[RFC] drivercore: Add of_match_table to the common device drivers

[Grant Likely <grant.likely@secretlab.ca>]

OF-style matching can be available to any device, on any type of bus.
This patch allows any driver to provide an OF match table when CONFIG_OF
is enabled so that drivers can be bound against devices described in
the device tree.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---

Hi Greg and Kay,

Here is a potentially even more controversial RFC patch, the relevant
chunk being the addition of an of-style match table to struct device_driver
when CONFIG_OF is set.  The idea being that OF style device binding is
applicable on any bus, regardless of the bus type.  Each bus' probe could
be trivially extended to allow for an OF-style probe match.

I've used a #ifdef in this version, but it doesn't have to be conditional
if that would make for cleaner code.  Either way, none of the core code
would need to have and #ifdef bits.

As with the previous patch, I want to get feedback before I proceed too
far down this path.

Thanks,
g.


 drivers/macintosh/macio_asic.c |    5 ++---
 drivers/of/of_bus.c            |    7 ++++---
 include/linux/device.h         |    4 ++++
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/macintosh/macio_asic.c b/drivers/macintosh/macio_asic.c
index 67fe13f..a5806ab 100644
--- a/drivers/macintosh/macio_asic.c
+++ b/drivers/macintosh/macio_asic.c
@@ -40,8 +40,7 @@ static struct macio_chip      *macio_on_hold;
 static int macio_bus_match(struct device *dev, struct device_driver *drv) 
 {
 	struct macio_dev * macio_dev = to_macio_device(dev);
-	struct macio_driver * macio_drv = to_macio_driver(drv);
-	const struct of_device_id * matches = macio_drv->match_table;
+	const struct of_device_id * matches = drv->match_table;
 
 	if (!matches) 
 		return 0;
@@ -84,7 +83,7 @@ static int macio_device_probe(struct device *dev)
 
 	macio_dev_get(macio_dev);
 
-	match = of_match_device(drv->match_table, &macio_dev->ofdev);
+	match = of_match_device(drv->driver.match_table, &macio_dev->ofdev);
 	if (match)
 		error = drv->probe(macio_dev, match);
 	if (error)
diff --git a/drivers/of/of_bus.c b/drivers/of/of_bus.c
index d58ade1..9fd7f7d 100644
--- a/drivers/of/of_bus.c
+++ b/drivers/of/of_bus.c
@@ -22,8 +22,7 @@ extern struct device_attribute of_platform_device_attrs[];
 static int of_platform_bus_match(struct device *dev, struct device_driver *drv)
 {
 	struct of_device *of_dev = to_of_device(dev);
-	struct of_platform_driver *of_drv = to_of_platform_driver(drv);
-	const struct of_device_id *matches = of_drv->match_table;
+	const struct of_device_id *matches = drv->of_match_table;
 
 	if (!matches)
 		return 0;
@@ -46,7 +45,7 @@ static int of_platform_device_probe(struct device *dev)
 
 	of_dev_get(of_dev);
 
-	match = of_match_device(drv->match_table, of_dev);
+	match = of_match_device(drv->driver.of_match_table, of_dev);
 	if (match)
 		error = drv->probe(of_dev, match);
 	if (error)
@@ -391,6 +390,8 @@ int of_register_driver(struct of_platform_driver *drv, struct bus_type *bus)
 		drv->driver.name = drv->name;
 	if (!drv->driver.owner)
 		drv->driver.owner = drv->owner;
+	if (!drv->driver.of_match_table)
+		drv->driver.of_match_table = drv->match_table;
 	drv->driver.bus = bus;
 
 	/* register with core */
diff --git a/include/linux/device.h b/include/linux/device.h
index c9b199a..0f998f5 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -129,6 +129,10 @@ struct device_driver {
 
 	bool suppress_bind_attrs;	/* disables bind/unbind via sysfs */
 
+#if defined(CONFIG_OF)
+	const struct of_device_id	*of_match_table;
+#endif
+
 	int (*probe) (struct device *dev);
 	int (*remove) (struct device *dev);
 	void (*shutdown) (struct device *dev);