diff mbox

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

Message ID 20160607204154.31967-14-maxime.ripard@free-electrons.com (mailing list archive)
State Superseded, archived
Headers show

Commit Message

Maxime Ripard June 7, 2016, 8:41 p.m. UTC
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

Comments

Stephen Boyd June 21, 2016, 1:42 a.m. UTC | #1
On 06/07, Maxime Ripard wrote:
> 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);

Is there a select for RATIONAL somewhere? If not please add it to
the Kconfig. I know that COMMON_CLK has it, but I think we should
try to reduce bloat by not forcing all the basic types on drivers
that aren't using them. Instead we should have drivers start
selecting that code. So it's best to not rely on the common clk
select.
diff mbox

Patch

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_ */