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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 | { |
2289711c | 43 | struct pwm_args pargs; |
cb85ca33 LM |
44 | unsigned long duty; |
45 | int ret = 0; | |
d82d5776 | 46 | |
2289711c BB |
47 | pwm_get_args(ctx->pwm, &pargs); |
48 | ||
d82d5776 | 49 | mutex_lock(&ctx->lock); |
d82d5776 | 50 | if (ctx->pwm_value == pwm) |
cb85ca33 | 51 | goto exit_set_pwm_err; |
d82d5776 | 52 | |
2289711c BB |
53 | duty = DIV_ROUND_UP(pwm * (pargs.period - 1), MAX_PWM); |
54 | ret = pwm_config(ctx->pwm, duty, pargs.period); | |
d82d5776 KD |
55 | if (ret) |
56 | goto exit_set_pwm_err; | |
57 | ||
f354169e AM |
58 | if (pwm == 0) |
59 | pwm_disable(ctx->pwm); | |
60 | ||
d82d5776 KD |
61 | if (ctx->pwm_value == 0) { |
62 | ret = pwm_enable(ctx->pwm); | |
63 | if (ret) | |
64 | goto exit_set_pwm_err; | |
65 | } | |
66 | ||
d82d5776 | 67 | ctx->pwm_value = pwm; |
d82d5776 KD |
68 | exit_set_pwm_err: |
69 | mutex_unlock(&ctx->lock); | |
70 | return ret; | |
71 | } | |
72 | ||
b6bddec0 LM |
73 | static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm) |
74 | { | |
75 | int i; | |
76 | ||
77 | for (i = 0; i < ctx->pwm_fan_max_state; ++i) | |
78 | if (pwm < ctx->pwm_fan_cooling_levels[i + 1]) | |
79 | break; | |
80 | ||
81 | ctx->pwm_fan_state = i; | |
82 | } | |
83 | ||
cb85ca33 LM |
84 | static ssize_t set_pwm(struct device *dev, struct device_attribute *attr, |
85 | const char *buf, size_t count) | |
86 | { | |
87 | struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); | |
88 | unsigned long pwm; | |
89 | int ret; | |
90 | ||
91 | if (kstrtoul(buf, 10, &pwm) || pwm > MAX_PWM) | |
92 | return -EINVAL; | |
93 | ||
94 | ret = __set_pwm(ctx, pwm); | |
95 | if (ret) | |
96 | return ret; | |
97 | ||
b6bddec0 | 98 | pwm_fan_update_state(ctx, pwm); |
cb85ca33 LM |
99 | return count; |
100 | } | |
101 | ||
d82d5776 KD |
102 | static ssize_t show_pwm(struct device *dev, |
103 | struct device_attribute *attr, char *buf) | |
104 | { | |
105 | struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); | |
106 | ||
107 | return sprintf(buf, "%u\n", ctx->pwm_value); | |
108 | } | |
109 | ||
110 | ||
111 | static SENSOR_DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm, 0); | |
112 | ||
113 | static struct attribute *pwm_fan_attrs[] = { | |
114 | &sensor_dev_attr_pwm1.dev_attr.attr, | |
115 | NULL, | |
116 | }; | |
117 | ||
118 | ATTRIBUTE_GROUPS(pwm_fan); | |
119 | ||
b6bddec0 LM |
120 | /* thermal cooling device callbacks */ |
121 | static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev, | |
122 | unsigned long *state) | |
123 | { | |
124 | struct pwm_fan_ctx *ctx = cdev->devdata; | |
125 | ||
126 | if (!ctx) | |
127 | return -EINVAL; | |
128 | ||
129 | *state = ctx->pwm_fan_max_state; | |
130 | ||
131 | return 0; | |
132 | } | |
133 | ||
134 | static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev, | |
135 | unsigned long *state) | |
136 | { | |
137 | struct pwm_fan_ctx *ctx = cdev->devdata; | |
138 | ||
139 | if (!ctx) | |
140 | return -EINVAL; | |
141 | ||
142 | *state = ctx->pwm_fan_state; | |
143 | ||
144 | return 0; | |
145 | } | |
146 | ||
147 | static int | |
148 | pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) | |
149 | { | |
150 | struct pwm_fan_ctx *ctx = cdev->devdata; | |
151 | int ret; | |
152 | ||
153 | if (!ctx || (state > ctx->pwm_fan_max_state)) | |
154 | return -EINVAL; | |
155 | ||
156 | if (state == ctx->pwm_fan_state) | |
157 | return 0; | |
158 | ||
159 | ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]); | |
160 | if (ret) { | |
161 | dev_err(&cdev->device, "Cannot set pwm!\n"); | |
162 | return ret; | |
163 | } | |
164 | ||
165 | ctx->pwm_fan_state = state; | |
166 | ||
167 | return ret; | |
168 | } | |
169 | ||
170 | static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = { | |
171 | .get_max_state = pwm_fan_get_max_state, | |
172 | .get_cur_state = pwm_fan_get_cur_state, | |
173 | .set_cur_state = pwm_fan_set_cur_state, | |
174 | }; | |
175 | ||
de52b049 GR |
176 | static int pwm_fan_of_get_cooling_data(struct device *dev, |
177 | struct pwm_fan_ctx *ctx) | |
2e5219c7 LM |
178 | { |
179 | struct device_node *np = dev->of_node; | |
180 | int num, i, ret; | |
181 | ||
182 | if (!of_find_property(np, "cooling-levels", NULL)) | |
183 | return 0; | |
184 | ||
185 | ret = of_property_count_u32_elems(np, "cooling-levels"); | |
186 | if (ret <= 0) { | |
187 | dev_err(dev, "Wrong data!\n"); | |
188 | return ret ? : -EINVAL; | |
189 | } | |
190 | ||
191 | num = ret; | |
192 | ctx->pwm_fan_cooling_levels = devm_kzalloc(dev, num * sizeof(u32), | |
193 | GFP_KERNEL); | |
194 | if (!ctx->pwm_fan_cooling_levels) | |
195 | return -ENOMEM; | |
196 | ||
197 | ret = of_property_read_u32_array(np, "cooling-levels", | |
198 | ctx->pwm_fan_cooling_levels, num); | |
199 | if (ret) { | |
200 | dev_err(dev, "Property 'cooling-levels' cannot be read!\n"); | |
201 | return ret; | |
202 | } | |
203 | ||
204 | for (i = 0; i < num; i++) { | |
205 | if (ctx->pwm_fan_cooling_levels[i] > MAX_PWM) { | |
206 | dev_err(dev, "PWM fan state[%d]:%d > %d\n", i, | |
207 | ctx->pwm_fan_cooling_levels[i], MAX_PWM); | |
208 | return -EINVAL; | |
209 | } | |
210 | } | |
211 | ||
212 | ctx->pwm_fan_max_state = num - 1; | |
213 | ||
214 | return 0; | |
215 | } | |
216 | ||
d82d5776 KD |
217 | static int pwm_fan_probe(struct platform_device *pdev) |
218 | { | |
b6bddec0 | 219 | struct thermal_cooling_device *cdev; |
d82d5776 | 220 | struct pwm_fan_ctx *ctx; |
2289711c | 221 | struct pwm_args pargs; |
b6bddec0 | 222 | struct device *hwmon; |
d82d5776 KD |
223 | int duty_cycle; |
224 | int ret; | |
225 | ||
226 | ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL); | |
227 | if (!ctx) | |
228 | return -ENOMEM; | |
229 | ||
230 | mutex_init(&ctx->lock); | |
231 | ||
232 | ctx->pwm = devm_of_pwm_get(&pdev->dev, pdev->dev.of_node, NULL); | |
233 | if (IS_ERR(ctx->pwm)) { | |
234 | dev_err(&pdev->dev, "Could not get PWM\n"); | |
235 | return PTR_ERR(ctx->pwm); | |
236 | } | |
237 | ||
d82d5776 KD |
238 | platform_set_drvdata(pdev, ctx); |
239 | ||
2289711c BB |
240 | /* |
241 | * FIXME: pwm_apply_args() should be removed when switching to the | |
242 | * atomic PWM API. | |
243 | */ | |
244 | pwm_apply_args(ctx->pwm); | |
245 | ||
d82d5776 | 246 | /* Set duty cycle to maximum allowed */ |
2289711c BB |
247 | pwm_get_args(ctx->pwm, &pargs); |
248 | ||
249 | duty_cycle = pargs.period - 1; | |
d82d5776 KD |
250 | ctx->pwm_value = MAX_PWM; |
251 | ||
2289711c | 252 | ret = pwm_config(ctx->pwm, duty_cycle, pargs.period); |
d82d5776 KD |
253 | if (ret) { |
254 | dev_err(&pdev->dev, "Failed to configure PWM\n"); | |
255 | return ret; | |
256 | } | |
257 | ||
258 | /* Enbale PWM output */ | |
259 | ret = pwm_enable(ctx->pwm); | |
260 | if (ret) { | |
261 | dev_err(&pdev->dev, "Failed to enable PWM\n"); | |
262 | return ret; | |
263 | } | |
264 | ||
265 | hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan", | |
266 | ctx, pwm_fan_groups); | |
267 | if (IS_ERR(hwmon)) { | |
268 | dev_err(&pdev->dev, "Failed to register hwmon device\n"); | |
269 | pwm_disable(ctx->pwm); | |
270 | return PTR_ERR(hwmon); | |
271 | } | |
2e5219c7 LM |
272 | |
273 | ret = pwm_fan_of_get_cooling_data(&pdev->dev, ctx); | |
274 | if (ret) | |
275 | return ret; | |
276 | ||
b6bddec0 LM |
277 | ctx->pwm_fan_state = ctx->pwm_fan_max_state; |
278 | if (IS_ENABLED(CONFIG_THERMAL)) { | |
279 | cdev = thermal_of_cooling_device_register(pdev->dev.of_node, | |
280 | "pwm-fan", ctx, | |
281 | &pwm_fan_cooling_ops); | |
282 | if (IS_ERR(cdev)) { | |
283 | dev_err(&pdev->dev, | |
284 | "Failed to register pwm-fan as cooling device"); | |
285 | pwm_disable(ctx->pwm); | |
286 | return PTR_ERR(cdev); | |
287 | } | |
288 | ctx->cdev = cdev; | |
289 | thermal_cdev_update(cdev); | |
290 | } | |
291 | ||
d82d5776 KD |
292 | return 0; |
293 | } | |
294 | ||
295 | static int pwm_fan_remove(struct platform_device *pdev) | |
296 | { | |
297 | struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev); | |
298 | ||
b6bddec0 | 299 | thermal_cooling_device_unregister(ctx->cdev); |
d82d5776 KD |
300 | if (ctx->pwm_value) |
301 | pwm_disable(ctx->pwm); | |
302 | return 0; | |
303 | } | |
304 | ||
305 | #ifdef CONFIG_PM_SLEEP | |
306 | static int pwm_fan_suspend(struct device *dev) | |
307 | { | |
308 | struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); | |
309 | ||
310 | if (ctx->pwm_value) | |
311 | pwm_disable(ctx->pwm); | |
312 | return 0; | |
313 | } | |
314 | ||
315 | static int pwm_fan_resume(struct device *dev) | |
316 | { | |
317 | struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); | |
2289711c | 318 | struct pwm_args pargs; |
48b9d5b4 KD |
319 | unsigned long duty; |
320 | int ret; | |
d82d5776 | 321 | |
48b9d5b4 KD |
322 | if (ctx->pwm_value == 0) |
323 | return 0; | |
324 | ||
2289711c BB |
325 | pwm_get_args(ctx->pwm, &pargs); |
326 | duty = DIV_ROUND_UP(ctx->pwm_value * (pargs.period - 1), MAX_PWM); | |
327 | ret = pwm_config(ctx->pwm, duty, pargs.period); | |
48b9d5b4 KD |
328 | if (ret) |
329 | return ret; | |
330 | return pwm_enable(ctx->pwm); | |
d82d5776 KD |
331 | } |
332 | #endif | |
333 | ||
334 | static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume); | |
335 | ||
d720acac | 336 | static const struct of_device_id of_pwm_fan_match[] = { |
d82d5776 KD |
337 | { .compatible = "pwm-fan", }, |
338 | {}, | |
339 | }; | |
f491e70c | 340 | MODULE_DEVICE_TABLE(of, of_pwm_fan_match); |
d82d5776 KD |
341 | |
342 | static struct platform_driver pwm_fan_driver = { | |
343 | .probe = pwm_fan_probe, | |
344 | .remove = pwm_fan_remove, | |
345 | .driver = { | |
346 | .name = "pwm-fan", | |
347 | .pm = &pwm_fan_pm, | |
348 | .of_match_table = of_pwm_fan_match, | |
349 | }, | |
350 | }; | |
351 | ||
352 | module_platform_driver(pwm_fan_driver); | |
353 | ||
354 | MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>"); | |
355 | MODULE_ALIAS("platform:pwm-fan"); | |
356 | MODULE_DESCRIPTION("PWM FAN driver"); | |
357 | MODULE_LICENSE("GPL"); |