For easy support of table based dividers.
Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
---
drivers/clk/Makefile | 2 +-
drivers/clk/clk-divider-table.c | 119 +++++++++++++++++++++++++++++++++++++++
include/linux/clk.h | 10 ++++
3 files changed, 130 insertions(+), 1 deletion(-)
create mode 100644 drivers/clk/clk-divider-table.c
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 3cc7163..656b859 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -1,3 +1,3 @@
obj-$(CONFIG_COMMON_CLK) += clk.o clk-fixed.o clk-divider.o clk-fixed-factor.o \
- clk-mux.o clk-gate.o
+ clk-mux.o clk-gate.o clk-divider-table.o
obj-$(CONFIG_CLKDEV_LOOKUP) += clkdev.o
diff --git a/drivers/clk/clk-divider-table.c b/drivers/clk/clk-divider-table.c
new file mode 100644
index 0000000..204e24d
--- /dev/null
+++ b/drivers/clk/clk-divider-table.c
@@ -0,0 +1,119 @@
+/*
+ * clk-divider-table.c - generic barebox clock support. Based on Linux clk support
+ *
+ * Copyright (c) 2012 Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>, 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_table {
+ struct clk clk;
+ u8 shift;
+ u8 width;
+ void __iomem *reg;
+ const char *parent;
+ const struct clk_div_table *table;
+ int table_size;
+ int max_div_index;
+};
+
+static int clk_divider_set_rate(struct clk *clk, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_divider_table *div =
+ container_of(clk, struct clk_divider_table, clk);
+ unsigned int val;
+ int i, div_index = -1;
+ unsigned long best = 0;
+
+ if (rate > parent_rate)
+ rate = parent_rate;
+ if (rate < parent_rate / div->table[div->max_div_index].div)
+ rate = parent_rate / div->table[div->max_div_index].div;
+
+ for (i = 0; i < div->table_size; i++) {
+ unsigned long now = parent_rate / div->table[i].div;
+
+ if (now <= rate && now >= best) {
+ best = now;
+ div_index = i;
+ }
+ }
+
+ val = readl(div->reg);
+ val &= ~(((1 << div->width) - 1) << div->shift);
+ val |= div_index << 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_table *div =
+ container_of(clk, struct clk_divider_table, clk);
+ unsigned int val;
+
+ val = readl(div->reg) >> div->shift;
+ val &= (1 << div->width) - 1;
+
+ if (val >= div->table_size)
+ return 0;
+
+ return parent_rate / div->table[val].div;
+}
+
+struct clk_ops clk_divider_table_ops = {
+ .set_rate = clk_divider_set_rate,
+ .recalc_rate = clk_divider_recalc_rate,
+};
+
+struct clk *clk_divider_table(const char *name,
+ const char *parent, void __iomem *reg, u8 shift, u8 width,
+ const struct clk_div_table *table)
+{
+ struct clk_divider_table *div = xzalloc(sizeof(*div));
+ const struct clk_div_table *clkt;
+ int ret, max_div = 0;
+
+ div->shift = shift;
+ div->reg = reg;
+ div->width = width;
+ div->parent = parent;
+ div->clk.ops = &clk_divider_table_ops;
+ div->clk.name = name;
+ div->clk.parent_names = &div->parent;
+ div->clk.num_parents = 1;
+ div->table = table;
+
+ for (clkt = div->table; clkt->div; clkt++) {
+ if (clkt->div > max_div) {
+ max_div = clkt->div;
+ div->max_div_index = div->table_size;
+ }
+ div->table_size++;
+ }
+
+ ret = clk_register(&div->clk);
+ if (ret) {
+ free(div);
+ return ERR_PTR(ret);
+ }
+
+ return &div->clk;
+}
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 00588bf..91574f2 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -181,9 +181,19 @@ struct clk {
struct clk **parents;
};
+#define CLK_ALWAYS_ENABLED (1 << 0)
+
+struct clk_div_table {
+ unsigned int val;
+ unsigned int div;
+};
+
struct clk *clk_fixed(const char *name, int rate);
struct clk *clk_divider(const char *name, const char *parent,
void __iomem *reg, u8 shift, u8 width);
+struct clk *clk_divider_table(const char *name,
+ const char *parent, void __iomem *reg, u8 shift, u8 width,
+ const struct clk_div_table *table);
struct clk *clk_fixed_factor(const char *name,
const char *parent, unsigned int mult, unsigned int div);
struct clk *clk_mux(const char *name, void __iomem *reg,
--
1.7.10.4
_______________________________________________
barebox mailing list
barebox@xxxxxxxxxxxxxxxxxxx
http://lists.infradead.org/mailman/listinfo/barebox
