1
2
3
4
5
6
7
8
9
10
11
12
13
14#include <linux/module.h>
15#include <linux/kernel.h>
16#include <linux/platform_device.h>
17#include <linux/slab.h>
18#include <linux/err.h>
19#include <linux/clk.h>
20#include <linux/io.h>
21#include <linux/pwm.h>
22
23#include <asm/div64.h>
24
25#define HAS_SECONDARY_PWM 0x10
26#define PWM_ID_BASE(d) ((d) & 0xf)
27
28static const struct platform_device_id pwm_id_table[] = {
29
30 { "pxa25x-pwm", 0 },
31 { "pxa27x-pwm", 0 | HAS_SECONDARY_PWM },
32 { "pxa168-pwm", 1 },
33 { "pxa910-pwm", 1 },
34 { },
35};
36MODULE_DEVICE_TABLE(platform, pwm_id_table);
37
38
39#define PWMCR (0x00)
40#define PWMDCR (0x04)
41#define PWMPCR (0x08)
42
43#define PWMCR_SD (1 << 6)
44#define PWMDCR_FD (1 << 10)
45
46struct pxa_pwm_chip {
47 struct pwm_chip chip;
48 struct device *dev;
49
50 struct clk *clk;
51 int clk_enabled;
52 void __iomem *mmio_base;
53};
54
55static inline struct pxa_pwm_chip *to_pxa_pwm_chip(struct pwm_chip *chip)
56{
57 return container_of(chip, struct pxa_pwm_chip, chip);
58}
59
60
61
62
63
64static int pxa_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
65 int duty_ns, int period_ns)
66{
67 struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
68 unsigned long long c;
69 unsigned long period_cycles, prescale, pv, dc;
70 unsigned long offset;
71 int rc;
72
73 if (period_ns == 0 || duty_ns > period_ns)
74 return -EINVAL;
75
76 offset = pwm->hwpwm ? 0x10 : 0;
77
78 c = clk_get_rate(pc->clk);
79 c = c * period_ns;
80 do_div(c, 1000000000);
81 period_cycles = c;
82
83 if (period_cycles < 1)
84 period_cycles = 1;
85 prescale = (period_cycles - 1) / 1024;
86 pv = period_cycles / (prescale + 1) - 1;
87
88 if (prescale > 63)
89 return -EINVAL;
90
91 if (duty_ns == period_ns)
92 dc = PWMDCR_FD;
93 else
94 dc = (pv + 1) * duty_ns / period_ns;
95
96
97
98
99 rc = clk_prepare_enable(pc->clk);
100 if (rc < 0)
101 return rc;
102
103 writel(prescale, pc->mmio_base + offset + PWMCR);
104 writel(dc, pc->mmio_base + offset + PWMDCR);
105 writel(pv, pc->mmio_base + offset + PWMPCR);
106
107 clk_disable_unprepare(pc->clk);
108 return 0;
109}
110
111static int pxa_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
112{
113 struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
114 int rc = 0;
115
116 if (!pc->clk_enabled) {
117 rc = clk_prepare_enable(pc->clk);
118 if (!rc)
119 pc->clk_enabled++;
120 }
121 return rc;
122}
123
124static void pxa_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
125{
126 struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
127
128 if (pc->clk_enabled) {
129 clk_disable_unprepare(pc->clk);
130 pc->clk_enabled--;
131 }
132}
133
134static struct pwm_ops pxa_pwm_ops = {
135 .config = pxa_pwm_config,
136 .enable = pxa_pwm_enable,
137 .disable = pxa_pwm_disable,
138 .owner = THIS_MODULE,
139};
140
141static int __devinit pwm_probe(struct platform_device *pdev)
142{
143 const struct platform_device_id *id = platform_get_device_id(pdev);
144 struct pxa_pwm_chip *pwm;
145 struct resource *r;
146 int ret = 0;
147
148 pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
149 if (pwm == NULL) {
150 dev_err(&pdev->dev, "failed to allocate memory\n");
151 return -ENOMEM;
152 }
153
154 pwm->clk = devm_clk_get(&pdev->dev, NULL);
155 if (IS_ERR(pwm->clk))
156 return PTR_ERR(pwm->clk);
157
158 pwm->clk_enabled = 0;
159
160 pwm->chip.dev = &pdev->dev;
161 pwm->chip.ops = &pxa_pwm_ops;
162 pwm->chip.base = -1;
163 pwm->chip.npwm = (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1;
164
165 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
166 if (r == NULL) {
167 dev_err(&pdev->dev, "no memory resource defined\n");
168 return -ENODEV;
169 }
170
171 pwm->mmio_base = devm_request_and_ioremap(&pdev->dev, r);
172 if (pwm->mmio_base == NULL)
173 return -EADDRNOTAVAIL;
174
175 ret = pwmchip_add(&pwm->chip);
176 if (ret < 0) {
177 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
178 return ret;
179 }
180
181 platform_set_drvdata(pdev, pwm);
182 return 0;
183}
184
185static int __devexit pwm_remove(struct platform_device *pdev)
186{
187 struct pxa_pwm_chip *chip;
188
189 chip = platform_get_drvdata(pdev);
190 if (chip == NULL)
191 return -ENODEV;
192
193 return pwmchip_remove(&chip->chip);
194}
195
196static struct platform_driver pwm_driver = {
197 .driver = {
198 .name = "pxa25x-pwm",
199 .owner = THIS_MODULE,
200 },
201 .probe = pwm_probe,
202 .remove = __devexit_p(pwm_remove),
203 .id_table = pwm_id_table,
204};
205
206static int __init pwm_init(void)
207{
208 return platform_driver_register(&pwm_driver);
209}
210arch_initcall(pwm_init);
211
212static void __exit pwm_exit(void)
213{
214 platform_driver_unregister(&pwm_driver);
215}
216module_exit(pwm_exit);
217
218MODULE_LICENSE("GPL v2");
219
