[RFC PATCH 4/6] of: Extract alloc/add functions from of_platform_device_create_pdata()

[Stephen Boyd <swboyd@chromium.org>]

Allow drivers to modify the 'struct device' for a device node by
splitting of_platform_device_create_pdata() into two functions. The
first function, of_platform_device_alloc(), allocates the platform
device and the second function, of_platform_device_add(), adds the
platform device to the platform bus. SoC power management drivers can
use these APIs to allocate a platform device for a node underneath the
soc node, attach pmdomains and/or set the device as runtime PM active,
and finally add the platform device to the platform bus.

Cc: Rob Herring <robh@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: <devicetree@vger.kernel.org>
Cc: Bjorn Andersson <andersson@kernel.org>
Cc: Konrad Dybcio <konradybcio@kernel.org>
Cc: <linux-arm-msm@vger.kernel.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---
 drivers/of/platform.c       | 80 ++++++++++++++++++++++++++++++-------
 include/linux/of_platform.h | 14 +++++++
 2 files changed, 79 insertions(+), 15 deletions(-)

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 63a80c30d515..d8ee2d38a382 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -138,6 +138,66 @@ struct platform_device *of_device_alloc(struct device_node *np,
 }
 EXPORT_SYMBOL(of_device_alloc);
 
+/**
+ * of_platform_device_alloc - Alloc and initialize an of_device
+ * @np: pointer to node to create device for
+ * @bus_id: name to assign device
+ * @parent: Linux device model parent device.
+ *
+ * Return: Pointer to created platform device, or NULL if a device was not
+ * allocated.  Unavailable devices will not get allocated.
+ */
+struct platform_device *
+of_platform_device_alloc(struct device_node *np, const char *bus_id,
+			  struct device *parent)
+{
+	struct platform_device *ofdev;
+
+	pr_debug("alloc platform device: %pOF\n", np);
+
+	if (!of_device_is_available(np) ||
+	    of_node_test_and_set_flag(np, OF_POPULATED))
+		return NULL;
+
+	ofdev = of_device_alloc(np, bus_id, parent);
+	if (!ofdev) {
+		of_node_clear_flag(np, OF_POPULATED);
+		return ofdev;
+	}
+
+	ofdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
+	if (!ofdev->dev.dma_mask)
+		ofdev->dev.dma_mask = &ofdev->dev.coherent_dma_mask;
+	ofdev->dev.bus = &platform_bus_type;
+	of_msi_configure(&ofdev->dev, ofdev->dev.of_node);
+
+	return ofdev;
+}
+EXPORT_SYMBOL(of_platform_device_alloc);
+
+/**
+ * of_platform_device_add - Add an of_device to the platform bus
+ * @ofdev: of_device to add
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int of_platform_device_add(struct platform_device *ofdev)
+{
+	struct device_node *np = ofdev->dev.of_node;
+	int ret;
+
+	pr_debug("adding platform device: %pOF\n", np);
+
+	ret = of_device_add(ofdev);
+	if (ret) {
+		platform_device_put(ofdev);
+		of_node_clear_flag(np, OF_POPULATED);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(of_platform_device_add);
+
 /**
  * of_platform_device_create_pdata - Alloc, initialize and register an of_device
  * @np: pointer to node to create device for
@@ -154,29 +214,19 @@ static struct platform_device *of_platform_device_create_pdata(
 					void *platform_data,
 					struct device *parent)
 {
+	int ret;
 	struct platform_device *dev;
 
 	pr_debug("create platform device: %pOF\n", np);
 
-	if (!of_device_is_available(np) ||
-	    of_node_test_and_set_flag(np, OF_POPULATED))
+	dev = of_platform_device_alloc(np, bus_id, parent);
+	if (!dev)
 		return NULL;
 
-	dev = of_device_alloc(np, bus_id, parent);
-	if (!dev)
-		goto err_clear_flag;
-
-	dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
-	if (!dev->dev.dma_mask)
-		dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
-	dev->dev.bus = &platform_bus_type;
 	dev->dev.platform_data = platform_data;
-	of_msi_configure(&dev->dev, dev->dev.of_node);
-
-	if (of_device_add(dev) != 0) {
-		platform_device_put(dev);
+	ret = of_platform_device_add(dev);
+	if (ret)
 		goto err_clear_flag;
-	}
 
 	return dev;
 
diff --git a/include/linux/of_platform.h b/include/linux/of_platform.h
index 17471ef8e092..e55c1371b560 100644
--- a/include/linux/of_platform.h
+++ b/include/linux/of_platform.h
@@ -71,6 +71,10 @@ extern int of_platform_bus_probe(struct device_node *root,
 
 #ifdef CONFIG_OF_ADDRESS
 /* Platform devices and busses creation */
+extern struct platform_device *of_platform_device_alloc(struct device_node *np,
+							const char *bus_id,
+							struct device *parent);
+extern int of_platform_device_add(struct platform_device *ofdev);
 extern struct platform_device *of_platform_device_create(struct device_node *np,
 						   const char *bus_id,
 						   struct device *parent);
@@ -91,6 +95,16 @@ extern int devm_of_platform_populate(struct device *dev);
 extern void devm_of_platform_depopulate(struct device *dev);
 #else
 /* Platform devices and busses creation */
+static inline struct platform_device *of_platform_device_alloc(struct device_node *np,
+							       const char *bus_id,
+							       struct device *parent)
+{
+	return NULL;
+}
+static inline int of_platform_device_add(struct platform_device *ofdev)
+{
+	return -ENODEV;
+}
 static inline struct platform_device *of_platform_device_create(struct device_node *np,
 								const char *bus_id,
 								struct device *parent)
-- 
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