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> | |
5a0e3ad6 | 17 | #include <linux/slab.h> |
75540c1a | 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> | |
75540c1a | 24 | |
3d2a98cd | 25 | #define HAS_SECONDARY_PWM 0x10 |
a757ad8b | 26 | #define PWM_ID_BASE(d) ((d) & 0xf) |
3d2a98cd EM |
27 | |
28 | static const struct platform_device_id pwm_id_table[] = { | |
29 | /* PWM has_secondary_pwm? */ | |
30 | { "pxa25x-pwm", 0 }, | |
a757ad8b | 31 | { "pxa27x-pwm", 0 | HAS_SECONDARY_PWM }, |
a27ba768 EM |
32 | { "pxa168-pwm", 1 }, |
33 | { "pxa910-pwm", 1 }, | |
3d2a98cd EM |
34 | { }, |
35 | }; | |
36 | MODULE_DEVICE_TABLE(platform, pwm_id_table); | |
37 | ||
75540c1a | 38 | /* PWM registers and bits definitions */ |
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 | ||
46 | struct pwm_device { | |
47 | struct list_head node; | |
3d2a98cd EM |
48 | struct pwm_device *secondary; |
49 | struct platform_device *pdev; | |
75540c1a | 50 | |
51 | const char *label; | |
52 | struct clk *clk; | |
c860d701 | 53 | int clk_enabled; |
75540c1a | 54 | void __iomem *mmio_base; |
55 | ||
56 | unsigned int use_count; | |
57 | unsigned int pwm_id; | |
58 | }; | |
59 | ||
60 | /* | |
61 | * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE | |
62 | * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE | |
63 | */ | |
64 | int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) | |
65 | { | |
66 | unsigned long long c; | |
67 | unsigned long period_cycles, prescale, pv, dc; | |
68 | ||
69 | if (pwm == NULL || period_ns == 0 || duty_ns > period_ns) | |
70 | return -EINVAL; | |
71 | ||
72 | c = clk_get_rate(pwm->clk); | |
73 | c = c * period_ns; | |
74 | do_div(c, 1000000000); | |
75 | period_cycles = c; | |
76 | ||
71a35d75 | 77 | if (period_cycles < 1) |
75540c1a | 78 | period_cycles = 1; |
79 | prescale = (period_cycles - 1) / 1024; | |
80 | pv = period_cycles / (prescale + 1) - 1; | |
81 | ||
82 | if (prescale > 63) | |
83 | return -EINVAL; | |
84 | ||
85 | if (duty_ns == period_ns) | |
86 | dc = PWMDCR_FD; | |
87 | else | |
88 | dc = (pv + 1) * duty_ns / period_ns; | |
89 | ||
90 | /* NOTE: the clock to PWM has to be enabled first | |
91 | * before writing to the registers | |
92 | */ | |
93 | clk_enable(pwm->clk); | |
94 | __raw_writel(prescale, pwm->mmio_base + PWMCR); | |
95 | __raw_writel(dc, pwm->mmio_base + PWMDCR); | |
96 | __raw_writel(pv, pwm->mmio_base + PWMPCR); | |
97 | clk_disable(pwm->clk); | |
98 | ||
99 | return 0; | |
100 | } | |
101 | EXPORT_SYMBOL(pwm_config); | |
102 | ||
103 | int pwm_enable(struct pwm_device *pwm) | |
104 | { | |
c860d701 RJ |
105 | int rc = 0; |
106 | ||
107 | if (!pwm->clk_enabled) { | |
108 | rc = clk_enable(pwm->clk); | |
109 | if (!rc) | |
110 | pwm->clk_enabled = 1; | |
111 | } | |
112 | return rc; | |
75540c1a | 113 | } |
114 | EXPORT_SYMBOL(pwm_enable); | |
115 | ||
116 | void pwm_disable(struct pwm_device *pwm) | |
117 | { | |
c860d701 RJ |
118 | if (pwm->clk_enabled) { |
119 | clk_disable(pwm->clk); | |
120 | pwm->clk_enabled = 0; | |
121 | } | |
75540c1a | 122 | } |
123 | EXPORT_SYMBOL(pwm_disable); | |
124 | ||
125 | static DEFINE_MUTEX(pwm_lock); | |
126 | static LIST_HEAD(pwm_list); | |
127 | ||
128 | struct pwm_device *pwm_request(int pwm_id, const char *label) | |
129 | { | |
130 | struct pwm_device *pwm; | |
131 | int found = 0; | |
132 | ||
133 | mutex_lock(&pwm_lock); | |
134 | ||
135 | list_for_each_entry(pwm, &pwm_list, node) { | |
43bda1a6 | 136 | if (pwm->pwm_id == pwm_id) { |
75540c1a | 137 | found = 1; |
138 | break; | |
139 | } | |
140 | } | |
141 | ||
43bda1a6 BD |
142 | if (found) { |
143 | if (pwm->use_count == 0) { | |
144 | pwm->use_count++; | |
145 | pwm->label = label; | |
146 | } else | |
147 | pwm = ERR_PTR(-EBUSY); | |
148 | } else | |
149 | pwm = ERR_PTR(-ENOENT); | |
75540c1a | 150 | |
43bda1a6 BD |
151 | mutex_unlock(&pwm_lock); |
152 | return pwm; | |
75540c1a | 153 | } |
154 | EXPORT_SYMBOL(pwm_request); | |
155 | ||
156 | void pwm_free(struct pwm_device *pwm) | |
157 | { | |
158 | mutex_lock(&pwm_lock); | |
159 | ||
160 | if (pwm->use_count) { | |
161 | pwm->use_count--; | |
162 | pwm->label = NULL; | |
163 | } else | |
164 | pr_warning("PWM device already freed\n"); | |
165 | ||
166 | mutex_unlock(&pwm_lock); | |
167 | } | |
168 | EXPORT_SYMBOL(pwm_free); | |
169 | ||
170 | static inline void __add_pwm(struct pwm_device *pwm) | |
171 | { | |
172 | mutex_lock(&pwm_lock); | |
173 | list_add_tail(&pwm->node, &pwm_list); | |
174 | mutex_unlock(&pwm_lock); | |
175 | } | |
176 | ||
3d2a98cd | 177 | static int __devinit pwm_probe(struct platform_device *pdev) |
75540c1a | 178 | { |
3d2a98cd EM |
179 | struct platform_device_id *id = platform_get_device_id(pdev); |
180 | struct pwm_device *pwm, *secondary = NULL; | |
75540c1a | 181 | struct resource *r; |
182 | int ret = 0; | |
183 | ||
184 | pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); | |
185 | if (pwm == NULL) { | |
186 | dev_err(&pdev->dev, "failed to allocate memory\n"); | |
3d2a98cd | 187 | return -ENOMEM; |
75540c1a | 188 | } |
189 | ||
e0d8b13a | 190 | pwm->clk = clk_get(&pdev->dev, NULL); |
75540c1a | 191 | if (IS_ERR(pwm->clk)) { |
192 | ret = PTR_ERR(pwm->clk); | |
193 | goto err_free; | |
194 | } | |
c860d701 | 195 | pwm->clk_enabled = 0; |
75540c1a | 196 | |
197 | pwm->use_count = 0; | |
a757ad8b | 198 | pwm->pwm_id = PWM_ID_BASE(id->driver_data) + pdev->id; |
75540c1a | 199 | pwm->pdev = pdev; |
200 | ||
75540c1a | 201 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
202 | if (r == NULL) { | |
203 | dev_err(&pdev->dev, "no memory resource defined\n"); | |
204 | ret = -ENODEV; | |
205 | goto err_free_clk; | |
206 | } | |
207 | ||
1692231c | 208 | r = request_mem_region(r->start, resource_size(r), pdev->name); |
75540c1a | 209 | if (r == NULL) { |
210 | dev_err(&pdev->dev, "failed to request memory resource\n"); | |
211 | ret = -EBUSY; | |
212 | goto err_free_clk; | |
213 | } | |
214 | ||
1692231c | 215 | pwm->mmio_base = ioremap(r->start, resource_size(r)); |
75540c1a | 216 | if (pwm->mmio_base == NULL) { |
217 | dev_err(&pdev->dev, "failed to ioremap() registers\n"); | |
218 | ret = -ENODEV; | |
219 | goto err_free_mem; | |
220 | } | |
221 | ||
3d2a98cd EM |
222 | if (id->driver_data & HAS_SECONDARY_PWM) { |
223 | secondary = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); | |
224 | if (secondary == NULL) { | |
225 | ret = -ENOMEM; | |
226 | goto err_free_mem; | |
227 | } | |
228 | ||
229 | *secondary = *pwm; | |
230 | pwm->secondary = secondary; | |
231 | ||
232 | /* registers for the second PWM has offset of 0x10 */ | |
233 | secondary->mmio_base = pwm->mmio_base + 0x10; | |
234 | secondary->pwm_id = pdev->id + 2; | |
235 | } | |
236 | ||
75540c1a | 237 | __add_pwm(pwm); |
3d2a98cd EM |
238 | if (secondary) |
239 | __add_pwm(secondary); | |
240 | ||
75540c1a | 241 | platform_set_drvdata(pdev, pwm); |
3d2a98cd | 242 | return 0; |
75540c1a | 243 | |
244 | err_free_mem: | |
1692231c | 245 | release_mem_region(r->start, resource_size(r)); |
75540c1a | 246 | err_free_clk: |
247 | clk_put(pwm->clk); | |
248 | err_free: | |
249 | kfree(pwm); | |
3d2a98cd | 250 | return ret; |
75540c1a | 251 | } |
252 | ||
253 | static int __devexit pwm_remove(struct platform_device *pdev) | |
254 | { | |
255 | struct pwm_device *pwm; | |
256 | struct resource *r; | |
257 | ||
258 | pwm = platform_get_drvdata(pdev); | |
259 | if (pwm == NULL) | |
260 | return -ENODEV; | |
261 | ||
262 | mutex_lock(&pwm_lock); | |
3d2a98cd EM |
263 | |
264 | if (pwm->secondary) { | |
265 | list_del(&pwm->secondary->node); | |
266 | kfree(pwm->secondary); | |
267 | } | |
268 | ||
75540c1a | 269 | list_del(&pwm->node); |
270 | mutex_unlock(&pwm_lock); | |
271 | ||
272 | iounmap(pwm->mmio_base); | |
273 | ||
274 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
1692231c | 275 | release_mem_region(r->start, resource_size(r)); |
75540c1a | 276 | |
277 | clk_put(pwm->clk); | |
278 | kfree(pwm); | |
279 | return 0; | |
280 | } | |
281 | ||
3d2a98cd | 282 | static struct platform_driver pwm_driver = { |
75540c1a | 283 | .driver = { |
284 | .name = "pxa25x-pwm", | |
3d2a98cd | 285 | .owner = THIS_MODULE, |
75540c1a | 286 | }, |
3d2a98cd | 287 | .probe = pwm_probe, |
75540c1a | 288 | .remove = __devexit_p(pwm_remove), |
3d2a98cd | 289 | .id_table = pwm_id_table, |
75540c1a | 290 | }; |
291 | ||
292 | static int __init pwm_init(void) | |
293 | { | |
3d2a98cd | 294 | return platform_driver_register(&pwm_driver); |
75540c1a | 295 | } |
296 | arch_initcall(pwm_init); | |
297 | ||
298 | static void __exit pwm_exit(void) | |
299 | { | |
3d2a98cd | 300 | platform_driver_unregister(&pwm_driver); |
75540c1a | 301 | } |
302 | module_exit(pwm_exit); | |
b5f0228a GL |
303 | |
304 | MODULE_LICENSE("GPL v2"); |