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1/*
2 * Ralink RT2880 timer
3 * Author: John Crispin
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published
7 * by the Free Software Foundation.
8 *
9 * Copyright (C) 2013 John Crispin <john@phrozen.org>
10*/
11
12#include <linux/platform_device.h>
13#include <linux/interrupt.h>
14#include <linux/timer.h>
15#include <linux/of_gpio.h>
16#include <linux/clk.h>
17
18#include <asm/mach-ralink/ralink_regs.h>
19
20#define TIMER_REG_TMRSTAT 0x00
21#define TIMER_REG_TMR0LOAD 0x10
22#define TIMER_REG_TMR0CTL 0x18
23
24#define TMRSTAT_TMR0INT BIT(0)
25
26#define TMR0CTL_ENABLE BIT(7)
27#define TMR0CTL_MODE_PERIODIC BIT(4)
28#define TMR0CTL_PRESCALER 1
29#define TMR0CTL_PRESCALE_VAL (0xf - TMR0CTL_PRESCALER)
30#define TMR0CTL_PRESCALE_DIV (65536 / BIT(TMR0CTL_PRESCALER))
31
32struct rt_timer {
33 struct device *dev;
34 void __iomem *membase;
35 int irq;
36 unsigned long timer_freq;
37 unsigned long timer_div;
38};
39
40static inline void rt_timer_w32(struct rt_timer *rt, u8 reg, u32 val)
41{
42 __raw_writel(val, rt->membase + reg);
43}
44
45static inline u32 rt_timer_r32(struct rt_timer *rt, u8 reg)
46{
47 return __raw_readl(rt->membase + reg);
48}
49
50static irqreturn_t rt_timer_irq(int irq, void *_rt)
51{
52 struct rt_timer *rt = (struct rt_timer *) _rt;
53
54 rt_timer_w32(rt, TIMER_REG_TMR0LOAD, rt->timer_freq / rt->timer_div);
55 rt_timer_w32(rt, TIMER_REG_TMRSTAT, TMRSTAT_TMR0INT);
56
57 return IRQ_HANDLED;
58}
59
60
61static int rt_timer_request(struct rt_timer *rt)
62{
63 int err = request_irq(rt->irq, rt_timer_irq, 0,
64 dev_name(rt->dev), rt);
65 if (err) {
66 dev_err(rt->dev, "failed to request irq\n");
67 } else {
68 u32 t = TMR0CTL_MODE_PERIODIC | TMR0CTL_PRESCALE_VAL;
69 rt_timer_w32(rt, TIMER_REG_TMR0CTL, t);
70 }
71 return err;
72}
73
74static int rt_timer_config(struct rt_timer *rt, unsigned long divisor)
75{
76 if (rt->timer_freq < divisor)
77 rt->timer_div = rt->timer_freq;
78 else
79 rt->timer_div = divisor;
80
81 rt_timer_w32(rt, TIMER_REG_TMR0LOAD, rt->timer_freq / rt->timer_div);
82
83 return 0;
84}
85
86static int rt_timer_enable(struct rt_timer *rt)
87{
88 u32 t;
89
90 rt_timer_w32(rt, TIMER_REG_TMR0LOAD, rt->timer_freq / rt->timer_div);
91
92 t = rt_timer_r32(rt, TIMER_REG_TMR0CTL);
93 t |= TMR0CTL_ENABLE;
94 rt_timer_w32(rt, TIMER_REG_TMR0CTL, t);
95
96 return 0;
97}
98
99static int rt_timer_probe(struct platform_device *pdev)
100{
101 struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
102 struct rt_timer *rt;
103 struct clk *clk;
104
105 rt = devm_kzalloc(&pdev->dev, sizeof(*rt), GFP_KERNEL);
106 if (!rt) {
107 dev_err(&pdev->dev, "failed to allocate memory\n");
108 return -ENOMEM;
109 }
110
111 rt->irq = platform_get_irq(pdev, 0);
112 if (rt->irq < 0) {
113 dev_err(&pdev->dev, "failed to load irq\n");
114 return rt->irq;
115 }
116
117 rt->membase = devm_ioremap_resource(&pdev->dev, res);
118 if (IS_ERR(rt->membase))
119 return PTR_ERR(rt->membase);
120
121 clk = devm_clk_get(&pdev->dev, NULL);
122 if (IS_ERR(clk)) {
123 dev_err(&pdev->dev, "failed get clock rate\n");
124 return PTR_ERR(clk);
125 }
126
127 rt->timer_freq = clk_get_rate(clk) / TMR0CTL_PRESCALE_DIV;
128 if (!rt->timer_freq)
129 return -EINVAL;
130
131 rt->dev = &pdev->dev;
132 platform_set_drvdata(pdev, rt);
133
134 rt_timer_request(rt);
135 rt_timer_config(rt, 2);
136 rt_timer_enable(rt);
137
138 dev_info(&pdev->dev, "maximum frequency is %luHz\n", rt->timer_freq);
139
140 return 0;
141}
142
143static const struct of_device_id rt_timer_match[] = {
144 { .compatible = "ralink,rt2880-timer" },
145 {},
146};
147
148static struct platform_driver rt_timer_driver = {
149 .probe = rt_timer_probe,
150 .driver = {
151 .name = "rt-timer",
152 .of_match_table = rt_timer_match,
153 .suppress_bind_attrs = true,
154 },
155};
156builtin_platform_driver(rt_timer_driver);
1/*
2 * This program is free software; you can redistribute it and/or modify it
3 * under the terms of the GNU General Public License version 2 as published
4 * by the Free Software Foundation.
5 *
6 * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
7*/
8
9#include <linux/module.h>
10#include <linux/platform_device.h>
11#include <linux/interrupt.h>
12#include <linux/timer.h>
13#include <linux/of_gpio.h>
14#include <linux/clk.h>
15
16#include <asm/mach-ralink/ralink_regs.h>
17
18#define TIMER_REG_TMRSTAT 0x00
19#define TIMER_REG_TMR0LOAD 0x10
20#define TIMER_REG_TMR0CTL 0x18
21
22#define TMRSTAT_TMR0INT BIT(0)
23
24#define TMR0CTL_ENABLE BIT(7)
25#define TMR0CTL_MODE_PERIODIC BIT(4)
26#define TMR0CTL_PRESCALER 1
27#define TMR0CTL_PRESCALE_VAL (0xf - TMR0CTL_PRESCALER)
28#define TMR0CTL_PRESCALE_DIV (65536 / BIT(TMR0CTL_PRESCALER))
29
30struct rt_timer {
31 struct device *dev;
32 void __iomem *membase;
33 int irq;
34 unsigned long timer_freq;
35 unsigned long timer_div;
36};
37
38static inline void rt_timer_w32(struct rt_timer *rt, u8 reg, u32 val)
39{
40 __raw_writel(val, rt->membase + reg);
41}
42
43static inline u32 rt_timer_r32(struct rt_timer *rt, u8 reg)
44{
45 return __raw_readl(rt->membase + reg);
46}
47
48static irqreturn_t rt_timer_irq(int irq, void *_rt)
49{
50 struct rt_timer *rt = (struct rt_timer *) _rt;
51
52 rt_timer_w32(rt, TIMER_REG_TMR0LOAD, rt->timer_freq / rt->timer_div);
53 rt_timer_w32(rt, TIMER_REG_TMRSTAT, TMRSTAT_TMR0INT);
54
55 return IRQ_HANDLED;
56}
57
58
59static int rt_timer_request(struct rt_timer *rt)
60{
61 int err = request_irq(rt->irq, rt_timer_irq, IRQF_DISABLED,
62 dev_name(rt->dev), rt);
63 if (err) {
64 dev_err(rt->dev, "failed to request irq\n");
65 } else {
66 u32 t = TMR0CTL_MODE_PERIODIC | TMR0CTL_PRESCALE_VAL;
67 rt_timer_w32(rt, TIMER_REG_TMR0CTL, t);
68 }
69 return err;
70}
71
72static void rt_timer_free(struct rt_timer *rt)
73{
74 free_irq(rt->irq, rt);
75}
76
77static int rt_timer_config(struct rt_timer *rt, unsigned long divisor)
78{
79 if (rt->timer_freq < divisor)
80 rt->timer_div = rt->timer_freq;
81 else
82 rt->timer_div = divisor;
83
84 rt_timer_w32(rt, TIMER_REG_TMR0LOAD, rt->timer_freq / rt->timer_div);
85
86 return 0;
87}
88
89static int rt_timer_enable(struct rt_timer *rt)
90{
91 u32 t;
92
93 rt_timer_w32(rt, TIMER_REG_TMR0LOAD, rt->timer_freq / rt->timer_div);
94
95 t = rt_timer_r32(rt, TIMER_REG_TMR0CTL);
96 t |= TMR0CTL_ENABLE;
97 rt_timer_w32(rt, TIMER_REG_TMR0CTL, t);
98
99 return 0;
100}
101
102static void rt_timer_disable(struct rt_timer *rt)
103{
104 u32 t;
105
106 t = rt_timer_r32(rt, TIMER_REG_TMR0CTL);
107 t &= ~TMR0CTL_ENABLE;
108 rt_timer_w32(rt, TIMER_REG_TMR0CTL, t);
109}
110
111static int rt_timer_probe(struct platform_device *pdev)
112{
113 struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
114 struct rt_timer *rt;
115 struct clk *clk;
116
117 rt = devm_kzalloc(&pdev->dev, sizeof(*rt), GFP_KERNEL);
118 if (!rt) {
119 dev_err(&pdev->dev, "failed to allocate memory\n");
120 return -ENOMEM;
121 }
122
123 rt->irq = platform_get_irq(pdev, 0);
124 if (!rt->irq) {
125 dev_err(&pdev->dev, "failed to load irq\n");
126 return -ENOENT;
127 }
128
129 rt->membase = devm_ioremap_resource(&pdev->dev, res);
130 if (IS_ERR(rt->membase))
131 return PTR_ERR(rt->membase);
132
133 clk = devm_clk_get(&pdev->dev, NULL);
134 if (IS_ERR(clk)) {
135 dev_err(&pdev->dev, "failed get clock rate\n");
136 return PTR_ERR(clk);
137 }
138
139 rt->timer_freq = clk_get_rate(clk) / TMR0CTL_PRESCALE_DIV;
140 if (!rt->timer_freq)
141 return -EINVAL;
142
143 rt->dev = &pdev->dev;
144 platform_set_drvdata(pdev, rt);
145
146 rt_timer_request(rt);
147 rt_timer_config(rt, 2);
148 rt_timer_enable(rt);
149
150 dev_info(&pdev->dev, "maximum frequency is %luHz\n", rt->timer_freq);
151
152 return 0;
153}
154
155static int rt_timer_remove(struct platform_device *pdev)
156{
157 struct rt_timer *rt = platform_get_drvdata(pdev);
158
159 rt_timer_disable(rt);
160 rt_timer_free(rt);
161
162 return 0;
163}
164
165static const struct of_device_id rt_timer_match[] = {
166 { .compatible = "ralink,rt2880-timer" },
167 {},
168};
169MODULE_DEVICE_TABLE(of, rt_timer_match);
170
171static struct platform_driver rt_timer_driver = {
172 .probe = rt_timer_probe,
173 .remove = rt_timer_remove,
174 .driver = {
175 .name = "rt-timer",
176 .owner = THIS_MODULE,
177 .of_match_table = rt_timer_match
178 },
179};
180
181module_platform_driver(rt_timer_driver);
182
183MODULE_DESCRIPTION("Ralink RT2880 timer");
184MODULE_AUTHOR("John Crispin <blogic@openwrt.org");
185MODULE_LICENSE("GPL");