Commit | Line | Data |
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75540c1a | 1 | /* |
2 | * linux/arch/arm/mach-pxa/pwm.c | |
3 | * | |
4 | * simple driver for PWM (Pulse Width Modulator) controller | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | * 2008-02-13 initial version | |
11 | * eric miao <eric.miao@marvell.com> | |
12 | */ | |
13 | ||
14 | #include <linux/module.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/platform_device.h> | |
17 | #include <linux/err.h> | |
18 | #include <linux/clk.h> | |
19 | #include <linux/io.h> | |
20 | #include <linux/pwm.h> | |
21 | ||
22 | #include <asm/div64.h> | |
75540c1a | 23 | |
3d2a98cd | 24 | #define HAS_SECONDARY_PWM 0x10 |
a757ad8b | 25 | #define PWM_ID_BASE(d) ((d) & 0xf) |
3d2a98cd EM |
26 | |
27 | static const struct platform_device_id pwm_id_table[] = { | |
28 | /* PWM has_secondary_pwm? */ | |
29 | { "pxa25x-pwm", 0 }, | |
a757ad8b | 30 | { "pxa27x-pwm", 0 | HAS_SECONDARY_PWM }, |
3d2a98cd EM |
31 | { }, |
32 | }; | |
33 | MODULE_DEVICE_TABLE(platform, pwm_id_table); | |
34 | ||
75540c1a | 35 | /* PWM registers and bits definitions */ |
36 | #define PWMCR (0x00) | |
37 | #define PWMDCR (0x04) | |
38 | #define PWMPCR (0x08) | |
39 | ||
40 | #define PWMCR_SD (1 << 6) | |
41 | #define PWMDCR_FD (1 << 10) | |
42 | ||
43 | struct pwm_device { | |
44 | struct list_head node; | |
3d2a98cd EM |
45 | struct pwm_device *secondary; |
46 | struct platform_device *pdev; | |
75540c1a | 47 | |
48 | const char *label; | |
49 | struct clk *clk; | |
c860d701 | 50 | int clk_enabled; |
75540c1a | 51 | void __iomem *mmio_base; |
52 | ||
53 | unsigned int use_count; | |
54 | unsigned int pwm_id; | |
55 | }; | |
56 | ||
57 | /* | |
58 | * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE | |
59 | * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE | |
60 | */ | |
61 | int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) | |
62 | { | |
63 | unsigned long long c; | |
64 | unsigned long period_cycles, prescale, pv, dc; | |
65 | ||
66 | if (pwm == NULL || period_ns == 0 || duty_ns > period_ns) | |
67 | return -EINVAL; | |
68 | ||
69 | c = clk_get_rate(pwm->clk); | |
70 | c = c * period_ns; | |
71 | do_div(c, 1000000000); | |
72 | period_cycles = c; | |
73 | ||
71a35d75 | 74 | if (period_cycles < 1) |
75540c1a | 75 | period_cycles = 1; |
76 | prescale = (period_cycles - 1) / 1024; | |
77 | pv = period_cycles / (prescale + 1) - 1; | |
78 | ||
79 | if (prescale > 63) | |
80 | return -EINVAL; | |
81 | ||
82 | if (duty_ns == period_ns) | |
83 | dc = PWMDCR_FD; | |
84 | else | |
85 | dc = (pv + 1) * duty_ns / period_ns; | |
86 | ||
87 | /* NOTE: the clock to PWM has to be enabled first | |
88 | * before writing to the registers | |
89 | */ | |
90 | clk_enable(pwm->clk); | |
91 | __raw_writel(prescale, pwm->mmio_base + PWMCR); | |
92 | __raw_writel(dc, pwm->mmio_base + PWMDCR); | |
93 | __raw_writel(pv, pwm->mmio_base + PWMPCR); | |
94 | clk_disable(pwm->clk); | |
95 | ||
96 | return 0; | |
97 | } | |
98 | EXPORT_SYMBOL(pwm_config); | |
99 | ||
100 | int pwm_enable(struct pwm_device *pwm) | |
101 | { | |
c860d701 RJ |
102 | int rc = 0; |
103 | ||
104 | if (!pwm->clk_enabled) { | |
105 | rc = clk_enable(pwm->clk); | |
106 | if (!rc) | |
107 | pwm->clk_enabled = 1; | |
108 | } | |
109 | return rc; | |
75540c1a | 110 | } |
111 | EXPORT_SYMBOL(pwm_enable); | |
112 | ||
113 | void pwm_disable(struct pwm_device *pwm) | |
114 | { | |
c860d701 RJ |
115 | if (pwm->clk_enabled) { |
116 | clk_disable(pwm->clk); | |
117 | pwm->clk_enabled = 0; | |
118 | } | |
75540c1a | 119 | } |
120 | EXPORT_SYMBOL(pwm_disable); | |
121 | ||
122 | static DEFINE_MUTEX(pwm_lock); | |
123 | static LIST_HEAD(pwm_list); | |
124 | ||
125 | struct pwm_device *pwm_request(int pwm_id, const char *label) | |
126 | { | |
127 | struct pwm_device *pwm; | |
128 | int found = 0; | |
129 | ||
130 | mutex_lock(&pwm_lock); | |
131 | ||
132 | list_for_each_entry(pwm, &pwm_list, node) { | |
43bda1a6 | 133 | if (pwm->pwm_id == pwm_id) { |
75540c1a | 134 | found = 1; |
135 | break; | |
136 | } | |
137 | } | |
138 | ||
43bda1a6 BD |
139 | if (found) { |
140 | if (pwm->use_count == 0) { | |
141 | pwm->use_count++; | |
142 | pwm->label = label; | |
143 | } else | |
144 | pwm = ERR_PTR(-EBUSY); | |
145 | } else | |
146 | pwm = ERR_PTR(-ENOENT); | |
75540c1a | 147 | |
43bda1a6 BD |
148 | mutex_unlock(&pwm_lock); |
149 | return pwm; | |
75540c1a | 150 | } |
151 | EXPORT_SYMBOL(pwm_request); | |
152 | ||
153 | void pwm_free(struct pwm_device *pwm) | |
154 | { | |
155 | mutex_lock(&pwm_lock); | |
156 | ||
157 | if (pwm->use_count) { | |
158 | pwm->use_count--; | |
159 | pwm->label = NULL; | |
160 | } else | |
161 | pr_warning("PWM device already freed\n"); | |
162 | ||
163 | mutex_unlock(&pwm_lock); | |
164 | } | |
165 | EXPORT_SYMBOL(pwm_free); | |
166 | ||
167 | static inline void __add_pwm(struct pwm_device *pwm) | |
168 | { | |
169 | mutex_lock(&pwm_lock); | |
170 | list_add_tail(&pwm->node, &pwm_list); | |
171 | mutex_unlock(&pwm_lock); | |
172 | } | |
173 | ||
3d2a98cd | 174 | static int __devinit pwm_probe(struct platform_device *pdev) |
75540c1a | 175 | { |
3d2a98cd EM |
176 | struct platform_device_id *id = platform_get_device_id(pdev); |
177 | struct pwm_device *pwm, *secondary = NULL; | |
75540c1a | 178 | struct resource *r; |
179 | int ret = 0; | |
180 | ||
181 | pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); | |
182 | if (pwm == NULL) { | |
183 | dev_err(&pdev->dev, "failed to allocate memory\n"); | |
3d2a98cd | 184 | return -ENOMEM; |
75540c1a | 185 | } |
186 | ||
e0d8b13a | 187 | pwm->clk = clk_get(&pdev->dev, NULL); |
75540c1a | 188 | if (IS_ERR(pwm->clk)) { |
189 | ret = PTR_ERR(pwm->clk); | |
190 | goto err_free; | |
191 | } | |
c860d701 | 192 | pwm->clk_enabled = 0; |
75540c1a | 193 | |
194 | pwm->use_count = 0; | |
a757ad8b | 195 | pwm->pwm_id = PWM_ID_BASE(id->driver_data) + pdev->id; |
75540c1a | 196 | pwm->pdev = pdev; |
197 | ||
75540c1a | 198 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
199 | if (r == NULL) { | |
200 | dev_err(&pdev->dev, "no memory resource defined\n"); | |
201 | ret = -ENODEV; | |
202 | goto err_free_clk; | |
203 | } | |
204 | ||
205 | r = request_mem_region(r->start, r->end - r->start + 1, pdev->name); | |
206 | if (r == NULL) { | |
207 | dev_err(&pdev->dev, "failed to request memory resource\n"); | |
208 | ret = -EBUSY; | |
209 | goto err_free_clk; | |
210 | } | |
211 | ||
212 | pwm->mmio_base = ioremap(r->start, r->end - r->start + 1); | |
213 | if (pwm->mmio_base == NULL) { | |
214 | dev_err(&pdev->dev, "failed to ioremap() registers\n"); | |
215 | ret = -ENODEV; | |
216 | goto err_free_mem; | |
217 | } | |
218 | ||
3d2a98cd EM |
219 | if (id->driver_data & HAS_SECONDARY_PWM) { |
220 | secondary = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); | |
221 | if (secondary == NULL) { | |
222 | ret = -ENOMEM; | |
223 | goto err_free_mem; | |
224 | } | |
225 | ||
226 | *secondary = *pwm; | |
227 | pwm->secondary = secondary; | |
228 | ||
229 | /* registers for the second PWM has offset of 0x10 */ | |
230 | secondary->mmio_base = pwm->mmio_base + 0x10; | |
231 | secondary->pwm_id = pdev->id + 2; | |
232 | } | |
233 | ||
75540c1a | 234 | __add_pwm(pwm); |
3d2a98cd EM |
235 | if (secondary) |
236 | __add_pwm(secondary); | |
237 | ||
75540c1a | 238 | platform_set_drvdata(pdev, pwm); |
3d2a98cd | 239 | return 0; |
75540c1a | 240 | |
241 | err_free_mem: | |
242 | release_mem_region(r->start, r->end - r->start + 1); | |
243 | err_free_clk: | |
244 | clk_put(pwm->clk); | |
245 | err_free: | |
246 | kfree(pwm); | |
3d2a98cd | 247 | return ret; |
75540c1a | 248 | } |
249 | ||
250 | static int __devexit pwm_remove(struct platform_device *pdev) | |
251 | { | |
252 | struct pwm_device *pwm; | |
253 | struct resource *r; | |
254 | ||
255 | pwm = platform_get_drvdata(pdev); | |
256 | if (pwm == NULL) | |
257 | return -ENODEV; | |
258 | ||
259 | mutex_lock(&pwm_lock); | |
3d2a98cd EM |
260 | |
261 | if (pwm->secondary) { | |
262 | list_del(&pwm->secondary->node); | |
263 | kfree(pwm->secondary); | |
264 | } | |
265 | ||
75540c1a | 266 | list_del(&pwm->node); |
267 | mutex_unlock(&pwm_lock); | |
268 | ||
269 | iounmap(pwm->mmio_base); | |
270 | ||
271 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
272 | release_mem_region(r->start, r->end - r->start + 1); | |
273 | ||
274 | clk_put(pwm->clk); | |
275 | kfree(pwm); | |
276 | return 0; | |
277 | } | |
278 | ||
3d2a98cd | 279 | static struct platform_driver pwm_driver = { |
75540c1a | 280 | .driver = { |
281 | .name = "pxa25x-pwm", | |
3d2a98cd | 282 | .owner = THIS_MODULE, |
75540c1a | 283 | }, |
3d2a98cd | 284 | .probe = pwm_probe, |
75540c1a | 285 | .remove = __devexit_p(pwm_remove), |
3d2a98cd | 286 | .id_table = pwm_id_table, |
75540c1a | 287 | }; |
288 | ||
289 | static int __init pwm_init(void) | |
290 | { | |
3d2a98cd | 291 | return platform_driver_register(&pwm_driver); |
75540c1a | 292 | } |
293 | arch_initcall(pwm_init); | |
294 | ||
295 | static void __exit pwm_exit(void) | |
296 | { | |
3d2a98cd | 297 | platform_driver_unregister(&pwm_driver); |
75540c1a | 298 | } |
299 | module_exit(pwm_exit); | |
b5f0228a GL |
300 | |
301 | MODULE_LICENSE("GPL v2"); |