[PATCH 11/16] clk: sunxi-ng: Add N-K-factor clock support

Maxime Ripard
2016-05-08T20:01:46Z

Introduce support for clocks that use a combination of two linear
multipliers.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
drivers/clk/sunxi-ng/Makefile | 1 +
drivers/clk/sunxi-ng/ccu_nk.c | 147 ++++++++++++++++++++++++++++++++++++++++++
drivers/clk/sunxi-ng/ccu_nk.h | 44 +++++++++++++
3 files changed, 192 insertions(+)
create mode 100644 drivers/clk/sunxi-ng/ccu_nk.c
create mode 100644 drivers/clk/sunxi-ng/ccu_nk.h

diff --git a/drivers/clk/sunxi-ng/Makefile b/drivers/clk/sunxi-ng/Makefile
index 09fce7467784..e29ddae99653 100644
--- a/drivers/clk/sunxi-ng/Makefile
+++ b/drivers/clk/sunxi-ng/Makefile
@@ -7,5 +7,6 @@ obj-y += ccu_gate.o
obj-y += ccu_m.o
obj-y += ccu_mp.o
obj-y += ccu_mux.o
+obj-y += ccu_nk.o
obj-y += ccu_p.o
obj-y += ccu_phase.o
diff --git a/drivers/clk/sunxi-ng/ccu_nk.c b/drivers/clk/sunxi-ng/ccu_nk.c
new file mode 100644
index 000000000000..46eede3e986e
--- /dev/null
+++ b/drivers/clk/sunxi-ng/ccu_nk.c
@@ -0,0 +1,147 @@
+/*
+ * Copyright (C) 2016 Maxime Ripard
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * 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.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/rational.h>
+
+#include "ccu_gate.h"
+#include "ccu_nk.h"
+
+void ccu_nk_find_best(unsigned long parent, unsigned long rate,
+ unsigned int max_n, unsigned int max_k,
+ unsigned int *n, unsigned int *k)
+{
+ unsigned long best_rate = 0;
+ unsigned int best_k = 0, best_n =0;
+ unsigned int _k, _n;
+
+ for (_k = 0; _k <= max_k; _k++) {
+ for (_n = 0; _n <= max_n; _n++) {
+ unsigned long tmp_rate = parent * _n * _k;
+
+ if (tmp_rate > rate)
+ continue;
+
+ if ((rate - tmp_rate) < (rate - best_rate)) {
+ best_rate = tmp_rate;
+ best_k = _k;
+ best_n = _n;
+ }
+ }
+ }
+
+ *k = best_k;
+ *n = best_n;
+}
+
+static void ccu_nk_disable(struct clk_hw *hw)
+{
+ struct ccu_nk *nk = hw_to_ccu_nk(hw);
+
+ return ccu_gate_helper_disable(&nk->common, nk->enable);
+}
+
+static int ccu_nk_enable(struct clk_hw *hw)
+{
+ struct ccu_nk *nk = hw_to_ccu_nk(hw);
+
+ return ccu_gate_helper_enable(&nk->common, nk->enable);
+}
+
+static int ccu_nk_is_enabled(struct clk_hw *hw)
+{
+ struct ccu_nk *nk = hw_to_ccu_nk(hw);
+
+ return ccu_gate_helper_is_enabled(&nk->common, nk->enable);
+}
+
+static unsigned long ccu_nk_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct ccu_nk *nk = hw_to_ccu_nk(hw);
+ unsigned long rate, n, k;
+ u32 reg;
+
+ reg = readl(nk->common.base + nk->common.reg);
+
+ n = reg >> nk->n.shift;
+ n &= (1 << nk->n.width) - 1;
+
+ k = reg >> nk->k.shift;
+ k &= (1 << nk->k.width) - 1;
+
+ rate = parent_rate * (n + 1) * (k + 1);
+
+ if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
+ rate = rate / nk->fixed_post_div;
+
+ return rate;
+}
+
+static long ccu_nk_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ struct ccu_nk *nk = hw_to_ccu_nk(hw);
+ unsigned int n, k;
+
+ if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
+ rate = rate * nk->fixed_post_div;
+
+ ccu_nk_find_best(*parent_rate, rate,
+ 1 << nk->n.width, 1 << nk->k.width,
+ &n, &k);
+
+ rate = *parent_rate * n * k;
+ if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
+ rate = rate / nk->fixed_post_div;
+
+ return rate;
+}
+
+static int ccu_nk_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct ccu_nk *nk = hw_to_ccu_nk(hw);
+ unsigned long flags;
+ unsigned int n, k;
+ u32 reg;
+
+ if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
+ rate = rate * nk->fixed_post_div;
+
+ ccu_nk_find_best(parent_rate, rate,
+ 1 << nk->n.width, 1 << nk->k.width,
+ &n, &k);
+
+ spin_lock_irqsave(nk->common.lock, flags);
+
+ reg = readl(nk->common.base + nk->common.reg);
+ reg &= ~GENMASK(nk->n.width + nk->n.shift, nk->n.shift);
+ reg &= ~GENMASK(nk->k.width + nk->k.shift, nk->k.shift);
+
+ writel(reg | ((k - 1) << nk->k.shift) | ((n - 1) << nk->n.shift),
+ nk->common.base + nk->common.reg);
+
+ spin_unlock_irqrestore(nk->common.lock, flags);
+
+ ccu_helper_wait_for_lock(&nk->common, nk->lock);
+
+ return 0;
+}
+
+const struct clk_ops ccu_nk_ops = {
+ .disable = ccu_nk_disable,
+ .enable = ccu_nk_enable,
+ .is_enabled = ccu_nk_is_enabled,
+
+ .recalc_rate = ccu_nk_recalc_rate,
+ .round_rate = ccu_nk_round_rate,
+ .set_rate = ccu_nk_set_rate,
+};
diff --git a/drivers/clk/sunxi-ng/ccu_nk.h b/drivers/clk/sunxi-ng/ccu_nk.h
new file mode 100644
index 000000000000..cdbbd45815c6
--- /dev/null
+++ b/drivers/clk/sunxi-ng/ccu_nk.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2016 Maxime Ripard. All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ */
+
+#ifndef _CCU_NK_H_
+#define _CCU_NK_H_
+
+#include <linux/clk-provider.h>
+
+#include "ccu_common.h"
+#include "ccu_factor.h"
+
+struct ccu_nk {
+ u16 reg;
+ u32 enable;
+ u32 lock;
+
+ struct ccu_factor n;
+ struct ccu_factor k;
+
+ unsigned int fixed_post_div;
+
+ struct ccu_common common;
+};
+
+static inline struct ccu_nk *hw_to_ccu_nk(struct clk_hw *hw)
+{
+ struct ccu_common *common = hw_to_ccu_common(hw);
+
+ return container_of(common, struct ccu_nk, common);
+}
+
+extern const struct clk_ops ccu_nk_ops;
+
+#endif /* _CCU_NK_H_ */
--
2.8.2

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