of: Move the request module helper logic to module.c

Depending on device.c for pure OF handling is considered
backwards. Let's extract the content of of_device_request_module() to
have the real logic under module.c.

The next step will be to convert users of of_device_request_module() to
use the new helper.
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230404172148.82422-11-srinivas.kandagatla@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/of/device.c

@@ -8,7 +8,6 @@
 #include <linux/dma-direct.h> /* for bus_dma_region */
 #include <linux/dma-map-ops.h>
 #include <linux/init.h>
-#include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/slab.h>
 #include <linux/platform_device.h>
@@ -249,30 +248,10 @@ EXPORT_SYMBOL(of_device_get_match_data);
 
 int of_device_request_module(struct device *dev)
 {
-	char *str;
-	ssize_t size;
-	int ret;
-
-	if (!dev || !dev->of_node)
+	if (!dev)
 		return -ENODEV;
 
-	size = of_modalias(dev->of_node, NULL, 0);
-	if (size < 0)
-		return size;
-
-	/* Reserve an additional byte for the trailing '\0' */
-	size++;
-
-	str = kmalloc(size, GFP_KERNEL);
-	if (!str)
-		return -ENOMEM;
-
-	of_modalias(dev->of_node, str, size);
-	str[size - 1] = '\0';
-	ret = request_module(str);
-	kfree(str);
-
-	return ret;
+	return of_request_module(dev->of_node);
 }
 EXPORT_SYMBOL_GPL(of_device_request_module);
 

drivers/of/module.c

@@ -4,6 +4,7 @@
  */
 
 #include <linux/of.h>
+#include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 
@@ -42,3 +43,32 @@ ssize_t of_modalias(const struct device_node *np, char *str, ssize_t len)
 
 	return tsize;
 }
+
+int of_request_module(const struct device_node *np)
+{
+	char *str;
+	ssize_t size;
+	int ret;
+
+	if (!np)
+		return -ENODEV;
+
+	size = of_modalias(np, NULL, 0);
+	if (size < 0)
+		return size;
+
+	/* Reserve an additional byte for the trailing '\0' */
+	size++;
+
+	str = kmalloc(size, GFP_KERNEL);
+	if (!str)
+		return -ENOMEM;
+
+	of_modalias(np, str, size);
+	str[size - 1] = '\0';
+	ret = request_module(str);
+	kfree(str);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(of_request_module);

include/linux/of.h

@@ -387,6 +387,7 @@ extern int of_count_phandle_with_args(const struct device_node *np,
 
 /* module functions */
 extern ssize_t of_modalias(const struct device_node *np, char *str, ssize_t len);
+extern int of_request_module(const struct device_node *np);
 
 /* phandle iterator functions */
 extern int of_phandle_iterator_init(struct of_phandle_iterator *it,
@@ -751,6 +752,11 @@ static inline ssize_t of_modalias(const struct device_node *np, char *str,
 	return -ENODEV;
 }
 
+static inline int of_request_module(const struct device_node *np)
+{
+	return -ENODEV;
+}
+
 static inline int of_phandle_iterator_init(struct of_phandle_iterator *it,
 					   const struct device_node *np,
 					   const char *list_name,