1 /*
2  * Copyright (C) 2012 ST Microelectronics
3  * Viresh Kumar <viresh.linux@gmail.com>
4  *
5  * This file is licensed under the terms of the GNU General Public
6  * License version 2. This program is licensed "as is" without any
7  * warranty of any kind, whether express or implied.
8  *
9  * Auxiliary Synthesizer clock implementation
10  */
11 
12 #define pr_fmt(fmt) "clk-aux-synth: " fmt
13 
14 #include <linux/clk-provider.h>
15 #include <linux/slab.h>
16 #include <linux/io.h>
17 #include <linux/err.h>
18 #include "clk.h"
19 
20 /*
21  * DOC: Auxiliary Synthesizer clock
22  *
23  * Aux synth gives rate for different values of eq, x and y
24  *
25  * Fout from synthesizer can be given from two equations:
26  * Fout1 = (Fin * X/Y)/2		EQ1
27  * Fout2 = Fin * X/Y			EQ2
28  */
29 
30 #define to_clk_aux(_hw) container_of(_hw, struct clk_aux, hw)
31 
32 static struct aux_clk_masks default_aux_masks = {
33 	.eq_sel_mask = AUX_EQ_SEL_MASK,
34 	.eq_sel_shift = AUX_EQ_SEL_SHIFT,
35 	.eq1_mask = AUX_EQ1_SEL,
36 	.eq2_mask = AUX_EQ2_SEL,
37 	.xscale_sel_mask = AUX_XSCALE_MASK,
38 	.xscale_sel_shift = AUX_XSCALE_SHIFT,
39 	.yscale_sel_mask = AUX_YSCALE_MASK,
40 	.yscale_sel_shift = AUX_YSCALE_SHIFT,
41 	.enable_bit = AUX_SYNT_ENB,
42 };
43 
44 static unsigned long aux_calc_rate(struct clk_hw *hw, unsigned long prate,
45 		int index)
46 {
47 	struct clk_aux *aux = to_clk_aux(hw);
48 	struct aux_rate_tbl *rtbl = aux->rtbl;
49 	u8 eq = rtbl[index].eq ? 1 : 2;
50 
51 	return (((prate / 10000) * rtbl[index].xscale) /
52 			(rtbl[index].yscale * eq)) * 10000;
53 }
54 
55 static long clk_aux_round_rate(struct clk_hw *hw, unsigned long drate,
56 		unsigned long *prate)
57 {
58 	struct clk_aux *aux = to_clk_aux(hw);
59 	int unused;
60 
61 	return clk_round_rate_index(hw, drate, *prate, aux_calc_rate,
62 			aux->rtbl_cnt, &unused);
63 }
64 
65 static unsigned long clk_aux_recalc_rate(struct clk_hw *hw,
66 		unsigned long parent_rate)
67 {
68 	struct clk_aux *aux = to_clk_aux(hw);
69 	unsigned int num = 1, den = 1, val, eqn;
70 	unsigned long flags = 0;
71 
72 	if (aux->lock)
73 		spin_lock_irqsave(aux->lock, flags);
74 
75 	val = readl_relaxed(aux->reg);
76 
77 	if (aux->lock)
78 		spin_unlock_irqrestore(aux->lock, flags);
79 
80 	eqn = (val >> aux->masks->eq_sel_shift) & aux->masks->eq_sel_mask;
81 	if (eqn == aux->masks->eq1_mask)
82 		den = 2;
83 
84 	/* calculate numerator */
85 	num = (val >> aux->masks->xscale_sel_shift) &
86 		aux->masks->xscale_sel_mask;
87 
88 	/* calculate denominator */
89 	den *= (val >> aux->masks->yscale_sel_shift) &
90 		aux->masks->yscale_sel_mask;
91 
92 	if (!den)
93 		return 0;
94 
95 	return (((parent_rate / 10000) * num) / den) * 10000;
96 }
97 
98 /* Configures new clock rate of aux */
99 static int clk_aux_set_rate(struct clk_hw *hw, unsigned long drate,
100 				unsigned long prate)
101 {
102 	struct clk_aux *aux = to_clk_aux(hw);
103 	struct aux_rate_tbl *rtbl = aux->rtbl;
104 	unsigned long val, flags = 0;
105 	int i;
106 
107 	clk_round_rate_index(hw, drate, prate, aux_calc_rate, aux->rtbl_cnt,
108 			&i);
109 
110 	if (aux->lock)
111 		spin_lock_irqsave(aux->lock, flags);
112 
113 	val = readl_relaxed(aux->reg) &
114 		~(aux->masks->eq_sel_mask << aux->masks->eq_sel_shift);
115 	val |= (rtbl[i].eq & aux->masks->eq_sel_mask) <<
116 		aux->masks->eq_sel_shift;
117 	val &= ~(aux->masks->xscale_sel_mask << aux->masks->xscale_sel_shift);
118 	val |= (rtbl[i].xscale & aux->masks->xscale_sel_mask) <<
119 		aux->masks->xscale_sel_shift;
120 	val &= ~(aux->masks->yscale_sel_mask << aux->masks->yscale_sel_shift);
121 	val |= (rtbl[i].yscale & aux->masks->yscale_sel_mask) <<
122 		aux->masks->yscale_sel_shift;
123 	writel_relaxed(val, aux->reg);
124 
125 	if (aux->lock)
126 		spin_unlock_irqrestore(aux->lock, flags);
127 
128 	return 0;
129 }
130 
131 static struct clk_ops clk_aux_ops = {
132 	.recalc_rate = clk_aux_recalc_rate,
133 	.round_rate = clk_aux_round_rate,
134 	.set_rate = clk_aux_set_rate,
135 };
136 
137 struct clk *clk_register_aux(const char *aux_name, const char *gate_name,
138 		const char *parent_name, unsigned long flags, void __iomem *reg,
139 		struct aux_clk_masks *masks, struct aux_rate_tbl *rtbl,
140 		u8 rtbl_cnt, spinlock_t *lock, struct clk **gate_clk)
141 {
142 	struct clk_aux *aux;
143 	struct clk_init_data init;
144 	struct clk *clk;
145 
146 	if (!aux_name || !parent_name || !reg || !rtbl || !rtbl_cnt) {
147 		pr_err("Invalid arguments passed");
148 		return ERR_PTR(-EINVAL);
149 	}
150 
151 	aux = kzalloc(sizeof(*aux), GFP_KERNEL);
152 	if (!aux) {
153 		pr_err("could not allocate aux clk\n");
154 		return ERR_PTR(-ENOMEM);
155 	}
156 
157 	/* struct clk_aux assignments */
158 	if (!masks)
159 		aux->masks = &default_aux_masks;
160 	else
161 		aux->masks = masks;
162 
163 	aux->reg = reg;
164 	aux->rtbl = rtbl;
165 	aux->rtbl_cnt = rtbl_cnt;
166 	aux->lock = lock;
167 	aux->hw.init = &init;
168 
169 	init.name = aux_name;
170 	init.ops = &clk_aux_ops;
171 	init.flags = flags;
172 	init.parent_names = &parent_name;
173 	init.num_parents = 1;
174 
175 	clk = clk_register(NULL, &aux->hw);
176 	if (IS_ERR_OR_NULL(clk))
177 		goto free_aux;
178 
179 	if (gate_name) {
180 		struct clk *tgate_clk;
181 
182 		tgate_clk = clk_register_gate(NULL, gate_name, aux_name,
183 				CLK_SET_RATE_PARENT, reg,
184 				aux->masks->enable_bit, 0, lock);
185 		if (IS_ERR_OR_NULL(tgate_clk))
186 			goto free_aux;
187 
188 		if (gate_clk)
189 			*gate_clk = tgate_clk;
190 	}
191 
192 	return clk;
193 
194 free_aux:
195 	kfree(aux);
196 	pr_err("clk register failed\n");
197 
198 	return NULL;
199 }
200