1 files changed, 98 insertions, 0 deletions
diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
new file mode 100644
index 0000000000..58a7ea564c
--- /dev/null
+++ b/drivers/clk/clk-divider.c
@@ -0,0 +1,98 @@
+/*
+ * clk-divider.c - generic barebox clock support. Based on Linux clk support
+ *
+ * Copyright (c) 2012 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
+ *
+ * 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.
+ *
+ */
+#include <common.h>
+#include <io.h>
+#include <malloc.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+
+struct clk_divider {
+	struct clk clk;
+	u8 shift;
+	u8 width;
+	void __iomem *reg;
+	const char *parent;
+};
+
+static int clk_divider_set_rate(struct clk *clk, unsigned long rate,
+		unsigned long parent_rate)
+{
+	struct clk_divider *div = container_of(clk, struct clk_divider, clk);
+	unsigned int val, divval;
+
+	if (rate > parent_rate)
+		rate = parent_rate;
+	if (!rate)
+		rate = 1;
+
+	divval = DIV_ROUND_UP(parent_rate, rate);
+
+	if (divval > (1 << div->width))
+		divval = 1 << (div->width);
+
+	divval--;
+
+	val = readl(div->reg);
+	val &= ~(((1 << div->width) - 1) << div->shift);
+	val |= divval << div->shift;
+	writel(val, div->reg);
+
+	return 0;
+}
+
+static unsigned long clk_divider_recalc_rate(struct clk *clk,
+		unsigned long parent_rate)
+{
+	struct clk_divider *div = container_of(clk, struct clk_divider, clk);
+	unsigned int val;
+
+	val = readl(div->reg) >> div->shift;
+	val &= (1 << div->width) - 1;
+
+	val++;
+
+	return parent_rate / val;
+}
+
+struct clk_ops clk_divider_ops = {
+	.set_rate = clk_divider_set_rate,
+	.recalc_rate = clk_divider_recalc_rate,
+};
+
+struct clk *clk_divider(const char *name, const char *parent,
+		void __iomem *reg, u8 shift, u8 width)
+{
+	struct clk_divider *div = xzalloc(sizeof(*div));
+	int ret;
+
+	div->shift = shift;
+	div->reg = reg;
+	div->width = width;
+	div->parent = parent;
+	div->clk.ops = &clk_divider_ops;
+	div->clk.name = name;
+	div->clk.parent_names = &div->parent;
+	div->clk.num_parents = 1;
+
+	ret = clk_register(&div->clk);
+	if (ret) {
+		free(div);
+		return ERR_PTR(ret);
+	}
+
+	return &div->clk;
+}