1 files changed, 139 insertions, 0 deletions

diff --git a/drivers/clk/mxs/clk-frac.c b/drivers/clk/mxs/clk-frac.c
new file mode 100644
index 000000000000..e6aa6b567d68
--- /dev/null
+++ b/drivers/clk/mxs/clk-frac.c
@@ -0,0 +1,139 @@
+/*
+ * Copyright 2012 Freescale Semiconductor, Inc.
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include "clk.h"
+
+/**
+ * struct clk_frac - mxs fractional divider clock
+ * @hw: clk_hw for the fractional divider clock
+ * @reg: register address
+ * @shift: the divider bit shift
+ * @width: the divider bit width
+ * @busy: busy bit shift
+ *
+ * The clock is an adjustable fractional divider with a busy bit to wait
+ * when the divider is adjusted.
+ */
+struct clk_frac {
+        struct clk_hw hw;
+        void __iomem *reg;
+        u8 shift;
+        u8 width;
+        u8 busy;
+};
+
+#define to_clk_frac(_hw) container_of(_hw, struct clk_frac, hw)
+
+static unsigned long clk_frac_recalc_rate(struct clk_hw *hw,
+                                          unsigned long parent_rate)
+{
+        struct clk_frac *frac = to_clk_frac(hw);
+        u32 div;
+
+        div = readl_relaxed(frac->reg) >> frac->shift;
+        div &= (1 << frac->width) - 1;
+
+        return (parent_rate >> frac->width) * div;
+}
+
+static long clk_frac_round_rate(struct clk_hw *hw, unsigned long rate,
+                                unsigned long *prate)
+{
+        struct clk_frac *frac = to_clk_frac(hw);
+        unsigned long parent_rate = *prate;
+        u32 div;
+        u64 tmp;
+
+        if (rate > parent_rate)
+                return -EINVAL;
+
+        tmp = rate;
+        tmp <<= frac->width;
+        do_div(tmp, parent_rate);
+        div = tmp;
+
+        if (!div)
+                return -EINVAL;
+
+        return (parent_rate >> frac->width) * div;
+}
+
+static int clk_frac_set_rate(struct clk_hw *hw, unsigned long rate,
+                             unsigned long parent_rate)
+{
+        struct clk_frac *frac = to_clk_frac(hw);
+        unsigned long flags;
+        u32 div, val;
+        u64 tmp;
+
+        if (rate > parent_rate)
+                return -EINVAL;
+
+        tmp = rate;
+        tmp <<= frac->width;
+        do_div(tmp, parent_rate);
+        div = tmp;
+
+        if (!div)
+                return -EINVAL;
+
+        spin_lock_irqsave(&mxs_lock, flags);
+
+        val = readl_relaxed(frac->reg);
+        val &= ~(((1 << frac->width) - 1) << frac->shift);
+        val |= div << frac->shift;
+        writel_relaxed(val, frac->reg);
+
+        spin_unlock_irqrestore(&mxs_lock, flags);
+
+        return mxs_clk_wait(frac->reg, frac->busy);
+}
+
+static struct clk_ops clk_frac_ops = {
+        .recalc_rate = clk_frac_recalc_rate,
+        .round_rate = clk_frac_round_rate,
+        .set_rate = clk_frac_set_rate,
+};
+
+struct clk *mxs_clk_frac(const char *name, const char *parent_name,
+                         void __iomem *reg, u8 shift, u8 width, u8 busy)
+{
+        struct clk_frac *frac;
+        struct clk *clk;
+        struct clk_init_data init;
+
+        frac = kzalloc(sizeof(*frac), GFP_KERNEL);
+        if (!frac)
+                return ERR_PTR(-ENOMEM);
+
+        init.name = name;
+        init.ops = &clk_frac_ops;
+        init.flags = CLK_SET_RATE_PARENT;
+        init.parent_names = (parent_name ? &parent_name: NULL);
+        init.num_parents = (parent_name ? 1 : 0);
+
+        frac->reg = reg;
+        frac->shift = shift;
+        frac->width = width;
+        frac->busy = busy;
+        frac->hw.init = &init;
+
+        clk = clk_register(NULL, &frac->hw);
+        if (IS_ERR(clk))
+                kfree(frac);
+
+        return clk;
+}