]> git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - drivers/leds/leds-pwm.c
Merge branch 'linus' into perf/core, to refresh the branch
[mirror_ubuntu-artful-kernel.git] / drivers / leds / leds-pwm.c
1 /*
2 * linux/drivers/leds-pwm.c
3 *
4 * simple PWM based LED control
5 *
6 * Copyright 2009 Luotao Fu @ Pengutronix (l.fu@pengutronix.de)
7 *
8 * based on leds-gpio.c by Raphael Assenat <raph@8d.com>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 */
14
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/platform_device.h>
18 #include <linux/of_platform.h>
19 #include <linux/fb.h>
20 #include <linux/leds.h>
21 #include <linux/err.h>
22 #include <linux/pwm.h>
23 #include <linux/leds_pwm.h>
24 #include <linux/slab.h>
25
26 struct led_pwm_data {
27 struct led_classdev cdev;
28 struct pwm_device *pwm;
29 unsigned int active_low;
30 unsigned int period;
31 int duty;
32 bool can_sleep;
33 };
34
35 struct led_pwm_priv {
36 int num_leds;
37 struct led_pwm_data leds[0];
38 };
39
40 static void __led_pwm_set(struct led_pwm_data *led_dat)
41 {
42 int new_duty = led_dat->duty;
43
44 pwm_config(led_dat->pwm, new_duty, led_dat->period);
45
46 if (new_duty == 0)
47 pwm_disable(led_dat->pwm);
48 else
49 pwm_enable(led_dat->pwm);
50 }
51
52 static void led_pwm_set(struct led_classdev *led_cdev,
53 enum led_brightness brightness)
54 {
55 struct led_pwm_data *led_dat =
56 container_of(led_cdev, struct led_pwm_data, cdev);
57 unsigned int max = led_dat->cdev.max_brightness;
58 unsigned long long duty = led_dat->period;
59
60 duty *= brightness;
61 do_div(duty, max);
62
63 if (led_dat->active_low)
64 duty = led_dat->period - duty;
65
66 led_dat->duty = duty;
67
68 __led_pwm_set(led_dat);
69 }
70
71 static int led_pwm_set_blocking(struct led_classdev *led_cdev,
72 enum led_brightness brightness)
73 {
74 led_pwm_set(led_cdev, brightness);
75 return 0;
76 }
77
78 static inline size_t sizeof_pwm_leds_priv(int num_leds)
79 {
80 return sizeof(struct led_pwm_priv) +
81 (sizeof(struct led_pwm_data) * num_leds);
82 }
83
84 static void led_pwm_cleanup(struct led_pwm_priv *priv)
85 {
86 while (priv->num_leds--)
87 led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
88 }
89
90 static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
91 struct led_pwm *led, struct device_node *child)
92 {
93 struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
94 struct pwm_args pargs;
95 int ret;
96
97 led_data->active_low = led->active_low;
98 led_data->cdev.name = led->name;
99 led_data->cdev.default_trigger = led->default_trigger;
100 led_data->cdev.brightness = LED_OFF;
101 led_data->cdev.max_brightness = led->max_brightness;
102 led_data->cdev.flags = LED_CORE_SUSPENDRESUME;
103
104 if (child)
105 led_data->pwm = devm_of_pwm_get(dev, child, NULL);
106 else
107 led_data->pwm = devm_pwm_get(dev, led->name);
108 if (IS_ERR(led_data->pwm)) {
109 ret = PTR_ERR(led_data->pwm);
110 dev_err(dev, "unable to request PWM for %s: %d\n",
111 led->name, ret);
112 return ret;
113 }
114
115 led_data->can_sleep = pwm_can_sleep(led_data->pwm);
116 if (!led_data->can_sleep)
117 led_data->cdev.brightness_set = led_pwm_set;
118 else
119 led_data->cdev.brightness_set_blocking = led_pwm_set_blocking;
120
121 /*
122 * FIXME: pwm_apply_args() should be removed when switching to the
123 * atomic PWM API.
124 */
125 pwm_apply_args(led_data->pwm);
126
127 pwm_get_args(led_data->pwm, &pargs);
128
129 led_data->period = pargs.period;
130 if (!led_data->period && (led->pwm_period_ns > 0))
131 led_data->period = led->pwm_period_ns;
132
133 ret = led_classdev_register(dev, &led_data->cdev);
134 if (ret == 0) {
135 priv->num_leds++;
136 led_pwm_set(&led_data->cdev, led_data->cdev.brightness);
137 } else {
138 dev_err(dev, "failed to register PWM led for %s: %d\n",
139 led->name, ret);
140 }
141
142 return ret;
143 }
144
145 static int led_pwm_create_of(struct device *dev, struct led_pwm_priv *priv)
146 {
147 struct device_node *child;
148 struct led_pwm led;
149 int ret = 0;
150
151 memset(&led, 0, sizeof(led));
152
153 for_each_child_of_node(dev->of_node, child) {
154 led.name = of_get_property(child, "label", NULL) ? :
155 child->name;
156
157 led.default_trigger = of_get_property(child,
158 "linux,default-trigger", NULL);
159 led.active_low = of_property_read_bool(child, "active-low");
160 of_property_read_u32(child, "max-brightness",
161 &led.max_brightness);
162
163 ret = led_pwm_add(dev, priv, &led, child);
164 if (ret) {
165 of_node_put(child);
166 break;
167 }
168 }
169
170 return ret;
171 }
172
173 static int led_pwm_probe(struct platform_device *pdev)
174 {
175 struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
176 struct led_pwm_priv *priv;
177 int count, i;
178 int ret = 0;
179
180 if (pdata)
181 count = pdata->num_leds;
182 else
183 count = of_get_child_count(pdev->dev.of_node);
184
185 if (!count)
186 return -EINVAL;
187
188 priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
189 GFP_KERNEL);
190 if (!priv)
191 return -ENOMEM;
192
193 if (pdata) {
194 for (i = 0; i < count; i++) {
195 ret = led_pwm_add(&pdev->dev, priv, &pdata->leds[i],
196 NULL);
197 if (ret)
198 break;
199 }
200 } else {
201 ret = led_pwm_create_of(&pdev->dev, priv);
202 }
203
204 if (ret) {
205 led_pwm_cleanup(priv);
206 return ret;
207 }
208
209 platform_set_drvdata(pdev, priv);
210
211 return 0;
212 }
213
214 static int led_pwm_remove(struct platform_device *pdev)
215 {
216 struct led_pwm_priv *priv = platform_get_drvdata(pdev);
217
218 led_pwm_cleanup(priv);
219
220 return 0;
221 }
222
223 static const struct of_device_id of_pwm_leds_match[] = {
224 { .compatible = "pwm-leds", },
225 {},
226 };
227 MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
228
229 static struct platform_driver led_pwm_driver = {
230 .probe = led_pwm_probe,
231 .remove = led_pwm_remove,
232 .driver = {
233 .name = "leds_pwm",
234 .of_match_table = of_pwm_leds_match,
235 },
236 };
237
238 module_platform_driver(led_pwm_driver);
239
240 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
241 MODULE_DESCRIPTION("generic PWM LED driver");
242 MODULE_LICENSE("GPL v2");
243 MODULE_ALIAS("platform:leds-pwm");