1 files changed, 48 insertions, 0 deletions

diff --git a/drivers/of/device.c b/drivers/of/device.c
index 8fbfeee53c1e..8a1d93a2bb81 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -104,3 +104,51 @@ void of_device_unregister(struct of_device *ofdev)
         device_unregister(&ofdev->dev);
 }
 EXPORT_SYMBOL(of_device_unregister);
+
+ssize_t of_device_get_modalias(struct of_device *ofdev,
+                                char *str, ssize_t len)
+{
+        const char *compat;
+        int cplen, i;
+        ssize_t tsize, csize, repend;
+
+        /* Name & Type */
+        csize = snprintf(str, len, "of:N%sT%s",
+                                ofdev->node->name, ofdev->node->type);
+
+        /* Get compatible property if any */
+        compat = of_get_property(ofdev->node, "compatible", &cplen);
+        if (!compat)
+                return csize;
+
+        /* Find true end (we tolerate multiple \0 at the end */
+        for (i = (cplen - 1); i >= 0 && !compat[i]; i--)
+                cplen--;
+        if (!cplen)
+                return csize;
+        cplen++;
+
+        /* Check space (need cplen+1 chars including final \0) */
+        tsize = csize + cplen;
+        repend = tsize;
+
+        if (csize >= len)               /* @ the limit, all is already filled */
+                return tsize;
+
+        if (tsize >= len) {             /* limit compat list */
+                cplen = len - csize - 1;
+                repend = len;
+        }
+
+        /* Copy and do char replacement */
+        memcpy(&str[csize + 1], compat, cplen);
+        for (i = csize; i < repend; i++) {
+                char c = str[i];
+                if (c == '\0')
+                        str[i] = 'C';
+                else if (c == ' ')
+                        str[i] = '_';
+        }
+
+        return tsize;
+}