[RFC] [PATCH 3/3] IRQ: irq domain: defer of irq ressoure resolve at platform_drv_probe

[Jean-Christophe PLAGNIOL-VILLARD]

Today in the current of implementation we populate all the ressources
at of_platform_populate time. But this leed to a chicken-egg dilemat
some the irq present in DT are from platform_device too. And you can
not resolve them as of_platform_populate. So delay the populate of irq
at platform_drv_probe.

And if the irq_domain is not yet present just defer the probe (GPIO as example)

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
Cc: Grant Likely <grant.likely at secretlab.ca>
Cc: Rob Herring <rob.herring at calxeda.com>
Cc: Arnd Bergmann <arnd at arndb.de>
Cc: Linus Walleij <linus.walleij at linaro.org>
Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
Cc: Ralf Baechle <ralf at linux-mips.org>
Cc: Nicolas Ferre <nicolas.ferre at atmel.com>
---
 drivers/base/platform.c     |    5 +++++
 drivers/of/platform.c       |   29 +++++++++++++++++++++++++++--
 include/linux/of_platform.h |    7 +++++++
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 9eda842..c0f7906 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -13,6 +13,7 @@
 #include <linux/string.h>
 #include <linux/platform_device.h>
 #include <linux/of_device.h>
+#include <linux/of_platform.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/dma-mapping.h>
@@ -484,6 +485,10 @@ static int platform_drv_probe(struct device *_dev)
 	struct platform_device *dev = to_platform_device(_dev);
 	int ret;
 
+	ret = of_device_init_irq(dev);
+	if (ret)
+		return ret;
+
 	if (ACPI_HANDLE(_dev))
 		acpi_dev_pm_attach(_dev, true);
 
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 00a0971..c290943 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -131,6 +131,32 @@ void of_device_make_bus_id(struct device *dev)
 }
 
 /**
+ * of_device_alloc_irq - initialize irq of an platfrom_device
+ * @dev: plaform_device to work on
+ */
+int of_device_init_irq(struct platform_device *dev)
+{
+	struct device_node *np = dev->dev.of_node;
+	int num_irq;
+	int ret;
+	struct resource *res = dev->resource;
+
+	if (!np)
+		return 0;
+
+	num_irq = of_irq_count(np);
+	if (!num_irq)
+		return 0;
+
+	res += dev->num_resources - num_irq;
+	ret = of_irq_to_resource_table(np, res, num_irq);
+	if (ret != num_irq)
+		return -EPROBE_DEFER;
+
+	return 0;
+}
+
+/**
  * of_device_alloc - Allocate and initialize an of_device
  * @np: device node to assign to device
  * @bus_id: Name to assign to the device.  May be null to use default name.
@@ -152,7 +178,7 @@ struct platform_device *of_device_alloc(struct device_node *np,
 	if (of_can_translate_address(np))
 		while (of_address_to_resource(np, num_reg, &temp_res) == 0)
 			num_reg++;
-	num_irq = of_irq_valid_count(np);
+	num_irq = of_irq_count(np);
 
 	/* Populate the resource table */
 	if (num_irq || num_reg) {
@@ -168,7 +194,6 @@ struct platform_device *of_device_alloc(struct device_node *np,
 			rc = of_address_to_resource(np, i, res);
 			WARN_ON(rc);
 		}
-		WARN_ON(of_irq_to_resource_table(np, res, num_irq) != num_irq);
 	}
 
 	dev->dev.of_node = of_node_get(np);
diff --git a/include/linux/of_platform.h b/include/linux/of_platform.h
index 3863a4d..b5f9bb6 100644
--- a/include/linux/of_platform.h
+++ b/include/linux/of_platform.h
@@ -79,6 +79,7 @@ extern const struct of_device_id of_default_bus_match_table[];
 extern struct platform_device *of_device_alloc(struct device_node *np,
 					 const char *bus_id,
 					 struct device *parent);
+extern int of_device_init_irq(struct platform_device *dev);
 extern struct platform_device *of_find_device_by_node(struct device_node *np);
 
 #ifdef CONFIG_OF_ADDRESS /* device reg helpers depend on OF_ADDRESS */
@@ -101,6 +102,7 @@ extern int of_platform_populate(struct device_node *root,
 #if !defined(CONFIG_OF_ADDRESS)
 struct of_dev_auxdata;
 struct device;
+struct platform_device;
 static inline int of_platform_populate(struct device_node *root,
 					const struct of_device_id *matches,
 					const struct of_dev_auxdata *lookup,
@@ -108,6 +110,11 @@ static inline int of_platform_populate(struct device_node *root,
 {
 	return -ENODEV;
 }
+
+static inline int of_device_init_irq(struct platform_device *dev)
+{
+	return 0;
+}
 #endif /* !CONFIG_OF_ADDRESS */
 
 #endif	/* _LINUX_OF_PLATFORM_H */
-- 
1.7.10.4