blob: 3e23003f78b01ca731e8c232f38e1132eccf251f [file] [log] [blame]
Kamil Debskid82d5772014-07-16 17:46:42 +02001/*
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>
Lukasz Majewskib6bddec2015-02-26 14:59:37 +010027#include <linux/thermal.h>
Kamil Debskid82d5772014-07-16 17:46:42 +020028
29#define MAX_PWM 255
30
31struct pwm_fan_ctx {
32 struct mutex lock;
33 struct pwm_device *pwm;
Lukasz Majewski2e5219c2015-02-26 14:59:36 +010034 unsigned int pwm_value;
35 unsigned int pwm_fan_state;
36 unsigned int pwm_fan_max_state;
37 unsigned int *pwm_fan_cooling_levels;
Lukasz Majewskib6bddec2015-02-26 14:59:37 +010038 struct thermal_cooling_device *cdev;
Kamil Debskid82d5772014-07-16 17:46:42 +020039};
40
Lukasz Majewskicb85ca32015-02-26 14:59:35 +010041static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
Kamil Debskid82d5772014-07-16 17:46:42 +020042{
Lukasz Majewskicb85ca32015-02-26 14:59:35 +010043 unsigned long duty;
44 int ret = 0;
Kamil Debskid82d5772014-07-16 17:46:42 +020045
46 mutex_lock(&ctx->lock);
Kamil Debskid82d5772014-07-16 17:46:42 +020047 if (ctx->pwm_value == pwm)
Lukasz Majewskicb85ca32015-02-26 14:59:35 +010048 goto exit_set_pwm_err;
Kamil Debskid82d5772014-07-16 17:46:42 +020049
Kamil Debskid82d5772014-07-16 17:46:42 +020050 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
Anand Moonf3541692015-04-13 04:14:11 +093055 if (pwm == 0)
56 pwm_disable(ctx->pwm);
57
Kamil Debskid82d5772014-07-16 17:46:42 +020058 if (ctx->pwm_value == 0) {
59 ret = pwm_enable(ctx->pwm);
60 if (ret)
61 goto exit_set_pwm_err;
62 }
63
Kamil Debskid82d5772014-07-16 17:46:42 +020064 ctx->pwm_value = pwm;
Kamil Debskid82d5772014-07-16 17:46:42 +020065exit_set_pwm_err:
66 mutex_unlock(&ctx->lock);
67 return ret;
68}
69
Lukasz Majewskib6bddec2015-02-26 14:59:37 +010070static 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
Lukasz Majewskicb85ca32015-02-26 14:59:35 +010081static 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
Lukasz Majewskib6bddec2015-02-26 14:59:37 +010095 pwm_fan_update_state(ctx, pwm);
Lukasz Majewskicb85ca32015-02-26 14:59:35 +010096 return count;
97}
98
Kamil Debskid82d5772014-07-16 17:46:42 +020099static 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
108static SENSOR_DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm, 0);
109
110static struct attribute *pwm_fan_attrs[] = {
111 &sensor_dev_attr_pwm1.dev_attr.attr,
112 NULL,
113};
114
115ATTRIBUTE_GROUPS(pwm_fan);
116
Lukasz Majewskib6bddec2015-02-26 14:59:37 +0100117/* thermal cooling device callbacks */
118static 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
131static 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
144static int
145pwm_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
167static 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
Guenter Roeckde52b042015-03-04 09:51:05 -0800173static int pwm_fan_of_get_cooling_data(struct device *dev,
174 struct pwm_fan_ctx *ctx)
Lukasz Majewski2e5219c2015-02-26 14:59:36 +0100175{
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
Kamil Debskid82d5772014-07-16 17:46:42 +0200214static int pwm_fan_probe(struct platform_device *pdev)
215{
Lukasz Majewskib6bddec2015-02-26 14:59:37 +0100216 struct thermal_cooling_device *cdev;
Kamil Debskid82d5772014-07-16 17:46:42 +0200217 struct pwm_fan_ctx *ctx;
Lukasz Majewskib6bddec2015-02-26 14:59:37 +0100218 struct device *hwmon;
Kamil Debskid82d5772014-07-16 17:46:42 +0200219 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
Kamil Debskid82d5772014-07-16 17:46:42 +0200234 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 }
Lukasz Majewski2e5219c2015-02-26 14:59:36 +0100260
261 ret = pwm_fan_of_get_cooling_data(&pdev->dev, ctx);
262 if (ret)
263 return ret;
264
Lukasz Majewskib6bddec2015-02-26 14:59:37 +0100265 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
Kamil Debskid82d5772014-07-16 17:46:42 +0200280 return 0;
281}
282
283static int pwm_fan_remove(struct platform_device *pdev)
284{
285 struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev);
286
Lukasz Majewskib6bddec2015-02-26 14:59:37 +0100287 thermal_cooling_device_unregister(ctx->cdev);
Kamil Debskid82d5772014-07-16 17:46:42 +0200288 if (ctx->pwm_value)
289 pwm_disable(ctx->pwm);
290 return 0;
291}
292
293#ifdef CONFIG_PM_SLEEP
294static 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
303static int pwm_fan_resume(struct device *dev)
304{
305 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
Kamil Debski48b9d5b2014-11-03 15:42:55 +0100306 unsigned long duty;
307 int ret;
Kamil Debskid82d5772014-07-16 17:46:42 +0200308
Kamil Debski48b9d5b2014-11-03 15:42:55 +0100309 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);
Kamil Debskid82d5772014-07-16 17:46:42 +0200317}
318#endif
319
320static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume);
321
Fabian Frederickd720aca2015-03-16 20:54:36 +0100322static const struct of_device_id of_pwm_fan_match[] = {
Kamil Debskid82d5772014-07-16 17:46:42 +0200323 { .compatible = "pwm-fan", },
324 {},
325};
Luis de Bethencourtf491e702015-09-17 18:09:55 +0200326MODULE_DEVICE_TABLE(of, of_pwm_fan_match);
Kamil Debskid82d5772014-07-16 17:46:42 +0200327
328static 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
338module_platform_driver(pwm_fan_driver);
339
340MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>");
341MODULE_ALIAS("platform:pwm-fan");
342MODULE_DESCRIPTION("PWM FAN driver");
343MODULE_LICENSE("GPL");