add $sys substitution

3 files changed, 18 insertions, 0 deletions

diff --git a/udev.7 b/udev.7
index a4b15886c7..4fbaf92432 100644
--- a/udev.7
+++ b/udev.7
@@ -362,6 +362,11 @@ The node name of the parent device.
 The udev_root value.
 .RE
 .PP
+\fB$sys\fR, \fB%S\fR
+.RS 4
+The sysfs mount point.
+.RE
+.PP
 \fB$tempnode\fR, \fB%N\fR
 .RS 4
 The name of a created temporary device node to provide access to the device from a external program before the real node is created.
diff --git a/udev.xml b/udev.xml
index 5ba3d3636c..1f9e6d9197 100644
--- a/udev.xml
+++ b/udev.xml
@@ -530,6 +530,13 @@
             </varlistentry>
 
             <varlistentry>
+              <term><option>$sys</option>, <option>%S</option></term>
+              <listitem>
+                <para>The sysfs mount point.</para>
+              </listitem>
+            </varlistentry>
+
+            <varlistentry>
               <term><option>$tempnode</option>, <option>%N</option></term>
               <listitem>
                 <para>The name of a created temporary device node to provide access to
diff --git a/udev_rules.c b/udev_rules.c
index 1139c99a7d..e61c9a69b0 100644
--- a/udev_rules.c
+++ b/udev_rules.c
@@ -292,6 +292,7 @@ void udev_rules_apply_format(struct udevice *udev, char *string, size_t maxsize)
 		SUBST_PARENT,
 		SUBST_TEMP_NODE,
 		SUBST_ROOT,
+		SUBST_SYS,
 		SUBST_ENV,
 	};
 	static const struct subst_map {
@@ -311,6 +312,7 @@ void udev_rules_apply_format(struct udevice *udev, char *string, size_t maxsize)
 		{ .name = "parent",	.fmt = 'P',	.type = SUBST_PARENT },
 		{ .name = "tempnode",	.fmt = 'N',	.type = SUBST_TEMP_NODE },
 		{ .name = "root",	.fmt = 'r',	.type = SUBST_ROOT },
+		{ .name = "sys",	.fmt = 'S',	.type = SUBST_SYS },
 		{ .name = "env",	.fmt = 'E',	.type = SUBST_ENV },
 		{ NULL, '\0', 0 }
 	};
@@ -516,6 +518,10 @@ found:
 			strlcat(string, udev_root, maxsize);
 			dbg("substitute udev_root '%s'", udev_root);
 			break;
+		case SUBST_SYS:
+			strlcat(string, sysfs_path, maxsize);
+			dbg("substitute sysfs_path '%s'", sysfs_path);
+			break;
 		case SUBST_ENV:
 			if (attr == NULL) {
 				dbg("missing attribute");