hsi: omap_ssi_port: use normal module refcounting

The ref_module() function is used for internal housekeeping of the module code, it's not normally used by subsystems or device drivers, and the use of ref_module in the omap_ssi_port driver causes a link build error when modules are disabled:

hsi/controllers/omap_ssi_port.c: In function 'ssi_port_probe':
hsi/controllers/omap_ssi_port.c:1119:2: error: implicit declaration of function 'ref_module' [-Werror=implicit-function-declaration]

This changes the omap_ssi_port driver to use try_module_get() and module_put() instead, which is the normal way to ensure that the driver providing a device used in another module does not go away.

index b8693f0..6eb7c28 100644
@@ -1116,8 +1116,7 @@ static int __init ssi_port_probe(struct platform_device *pd)
 
 	dev_dbg(&pd->dev, "init ssi port...\n");
 
-	err = ref_module(THIS_MODULE, ssi->owner);
-	if (err) {
+	if (!try_module_get(ssi->owner)) {
 		dev_err(&pd->dev, "could not increment parent module refcount (err=%d)\n",
 			err);
 		return -ENODEV;

@@ -1254,6 +1253,7 @@ static int __exit ssi_port_remove(struct platform_device *pd)
 
 	omap_ssi->port[omap_port->port_id] = NULL;
 	platform_set_drvdata(pd, NULL);
+	module_put(port->owner);
 	pm_runtime_disable(&pd->dev);
 
 	return 0;

The ref_module() function is used for internal housekeeping of the module code, it's not normally used by subsystems or device drivers, and the use of ref_module in the omap_ssi_port driver causes a link build error when modules are disabled:

hsi/controllers/omap_ssi_port.c: In function 'ssi_port_probe':
hsi/controllers/omap_ssi_port.c:1119:2: error: implicit declaration of function 'ref_module' [-Werror=implicit-function-declaration]

This changes the omap_ssi_port driver to use try_module_get() and module_put() instead, which is the normal way to ensure that the driver providing a device used in another module does not go away.

---
v2: fix a stupid typo, I accidentally sent out the wrong version of the patch

index b8693f0..29aea0b 100644
@@ -1116,8 +1116,7 @@ static int __init ssi_port_probe(struct platform_device *pd)
 
 	dev_dbg(&pd->dev, "init ssi port...\n");
 
-	err = ref_module(THIS_MODULE, ssi->owner);
-	if (err) {
+	if (!try_module_get(ssi->owner)) {
 		dev_err(&pd->dev, "could not increment parent module refcount (err=%d)\n",
 			err);
 		return -ENODEV;

@@ -1254,6 +1253,7 @@ static int __exit ssi_port_remove(struct platform_device *pd)
 
 	omap_ssi->port[omap_port->port_id] = NULL;
 	platform_set_drvdata(pd, NULL);
+	module_put(ssi->owner);
 	pm_runtime_disable(&pd->dev);
 
 	return 0;

Hi,

Thanks, applied:

https://git.kernel.org/cgit/linux/kernel/git/sre/linux-hsi.git/commit/?h=for-next&id=b357d7b58f379ebe8038cd97b6204f2f5c52220d

-- Sebastian
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