clk: sunxi-ng: Add N-K-factor clock support

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

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/20160629190535.11855-10-maxime.ripard@free-electrons.com

diff --git a/drivers/clk/sunxi-ng/Kconfig b/drivers/clk/sunxi-ng/Kconfig
index fc970b5..2eb0fc6 100644 (file)
--- a/drivers/clk/sunxi-ng/Kconfig
+++ b/drivers/clk/sunxi-ng/Kconfig
@@ -24,6 +24,10 @@ config SUNXI_CCU_PHASE
 
 # Multi-factor clocks
 
+config SUNXI_CCU_NK
+       bool
+       select SUNXI_CCU_GATE
+
 config SUNXI_CCU_MP
        bool
        select SUNXI_CCU_GATE

diff --git a/drivers/clk/sunxi-ng/Makefile b/drivers/clk/sunxi-ng/Makefile
index 501dec9..22951e6 100644 (file)
--- a/drivers/clk/sunxi-ng/Makefile
+++ b/drivers/clk/sunxi-ng/Makefile
@@ -10,4 +10,5 @@ obj-$(CONFIG_SUNXI_CCU_MUX)   += ccu_mux.o
 obj-$(CONFIG_SUNXI_CCU_PHASE)  += ccu_phase.o
 
 # Multi-factor clocks
+obj-$(CONFIG_SUNXI_CCU_NK)     += ccu_nk.o
 obj-$(CONFIG_SUNXI_CCU_MP)     += ccu_mp.o

diff --git a/drivers/clk/sunxi-ng/ccu_nk.c b/drivers/clk/sunxi-ng/ccu_nk.c
new file mode 100644 (file)
index 0000000..4470ffc
--- /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 = 1; _k <= max_k; _k++) {
+               for (_n = 1; _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 /= 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 *= 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 - 1, nk->n.shift);
+       reg &= ~GENMASK(nk->k.width + nk->k.shift - 1, 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 (file)
index 0000000..4b52da0
--- /dev/null
+++ b/drivers/clk/sunxi-ng/ccu_nk.h
@@ -0,0 +1,71 @@
+/*
+ * 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_div.h"
+#include "ccu_mult.h"
+
+/*
+ * struct ccu_nk - Definition of an N-K clock
+ *
+ * Clocks based on the formula parent * N * K
+ */
+struct ccu_nk {
+       u16                     reg;
+       u32                     enable;
+       u32                     lock;
+
+       struct _ccu_mult        n;
+       struct _ccu_mult        k;
+
+       unsigned int            fixed_post_div;
+
+       struct ccu_common       common;
+};
+
+#define SUNXI_CCU_NK_WITH_GATE_LOCK_POSTDIV(_struct, _name, _parent, _reg, \
+                                           _nshift, _nwidth,           \
+                                           _kshift, _kwidth,           \
+                                           _gate, _lock, _postdiv,     \
+                                           _flags)                     \
+       struct ccu_nk _struct = {                                       \
+               .enable         = _gate,                                \
+               .lock           = _lock,                                \
+               .k              = _SUNXI_CCU_MULT(_kshift, _kwidth),    \
+               .n              = _SUNXI_CCU_MULT(_nshift, _nwidth),    \
+               .fixed_post_div = _postdiv,                             \
+               .common         = {                                     \
+                       .reg            = _reg,                         \
+                       .features       = CCU_FEATURE_FIXED_POSTDIV,    \
+                       .hw.init        = CLK_HW_INIT(_name,            \
+                                                     _parent,          \
+                                                     &ccu_nk_ops,      \
+                                                     _flags),          \
+               },                                                      \
+       }
+
+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_ */