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/regulator/consumer.h>
27#include <linux/sysfs.h>
28#include <linux/thermal.h>
29
30#define MAX_PWM 255
31
32struct pwm_fan_ctx {
33 struct mutex lock;
34 struct pwm_device *pwm;
35 struct regulator *reg_en;
36 unsigned int pwm_value;
37 unsigned int pwm_fan_state;
38 unsigned int pwm_fan_max_state;
39 unsigned int *pwm_fan_cooling_levels;
40 struct thermal_cooling_device *cdev;
41};
42
43static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
44{
45 unsigned long period;
46 int ret = 0;
47 struct pwm_state state = { };
48
49 mutex_lock(&ctx->lock);
50 if (ctx->pwm_value == pwm)
51 goto exit_set_pwm_err;
52
53 pwm_init_state(ctx->pwm, &state);
54 period = ctx->pwm->args.period;
55 state.duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);
56 state.enabled = pwm ? true : false;
57
58 ret = pwm_apply_state(ctx->pwm, &state);
59 if (!ret)
60 ctx->pwm_value = pwm;
61exit_set_pwm_err:
62 mutex_unlock(&ctx->lock);
63 return ret;
64}
65
66static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm)
67{
68 int i;
69
70 for (i = 0; i < ctx->pwm_fan_max_state; ++i)
71 if (pwm < ctx->pwm_fan_cooling_levels[i + 1])
72 break;
73
74 ctx->pwm_fan_state = i;
75}
76
77static ssize_t pwm_store(struct device *dev, struct device_attribute *attr,
78 const char *buf, size_t count)
79{
80 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
81 unsigned long pwm;
82 int ret;
83
84 if (kstrtoul(buf, 10, &pwm) || pwm > MAX_PWM)
85 return -EINVAL;
86
87 ret = __set_pwm(ctx, pwm);
88 if (ret)
89 return ret;
90
91 pwm_fan_update_state(ctx, pwm);
92 return count;
93}
94
95static ssize_t pwm_show(struct device *dev, struct device_attribute *attr,
96 char *buf)
97{
98 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
99
100 return sprintf(buf, "%u\n", ctx->pwm_value);
101}
102
103
104static SENSOR_DEVICE_ATTR_RW(pwm1, pwm, 0);
105
106static struct attribute *pwm_fan_attrs[] = {
107 &sensor_dev_attr_pwm1.dev_attr.attr,
108 NULL,
109};
110
111ATTRIBUTE_GROUPS(pwm_fan);
112
113/* thermal cooling device callbacks */
114static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev,
115 unsigned long *state)
116{
117 struct pwm_fan_ctx *ctx = cdev->devdata;
118
119 if (!ctx)
120 return -EINVAL;
121
122 *state = ctx->pwm_fan_max_state;
123
124 return 0;
125}
126
127static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev,
128 unsigned long *state)
129{
130 struct pwm_fan_ctx *ctx = cdev->devdata;
131
132 if (!ctx)
133 return -EINVAL;
134
135 *state = ctx->pwm_fan_state;
136
137 return 0;
138}
139
140static int
141pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
142{
143 struct pwm_fan_ctx *ctx = cdev->devdata;
144 int ret;
145
146 if (!ctx || (state > ctx->pwm_fan_max_state))
147 return -EINVAL;
148
149 if (state == ctx->pwm_fan_state)
150 return 0;
151
152 ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]);
153 if (ret) {
154 dev_err(&cdev->device, "Cannot set pwm!\n");
155 return ret;
156 }
157
158 ctx->pwm_fan_state = state;
159
160 return ret;
161}
162
163static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = {
164 .get_max_state = pwm_fan_get_max_state,
165 .get_cur_state = pwm_fan_get_cur_state,
166 .set_cur_state = pwm_fan_set_cur_state,
167};
168
169static int pwm_fan_of_get_cooling_data(struct device *dev,
170 struct pwm_fan_ctx *ctx)
171{
172 struct device_node *np = dev->of_node;
173 int num, i, ret;
174
175 if (!of_find_property(np, "cooling-levels", NULL))
176 return 0;
177
178 ret = of_property_count_u32_elems(np, "cooling-levels");
179 if (ret <= 0) {
180 dev_err(dev, "Wrong data!\n");
181 return ret ? : -EINVAL;
182 }
183
184 num = ret;
185 ctx->pwm_fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32),
186 GFP_KERNEL);
187 if (!ctx->pwm_fan_cooling_levels)
188 return -ENOMEM;
189
190 ret = of_property_read_u32_array(np, "cooling-levels",
191 ctx->pwm_fan_cooling_levels, num);
192 if (ret) {
193 dev_err(dev, "Property 'cooling-levels' cannot be read!\n");
194 return ret;
195 }
196
197 for (i = 0; i < num; i++) {
198 if (ctx->pwm_fan_cooling_levels[i] > MAX_PWM) {
199 dev_err(dev, "PWM fan state[%d]:%d > %d\n", i,
200 ctx->pwm_fan_cooling_levels[i], MAX_PWM);
201 return -EINVAL;
202 }
203 }
204
205 ctx->pwm_fan_max_state = num - 1;
206
207 return 0;
208}
209
210static int pwm_fan_probe(struct platform_device *pdev)
211{
212 struct thermal_cooling_device *cdev;
213 struct pwm_fan_ctx *ctx;
214 struct device *hwmon;
215 int ret;
216 struct pwm_state state = { };
217
218 ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
219 if (!ctx)
220 return -ENOMEM;
221
222 mutex_init(&ctx->lock);
223
224 ctx->pwm = devm_of_pwm_get(&pdev->dev, pdev->dev.of_node, NULL);
225 if (IS_ERR(ctx->pwm)) {
226 ret = PTR_ERR(ctx->pwm);
227
228 if (ret != -EPROBE_DEFER)
229 dev_err(&pdev->dev, "Could not get PWM: %d\n", ret);
230
231 return ret;
232 }
233
234 platform_set_drvdata(pdev, ctx);
235
236 ctx->reg_en = devm_regulator_get_optional(&pdev->dev, "fan");
237 if (IS_ERR(ctx->reg_en)) {
238 if (PTR_ERR(ctx->reg_en) != -ENODEV)
239 return PTR_ERR(ctx->reg_en);
240
241 ctx->reg_en = NULL;
242 } else {
243 ret = regulator_enable(ctx->reg_en);
244 if (ret) {
245 dev_err(&pdev->dev,
246 "Failed to enable fan supply: %d\n", ret);
247 return ret;
248 }
249 }
250
251 ctx->pwm_value = MAX_PWM;
252
253 /* Set duty cycle to maximum allowed and enable PWM output */
254 pwm_init_state(ctx->pwm, &state);
255 state.duty_cycle = ctx->pwm->args.period - 1;
256 state.enabled = true;
257
258 ret = pwm_apply_state(ctx->pwm, &state);
259 if (ret) {
260 dev_err(&pdev->dev, "Failed to configure PWM\n");
261 goto err_reg_disable;
262 }
263
264 hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan",
265 ctx, pwm_fan_groups);
266 if (IS_ERR(hwmon)) {
267 dev_err(&pdev->dev, "Failed to register hwmon device\n");
268 ret = PTR_ERR(hwmon);
269 goto err_pwm_disable;
270 }
271
272 ret = pwm_fan_of_get_cooling_data(&pdev->dev, ctx);
273 if (ret)
274 return ret;
275
276 ctx->pwm_fan_state = ctx->pwm_fan_max_state;
277 if (IS_ENABLED(CONFIG_THERMAL)) {
278 cdev = thermal_of_cooling_device_register(pdev->dev.of_node,
279 "pwm-fan", ctx,
280 &pwm_fan_cooling_ops);
281 if (IS_ERR(cdev)) {
282 dev_err(&pdev->dev,
283 "Failed to register pwm-fan as cooling device");
284 ret = PTR_ERR(cdev);
285 goto err_pwm_disable;
286 }
287 ctx->cdev = cdev;
288 thermal_cdev_update(cdev);
289 }
290
291 return 0;
292
293err_pwm_disable:
294 state.enabled = false;
295 pwm_apply_state(ctx->pwm, &state);
296
297err_reg_disable:
298 if (ctx->reg_en)
299 regulator_disable(ctx->reg_en);
300
301 return ret;
302}
303
304static int pwm_fan_remove(struct platform_device *pdev)
305{
306 struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev);
307
308 thermal_cooling_device_unregister(ctx->cdev);
309 if (ctx->pwm_value)
310 pwm_disable(ctx->pwm);
311
312 if (ctx->reg_en)
313 regulator_disable(ctx->reg_en);
314
315 return 0;
316}
317
318#ifdef CONFIG_PM_SLEEP
319static int pwm_fan_suspend(struct device *dev)
320{
321 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
322 struct pwm_args args;
323 int ret;
324
325 pwm_get_args(ctx->pwm, &args);
326
327 if (ctx->pwm_value) {
328 ret = pwm_config(ctx->pwm, 0, args.period);
329 if (ret < 0)
330 return ret;
331
332 pwm_disable(ctx->pwm);
333 }
334
335 if (ctx->reg_en) {
336 ret = regulator_disable(ctx->reg_en);
337 if (ret) {
338 dev_err(dev, "Failed to disable fan supply: %d\n", ret);
339 return ret;
340 }
341 }
342
343 return 0;
344}
345
346static int pwm_fan_resume(struct device *dev)
347{
348 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
349 struct pwm_args pargs;
350 unsigned long duty;
351 int ret;
352
353 if (ctx->reg_en) {
354 ret = regulator_enable(ctx->reg_en);
355 if (ret) {
356 dev_err(dev, "Failed to enable fan supply: %d\n", ret);
357 return ret;
358 }
359 }
360
361 if (ctx->pwm_value == 0)
362 return 0;
363
364 pwm_get_args(ctx->pwm, &pargs);
365 duty = DIV_ROUND_UP(ctx->pwm_value * (pargs.period - 1), MAX_PWM);
366 ret = pwm_config(ctx->pwm, duty, pargs.period);
367 if (ret)
368 return ret;
369 return pwm_enable(ctx->pwm);
370}
371#endif
372
373static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume);
374
375static const struct of_device_id of_pwm_fan_match[] = {
376 { .compatible = "pwm-fan", },
377 {},
378};
379MODULE_DEVICE_TABLE(of, of_pwm_fan_match);
380
381static struct platform_driver pwm_fan_driver = {
382 .probe = pwm_fan_probe,
383 .remove = pwm_fan_remove,
384 .driver = {
385 .name = "pwm-fan",
386 .pm = &pwm_fan_pm,
387 .of_match_table = of_pwm_fan_match,
388 },
389};
390
391module_platform_driver(pwm_fan_driver);
392
393MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>");
394MODULE_ALIAS("platform:pwm-fan");
395MODULE_DESCRIPTION("PWM FAN driver");
396MODULE_LICENSE("GPL");
397