SPEAr: clk: Add Auxiliary Synthesizer clock

All SPEAr SoC's contain Auxiliary Synthesizers. Their Fout is derived based on
values of eq, x and y.

Fout from synthesizer can be given from two equations:
Fout1 = (Fin * X/Y)/2		EQ1
Fout2 = Fin * X/Y		EQ2

This patch adds in support for this type of clock.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Reviewed-by: Mike Turquette <mturquette@linaro.org>

drivers/clk/spear/Makefile

@@ -2,4 +2,4 @@
 # SPEAr Clock specific Makefile
 #
 
-obj-y	+= clk.o clk-vco-pll.o
+obj-y	+= clk.o clk-aux-synth.o clk-vco-pll.o

drivers/clk/spear/clk-aux-synth.c

+/*
+ * Copyright (C) 2012 ST Microelectronics
+ * Viresh Kumar <viresh.kumar@st.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.
+ *
+ * Auxiliary Synthesizer clock implementation
+ */
+
+#define pr_fmt(fmt) "clk-aux-synth: " fmt
+
+#include <linux/clk-provider.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include "clk.h"
+
+/*
+ * DOC: Auxiliary Synthesizer clock
+ *
+ * Aux synth gives rate for different values of eq, x and y
+ *
+ * Fout from synthesizer can be given from two equations:
+ * Fout1 = (Fin * X/Y)/2		EQ1
+ * Fout2 = Fin * X/Y			EQ2
+ */
+
+#define to_clk_aux(_hw) container_of(_hw, struct clk_aux, hw)
+
+static struct aux_clk_masks default_aux_masks = {
+	.eq_sel_mask = AUX_EQ_SEL_MASK,
+	.eq_sel_shift = AUX_EQ_SEL_SHIFT,
+	.eq1_mask = AUX_EQ1_SEL,
+	.eq2_mask = AUX_EQ2_SEL,
+	.xscale_sel_mask = AUX_XSCALE_MASK,
+	.xscale_sel_shift = AUX_XSCALE_SHIFT,
+	.yscale_sel_mask = AUX_YSCALE_MASK,
+	.yscale_sel_shift = AUX_YSCALE_SHIFT,
+	.enable_bit = AUX_SYNT_ENB,
+};
+
+static unsigned long aux_calc_rate(struct clk_hw *hw, unsigned long prate,
+		int index)
+{
+	struct clk_aux *aux = to_clk_aux(hw);
+	struct aux_rate_tbl *rtbl = aux->rtbl;
+	u8 eq = rtbl[index].eq ? 1 : 2;
+
+	return (((prate / 10000) * rtbl[index].xscale) /
+			(rtbl[index].yscale * eq)) * 10000;
+}
+
+static long clk_aux_round_rate(struct clk_hw *hw, unsigned long drate,
+		unsigned long *prate)
+{
+	struct clk_aux *aux = to_clk_aux(hw);
+	int unused;
+
+	return clk_round_rate_index(hw, drate, *prate, aux_calc_rate,
+			aux->rtbl_cnt, &unused);
+}
+
+static unsigned long clk_aux_recalc_rate(struct clk_hw *hw,
+		unsigned long parent_rate)
+{
+	struct clk_aux *aux = to_clk_aux(hw);
+	unsigned int num = 1, den = 1, val, eqn;
+	unsigned long flags = 0;
+
+	if (aux->lock)
+		spin_lock_irqsave(aux->lock, flags);
+
+	val = readl_relaxed(aux->reg);
+
+	if (aux->lock)
+		spin_unlock_irqrestore(aux->lock, flags);
+
+	eqn = (val >> aux->masks->eq_sel_shift) & aux->masks->eq_sel_mask;
+	if (eqn == aux->masks->eq1_mask)
+		den = 2;
+
+	/* calculate numerator */
+	num = (val >> aux->masks->xscale_sel_shift) &
+		aux->masks->xscale_sel_mask;
+
+	/* calculate denominator */
+	den *= (val >> aux->masks->yscale_sel_shift) &
+		aux->masks->yscale_sel_mask;
+
+	if (!den)
+		return 0;
+
+	return (((parent_rate / 10000) * num) / den) * 10000;
+}
+
+/* Configures new clock rate of aux */
+static int clk_aux_set_rate(struct clk_hw *hw, unsigned long drate,
+				unsigned long prate)
+{
+	struct clk_aux *aux = to_clk_aux(hw);
+	struct aux_rate_tbl *rtbl = aux->rtbl;
+	unsigned long val, flags = 0;
+	int i;
+
+	clk_round_rate_index(hw, drate, prate, aux_calc_rate, aux->rtbl_cnt,
+			&i);
+
+	if (aux->lock)
+		spin_lock_irqsave(aux->lock, flags);
+
+	val = readl_relaxed(aux->reg) &
+		~(aux->masks->eq_sel_mask << aux->masks->eq_sel_shift);
+	val |= (rtbl[i].eq & aux->masks->eq_sel_mask) <<
+		aux->masks->eq_sel_shift;
+	val &= ~(aux->masks->xscale_sel_mask << aux->masks->xscale_sel_shift);
+	val |= (rtbl[i].xscale & aux->masks->xscale_sel_mask) <<
+		aux->masks->xscale_sel_shift;
+	val &= ~(aux->masks->yscale_sel_mask << aux->masks->yscale_sel_shift);
+	val |= (rtbl[i].yscale & aux->masks->yscale_sel_mask) <<
+		aux->masks->yscale_sel_shift;
+	writel_relaxed(val, aux->reg);
+
+	if (aux->lock)
+		spin_unlock_irqrestore(aux->lock, flags);
+
+	return 0;
+}
+
+static struct clk_ops clk_aux_ops = {
+	.recalc_rate = clk_aux_recalc_rate,
+	.round_rate = clk_aux_round_rate,
+	.set_rate = clk_aux_set_rate,
+};
+
+struct clk *clk_register_aux(const char *aux_name, const char *gate_name,
+		const char *parent_name, unsigned long flags, void __iomem *reg,
+		struct aux_clk_masks *masks, struct aux_rate_tbl *rtbl,
+		u8 rtbl_cnt, spinlock_t *lock, struct clk **gate_clk)
+{
+	struct clk_aux *aux;
+	struct clk_init_data init;
+	struct clk *clk;
+
+	if (!aux_name || !parent_name || !reg || !rtbl || !rtbl_cnt) {
+		pr_err("Invalid arguments passed");
+		return ERR_PTR(-EINVAL);
+	}
+
+	aux = kzalloc(sizeof(*aux), GFP_KERNEL);
+	if (!aux) {
+		pr_err("could not allocate aux clk\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	/* struct clk_aux assignments */
+	if (!masks)
+		aux->masks = &default_aux_masks;
+	else
+		aux->masks = masks;
+
+	aux->reg = reg;
+	aux->rtbl = rtbl;
+	aux->rtbl_cnt = rtbl_cnt;
+	aux->lock = lock;
+	aux->hw.init = &init;
+
+	init.name = aux_name;
+	init.ops = &clk_aux_ops;
+	init.flags = flags;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+
+	clk = clk_register(NULL, &aux->hw);
+	if (IS_ERR_OR_NULL(clk))
+		goto free_aux;
+
+	if (gate_name) {
+		struct clk *tgate_clk;
+
+		tgate_clk = clk_register_gate(NULL, gate_name, aux_name, 0, reg,
+				aux->masks->enable_bit, 0, lock);
+		if (IS_ERR_OR_NULL(tgate_clk))
+			goto free_aux;
+
+		if (gate_clk)
+			*gate_clk = tgate_clk;
+	}
+
+	return clk;
+
+free_aux:
+	kfree(aux);
+	pr_err("clk register failed\n");
+
+	return NULL;
+}

drivers/clk/spear/clk.h

@@ -16,6 +16,45 @@
 #include <linux/spinlock_types.h>
 #include <linux/types.h>
 
+/* Auxiliary Synth clk */
+/* Default masks */
+#define AUX_EQ_SEL_SHIFT	30
+#define AUX_EQ_SEL_MASK		1
+#define AUX_EQ1_SEL		0
+#define AUX_EQ2_SEL		1
+#define AUX_XSCALE_SHIFT	16
+#define AUX_XSCALE_MASK		0xFFF
+#define AUX_YSCALE_SHIFT	0
+#define AUX_YSCALE_MASK		0xFFF
+#define AUX_SYNT_ENB		31
+
+struct aux_clk_masks {
+	u32 eq_sel_mask;
+	u32 eq_sel_shift;
+	u32 eq1_mask;
+	u32 eq2_mask;
+	u32 xscale_sel_mask;
+	u32 xscale_sel_shift;
+	u32 yscale_sel_mask;
+	u32 yscale_sel_shift;
+	u32 enable_bit;
+};
+
+struct aux_rate_tbl {
+	u16 xscale;
+	u16 yscale;
+	u8 eq;
+};
+
+struct clk_aux {
+	struct			clk_hw hw;
+	void __iomem		*reg;
+	struct aux_clk_masks	*masks;
+	struct aux_rate_tbl	*rtbl;
+	u8			rtbl_cnt;
+	spinlock_t		*lock;
+};
+
 /* VCO-PLL clk */
 struct pll_rate_tbl {
 	u8 mode;
@@ -44,6 +83,10 @@ typedef unsigned long (*clk_calc_rate)(struct clk_hw *hw, unsigned long prate,
 		int index);
 
 /* clk register routines */
+struct clk *clk_register_aux(const char *aux_name, const char *gate_name,
+		const char *parent_name, unsigned long flags, void __iomem *reg,
+		struct aux_clk_masks *masks, struct aux_rate_tbl *rtbl,
+		u8 rtbl_cnt, spinlock_t *lock, struct clk **gate_clk);
 struct clk *clk_register_vco_pll(const char *vco_name, const char *pll_name,
 		const char *vco_gate_name, const char *parent_name,
 		unsigned long flags, void __iomem *mode_reg, void __iomem