Merge branch 'acpi-modules'

* acpi-modules:
  platform: introduce OF style 'modalias' support for platform bus
  ACPI: fix module autoloading for ACPI enumerated devices
  ACPI: add module autoloading support for ACPI enumerated devices
  ACPI: fix create_modalias() return value handling

1 files changed, 67 insertions, 6 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index c0f57ff15024..e00365ccb897 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -86,6 +86,9 @@ int acpi_scan_add_handler_with_hotplug(struct acpi_scan_handler *handler,
  * Creates hid/cid(s) string needed for modalias and uevent
  * e.g. on a device with hid:IBM0001 and cid:ACPI0001 you get:
  * char *modalias: "acpi:IBM0001:ACPI0001"
+ * Return: 0: no _HID and no _CID
+ *         -EINVAL: output error
+ *         -ENOMEM: output is truncated
 */
 static int create_modalias(struct acpi_device *acpi_dev, char *modalias,
                            int size)
@@ -102,8 +105,10 @@ static int create_modalias(struct acpi_device *acpi_dev, char *modalias,
 
         list_for_each_entry(id, &acpi_dev->pnp.ids, list) {
                 count = snprintf(&modalias[len], size, "%s:", id->id);
-                if (count < 0 || count >= size)
-                        return -EINVAL;
+                if (count < 0)
+                        return EINVAL;
+                if (count >= size)
+                        return -ENOMEM;
                 len += count;
                 size -= count;
         }
@@ -112,15 +117,71 @@ static int create_modalias(struct acpi_device *acpi_dev, char *modalias,
         return len;
 }
 
+/*
+ * Creates uevent modalias field for ACPI enumerated devices.
+ * Because the other buses does not support ACPI HIDs & CIDs.
+ * e.g. for a device with hid:IBM0001 and cid:ACPI0001 you get:
+ * "acpi:IBM0001:ACPI0001"
+ */
+int acpi_device_uevent_modalias(struct device *dev, struct kobj_uevent_env *env)
+{
+        struct acpi_device *acpi_dev;
+        int len;
+
+        acpi_dev = ACPI_COMPANION(dev);
+        if (!acpi_dev)
+                return -ENODEV;
+
+        /* Fall back to bus specific way of modalias exporting */
+        if (list_empty(&acpi_dev->pnp.ids))
+                return -ENODEV;
+
+        if (add_uevent_var(env, "MODALIAS="))
+                return -ENOMEM;
+        len = create_modalias(acpi_dev, &env->buf[env->buflen - 1],
+                                sizeof(env->buf) - env->buflen);
+        if (len <= 0)
+                return len;
+        env->buflen += len;
+        return 0;
+}
+EXPORT_SYMBOL_GPL(acpi_device_uevent_modalias);
+
+/*
+ * Creates modalias sysfs attribute for ACPI enumerated devices.
+ * Because the other buses does not support ACPI HIDs & CIDs.
+ * e.g. for a device with hid:IBM0001 and cid:ACPI0001 you get:
+ * "acpi:IBM0001:ACPI0001"
+ */
+int acpi_device_modalias(struct device *dev, char *buf, int size)
+{
+        struct acpi_device *acpi_dev;
+        int len;
+
+        acpi_dev = ACPI_COMPANION(dev);
+        if (!acpi_dev)
+                return -ENODEV;
+
+        /* Fall back to bus specific way of modalias exporting */
+        if (list_empty(&acpi_dev->pnp.ids))
+                return -ENODEV;
+
+        len = create_modalias(acpi_dev, buf, size -1);
+        if (len <= 0)
+                return len;
+        buf[len++] = '\n';
+        return len;
+}
+EXPORT_SYMBOL_GPL(acpi_device_modalias);
+
 static ssize_t
 acpi_device_modalias_show(struct device *dev, struct device_attribute *attr, char *buf) {
         struct acpi_device *acpi_dev = to_acpi_device(dev);
         int len;
 
-        /* Device has no HID and no CID or string is >1024 */
         len = create_modalias(acpi_dev, buf, 1024);
         if (len <= 0)
-                return 0;
+                return len;
         buf[len++] = '\n';
         return len;
 }
@@ -839,8 +900,8 @@ static int acpi_device_uevent(struct device *dev, struct kobj_uevent_env *env)
                 return -ENOMEM;
         len = create_modalias(acpi_dev, &env->buf[env->buflen - 1],
                               sizeof(env->buf) - env->buflen);
-        if (len >= (sizeof(env->buf) - env->buflen))
-                return -ENOMEM;
+        if (len <= 0)
+                return len;
         env->buflen += len;
         return 0;
 }