parisc: add uevent helper for parisc bus

parisc: add uevent helper for parisc bus

udev device-driver auto detection was failing to work on the GSC bus, since
udev didn't knew wich driver to load due to a missing MODALIAS environment
variable from kernel.

This patch fixes this by adding the MODALIAS environment variable to the
uevent kernel notifications.
Since modalias_show() generated the modalias string already, I splitted this
out and created a new static function make_modalias() which is now used by
modalias_show() and the new parisc_uevent() function.

Tested on 715/64 and c3000.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>

arch/parisc/kernel/drivers.c

@@ -549,6 +549,38 @@ static int parisc_generic_match(struct device *dev, struct device_driver *drv)
 	return match_device(to_parisc_driver(drv), to_parisc_device(dev));
 }
 
+static ssize_t make_modalias(struct device *dev, char *buf)
+{
+	const struct parisc_device *padev = to_parisc_device(dev);
+	const struct parisc_device_id *id = &padev->id;
+
+	return sprintf(buf, "parisc:t%02Xhv%04Xrev%02Xsv%08X\n",
+		(u8)id->hw_type, (u16)id->hversion, (u8)id->hversion_rev,
+		(u32)id->sversion);
+}
+
+static int parisc_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	const struct parisc_device *padev;
+	char modalias[40];
+
+	if (!dev)
+		return -ENODEV;
+
+	padev = to_parisc_device(dev);
+	if (!padev)
+		return -ENODEV;
+
+	if (add_uevent_var(env, "PARISC_NAME=%s", padev->name))
+		return -ENOMEM;
+
+	make_modalias(dev, modalias);
+	if (add_uevent_var(env, "MODALIAS=%s", modalias))
+		return -ENOMEM;
+
+	return 0;
+}
+
 #define pa_dev_attr(name, field, format_string)				\
 static ssize_t name##_show(struct device *dev, struct device_attribute *attr, char *buf)		\
 {									\
@@ -566,12 +598,7 @@ pa_dev_attr_id(sversion, "0x%05x\n");
 
 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct parisc_device *padev = to_parisc_device(dev);
-	struct parisc_device_id *id = &padev->id;
-
-	return sprintf(buf, "parisc:t%02Xhv%04Xrev%02Xsv%08X\n",
-		(u8)id->hw_type, (u16)id->hversion, (u8)id->hversion_rev,
-		(u32)id->sversion);
+	return make_modalias(dev, buf);
 }
 
 static struct device_attribute parisc_device_attrs[] = {
@@ -587,6 +614,7 @@ static struct device_attribute parisc_device_attrs[] = {
 struct bus_type parisc_bus_type = {
 	.name = "parisc",
 	.match = parisc_generic_match,
+	.uevent = parisc_uevent,
 	.dev_attrs = parisc_device_attrs,
 	.probe = parisc_driver_probe,
 	.remove = parisc_driver_remove,