clk: mvebu: add mvebu core clocks.

This driver allows to provide DT clocks for core clocks found on
Marvell Kirkwood, Dove & 370/XP SoCs. The core clock frequencies and
ratios are determined by decoding the Sample-At-Reset registers.

Although technically correct, using a divider of 0 will lead to
div_by_zero panic. Let's use a ratio of 0/1 instead to fail later
with a zero clock.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by Gregory CLEMENT <gregory.clement@free-electrons.com>

include/linux/clk/mvebu.h

@@ -0,0 +1,22 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef __CLK_MVEBU_H_
+#define __CLK_MVEBU_H_
+
+void __init mvebu_clocks_init(void);
+
+#endif