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>

3 files changed, 242 insertions, 1 deletions

diff --git a/drivers/clk/spear/Makefile b/drivers/clk/spear/Makefile
index 3fc2a3026cc1..e36d8c665724 100644
--- a/drivers/clk/spear/Makefile
+++ b/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
diff --git a/drivers/clk/spear/clk-aux-synth.c b/drivers/clk/spear/clk-aux-synth.c
new file mode 100644
index 000000000000..af34074e702b
--- /dev/null
+++ b/drivers/clk/spear/clk-aux-synth.c
@@ -0,0 +1,198 @@
+/*
+ * 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;
+}
diff --git a/drivers/clk/spear/clk.h b/drivers/clk/spear/clk.h
index 9979b7f7e767..c2290800503a 100644
--- a/drivers/clk/spear/clk.h
+++ b/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