1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun * Copyright (C) 2012 ST Microelectronics
3*4882a593Smuzhiyun * Viresh Kumar <vireshk@kernel.org>
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * This file is licensed under the terms of the GNU General Public
6*4882a593Smuzhiyun * License version 2. This program is licensed "as is" without any
7*4882a593Smuzhiyun * warranty of any kind, whether express or implied.
8*4882a593Smuzhiyun *
9*4882a593Smuzhiyun * General Purpose Timer Synthesizer clock implementation
10*4882a593Smuzhiyun */
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun #define pr_fmt(fmt) "clk-gpt-synth: " fmt
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun #include <linux/clk-provider.h>
15*4882a593Smuzhiyun #include <linux/slab.h>
16*4882a593Smuzhiyun #include <linux/io.h>
17*4882a593Smuzhiyun #include <linux/err.h>
18*4882a593Smuzhiyun #include "clk.h"
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun #define GPT_MSCALE_MASK 0xFFF
21*4882a593Smuzhiyun #define GPT_NSCALE_SHIFT 12
22*4882a593Smuzhiyun #define GPT_NSCALE_MASK 0xF
23*4882a593Smuzhiyun
24*4882a593Smuzhiyun /*
25*4882a593Smuzhiyun * DOC: General Purpose Timer Synthesizer clock
26*4882a593Smuzhiyun *
27*4882a593Smuzhiyun * Calculates gpt synth clk rate for different values of mscale and nscale
28*4882a593Smuzhiyun *
29*4882a593Smuzhiyun * Fout= Fin/((2 ^ (N+1)) * (M+1))
30*4882a593Smuzhiyun */
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun #define to_clk_gpt(_hw) container_of(_hw, struct clk_gpt, hw)
33*4882a593Smuzhiyun
gpt_calc_rate(struct clk_hw * hw,unsigned long prate,int index)34*4882a593Smuzhiyun static unsigned long gpt_calc_rate(struct clk_hw *hw, unsigned long prate,
35*4882a593Smuzhiyun int index)
36*4882a593Smuzhiyun {
37*4882a593Smuzhiyun struct clk_gpt *gpt = to_clk_gpt(hw);
38*4882a593Smuzhiyun struct gpt_rate_tbl *rtbl = gpt->rtbl;
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun prate /= ((1 << (rtbl[index].nscale + 1)) * (rtbl[index].mscale + 1));
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun return prate;
43*4882a593Smuzhiyun }
44*4882a593Smuzhiyun
clk_gpt_round_rate(struct clk_hw * hw,unsigned long drate,unsigned long * prate)45*4882a593Smuzhiyun static long clk_gpt_round_rate(struct clk_hw *hw, unsigned long drate,
46*4882a593Smuzhiyun unsigned long *prate)
47*4882a593Smuzhiyun {
48*4882a593Smuzhiyun struct clk_gpt *gpt = to_clk_gpt(hw);
49*4882a593Smuzhiyun int unused;
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun return clk_round_rate_index(hw, drate, *prate, gpt_calc_rate,
52*4882a593Smuzhiyun gpt->rtbl_cnt, &unused);
53*4882a593Smuzhiyun }
54*4882a593Smuzhiyun
clk_gpt_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)55*4882a593Smuzhiyun static unsigned long clk_gpt_recalc_rate(struct clk_hw *hw,
56*4882a593Smuzhiyun unsigned long parent_rate)
57*4882a593Smuzhiyun {
58*4882a593Smuzhiyun struct clk_gpt *gpt = to_clk_gpt(hw);
59*4882a593Smuzhiyun unsigned long flags = 0;
60*4882a593Smuzhiyun unsigned int div = 1, val;
61*4882a593Smuzhiyun
62*4882a593Smuzhiyun if (gpt->lock)
63*4882a593Smuzhiyun spin_lock_irqsave(gpt->lock, flags);
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun val = readl_relaxed(gpt->reg);
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun if (gpt->lock)
68*4882a593Smuzhiyun spin_unlock_irqrestore(gpt->lock, flags);
69*4882a593Smuzhiyun
70*4882a593Smuzhiyun div += val & GPT_MSCALE_MASK;
71*4882a593Smuzhiyun div *= 1 << (((val >> GPT_NSCALE_SHIFT) & GPT_NSCALE_MASK) + 1);
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun if (!div)
74*4882a593Smuzhiyun return 0;
75*4882a593Smuzhiyun
76*4882a593Smuzhiyun return parent_rate / div;
77*4882a593Smuzhiyun }
78*4882a593Smuzhiyun
79*4882a593Smuzhiyun /* Configures new clock rate of gpt */
clk_gpt_set_rate(struct clk_hw * hw,unsigned long drate,unsigned long prate)80*4882a593Smuzhiyun static int clk_gpt_set_rate(struct clk_hw *hw, unsigned long drate,
81*4882a593Smuzhiyun unsigned long prate)
82*4882a593Smuzhiyun {
83*4882a593Smuzhiyun struct clk_gpt *gpt = to_clk_gpt(hw);
84*4882a593Smuzhiyun struct gpt_rate_tbl *rtbl = gpt->rtbl;
85*4882a593Smuzhiyun unsigned long flags = 0, val;
86*4882a593Smuzhiyun int i;
87*4882a593Smuzhiyun
88*4882a593Smuzhiyun clk_round_rate_index(hw, drate, prate, gpt_calc_rate, gpt->rtbl_cnt,
89*4882a593Smuzhiyun &i);
90*4882a593Smuzhiyun
91*4882a593Smuzhiyun if (gpt->lock)
92*4882a593Smuzhiyun spin_lock_irqsave(gpt->lock, flags);
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun val = readl(gpt->reg) & ~GPT_MSCALE_MASK;
95*4882a593Smuzhiyun val &= ~(GPT_NSCALE_MASK << GPT_NSCALE_SHIFT);
96*4882a593Smuzhiyun
97*4882a593Smuzhiyun val |= rtbl[i].mscale & GPT_MSCALE_MASK;
98*4882a593Smuzhiyun val |= (rtbl[i].nscale & GPT_NSCALE_MASK) << GPT_NSCALE_SHIFT;
99*4882a593Smuzhiyun
100*4882a593Smuzhiyun writel_relaxed(val, gpt->reg);
101*4882a593Smuzhiyun
102*4882a593Smuzhiyun if (gpt->lock)
103*4882a593Smuzhiyun spin_unlock_irqrestore(gpt->lock, flags);
104*4882a593Smuzhiyun
105*4882a593Smuzhiyun return 0;
106*4882a593Smuzhiyun }
107*4882a593Smuzhiyun
108*4882a593Smuzhiyun static const struct clk_ops clk_gpt_ops = {
109*4882a593Smuzhiyun .recalc_rate = clk_gpt_recalc_rate,
110*4882a593Smuzhiyun .round_rate = clk_gpt_round_rate,
111*4882a593Smuzhiyun .set_rate = clk_gpt_set_rate,
112*4882a593Smuzhiyun };
113*4882a593Smuzhiyun
clk_register_gpt(const char * name,const char * parent_name,unsigned long flags,void __iomem * reg,struct gpt_rate_tbl * rtbl,u8 rtbl_cnt,spinlock_t * lock)114*4882a593Smuzhiyun struct clk *clk_register_gpt(const char *name, const char *parent_name, unsigned
115*4882a593Smuzhiyun long flags, void __iomem *reg, struct gpt_rate_tbl *rtbl, u8
116*4882a593Smuzhiyun rtbl_cnt, spinlock_t *lock)
117*4882a593Smuzhiyun {
118*4882a593Smuzhiyun struct clk_init_data init;
119*4882a593Smuzhiyun struct clk_gpt *gpt;
120*4882a593Smuzhiyun struct clk *clk;
121*4882a593Smuzhiyun
122*4882a593Smuzhiyun if (!name || !parent_name || !reg || !rtbl || !rtbl_cnt) {
123*4882a593Smuzhiyun pr_err("Invalid arguments passed\n");
124*4882a593Smuzhiyun return ERR_PTR(-EINVAL);
125*4882a593Smuzhiyun }
126*4882a593Smuzhiyun
127*4882a593Smuzhiyun gpt = kzalloc(sizeof(*gpt), GFP_KERNEL);
128*4882a593Smuzhiyun if (!gpt)
129*4882a593Smuzhiyun return ERR_PTR(-ENOMEM);
130*4882a593Smuzhiyun
131*4882a593Smuzhiyun /* struct clk_gpt assignments */
132*4882a593Smuzhiyun gpt->reg = reg;
133*4882a593Smuzhiyun gpt->rtbl = rtbl;
134*4882a593Smuzhiyun gpt->rtbl_cnt = rtbl_cnt;
135*4882a593Smuzhiyun gpt->lock = lock;
136*4882a593Smuzhiyun gpt->hw.init = &init;
137*4882a593Smuzhiyun
138*4882a593Smuzhiyun init.name = name;
139*4882a593Smuzhiyun init.ops = &clk_gpt_ops;
140*4882a593Smuzhiyun init.flags = flags;
141*4882a593Smuzhiyun init.parent_names = &parent_name;
142*4882a593Smuzhiyun init.num_parents = 1;
143*4882a593Smuzhiyun
144*4882a593Smuzhiyun clk = clk_register(NULL, &gpt->hw);
145*4882a593Smuzhiyun if (!IS_ERR_OR_NULL(clk))
146*4882a593Smuzhiyun return clk;
147*4882a593Smuzhiyun
148*4882a593Smuzhiyun pr_err("clk register failed\n");
149*4882a593Smuzhiyun kfree(gpt);
150*4882a593Smuzhiyun
151*4882a593Smuzhiyun return NULL;
152*4882a593Smuzhiyun }
153