[PATCH (Option 1)] of/i2c: fix module load order issue caused byof_i2c.c

From: Grant Likely
Date: Fri Sep 24 2010 - 18:15:01 EST


Commit 959e85f7, "i2c: add OF-style registration and binding" caused a
module dependency loop where of_i2c.c calls functions in i2c-core, and
i2c-core calls of_i2c_register_devices() in of_i2c. This means that
when i2c support is built as a module when CONFIG_OF is set, then
neither i2c_core nor of_i2c are able to be loaded.

This patch fixes the problem by moving the of_i2c_register_devices()
function into the body of i2c_core and renaming it to
i2c_scan_of_devices (of_i2c_register_devices is analogous to the
existing i2c_scan_static_board_info function and so should be named
similarly). This function isn't called by any code outside of
i2c_core, and it must always be present when CONFIG_OF is selected, so
it makes sense to locate it there. When CONFIG_OF is not selected,
of_i2c_register_devices() becomes a no-op.

Signed-off-by: Grant Likely <grant.likely@xxxxxxxxxxxx>
---
drivers/i2c/i2c-core.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++--
drivers/of/of_i2c.c | 57 ---------------------------------------------
include/linux/of_i2c.h | 7 ------
3 files changed, 59 insertions(+), 66 deletions(-)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 6649176..64a261b 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -32,8 +32,8 @@
#include <linux/init.h>
#include <linux/idr.h>
#include <linux/mutex.h>
-#include <linux/of_i2c.h>
#include <linux/of_device.h>
+#include <linux/of_irq.h>
#include <linux/completion.h>
#include <linux/hardirq.h>
#include <linux/irqflags.h>
@@ -818,6 +818,63 @@ static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
up_read(&__i2c_board_lock);
}

+#ifdef CONFIG_OF
+void i2c_scan_of_devices(struct i2c_adapter *adap)
+{
+ void *result;
+ struct device_node *node;
+
+ /* Only register child devices if the adapter has a node pointer set */
+ if (!adap->dev.of_node)
+ return;
+
+ for_each_child_of_node(adap->dev.of_node, node) {
+ struct i2c_board_info info = {};
+ struct dev_archdata dev_ad = {};
+ const __be32 *addr;
+ int len;
+
+ dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
+ if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
+ dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
+ node->full_name);
+ continue;
+ }
+
+ addr = of_get_property(node, "reg", &len);
+ if (!addr || (len < sizeof(int))) {
+ dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
+ node->full_name);
+ continue;
+ }
+
+ info.addr = be32_to_cpup(addr);
+ if (info.addr > (1 << 10) - 1) {
+ dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
+ info.addr, node->full_name);
+ continue;
+ }
+
+ info.irq = irq_of_parse_and_map(node, 0);
+ info.of_node = of_node_get(node);
+ info.archdata = &dev_ad;
+
+ request_module("%s", info.type);
+
+ result = i2c_new_device(adap, &info);
+ if (result == NULL) {
+ dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
+ node->full_name);
+ of_node_put(node);
+ irq_dispose_mapping(info.irq);
+ continue;
+ }
+ }
+}
+#else
+static inline void i2c_scan_of_devices(struct i2c_adapter *adap) { }
+#endif
+
static int i2c_do_add_adapter(struct i2c_driver *driver,
struct i2c_adapter *adap)
{
@@ -877,7 +934,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
i2c_scan_static_board_info(adap);

/* Register devices from the device tree */
- of_i2c_register_devices(adap);
+ i2c_scan_of_devices(adap);

/* Notify drivers */
mutex_lock(&core_lock);
diff --git a/drivers/of/of_i2c.c b/drivers/of/of_i2c.c
index 0a694de..e0c3841 100644
--- a/drivers/of/of_i2c.c
+++ b/drivers/of/of_i2c.c
@@ -17,63 +17,6 @@
#include <linux/of_irq.h>
#include <linux/module.h>

-void of_i2c_register_devices(struct i2c_adapter *adap)
-{
- void *result;
- struct device_node *node;
-
- /* Only register child devices if the adapter has a node pointer set */
- if (!adap->dev.of_node)
- return;
-
- dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
-
- for_each_child_of_node(adap->dev.of_node, node) {
- struct i2c_board_info info = {};
- struct dev_archdata dev_ad = {};
- const __be32 *addr;
- int len;
-
- dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
-
- if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
- dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
- node->full_name);
- continue;
- }
-
- addr = of_get_property(node, "reg", &len);
- if (!addr || (len < sizeof(int))) {
- dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
- node->full_name);
- continue;
- }
-
- info.addr = be32_to_cpup(addr);
- if (info.addr > (1 << 10) - 1) {
- dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
- info.addr, node->full_name);
- continue;
- }
-
- info.irq = irq_of_parse_and_map(node, 0);
- info.of_node = of_node_get(node);
- info.archdata = &dev_ad;
-
- request_module("%s", info.type);
-
- result = i2c_new_device(adap, &info);
- if (result == NULL) {
- dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
- node->full_name);
- of_node_put(node);
- irq_dispose_mapping(info.irq);
- continue;
- }
- }
-}
-EXPORT_SYMBOL(of_i2c_register_devices);
-
static int of_dev_node_match(struct device *dev, void *data)
{
return dev->of_node == data;
diff --git a/include/linux/of_i2c.h b/include/linux/of_i2c.h
index 0efe8d4..1998cf8 100644
--- a/include/linux/of_i2c.h
+++ b/include/linux/of_i2c.h
@@ -15,16 +15,9 @@
#if defined(CONFIG_OF_I2C) || defined(CONFIG_OF_I2C_MODULE)
#include <linux/i2c.h>

-extern void of_i2c_register_devices(struct i2c_adapter *adap);
-
/* must call put_device() when done with returned i2c_client device */
extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);

-#else
-static inline void of_i2c_register_devices(struct i2c_adapter *adap)
-{
- return;
-}
#endif /* CONFIG_OF_I2C */

#endif /* __LINUX_OF_I2C_H */

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