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 }, |
a27ba768 EM |
31 | { "pxa168-pwm", 1 }, |
32 | { "pxa910-pwm", 1 }, | |
3d2a98cd EM |
33 | { }, |
34 | }; | |
35 | MODULE_DEVICE_TABLE(platform, pwm_id_table); | |
36 | ||
75540c1a | 37 | /* PWM registers and bits definitions */ |
38 | #define PWMCR (0x00) | |
39 | #define PWMDCR (0x04) | |
40 | #define PWMPCR (0x08) | |
41 | ||
42 | #define PWMCR_SD (1 << 6) | |
43 | #define PWMDCR_FD (1 << 10) | |
44 | ||
45 | struct pwm_device { | |
46 | struct list_head node; | |
3d2a98cd EM |
47 | struct pwm_device *secondary; |
48 | struct platform_device *pdev; | |
75540c1a | 49 | |
50 | const char *label; | |
51 | struct clk *clk; | |
c860d701 | 52 | int clk_enabled; |
75540c1a | 53 | void __iomem *mmio_base; |
54 | ||
55 | unsigned int use_count; | |
56 | unsigned int pwm_id; | |
57 | }; | |
58 | ||
59 | /* | |
60 | * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE | |
61 | * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE | |
62 | */ | |
63 | int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) | |
64 | { | |
65 | unsigned long long c; | |
66 | unsigned long period_cycles, prescale, pv, dc; | |
67 | ||
68 | if (pwm == NULL || period_ns == 0 || duty_ns > period_ns) | |
69 | return -EINVAL; | |
70 | ||
71 | c = clk_get_rate(pwm->clk); | |
72 | c = c * period_ns; | |
73 | do_div(c, 1000000000); | |
74 | period_cycles = c; | |
75 | ||
71a35d75 | 76 | if (period_cycles < 1) |
75540c1a | 77 | period_cycles = 1; |
78 | prescale = (period_cycles - 1) / 1024; | |
79 | pv = period_cycles / (prescale + 1) - 1; | |
80 | ||
81 | if (prescale > 63) | |
82 | return -EINVAL; | |
83 | ||
84 | if (duty_ns == period_ns) | |
85 | dc = PWMDCR_FD; | |
86 | else | |
87 | dc = (pv + 1) * duty_ns / period_ns; | |
88 | ||
89 | /* NOTE: the clock to PWM has to be enabled first | |
90 | * before writing to the registers | |
91 | */ | |
92 | clk_enable(pwm->clk); | |
93 | __raw_writel(prescale, pwm->mmio_base + PWMCR); | |
94 | __raw_writel(dc, pwm->mmio_base + PWMDCR); | |
95 | __raw_writel(pv, pwm->mmio_base + PWMPCR); | |
96 | clk_disable(pwm->clk); | |
97 | ||
98 | return 0; | |
99 | } | |
100 | EXPORT_SYMBOL(pwm_config); | |
101 | ||
102 | int pwm_enable(struct pwm_device *pwm) | |
103 | { | |
c860d701 RJ |
104 | int rc = 0; |
105 | ||
106 | if (!pwm->clk_enabled) { | |
107 | rc = clk_enable(pwm->clk); | |
108 | if (!rc) | |
109 | pwm->clk_enabled = 1; | |
110 | } | |
111 | return rc; | |
75540c1a | 112 | } |
113 | EXPORT_SYMBOL(pwm_enable); | |
114 | ||
115 | void pwm_disable(struct pwm_device *pwm) | |
116 | { | |
c860d701 RJ |
117 | if (pwm->clk_enabled) { |
118 | clk_disable(pwm->clk); | |
119 | pwm->clk_enabled = 0; | |
120 | } | |
75540c1a | 121 | } |
122 | EXPORT_SYMBOL(pwm_disable); | |
123 | ||
124 | static DEFINE_MUTEX(pwm_lock); | |
125 | static LIST_HEAD(pwm_list); | |
126 | ||
127 | struct pwm_device *pwm_request(int pwm_id, const char *label) | |
128 | { | |
129 | struct pwm_device *pwm; | |
130 | int found = 0; | |
131 | ||
132 | mutex_lock(&pwm_lock); | |
133 | ||
134 | list_for_each_entry(pwm, &pwm_list, node) { | |
43bda1a6 | 135 | if (pwm->pwm_id == pwm_id) { |
75540c1a | 136 | found = 1; |
137 | break; | |
138 | } | |
139 | } | |
140 | ||
43bda1a6 BD |
141 | if (found) { |
142 | if (pwm->use_count == 0) { | |
143 | pwm->use_count++; | |
144 | pwm->label = label; | |
145 | } else | |
146 | pwm = ERR_PTR(-EBUSY); | |
147 | } else | |
148 | pwm = ERR_PTR(-ENOENT); | |
75540c1a | 149 | |
43bda1a6 BD |
150 | mutex_unlock(&pwm_lock); |
151 | return pwm; | |
75540c1a | 152 | } |
153 | EXPORT_SYMBOL(pwm_request); | |
154 | ||
155 | void pwm_free(struct pwm_device *pwm) | |
156 | { | |
157 | mutex_lock(&pwm_lock); | |
158 | ||
159 | if (pwm->use_count) { | |
160 | pwm->use_count--; | |
161 | pwm->label = NULL; | |
162 | } else | |
163 | pr_warning("PWM device already freed\n"); | |
164 | ||
165 | mutex_unlock(&pwm_lock); | |
166 | } | |
167 | EXPORT_SYMBOL(pwm_free); | |
168 | ||
169 | static inline void __add_pwm(struct pwm_device *pwm) | |
170 | { | |
171 | mutex_lock(&pwm_lock); | |
172 | list_add_tail(&pwm->node, &pwm_list); | |
173 | mutex_unlock(&pwm_lock); | |
174 | } | |
175 | ||
3d2a98cd | 176 | static int __devinit pwm_probe(struct platform_device *pdev) |
75540c1a | 177 | { |
3d2a98cd EM |
178 | struct platform_device_id *id = platform_get_device_id(pdev); |
179 | struct pwm_device *pwm, *secondary = NULL; | |
75540c1a | 180 | struct resource *r; |
181 | int ret = 0; | |
182 | ||
183 | pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); | |
184 | if (pwm == NULL) { | |
185 | dev_err(&pdev->dev, "failed to allocate memory\n"); | |
3d2a98cd | 186 | return -ENOMEM; |
75540c1a | 187 | } |
188 | ||
e0d8b13a | 189 | pwm->clk = clk_get(&pdev->dev, NULL); |
75540c1a | 190 | if (IS_ERR(pwm->clk)) { |
191 | ret = PTR_ERR(pwm->clk); | |
192 | goto err_free; | |
193 | } | |
c860d701 | 194 | pwm->clk_enabled = 0; |
75540c1a | 195 | |
196 | pwm->use_count = 0; | |
a757ad8b | 197 | pwm->pwm_id = PWM_ID_BASE(id->driver_data) + pdev->id; |
75540c1a | 198 | pwm->pdev = pdev; |
199 | ||
75540c1a | 200 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
201 | if (r == NULL) { | |
202 | dev_err(&pdev->dev, "no memory resource defined\n"); | |
203 | ret = -ENODEV; | |
204 | goto err_free_clk; | |
205 | } | |
206 | ||
1692231c | 207 | r = request_mem_region(r->start, resource_size(r), pdev->name); |
75540c1a | 208 | if (r == NULL) { |
209 | dev_err(&pdev->dev, "failed to request memory resource\n"); | |
210 | ret = -EBUSY; | |
211 | goto err_free_clk; | |
212 | } | |
213 | ||
1692231c | 214 | pwm->mmio_base = ioremap(r->start, resource_size(r)); |
75540c1a | 215 | if (pwm->mmio_base == NULL) { |
216 | dev_err(&pdev->dev, "failed to ioremap() registers\n"); | |
217 | ret = -ENODEV; | |
218 | goto err_free_mem; | |
219 | } | |
220 | ||
3d2a98cd EM |
221 | if (id->driver_data & HAS_SECONDARY_PWM) { |
222 | secondary = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); | |
223 | if (secondary == NULL) { | |
224 | ret = -ENOMEM; | |
225 | goto err_free_mem; | |
226 | } | |
227 | ||
228 | *secondary = *pwm; | |
229 | pwm->secondary = secondary; | |
230 | ||
231 | /* registers for the second PWM has offset of 0x10 */ | |
232 | secondary->mmio_base = pwm->mmio_base + 0x10; | |
233 | secondary->pwm_id = pdev->id + 2; | |
234 | } | |
235 | ||
75540c1a | 236 | __add_pwm(pwm); |
3d2a98cd EM |
237 | if (secondary) |
238 | __add_pwm(secondary); | |
239 | ||
75540c1a | 240 | platform_set_drvdata(pdev, pwm); |
3d2a98cd | 241 | return 0; |
75540c1a | 242 | |
243 | err_free_mem: | |
1692231c | 244 | release_mem_region(r->start, resource_size(r)); |
75540c1a | 245 | err_free_clk: |
246 | clk_put(pwm->clk); | |
247 | err_free: | |
248 | kfree(pwm); | |
3d2a98cd | 249 | return ret; |
75540c1a | 250 | } |
251 | ||
252 | static int __devexit pwm_remove(struct platform_device *pdev) | |
253 | { | |
254 | struct pwm_device *pwm; | |
255 | struct resource *r; | |
256 | ||
257 | pwm = platform_get_drvdata(pdev); | |
258 | if (pwm == NULL) | |
259 | return -ENODEV; | |
260 | ||
261 | mutex_lock(&pwm_lock); | |
3d2a98cd EM |
262 | |
263 | if (pwm->secondary) { | |
264 | list_del(&pwm->secondary->node); | |
265 | kfree(pwm->secondary); | |
266 | } | |
267 | ||
75540c1a | 268 | list_del(&pwm->node); |
269 | mutex_unlock(&pwm_lock); | |
270 | ||
271 | iounmap(pwm->mmio_base); | |
272 | ||
273 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
1692231c | 274 | release_mem_region(r->start, resource_size(r)); |
75540c1a | 275 | |
276 | clk_put(pwm->clk); | |
277 | kfree(pwm); | |
278 | return 0; | |
279 | } | |
280 | ||
3d2a98cd | 281 | static struct platform_driver pwm_driver = { |
75540c1a | 282 | .driver = { |
283 | .name = "pxa25x-pwm", | |
3d2a98cd | 284 | .owner = THIS_MODULE, |
75540c1a | 285 | }, |
3d2a98cd | 286 | .probe = pwm_probe, |
75540c1a | 287 | .remove = __devexit_p(pwm_remove), |
3d2a98cd | 288 | .id_table = pwm_id_table, |
75540c1a | 289 | }; |
290 | ||
291 | static int __init pwm_init(void) | |
292 | { | |
3d2a98cd | 293 | return platform_driver_register(&pwm_driver); |
75540c1a | 294 | } |
295 | arch_initcall(pwm_init); | |
296 | ||
297 | static void __exit pwm_exit(void) | |
298 | { | |
3d2a98cd | 299 | platform_driver_unregister(&pwm_driver); |
75540c1a | 300 | } |
301 | module_exit(pwm_exit); | |
b5f0228a GL |
302 | |
303 | MODULE_LICENSE("GPL v2"); |