@@ -29,6 +31,7 @@ Example:
 	lcd0: power-domain-lcd0 {
 		compatible = "samsung,exynos4210-pd";
 		reg = <0x10023C00 0x10>;
+		#power-domain-cells = <0>;
 	};
 
 	mfc_pd: power-domain at 10044060 {

@@ -37,12 +40,8 @@ Example:
 		clocks = <&clock CLK_FIN_PLL>, <&clock CLK_MOUT_SW_ACLK333>,
 			<&clock CLK_MOUT_USER_ACLK333>;
 		clock-names = "oscclk", "pclk0", "clk0";
+		#power-domain-cells = <0>;
 	};
 
-Example of the node using power domain:
-
-	node {
-		/* ... */
-		samsung,power-domain = <&lcd0>;
-		/* ... */
-	};
+See Documentation/devicetree/bindings/power/power_domain.txt for description
+of consumer-side bindings.

diff --git a/arch/arm/mach-exynos/pm_domains.c b/arch/arm/mach-exynos/pm_domains.c
index fd76e1b..46b6502 100644
--- a/arch/arm/mach-exynos/pm_domains.c
+++ b/arch/arm/mach-exynos/pm_domains.c

@@ -105,78 +105,6 @@ static int exynos_pd_power_off(struct generic_pm_domain *domain)
 	return exynos_pd_power(domain, false);
 }
 
-static void exynos_add_device_to_domain(struct exynos_pm_domain *pd,
-					 struct device *dev)
-{
-	int ret;
-
-	dev_dbg(dev, "adding to power domain %s\n", pd->pd.name);
-
-	while (1) {
-		ret = pm_genpd_add_device(&pd->pd, dev);
-		if (ret != -EAGAIN)
-			break;
-		cond_resched();
-	}
-
-	pm_genpd_dev_need_restore(dev, true);
-}
-
-static void exynos_remove_device_from_domain(struct device *dev)
-{
-	struct generic_pm_domain *genpd = dev_to_genpd(dev);
-	int ret;
-
-	dev_dbg(dev, "removing from power domain %s\n", genpd->name);
-
-	while (1) {
-		ret = pm_genpd_remove_device(genpd, dev);
-		if (ret != -EAGAIN)
-			break;
-		cond_resched();
-	}
-}
-
-static void exynos_read_domain_from_dt(struct device *dev)
-{
-	struct platform_device *pd_pdev;
-	struct exynos_pm_domain *pd;
-	struct device_node *node;
-
-	node = of_parse_phandle(dev->of_node, "samsung,power-domain", 0);
-	if (!node)
-		return;
-	pd_pdev = of_find_device_by_node(node);
-	if (!pd_pdev)
-		return;
-	pd = platform_get_drvdata(pd_pdev);
-	exynos_add_device_to_domain(pd, dev);
-}
-
-static int exynos_pm_notifier_call(struct notifier_block *nb,
-				    unsigned long event, void *data)
-{
-	struct device *dev = data;
-
-	switch (event) {
-	case BUS_NOTIFY_BIND_DRIVER:
-		if (dev->of_node)
-			exynos_read_domain_from_dt(dev);
-
-		break;
-
-	case BUS_NOTIFY_UNBOUND_DRIVER:
-		exynos_remove_device_from_domain(dev);
-
-		break;
-	}
-	return NOTIFY_DONE;
-}
-
-static struct notifier_block platform_nb = {
-	.notifier_call = exynos_pm_notifier_call,
-};
-
 static __init int exynos4_pm_init_power_domain(void)
 {
 	struct platform_device *pdev;

@@ -202,7 +130,6 @@ static __init int exynos4_pm_init_power_domain(void)
 		pd->base = of_iomap(np, 0);
 		pd->pd.power_off = exynos_pd_power_off;
 		pd->pd.power_on = exynos_pd_power_on;
-		pd->pd.of_node = np;
 
 		pd->oscclk = clk_get(dev, "oscclk");
 		if (IS_ERR(pd->oscclk))

@@ -228,15 +155,12 @@ static __init int exynos4_pm_init_power_domain(void)
 			clk_put(pd->oscclk);
 
 no_clk:
-		platform_set_drvdata(pdev, pd);
-
 		on = __raw_readl(pd->base + 0x4) & INT_LOCAL_PWR_EN;
 
 		pm_genpd_init(&pd->pd, NULL, !on);
+		of_genpd_add_provider(np, of_genpd_xlate_simple, &pd->pd);
 	}
 
-	bus_register_notifier(&platform_bus_type, &platform_nb);
-
 	return 0;
 }
 arch_initcall(exynos4_pm_init_power_domain);

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 897619b..bbef57f 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig

@@ -304,7 +304,7 @@ config PM_GENERIC_DOMAINS_RUNTIME
 
 config PM_GENERIC_DOMAINS_OF
 	def_bool y
-	depends on PM_GENERIC_DOMAINS && OF && !ARCH_EXYNOS
+	depends on PM_GENERIC_DOMAINS && OF
 
 config CPU_PM
 	bool

-- 
1.9.1

Hi Ulf, Tomasz,

On Thu, Aug 28, 2014 at 10:38 AM, Ulf Hansson [off-list ref] wrote:

From: Tomasz Figa <redacted>

This patch introduces generic code to perform power domain look-up using

Should "power domain" be replaced by "PM domain" here (and everywhere else
in this patch), too, cfr. Rafael's earlier comment?

specifiers

+of length specified by #power-domain-cells property in the power domain

the #power-domain-cells property

+provider node.
+
+==Power domain providers==
+
+Required properties:
+ - #power-domain-cells : Number of cells in a power domain specifier;
+   Typically 0 for nodes representing a single power domain and 1 for nodes
+   providing multiple power domains (e.g. power controllers), but can be
+   any value as specified by device tree binding documentation of particular
+   provider.
+
+Example:
+
+       power: power-controller at 12340000 {
+               compatible = "foo,power-controller";
+               reg = <0x12340000 0x1000>;
+               #power-domain-cells = <1>;
+       };
+
+The node above defines a power controller that is a power domain provider
+and expects one cell as its phandle argument.
+
+==Power domain consumers==
+
+Required properties:
+ - power-domains : A phandle and power domain specifier as defined by bindings
+                   of power controller specified by phandle.

the power controller

+
+Example:
+
+       leaky-device at 12350000 {
+               compatible = "foo,i-leak-current";
+               reg = <0x12350000 0x1000>;
+               power-domains = <&power 0>;
+       };
+
+The node above defines a typical power domain consumer device, which is located
+inside power domain with index 0 of power controller represented by node with

the power domain ... the power controller ... the node

+label "power".

+#ifdef CONFIG_PM_GENERIC_DOMAINS_OF
+/*
+ * Device Tree based power domain providers.
+ *
+ * The code below implements generic device tree based power domain providers
+ * that bind device tree nodes with generic power domains registered in the
+ * system.
+ *
+ * Any driver that registers generic power domains and need to support binding

needs

+ * of devices to these domains is supposed to register a power domain provider,
+ * which maps a power domain specifier retrieved from device tree to a power

the device tree

+/**
+ * of_genpd_xlate_onecell() - Xlate function for providers using single index.

a single index

+ * @genpdspec: OF phandle args to map into a power domain
+ * @data: xlate function private data - pointer to struct genpd_onecell_data
+ *
+ * This is a generic xlate function that can be used to model simple power
+ * domain controllers that have one device tree node and provide multiple
+ * power domains. A single cell is used as an index to an array of power

an index into

+ * domains specified in genpd_onecell_data struct when registering the

the genpd_onecell_data struct

+ * provider.
+ */
+struct generic_pm_domain *of_genpd_xlate_onecell(
+                                       struct of_phandle_args *genpdspec,
+                                       void *data)
+{
+       struct genpd_onecell_data *genpd_data = data;
+       unsigned int idx = genpdspec->args[0];
+
+       if (genpdspec->args_count != 1)
+               return ERR_PTR(-EINVAL);
+
+       if (idx >= genpd_data->domain_num) {
+               pr_err("%s: invalid domain index %d\n", __func__, idx);

%u for unsigned int idx

+               return ERR_PTR(-EINVAL);
+       }
+
+       return genpd_data->domains[idx];

This assumes ->domains[] is a contiguous array.

I'd add a NULL check here, to translate NULL to ERR_PTR(-Esomething),
so it can support sparse power domain spaces.
E.g. indexed by the "bit_shift" value of struct rmobile_pm_domain, which
is the actual bit number to use to power up/down an R-Mobile domain.
Different members of the R-Mobile family have different numbers of
domains, and use more or less bits in the same power up/down registers.
This would be similar to the sparse clock-indices handling in
renesas,cpg-mstp-clocks.

+}
+EXPORT_SYMBOL_GPL(of_genpd_xlate_onecell);
+
+/**
+ * of_genpd_add_provider() - Register a domain provider for a node
+ * @np: Device node pointer associated with domain provider.

the domain provider

+/**
+ * of_genpd_del_provider() - Remove a previously registered domain provider
+ * @np: Device node pointer associated with domain provider

the domain provider

+/**
+ * of_genpd_get_from_provider() - Look-up power domain
+ * @genpdspec: OF phandle args to use for look-up
+ *
+ * Looks for domain provider under node specified by @genpdspec and if found

a domain provider ... under the node

+ * uses xlate function of the provider to map phandle args to a power domain.

+/**
+ * genpd_dev_pm_attach - Attach a device to it's power domain using DT.

its

+ * @dev: Device to attach.

+/**
+ * genpd_dev_pm_detach - Detach a device from it's power domain.

its

+ * @dev: Device to attach.
+ *
+ * Try to locate a corresponding generic power domain, which the device
+ * then previously were attached to. If found the device is detached from

"was attached to previously"?

+ * the power domain.

This is the number of domains: "num_domains"?

+};
+
+typedef struct generic_pm_domain *(*genpd_xlate_t)(struct of_phandle_args *args,
+                                                  void *data);
+
+#ifdef CONFIG_PM_GENERIC_DOMAINS_OF
+int of_genpd_add_provider(struct device_node *np, genpd_xlate_t xlate,
+                         void *data);
+void of_genpd_del_provider(struct device_node *np);
+
+struct generic_pm_domain *of_genpd_xlate_simple(
+                                       struct of_phandle_args *genpdspec,
+                                       void *data);
+struct generic_pm_domain *of_genpd_xlate_onecell(
+                                       struct of_phandle_args *genpdspec,
+                                       void *data);
+
+int genpd_dev_pm_attach(struct device *dev);
+int genpd_dev_pm_detach(struct device *dev);
+#else /* !CONFIG_PM_GENERIC_DOMAINS_OF */
+static inline int of_genpd_add_provider(struct device_node *np,
+                                       genpd_xlate_t xlate, void *data)
+{
+       return 0;
+}
+static inline void of_genpd_del_provider(struct device_node *np) {}
+
+#define of_genpd_xlate_simple          NULL
+#define of_genpd_xlate_onecell         NULL
+
+static inline int genpd_dev_pm_attach(struct device *dev)
+{
+       return -ENODEV;
+}
+static inline int genpd_dev_pm_detach(struct device *dev)
+{
+       return -ENODEV;
+}
+#endif /* CONFIG_PM_GENERIC_DOMAINS_OF */

As of_genpd_add_provider() provides no compile-time type-checking for
"void *data", I propose to prepend a double underscore to
of_genpd_add_provider(), and to the xlate helpers of_genpd_xlate_simple()
and of_genpd_xlate_onecell(), and provide type-checking wrappers:

static inline int of_genpd_add_provider_simple(struct device_node *np,
                                               struct generic_pm_domain *genpd)
{
        return __of_genpd_add_provider(np, __of_genpd_xlate_simple, genpd);
}
static inline int of_genpd_add_provider_onecell(struct device_node *np,
                                                struct genpd_onecell_data *data)
{
        return __of_genpd_add_provider(np, __of_genpd_xlate_onecell, data);
}

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

On 2 September 2014 20:28, Geert Uytterhoeven [off-list ref] wrote:

Hi Ulf, Tomasz,

On Thu, Aug 28, 2014 at 10:38 AM, Ulf Hansson [off-list ref] wrote:

quoted

From: Tomasz Figa <redacted>

This patch introduces generic code to perform power domain look-up using

Should "power domain" be replaced by "PM domain" here (and everywhere else
in this patch), too, cfr. Rafael's earlier comment?

Hi Geert,

Thanks for reviewing!

I changed some of the other patches according to Rafael's earlier
comment, but decided to keep this as is. The reason is that in
drivers/base/power/domain.c there are already a mix between using
"power domain" and "PM domain", thus I couldn't decide which way to
go.

I have no strong opinion of what terminology we use, I am happy to
change this patch. Since I anyway will be sending new version, I will
update to "PM domain".

quoted

+++ b/Documentation/devicetree/bindings/power/power_domain.txt

@@ -0,0 +1,51 @@
+* Generic power domains
+
+System on chip designs are often divided into multiple power domains that
+can be used for power gating of selected IP blocks for power saving by
+reduced leakage current.
+
+This device tree binding can be used to bind power domain consumer devices
+with their power domains provided by power domain providers. A power domain
+provider can be represented by any node in the device tree and can provide
+one or more power domains. A consumer node can refer to the provider by
+a phandle and a set of phandle arguments (so called power domain specifier)

specifiers

quoted

+of length specified by #power-domain-cells property in the power domain

the #power-domain-cells property

quoted

+provider node.
+
+==Power domain providers==
+
+Required properties:
+ - #power-domain-cells : Number of cells in a power domain specifier;
+   Typically 0 for nodes representing a single power domain and 1 for nodes
+   providing multiple power domains (e.g. power controllers), but can be
+   any value as specified by device tree binding documentation of particular
+   provider.
+
+Example:
+
+       power: power-controller at 12340000 {
+               compatible = "foo,power-controller";
+               reg = <0x12340000 0x1000>;
+               #power-domain-cells = <1>;
+       };
+
+The node above defines a power controller that is a power domain provider
+and expects one cell as its phandle argument.
+
+==Power domain consumers==
+
+Required properties:
+ - power-domains : A phandle and power domain specifier as defined by bindings
+                   of power controller specified by phandle.

the power controller

quoted

+
+Example:
+
+       leaky-device at 12350000 {
+               compatible = "foo,i-leak-current";
+               reg = <0x12350000 0x1000>;
+               power-domains = <&power 0>;
+       };
+
+The node above defines a typical power domain consumer device, which is located
+inside power domain with index 0 of power controller represented by node with

the power domain ... the power controller ... the node

quoted

+label "power".

quoted

--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c

quoted

+#ifdef CONFIG_PM_GENERIC_DOMAINS_OF
+/*
+ * Device Tree based power domain providers.
+ *
+ * The code below implements generic device tree based power domain providers
+ * that bind device tree nodes with generic power domains registered in the
+ * system.
+ *
+ * Any driver that registers generic power domains and need to support binding

needs

quoted

+ * of devices to these domains is supposed to register a power domain provider,
+ * which maps a power domain specifier retrieved from device tree to a power

the device tree

quoted

+/**
+ * of_genpd_xlate_onecell() - Xlate function for providers using single index.

a single index

quoted

+ * @genpdspec: OF phandle args to map into a power domain
+ * @data: xlate function private data - pointer to struct genpd_onecell_data
+ *
+ * This is a generic xlate function that can be used to model simple power
+ * domain controllers that have one device tree node and provide multiple
+ * power domains. A single cell is used as an index to an array of power

an index into

quoted

+ * domains specified in genpd_onecell_data struct when registering the

the genpd_onecell_data struct

quoted

+ * provider.
+ */
+struct generic_pm_domain *of_genpd_xlate_onecell(
+                                       struct of_phandle_args *genpdspec,
+                                       void *data)
+{
+       struct genpd_onecell_data *genpd_data = data;
+       unsigned int idx = genpdspec->args[0];
+
+       if (genpdspec->args_count != 1)
+               return ERR_PTR(-EINVAL);
+
+       if (idx >= genpd_data->domain_num) {
+               pr_err("%s: invalid domain index %d\n", __func__, idx);

%u for unsigned int idx

quoted

+               return ERR_PTR(-EINVAL);
+       }
+
+       return genpd_data->domains[idx];

This assumes ->domains[] is a contiguous array.

I'd add a NULL check here, to translate NULL to ERR_PTR(-Esomething),
so it can support sparse power domain spaces.
E.g. indexed by the "bit_shift" value of struct rmobile_pm_domain, which
is the actual bit number to use to power up/down an R-Mobile domain.
Different members of the R-Mobile family have different numbers of
domains, and use more or less bits in the same power up/down registers.
This would be similar to the sparse clock-indices handling in
renesas,cpg-mstp-clocks.

OK, will do!

quoted

+}
+EXPORT_SYMBOL_GPL(of_genpd_xlate_onecell);
+
+/**
+ * of_genpd_add_provider() - Register a domain provider for a node
+ * @np: Device node pointer associated with domain provider.

the domain provider

quoted

+/**
+ * of_genpd_del_provider() - Remove a previously registered domain provider
+ * @np: Device node pointer associated with domain provider

the domain provider

quoted

+/**
+ * of_genpd_get_from_provider() - Look-up power domain
+ * @genpdspec: OF phandle args to use for look-up
+ *
+ * Looks for domain provider under node specified by @genpdspec and if found

a domain provider ... under the node

quoted

+ * uses xlate function of the provider to map phandle args to a power domain.

quoted

+/**
+ * genpd_dev_pm_attach - Attach a device to it's power domain using DT.

its

quoted

+ * @dev: Device to attach.

quoted

+/**
+ * genpd_dev_pm_detach - Detach a device from it's power domain.

its

quoted

+ * @dev: Device to attach.
+ *
+ * Try to locate a corresponding generic power domain, which the device
+ * then previously were attached to. If found the device is detached from

"was attached to previously"?

quoted

+ * the power domain.

quoted

diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 7c1d252..5989758 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h

@@ -310,4 +310,50 @@ static inline void pm_genpd_syscore_poweron(struct device *dev)
        pm_genpd_syscore_switch(dev, false);
 }

+/* OF power domain providers */
+struct of_device_id;
+
+struct genpd_onecell_data {
+       struct generic_pm_domain **domains;
+       unsigned int domain_num;

This is the number of domains: "num_domains"?

OK, that describes it better.

quoted

+};
+
+typedef struct generic_pm_domain *(*genpd_xlate_t)(struct of_phandle_args *args,
+                                                  void *data);
+
+#ifdef CONFIG_PM_GENERIC_DOMAINS_OF
+int of_genpd_add_provider(struct device_node *np, genpd_xlate_t xlate,
+                         void *data);
+void of_genpd_del_provider(struct device_node *np);
+
+struct generic_pm_domain *of_genpd_xlate_simple(
+                                       struct of_phandle_args *genpdspec,
+                                       void *data);
+struct generic_pm_domain *of_genpd_xlate_onecell(
+                                       struct of_phandle_args *genpdspec,
+                                       void *data);
+
+int genpd_dev_pm_attach(struct device *dev);
+int genpd_dev_pm_detach(struct device *dev);
+#else /* !CONFIG_PM_GENERIC_DOMAINS_OF */
+static inline int of_genpd_add_provider(struct device_node *np,
+                                       genpd_xlate_t xlate, void *data)
+{
+       return 0;
+}
+static inline void of_genpd_del_provider(struct device_node *np) {}
+
+#define of_genpd_xlate_simple          NULL
+#define of_genpd_xlate_onecell         NULL
+
+static inline int genpd_dev_pm_attach(struct device *dev)
+{
+       return -ENODEV;
+}
+static inline int genpd_dev_pm_detach(struct device *dev)
+{
+       return -ENODEV;
+}
+#endif /* CONFIG_PM_GENERIC_DOMAINS_OF */

As of_genpd_add_provider() provides no compile-time type-checking for
"void *data", I propose to prepend a double underscore to
of_genpd_add_provider(), and to the xlate helpers of_genpd_xlate_simple()
and of_genpd_xlate_onecell(), and provide type-checking wrappers:

Good idea, I will give it a try in next version.

static inline int of_genpd_add_provider_simple(struct device_node *np,
                                               struct generic_pm_domain *genpd)
{
        return __of_genpd_add_provider(np, __of_genpd_xlate_simple, genpd);
}
static inline int of_genpd_add_provider_onecell(struct device_node *np,
                                                struct genpd_onecell_data *data)
{
        return __of_genpd_add_provider(np, __of_genpd_xlate_onecell, data);
}

Thanks for all the grammar/English corrections as well. Will update.

Kind regards
Uffe