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d82d5776 KD |
1 | /* |
2 | * pwm-fan.c - Hwmon driver for fans connected to PWM lines. | |
3 | * | |
4 | * Copyright (c) 2014 Samsung Electronics Co., Ltd. | |
5 | * | |
6 | * Author: Kamil Debski <k.debski@samsung.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; either version 2 of the License, or | |
11 | * (at your option) any later version. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | */ | |
18 | ||
19 | #include <linux/hwmon.h> | |
20 | #include <linux/hwmon-sysfs.h> | |
21 | #include <linux/module.h> | |
22 | #include <linux/mutex.h> | |
23 | #include <linux/of.h> | |
24 | #include <linux/platform_device.h> | |
25 | #include <linux/pwm.h> | |
26 | #include <linux/sysfs.h> | |
b6bddec0 | 27 | #include <linux/thermal.h> |
d82d5776 KD |
28 | |
29 | #define MAX_PWM 255 | |
30 | ||
31 | struct pwm_fan_ctx { | |
32 | struct mutex lock; | |
33 | struct pwm_device *pwm; | |
2e5219c7 LM |
34 | unsigned int pwm_value; |
35 | unsigned int pwm_fan_state; | |
36 | unsigned int pwm_fan_max_state; | |
37 | unsigned int *pwm_fan_cooling_levels; | |
b6bddec0 | 38 | struct thermal_cooling_device *cdev; |
d82d5776 KD |
39 | }; |
40 | ||
cb85ca33 | 41 | static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) |
d82d5776 | 42 | { |
cb85ca33 LM |
43 | unsigned long duty; |
44 | int ret = 0; | |
d82d5776 KD |
45 | |
46 | mutex_lock(&ctx->lock); | |
d82d5776 | 47 | if (ctx->pwm_value == pwm) |
cb85ca33 | 48 | goto exit_set_pwm_err; |
d82d5776 | 49 | |
d82d5776 KD |
50 | duty = DIV_ROUND_UP(pwm * (ctx->pwm->period - 1), MAX_PWM); |
51 | ret = pwm_config(ctx->pwm, duty, ctx->pwm->period); | |
52 | if (ret) | |
53 | goto exit_set_pwm_err; | |
54 | ||
f354169e AM |
55 | if (pwm == 0) |
56 | pwm_disable(ctx->pwm); | |
57 | ||
d82d5776 KD |
58 | if (ctx->pwm_value == 0) { |
59 | ret = pwm_enable(ctx->pwm); | |
60 | if (ret) | |
61 | goto exit_set_pwm_err; | |
62 | } | |
63 | ||
d82d5776 | 64 | ctx->pwm_value = pwm; |
d82d5776 KD |
65 | exit_set_pwm_err: |
66 | mutex_unlock(&ctx->lock); | |
67 | return ret; | |
68 | } | |
69 | ||
b6bddec0 LM |
70 | static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm) |
71 | { | |
72 | int i; | |
73 | ||
74 | for (i = 0; i < ctx->pwm_fan_max_state; ++i) | |
75 | if (pwm < ctx->pwm_fan_cooling_levels[i + 1]) | |
76 | break; | |
77 | ||
78 | ctx->pwm_fan_state = i; | |
79 | } | |
80 | ||
cb85ca33 LM |
81 | static ssize_t set_pwm(struct device *dev, struct device_attribute *attr, |
82 | const char *buf, size_t count) | |
83 | { | |
84 | struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); | |
85 | unsigned long pwm; | |
86 | int ret; | |
87 | ||
88 | if (kstrtoul(buf, 10, &pwm) || pwm > MAX_PWM) | |
89 | return -EINVAL; | |
90 | ||
91 | ret = __set_pwm(ctx, pwm); | |
92 | if (ret) | |
93 | return ret; | |
94 | ||
b6bddec0 | 95 | pwm_fan_update_state(ctx, pwm); |
cb85ca33 LM |
96 | return count; |
97 | } | |
98 | ||
d82d5776 KD |
99 | static ssize_t show_pwm(struct device *dev, |
100 | struct device_attribute *attr, char *buf) | |
101 | { | |
102 | struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); | |
103 | ||
104 | return sprintf(buf, "%u\n", ctx->pwm_value); | |
105 | } | |
106 | ||
107 | ||
108 | static SENSOR_DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm, 0); | |
109 | ||
110 | static struct attribute *pwm_fan_attrs[] = { | |
111 | &sensor_dev_attr_pwm1.dev_attr.attr, | |
112 | NULL, | |
113 | }; | |
114 | ||
115 | ATTRIBUTE_GROUPS(pwm_fan); | |
116 | ||
b6bddec0 LM |
117 | /* thermal cooling device callbacks */ |
118 | static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev, | |
119 | unsigned long *state) | |
120 | { | |
121 | struct pwm_fan_ctx *ctx = cdev->devdata; | |
122 | ||
123 | if (!ctx) | |
124 | return -EINVAL; | |
125 | ||
126 | *state = ctx->pwm_fan_max_state; | |
127 | ||
128 | return 0; | |
129 | } | |
130 | ||
131 | static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev, | |
132 | unsigned long *state) | |
133 | { | |
134 | struct pwm_fan_ctx *ctx = cdev->devdata; | |
135 | ||
136 | if (!ctx) | |
137 | return -EINVAL; | |
138 | ||
139 | *state = ctx->pwm_fan_state; | |
140 | ||
141 | return 0; | |
142 | } | |
143 | ||
144 | static int | |
145 | pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) | |
146 | { | |
147 | struct pwm_fan_ctx *ctx = cdev->devdata; | |
148 | int ret; | |
149 | ||
150 | if (!ctx || (state > ctx->pwm_fan_max_state)) | |
151 | return -EINVAL; | |
152 | ||
153 | if (state == ctx->pwm_fan_state) | |
154 | return 0; | |
155 | ||
156 | ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]); | |
157 | if (ret) { | |
158 | dev_err(&cdev->device, "Cannot set pwm!\n"); | |
159 | return ret; | |
160 | } | |
161 | ||
162 | ctx->pwm_fan_state = state; | |
163 | ||
164 | return ret; | |
165 | } | |
166 | ||
167 | static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = { | |
168 | .get_max_state = pwm_fan_get_max_state, | |
169 | .get_cur_state = pwm_fan_get_cur_state, | |
170 | .set_cur_state = pwm_fan_set_cur_state, | |
171 | }; | |
172 | ||
de52b049 GR |
173 | static int pwm_fan_of_get_cooling_data(struct device *dev, |
174 | struct pwm_fan_ctx *ctx) | |
2e5219c7 LM |
175 | { |
176 | struct device_node *np = dev->of_node; | |
177 | int num, i, ret; | |
178 | ||
179 | if (!of_find_property(np, "cooling-levels", NULL)) | |
180 | return 0; | |
181 | ||
182 | ret = of_property_count_u32_elems(np, "cooling-levels"); | |
183 | if (ret <= 0) { | |
184 | dev_err(dev, "Wrong data!\n"); | |
185 | return ret ? : -EINVAL; | |
186 | } | |
187 | ||
188 | num = ret; | |
189 | ctx->pwm_fan_cooling_levels = devm_kzalloc(dev, num * sizeof(u32), | |
190 | GFP_KERNEL); | |
191 | if (!ctx->pwm_fan_cooling_levels) | |
192 | return -ENOMEM; | |
193 | ||
194 | ret = of_property_read_u32_array(np, "cooling-levels", | |
195 | ctx->pwm_fan_cooling_levels, num); | |
196 | if (ret) { | |
197 | dev_err(dev, "Property 'cooling-levels' cannot be read!\n"); | |
198 | return ret; | |
199 | } | |
200 | ||
201 | for (i = 0; i < num; i++) { | |
202 | if (ctx->pwm_fan_cooling_levels[i] > MAX_PWM) { | |
203 | dev_err(dev, "PWM fan state[%d]:%d > %d\n", i, | |
204 | ctx->pwm_fan_cooling_levels[i], MAX_PWM); | |
205 | return -EINVAL; | |
206 | } | |
207 | } | |
208 | ||
209 | ctx->pwm_fan_max_state = num - 1; | |
210 | ||
211 | return 0; | |
212 | } | |
213 | ||
d82d5776 KD |
214 | static int pwm_fan_probe(struct platform_device *pdev) |
215 | { | |
b6bddec0 | 216 | struct thermal_cooling_device *cdev; |
d82d5776 | 217 | struct pwm_fan_ctx *ctx; |
b6bddec0 | 218 | struct device *hwmon; |
d82d5776 KD |
219 | int duty_cycle; |
220 | int ret; | |
221 | ||
222 | ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL); | |
223 | if (!ctx) | |
224 | return -ENOMEM; | |
225 | ||
226 | mutex_init(&ctx->lock); | |
227 | ||
228 | ctx->pwm = devm_of_pwm_get(&pdev->dev, pdev->dev.of_node, NULL); | |
229 | if (IS_ERR(ctx->pwm)) { | |
230 | dev_err(&pdev->dev, "Could not get PWM\n"); | |
231 | return PTR_ERR(ctx->pwm); | |
232 | } | |
233 | ||
d82d5776 KD |
234 | platform_set_drvdata(pdev, ctx); |
235 | ||
236 | /* Set duty cycle to maximum allowed */ | |
237 | duty_cycle = ctx->pwm->period - 1; | |
238 | ctx->pwm_value = MAX_PWM; | |
239 | ||
240 | ret = pwm_config(ctx->pwm, duty_cycle, ctx->pwm->period); | |
241 | if (ret) { | |
242 | dev_err(&pdev->dev, "Failed to configure PWM\n"); | |
243 | return ret; | |
244 | } | |
245 | ||
246 | /* Enbale PWM output */ | |
247 | ret = pwm_enable(ctx->pwm); | |
248 | if (ret) { | |
249 | dev_err(&pdev->dev, "Failed to enable PWM\n"); | |
250 | return ret; | |
251 | } | |
252 | ||
253 | hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan", | |
254 | ctx, pwm_fan_groups); | |
255 | if (IS_ERR(hwmon)) { | |
256 | dev_err(&pdev->dev, "Failed to register hwmon device\n"); | |
257 | pwm_disable(ctx->pwm); | |
258 | return PTR_ERR(hwmon); | |
259 | } | |
2e5219c7 LM |
260 | |
261 | ret = pwm_fan_of_get_cooling_data(&pdev->dev, ctx); | |
262 | if (ret) | |
263 | return ret; | |
264 | ||
b6bddec0 LM |
265 | ctx->pwm_fan_state = ctx->pwm_fan_max_state; |
266 | if (IS_ENABLED(CONFIG_THERMAL)) { | |
267 | cdev = thermal_of_cooling_device_register(pdev->dev.of_node, | |
268 | "pwm-fan", ctx, | |
269 | &pwm_fan_cooling_ops); | |
270 | if (IS_ERR(cdev)) { | |
271 | dev_err(&pdev->dev, | |
272 | "Failed to register pwm-fan as cooling device"); | |
273 | pwm_disable(ctx->pwm); | |
274 | return PTR_ERR(cdev); | |
275 | } | |
276 | ctx->cdev = cdev; | |
277 | thermal_cdev_update(cdev); | |
278 | } | |
279 | ||
d82d5776 KD |
280 | return 0; |
281 | } | |
282 | ||
283 | static int pwm_fan_remove(struct platform_device *pdev) | |
284 | { | |
285 | struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev); | |
286 | ||
b6bddec0 | 287 | thermal_cooling_device_unregister(ctx->cdev); |
d82d5776 KD |
288 | if (ctx->pwm_value) |
289 | pwm_disable(ctx->pwm); | |
290 | return 0; | |
291 | } | |
292 | ||
293 | #ifdef CONFIG_PM_SLEEP | |
294 | static int pwm_fan_suspend(struct device *dev) | |
295 | { | |
296 | struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); | |
297 | ||
298 | if (ctx->pwm_value) | |
299 | pwm_disable(ctx->pwm); | |
300 | return 0; | |
301 | } | |
302 | ||
303 | static int pwm_fan_resume(struct device *dev) | |
304 | { | |
305 | struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); | |
48b9d5b4 KD |
306 | unsigned long duty; |
307 | int ret; | |
d82d5776 | 308 | |
48b9d5b4 KD |
309 | if (ctx->pwm_value == 0) |
310 | return 0; | |
311 | ||
312 | duty = DIV_ROUND_UP(ctx->pwm_value * (ctx->pwm->period - 1), MAX_PWM); | |
313 | ret = pwm_config(ctx->pwm, duty, ctx->pwm->period); | |
314 | if (ret) | |
315 | return ret; | |
316 | return pwm_enable(ctx->pwm); | |
d82d5776 KD |
317 | } |
318 | #endif | |
319 | ||
320 | static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume); | |
321 | ||
d720acac | 322 | static const struct of_device_id of_pwm_fan_match[] = { |
d82d5776 KD |
323 | { .compatible = "pwm-fan", }, |
324 | {}, | |
325 | }; | |
f491e70c | 326 | MODULE_DEVICE_TABLE(of, of_pwm_fan_match); |
d82d5776 KD |
327 | |
328 | static struct platform_driver pwm_fan_driver = { | |
329 | .probe = pwm_fan_probe, | |
330 | .remove = pwm_fan_remove, | |
331 | .driver = { | |
332 | .name = "pwm-fan", | |
333 | .pm = &pwm_fan_pm, | |
334 | .of_match_table = of_pwm_fan_match, | |
335 | }, | |
336 | }; | |
337 | ||
338 | module_platform_driver(pwm_fan_driver); | |
339 | ||
340 | MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>"); | |
341 | MODULE_ALIAS("platform:pwm-fan"); | |
342 | MODULE_DESCRIPTION("PWM FAN driver"); | |
343 | MODULE_LICENSE("GPL"); |