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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>
27#include <linux/thermal.h>
28
29#define MAX_PWM 255
30
31struct pwm_fan_ctx {
32 struct mutex lock;
33 struct pwm_device *pwm;
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;
38 struct thermal_cooling_device *cdev;
39};
40
41static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
42{
43 unsigned long period;
44 int ret = 0;
45 struct pwm_state state = { };
46
47 mutex_lock(&ctx->lock);
48 if (ctx->pwm_value == pwm)
49 goto exit_set_pwm_err;
50
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;
55
56 ret = pwm_apply_state(ctx->pwm, &state);
57 if (!ret)
58 ctx->pwm_value = pwm;
59exit_set_pwm_err:
60 mutex_unlock(&ctx->lock);
61 return ret;
62}
63
64static 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
75static 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
89 pwm_fan_update_state(ctx, pwm);
90 return count;
91}
92
93static 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
102static SENSOR_DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm, 0);
103
104static struct attribute *pwm_fan_attrs[] = {
105 &sensor_dev_attr_pwm1.dev_attr.attr,
106 NULL,
107};
108
109ATTRIBUTE_GROUPS(pwm_fan);
110
111
112static 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
125static 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
138static int
139pwm_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
161static 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
167static int pwm_fan_of_get_cooling_data(struct device *dev,
168 struct pwm_fan_ctx *ctx)
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;
183 ctx->pwm_fan_cooling_levels = devm_kzalloc(dev, num * sizeof(u32),
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
208static int pwm_fan_probe(struct platform_device *pdev)
209{
210 struct thermal_cooling_device *cdev;
211 struct pwm_fan_ctx *ctx;
212 struct device *hwmon;
213 int ret;
214 struct pwm_state state = { };
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
228 platform_set_drvdata(pdev, ctx);
229
230 ctx->pwm_value = MAX_PWM;
231
232
233 pwm_init_state(ctx->pwm, &state);
234 state.duty_cycle = ctx->pwm->args.period - 1;
235 state.enabled = true;
236
237 ret = pwm_apply_state(ctx->pwm, &state);
238 if (ret) {
239 dev_err(&pdev->dev, "Failed to configure PWM\n");
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");
247 ret = PTR_ERR(hwmon);
248 goto err_pwm_disable;
249 }
250
251 ret = pwm_fan_of_get_cooling_data(&pdev->dev, ctx);
252 if (ret)
253 return ret;
254
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");
263 ret = PTR_ERR(cdev);
264 goto err_pwm_disable;
265 }
266 ctx->cdev = cdev;
267 thermal_cdev_update(cdev);
268 }
269
270 return 0;
271
272err_pwm_disable:
273 state.enabled = false;
274 pwm_apply_state(ctx->pwm, &state);
275
276 return ret;
277}
278
279static int pwm_fan_remove(struct platform_device *pdev)
280{
281 struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev);
282
283 thermal_cooling_device_unregister(ctx->cdev);
284 if (ctx->pwm_value)
285 pwm_disable(ctx->pwm);
286 return 0;
287}
288
289#ifdef CONFIG_PM_SLEEP
290static 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
299static int pwm_fan_resume(struct device *dev)
300{
301 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
302 struct pwm_args pargs;
303 unsigned long duty;
304 int ret;
305
306 if (ctx->pwm_value == 0)
307 return 0;
308
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);
312 if (ret)
313 return ret;
314 return pwm_enable(ctx->pwm);
315}
316#endif
317
318static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume);
319
320static const struct of_device_id of_pwm_fan_match[] = {
321 { .compatible = "pwm-fan", },
322 {},
323};
324MODULE_DEVICE_TABLE(of, of_pwm_fan_match);
325
326static 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
336module_platform_driver(pwm_fan_driver);
337
338MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>");
339MODULE_ALIAS("platform:pwm-fan");
340MODULE_DESCRIPTION("PWM FAN driver");
341MODULE_LICENSE("GPL");
342
