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path: root/drivers/clk/mmp/clk-frac.c
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-rw-r--r--drivers/clk/mmp/clk-frac.c153
1 files changed, 153 insertions, 0 deletions
diff --git a/drivers/clk/mmp/clk-frac.c b/drivers/clk/mmp/clk-frac.c
new file mode 100644
index 000000000000..80c1dd15d15c
--- /dev/null
+++ b/drivers/clk/mmp/clk-frac.c
@@ -0,0 +1,153 @@
+/*
+ * mmp factor clock operation source file
+ *
+ * Copyright (C) 2012 Marvell
+ * Chao Xie <xiechao.mail@gmail.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/err.h>
+
+#include "clk.h"
+/*
+ * It is M/N clock
+ *
+ * Fout from synthesizer can be given from two equations:
+ * numerator/denominator = Fin / (Fout * factor)
+ */
+
+#define to_clk_factor(hw) container_of(hw, struct clk_factor, hw)
+struct clk_factor {
+ struct clk_hw hw;
+ void __iomem *base;
+ struct clk_factor_masks *masks;
+ struct clk_factor_tbl *ftbl;
+ unsigned int ftbl_cnt;
+};
+
+static long clk_factor_round_rate(struct clk_hw *hw, unsigned long drate,
+ unsigned long *prate)
+{
+ struct clk_factor *factor = to_clk_factor(hw);
+ unsigned long rate = 0, prev_rate;
+ int i;
+
+ for (i = 0; i < factor->ftbl_cnt; i++) {
+ prev_rate = rate;
+ rate = (((*prate / 10000) * factor->ftbl[i].num) /
+ (factor->ftbl[i].den * factor->masks->factor)) * 10000;
+ if (rate > drate)
+ break;
+ }
+ if (i == 0)
+ return rate;
+ else
+ return prev_rate;
+}
+
+static unsigned long clk_factor_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clk_factor *factor = to_clk_factor(hw);
+ struct clk_factor_masks *masks = factor->masks;
+ unsigned int val, num, den;
+
+ val = readl_relaxed(factor->base);
+
+ /* calculate numerator */
+ num = (val >> masks->num_shift) & masks->num_mask;
+
+ /* calculate denominator */
+ den = (val >> masks->den_shift) & masks->num_mask;
+
+ if (!den)
+ return 0;
+
+ return (((parent_rate / 10000) * den) /
+ (num * factor->masks->factor)) * 10000;
+}
+
+/* Configures new clock rate*/
+static int clk_factor_set_rate(struct clk_hw *hw, unsigned long drate,
+ unsigned long prate)
+{
+ struct clk_factor *factor = to_clk_factor(hw);
+ struct clk_factor_masks *masks = factor->masks;
+ int i;
+ unsigned long val;
+ unsigned long prev_rate, rate = 0;
+
+ for (i = 0; i < factor->ftbl_cnt; i++) {
+ prev_rate = rate;
+ rate = (((prate / 10000) * factor->ftbl[i].num) /
+ (factor->ftbl[i].den * factor->masks->factor)) * 10000;
+ if (rate > drate)
+ break;
+ }
+ if (i > 0)
+ i--;
+
+ val = readl_relaxed(factor->base);
+
+ val &= ~(masks->num_mask << masks->num_shift);
+ val |= (factor->ftbl[i].num & masks->num_mask) << masks->num_shift;
+
+ val &= ~(masks->den_mask << masks->den_shift);
+ val |= (factor->ftbl[i].den & masks->den_mask) << masks->den_shift;
+
+ writel_relaxed(val, factor->base);
+
+ return 0;
+}
+
+static struct clk_ops clk_factor_ops = {
+ .recalc_rate = clk_factor_recalc_rate,
+ .round_rate = clk_factor_round_rate,
+ .set_rate = clk_factor_set_rate,
+};
+
+struct clk *mmp_clk_register_factor(const char *name, const char *parent_name,
+ unsigned long flags, void __iomem *base,
+ struct clk_factor_masks *masks, struct clk_factor_tbl *ftbl,
+ unsigned int ftbl_cnt)
+{
+ struct clk_factor *factor;
+ struct clk_init_data init;
+ struct clk *clk;
+
+ if (!masks) {
+ pr_err("%s: must pass a clk_factor_mask\n", __func__);
+ return ERR_PTR(-EINVAL);
+ }
+
+ factor = kzalloc(sizeof(*factor), GFP_KERNEL);
+ if (!factor) {
+ pr_err("%s: could not allocate factor clk\n", __func__);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ /* struct clk_aux assignments */
+ factor->base = base;
+ factor->masks = masks;
+ factor->ftbl = ftbl;
+ factor->ftbl_cnt = ftbl_cnt;
+ factor->hw.init = &init;
+
+ init.name = name;
+ init.ops = &clk_factor_ops;
+ init.flags = flags;
+ init.parent_names = &parent_name;
+ init.num_parents = 1;
+
+ clk = clk_register(NULL, &factor->hw);
+ if (IS_ERR_OR_NULL(clk))
+ kfree(factor);
+
+ return clk;
+}