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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 | { |
677252a1 | 43 | unsigned long period; |
cb85ca33 | 44 | int ret = 0; |
677252a1 | 45 | struct pwm_state state = { }; |
2289711c | 46 | |
d82d5776 | 47 | mutex_lock(&ctx->lock); |
d82d5776 | 48 | if (ctx->pwm_value == pwm) |
cb85ca33 | 49 | goto exit_set_pwm_err; |
d82d5776 | 50 | |
677252a1 BZ |
51 | pwm_init_state(ctx->pwm, &state); |
52 | period = ctx->pwm->args.period; | |
53 | state.duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM); | |
54 | state.enabled = pwm ? true : false; | |
f354169e | 55 | |
677252a1 BZ |
56 | ret = pwm_apply_state(ctx->pwm, &state); |
57 | if (!ret) | |
58 | ctx->pwm_value = pwm; | |
d82d5776 KD |
59 | exit_set_pwm_err: |
60 | mutex_unlock(&ctx->lock); | |
61 | return ret; | |
62 | } | |
63 | ||
b6bddec0 LM |
64 | static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm) |
65 | { | |
66 | int i; | |
67 | ||
68 | for (i = 0; i < ctx->pwm_fan_max_state; ++i) | |
69 | if (pwm < ctx->pwm_fan_cooling_levels[i + 1]) | |
70 | break; | |
71 | ||
72 | ctx->pwm_fan_state = i; | |
73 | } | |
74 | ||
cb85ca33 LM |
75 | static ssize_t set_pwm(struct device *dev, struct device_attribute *attr, |
76 | const char *buf, size_t count) | |
77 | { | |
78 | struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); | |
79 | unsigned long pwm; | |
80 | int ret; | |
81 | ||
82 | if (kstrtoul(buf, 10, &pwm) || pwm > MAX_PWM) | |
83 | return -EINVAL; | |
84 | ||
85 | ret = __set_pwm(ctx, pwm); | |
86 | if (ret) | |
87 | return ret; | |
88 | ||
b6bddec0 | 89 | pwm_fan_update_state(ctx, pwm); |
cb85ca33 LM |
90 | return count; |
91 | } | |
92 | ||
d82d5776 KD |
93 | static ssize_t show_pwm(struct device *dev, |
94 | struct device_attribute *attr, char *buf) | |
95 | { | |
96 | struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); | |
97 | ||
98 | return sprintf(buf, "%u\n", ctx->pwm_value); | |
99 | } | |
100 | ||
101 | ||
102 | static SENSOR_DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm, 0); | |
103 | ||
104 | static struct attribute *pwm_fan_attrs[] = { | |
105 | &sensor_dev_attr_pwm1.dev_attr.attr, | |
106 | NULL, | |
107 | }; | |
108 | ||
109 | ATTRIBUTE_GROUPS(pwm_fan); | |
110 | ||
b6bddec0 LM |
111 | /* thermal cooling device callbacks */ |
112 | static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev, | |
113 | unsigned long *state) | |
114 | { | |
115 | struct pwm_fan_ctx *ctx = cdev->devdata; | |
116 | ||
117 | if (!ctx) | |
118 | return -EINVAL; | |
119 | ||
120 | *state = ctx->pwm_fan_max_state; | |
121 | ||
122 | return 0; | |
123 | } | |
124 | ||
125 | static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev, | |
126 | unsigned long *state) | |
127 | { | |
128 | struct pwm_fan_ctx *ctx = cdev->devdata; | |
129 | ||
130 | if (!ctx) | |
131 | return -EINVAL; | |
132 | ||
133 | *state = ctx->pwm_fan_state; | |
134 | ||
135 | return 0; | |
136 | } | |
137 | ||
138 | static int | |
139 | pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) | |
140 | { | |
141 | struct pwm_fan_ctx *ctx = cdev->devdata; | |
142 | int ret; | |
143 | ||
144 | if (!ctx || (state > ctx->pwm_fan_max_state)) | |
145 | return -EINVAL; | |
146 | ||
147 | if (state == ctx->pwm_fan_state) | |
148 | return 0; | |
149 | ||
150 | ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]); | |
151 | if (ret) { | |
152 | dev_err(&cdev->device, "Cannot set pwm!\n"); | |
153 | return ret; | |
154 | } | |
155 | ||
156 | ctx->pwm_fan_state = state; | |
157 | ||
158 | return ret; | |
159 | } | |
160 | ||
161 | static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = { | |
162 | .get_max_state = pwm_fan_get_max_state, | |
163 | .get_cur_state = pwm_fan_get_cur_state, | |
164 | .set_cur_state = pwm_fan_set_cur_state, | |
165 | }; | |
166 | ||
de52b049 GR |
167 | static int pwm_fan_of_get_cooling_data(struct device *dev, |
168 | struct pwm_fan_ctx *ctx) | |
2e5219c7 LM |
169 | { |
170 | struct device_node *np = dev->of_node; | |
171 | int num, i, ret; | |
172 | ||
173 | if (!of_find_property(np, "cooling-levels", NULL)) | |
174 | return 0; | |
175 | ||
176 | ret = of_property_count_u32_elems(np, "cooling-levels"); | |
177 | if (ret <= 0) { | |
178 | dev_err(dev, "Wrong data!\n"); | |
179 | return ret ? : -EINVAL; | |
180 | } | |
181 | ||
182 | num = ret; | |
a86854d0 | 183 | ctx->pwm_fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32), |
2e5219c7 LM |
184 | GFP_KERNEL); |
185 | if (!ctx->pwm_fan_cooling_levels) | |
186 | return -ENOMEM; | |
187 | ||
188 | ret = of_property_read_u32_array(np, "cooling-levels", | |
189 | ctx->pwm_fan_cooling_levels, num); | |
190 | if (ret) { | |
191 | dev_err(dev, "Property 'cooling-levels' cannot be read!\n"); | |
192 | return ret; | |
193 | } | |
194 | ||
195 | for (i = 0; i < num; i++) { | |
196 | if (ctx->pwm_fan_cooling_levels[i] > MAX_PWM) { | |
197 | dev_err(dev, "PWM fan state[%d]:%d > %d\n", i, | |
198 | ctx->pwm_fan_cooling_levels[i], MAX_PWM); | |
199 | return -EINVAL; | |
200 | } | |
201 | } | |
202 | ||
203 | ctx->pwm_fan_max_state = num - 1; | |
204 | ||
205 | return 0; | |
206 | } | |
207 | ||
d82d5776 KD |
208 | static int pwm_fan_probe(struct platform_device *pdev) |
209 | { | |
b6bddec0 | 210 | struct thermal_cooling_device *cdev; |
d82d5776 | 211 | struct pwm_fan_ctx *ctx; |
b6bddec0 | 212 | struct device *hwmon; |
d82d5776 | 213 | int ret; |
677252a1 | 214 | struct pwm_state state = { }; |
d82d5776 KD |
215 | |
216 | ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL); | |
217 | if (!ctx) | |
218 | return -ENOMEM; | |
219 | ||
220 | mutex_init(&ctx->lock); | |
221 | ||
222 | ctx->pwm = devm_of_pwm_get(&pdev->dev, pdev->dev.of_node, NULL); | |
223 | if (IS_ERR(ctx->pwm)) { | |
224 | dev_err(&pdev->dev, "Could not get PWM\n"); | |
225 | return PTR_ERR(ctx->pwm); | |
226 | } | |
227 | ||
d82d5776 KD |
228 | platform_set_drvdata(pdev, ctx); |
229 | ||
d82d5776 KD |
230 | ctx->pwm_value = MAX_PWM; |
231 | ||
677252a1 BZ |
232 | /* Set duty cycle to maximum allowed and enable PWM output */ |
233 | pwm_init_state(ctx->pwm, &state); | |
234 | state.duty_cycle = ctx->pwm->args.period - 1; | |
235 | state.enabled = true; | |
d82d5776 | 236 | |
677252a1 | 237 | ret = pwm_apply_state(ctx->pwm, &state); |
d82d5776 | 238 | if (ret) { |
677252a1 | 239 | dev_err(&pdev->dev, "Failed to configure PWM\n"); |
d82d5776 KD |
240 | return ret; |
241 | } | |
242 | ||
243 | hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan", | |
244 | ctx, pwm_fan_groups); | |
245 | if (IS_ERR(hwmon)) { | |
246 | dev_err(&pdev->dev, "Failed to register hwmon device\n"); | |
677252a1 BZ |
247 | ret = PTR_ERR(hwmon); |
248 | goto err_pwm_disable; | |
d82d5776 | 249 | } |
2e5219c7 LM |
250 | |
251 | ret = pwm_fan_of_get_cooling_data(&pdev->dev, ctx); | |
252 | if (ret) | |
253 | return ret; | |
254 | ||
b6bddec0 LM |
255 | ctx->pwm_fan_state = ctx->pwm_fan_max_state; |
256 | if (IS_ENABLED(CONFIG_THERMAL)) { | |
257 | cdev = thermal_of_cooling_device_register(pdev->dev.of_node, | |
258 | "pwm-fan", ctx, | |
259 | &pwm_fan_cooling_ops); | |
260 | if (IS_ERR(cdev)) { | |
261 | dev_err(&pdev->dev, | |
262 | "Failed to register pwm-fan as cooling device"); | |
677252a1 BZ |
263 | ret = PTR_ERR(cdev); |
264 | goto err_pwm_disable; | |
b6bddec0 LM |
265 | } |
266 | ctx->cdev = cdev; | |
267 | thermal_cdev_update(cdev); | |
268 | } | |
269 | ||
d82d5776 | 270 | return 0; |
677252a1 BZ |
271 | |
272 | err_pwm_disable: | |
273 | state.enabled = false; | |
274 | pwm_apply_state(ctx->pwm, &state); | |
275 | ||
276 | return ret; | |
d82d5776 KD |
277 | } |
278 | ||
279 | static int pwm_fan_remove(struct platform_device *pdev) | |
280 | { | |
281 | struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev); | |
282 | ||
b6bddec0 | 283 | thermal_cooling_device_unregister(ctx->cdev); |
d82d5776 KD |
284 | if (ctx->pwm_value) |
285 | pwm_disable(ctx->pwm); | |
286 | return 0; | |
287 | } | |
288 | ||
289 | #ifdef CONFIG_PM_SLEEP | |
290 | static int pwm_fan_suspend(struct device *dev) | |
291 | { | |
292 | struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); | |
293 | ||
294 | if (ctx->pwm_value) | |
295 | pwm_disable(ctx->pwm); | |
296 | return 0; | |
297 | } | |
298 | ||
299 | static int pwm_fan_resume(struct device *dev) | |
300 | { | |
301 | struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); | |
2289711c | 302 | struct pwm_args pargs; |
48b9d5b4 KD |
303 | unsigned long duty; |
304 | int ret; | |
d82d5776 | 305 | |
48b9d5b4 KD |
306 | if (ctx->pwm_value == 0) |
307 | return 0; | |
308 | ||
2289711c BB |
309 | pwm_get_args(ctx->pwm, &pargs); |
310 | duty = DIV_ROUND_UP(ctx->pwm_value * (pargs.period - 1), MAX_PWM); | |
311 | ret = pwm_config(ctx->pwm, duty, pargs.period); | |
48b9d5b4 KD |
312 | if (ret) |
313 | return ret; | |
314 | return pwm_enable(ctx->pwm); | |
d82d5776 KD |
315 | } |
316 | #endif | |
317 | ||
318 | static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume); | |
319 | ||
d720acac | 320 | static const struct of_device_id of_pwm_fan_match[] = { |
d82d5776 KD |
321 | { .compatible = "pwm-fan", }, |
322 | {}, | |
323 | }; | |
f491e70c | 324 | MODULE_DEVICE_TABLE(of, of_pwm_fan_match); |
d82d5776 KD |
325 | |
326 | static struct platform_driver pwm_fan_driver = { | |
327 | .probe = pwm_fan_probe, | |
328 | .remove = pwm_fan_remove, | |
329 | .driver = { | |
330 | .name = "pwm-fan", | |
331 | .pm = &pwm_fan_pm, | |
332 | .of_match_table = of_pwm_fan_match, | |
333 | }, | |
334 | }; | |
335 | ||
336 | module_platform_driver(pwm_fan_driver); | |
337 | ||
338 | MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>"); | |
339 | MODULE_ALIAS("platform:pwm-fan"); | |
340 | MODULE_DESCRIPTION("PWM FAN driver"); | |
341 | MODULE_LICENSE("GPL"); |