[PATCH v2 13/15] clk: sunxi-ng: Add N-K-M-P factor clock

Maxime Ripard
2016-06-07T20:41:52Z

Introduce support for clocks that use a combination of two linear
multipliers (N and K factors), one linear divider (M) and one power of two
divider (P).

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

---
Changes from v1:
- Declared our find_best function static
- Fixed our set_rate function that was always writing the various factors
at the same offset.
---
drivers/clk/sunxi-ng/Makefile | 1 +
drivers/clk/sunxi-ng/ccu_nkmp.c | 167 ++++++++++++++++++++++++++++++++++++++++
drivers/clk/sunxi-ng/ccu_nkmp.h | 73 ++++++++++++++++++
3 files changed, 241 insertions(+)
create mode 100644 drivers/clk/sunxi-ng/ccu_nkmp.c
create mode 100644 drivers/clk/sunxi-ng/ccu_nkmp.h

diff --git a/drivers/clk/sunxi-ng/Makefile b/drivers/clk/sunxi-ng/Makefile
index f157efe076fa..ddcf456df719 100644
--- a/drivers/clk/sunxi-ng/Makefile
+++ b/drivers/clk/sunxi-ng/Makefile
@@ -10,5 +10,6 @@ obj-y += ccu_mp.o
obj-y += ccu_mux.o
obj-y += ccu_nk.o
obj-y += ccu_nkm.o
+obj-y += ccu_nkmp.o
obj-y += ccu_nm.o
obj-y += ccu_phase.o
diff --git a/drivers/clk/sunxi-ng/ccu_nkmp.c b/drivers/clk/sunxi-ng/ccu_nkmp.c
new file mode 100644
index 000000000000..9f2b98e19dc9
--- /dev/null
+++ b/drivers/clk/sunxi-ng/ccu_nkmp.c
@@ -0,0 +1,167 @@
+/*
+ * 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_nkmp.h"
+
+struct _ccu_nkmp {
+ unsigned long n, max_n;
+ unsigned long k, max_k;
+ unsigned long m, max_m;
+ unsigned long p, max_p;
+};
+
+static void ccu_nkmp_find_best(unsigned long parent, unsigned long rate,
+ struct _ccu_nkmp *nkmp)
+{
+ unsigned long best_rate = 0;
+ unsigned long best_n = 0, best_k = 0, best_m = 0, best_p = 0;
+ unsigned long _n, _k, _m, _p;
+
+ for (_k = 1; _k <= nkmp->max_k; _k++) {
+ for (_p = 0; _p <= nkmp->max_p; _p++) {
+ unsigned long tmp_rate;
+
+ rational_best_approximation(rate / _k, parent >> _p,
+ nkmp->max_n, nkmp->max_m,
+ &_n, &_m);
+
+ tmp_rate = (parent * _n * _k >> _p) / _m;
+
+ if (tmp_rate > rate)
+ continue;
+
+ if ((rate - tmp_rate) < (rate - best_rate)) {
+ best_rate = tmp_rate;
+ best_n = _n;
+ best_k = _k;
+ best_m = _m;
+ best_p = _p;
+ }
+ }
+ }
+
+ nkmp->n = best_n;
+ nkmp->k = best_k;
+ nkmp->m = best_m;
+ nkmp->p = best_p;
+}
+
+static void ccu_nkmp_disable(struct clk_hw *hw)
+{
+ struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);
+
+ return ccu_gate_helper_disable(&nkmp->common, nkmp->enable);
+}
+
+static int ccu_nkmp_enable(struct clk_hw *hw)
+{
+ struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);
+
+ return ccu_gate_helper_enable(&nkmp->common, nkmp->enable);
+}
+
+static int ccu_nkmp_is_enabled(struct clk_hw *hw)
+{
+ struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);
+
+ return ccu_gate_helper_is_enabled(&nkmp->common, nkmp->enable);
+}
+
+static unsigned long ccu_nkmp_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);
+ unsigned long n, m, k, p;
+ u32 reg;
+
+ reg = readl(nkmp->common.base + nkmp->common.reg);
+
+ n = reg >> nkmp->n.shift;
+ n &= (1 << nkmp->n.width) - 1;
+
+ k = reg >> nkmp->k.shift;
+ k &= (1 << nkmp->k.width) - 1;
+
+ m = reg >> nkmp->m.shift;
+ m &= (1 << nkmp->m.width) - 1;
+
+ p = reg >> nkmp->p.shift;
+ p &= (1 << nkmp->p.width) - 1;
+
+ return (parent_rate * (n + 1) * (k + 1) >> p) / (m + 1);
+}
+
+static long ccu_nkmp_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);
+ struct _ccu_nkmp _nkmp;
+
+ _nkmp.max_n = 1 << nkmp->n.width;
+ _nkmp.max_k = 1 << nkmp->k.width;
+ _nkmp.max_m = 1 << nkmp->m.width;
+ _nkmp.max_p = (1 << nkmp->p.width) - 1;
+
+ ccu_nkmp_find_best(*parent_rate, rate,
+ &_nkmp);
+
+ return (*parent_rate * _nkmp.n * _nkmp.k >> _nkmp.p) / _nkmp.m;
+}
+
+static int ccu_nkmp_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);
+ struct _ccu_nkmp _nkmp;
+ unsigned long flags;
+ u32 reg;
+
+ _nkmp.max_n = 1 << nkmp->n.width;
+ _nkmp.max_k = 1 << nkmp->k.width;
+ _nkmp.max_m = 1 << nkmp->m.width;
+ _nkmp.max_p = (1 << nkmp->p.width) - 1;
+
+ ccu_nkmp_find_best(parent_rate, rate, &_nkmp);
+
+ spin_lock_irqsave(nkmp->common.lock, flags);
+
+ reg = readl(nkmp->common.base + nkmp->common.reg);
+ reg &= ~GENMASK(nkmp->n.width + nkmp->n.shift - 1, nkmp->n.shift);
+ reg &= ~GENMASK(nkmp->k.width + nkmp->k.shift - 1, nkmp->k.shift);
+ reg &= ~GENMASK(nkmp->m.width + nkmp->m.shift - 1, nkmp->m.shift);
+ reg &= ~GENMASK(nkmp->p.width + nkmp->p.shift - 1, nkmp->p.shift);
+
+ reg |= (_nkmp.n - 1) << nkmp->n.shift;
+ reg |= (_nkmp.k - 1) << nkmp->k.shift;
+ reg |= (_nkmp.m - 1) << nkmp->m.shift;
+ reg |= _nkmp.p << nkmp->p.shift;
+
+ writel(reg, nkmp->common.base + nkmp->common.reg);
+
+ spin_unlock_irqrestore(nkmp->common.lock, flags);
+
+ ccu_helper_wait_for_lock(&nkmp->common, nkmp->lock);
+
+ return 0;
+}
+
+const struct clk_ops ccu_nkmp_ops = {
+ .disable = ccu_nkmp_disable,
+ .enable = ccu_nkmp_enable,
+ .is_enabled = ccu_nkmp_is_enabled,
+
+ .recalc_rate = ccu_nkmp_recalc_rate,
+ .round_rate = ccu_nkmp_round_rate,
+ .set_rate = ccu_nkmp_set_rate,
+};
diff --git a/drivers/clk/sunxi-ng/ccu_nkmp.h b/drivers/clk/sunxi-ng/ccu_nkmp.h
new file mode 100644
index 000000000000..44cfa203be07
--- /dev/null
+++ b/drivers/clk/sunxi-ng/ccu_nkmp.h
@@ -0,0 +1,73 @@
+/*
+ * 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_NKMP_H_
+#define _CCU_NKMP_H_
+
+#include <linux/clk-provider.h>
+
+#include "ccu_common.h"
+#include "ccu_div.h"
+#include "ccu_mult.h"
+
+/*
+ * struct ccu_nkmp - Definition of an N-K-M-P clock
+ *
+ * Clocks based on the formula parent * N * K >> P / M
+ */
+struct ccu_nkmp {
+ u32 enable;
+ u32 lock;
+
+ struct _ccu_mult n;
+ struct _ccu_mult k;
+ struct _ccu_div m;
+ struct _ccu_div p;
+
+ struct ccu_common common;
+};
+
+#define SUNXI_CCU_NKMP_WITH_GATE_LOCK(_struct, _name, _parent, _reg, \
+ _nshift, _nwidth, \
+ _kshift, _kwidth, \
+ _mshift, _mwidth, \
+ _pshift, _pwidth, \
+ _gate, _lock, _flags) \
+ struct ccu_nkmp _struct = { \
+ .enable = _gate, \
+ .lock = _lock, \
+ .n = _SUNXI_CCU_MULT(_nshift, _nwidth), \
+ .k = _SUNXI_CCU_MULT(_kshift, _kwidth), \
+ .m = _SUNXI_CCU_DIV(_mshift, _mwidth), \
+ .p = _SUNXI_CCU_DIV(_pshift, _pwidth), \
+ .common = { \
+ .reg = _reg, \
+ .features = (CCU_FEATURE_GATE | \
+ CCU_FEATURE_PLL_LOCK), \
+ .hw.init = SUNXI_HW_INIT(_name, \
+ _parent, \
+ &ccu_nkmp_ops, \
+ _flags), \
+ }, \
+ }
+
+static inline struct ccu_nkmp *hw_to_ccu_nkmp(struct clk_hw *hw)
+{
+ struct ccu_common *common = hw_to_ccu_common(hw);
+
+ return container_of(common, struct ccu_nkmp, common);
+}
+
+extern const struct clk_ops ccu_nkmp_ops;
+
+#endif /* _CCU_NKMP_H_ */
--
2.8.3