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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/init.h>
18#include <linux/platform_device.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
26struct led_pwm_data {
27 struct led_classdev cdev;
28 struct pwm_device *pwm;
29 unsigned int active_low;
30 unsigned int period;
31};
32
33static void led_pwm_set(struct led_classdev *led_cdev,
34 enum led_brightness brightness)
35{
36 struct led_pwm_data *led_dat =
37 container_of(led_cdev, struct led_pwm_data, cdev);
38 unsigned int max = led_dat->cdev.max_brightness;
39 unsigned int period = led_dat->period;
40
41 if (brightness == 0) {
42 pwm_config(led_dat->pwm, 0, period);
43 pwm_disable(led_dat->pwm);
44 } else {
45 pwm_config(led_dat->pwm, brightness * period / max, period);
46 pwm_enable(led_dat->pwm);
47 }
48}
49
50static int led_pwm_probe(struct platform_device *pdev)
51{
52 struct led_pwm_platform_data *pdata = pdev->dev.platform_data;
53 struct led_pwm *cur_led;
54 struct led_pwm_data *leds_data, *led_dat;
55 int i, ret = 0;
56
57 if (!pdata)
58 return -EBUSY;
59
60 leds_data = kzalloc(sizeof(struct led_pwm_data) * pdata->num_leds,
61 GFP_KERNEL);
62 if (!leds_data)
63 return -ENOMEM;
64
65 for (i = 0; i < pdata->num_leds; i++) {
66 cur_led = &pdata->leds[i];
67 led_dat = &leds_data[i];
68
69 led_dat->pwm = pwm_request(cur_led->pwm_id,
70 cur_led->name);
71 if (IS_ERR(led_dat->pwm)) {
72 ret = PTR_ERR(led_dat->pwm);
73 dev_err(&pdev->dev, "unable to request PWM %d\n",
74 cur_led->pwm_id);
75 goto err;
76 }
77
78 led_dat->cdev.name = cur_led->name;
79 led_dat->cdev.default_trigger = cur_led->default_trigger;
80 led_dat->active_low = cur_led->active_low;
81 led_dat->period = cur_led->pwm_period_ns;
82 led_dat->cdev.brightness_set = led_pwm_set;
83 led_dat->cdev.brightness = LED_OFF;
84 led_dat->cdev.max_brightness = cur_led->max_brightness;
85 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
86
87 ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
88 if (ret < 0) {
89 pwm_free(led_dat->pwm);
90 goto err;
91 }
92 }
93
94 platform_set_drvdata(pdev, leds_data);
95
96 return 0;
97
98err:
99 if (i > 0) {
100 for (i = i - 1; i >= 0; i--) {
101 led_classdev_unregister(&leds_data[i].cdev);
102 pwm_free(leds_data[i].pwm);
103 }
104 }
105
106 kfree(leds_data);
107
108 return ret;
109}
110
111static int __devexit led_pwm_remove(struct platform_device *pdev)
112{
113 int i;
114 struct led_pwm_platform_data *pdata = pdev->dev.platform_data;
115 struct led_pwm_data *leds_data;
116
117 leds_data = platform_get_drvdata(pdev);
118
119 for (i = 0; i < pdata->num_leds; i++) {
120 led_classdev_unregister(&leds_data[i].cdev);
121 pwm_free(leds_data[i].pwm);
122 }
123
124 kfree(leds_data);
125
126 return 0;
127}
128
129static struct platform_driver led_pwm_driver = {
130 .probe = led_pwm_probe,
131 .remove = __devexit_p(led_pwm_remove),
132 .driver = {
133 .name = "leds_pwm",
134 .owner = THIS_MODULE,
135 },
136};
137
138module_platform_driver(led_pwm_driver);
139
140MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
141MODULE_DESCRIPTION("PWM LED driver for PXA");
142MODULE_LICENSE("GPL");
143MODULE_ALIAS("platform:leds-pwm");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/drivers/leds-pwm.c
4 *
5 * simple PWM based LED control
6 *
7 * Copyright 2009 Luotao Fu @ Pengutronix (l.fu@pengutronix.de)
8 *
9 * based on leds-gpio.c by Raphael Assenat <raph@8d.com>
10 */
11
12#include <linux/module.h>
13#include <linux/kernel.h>
14#include <linux/platform_device.h>
15#include <linux/of_platform.h>
16#include <linux/leds.h>
17#include <linux/err.h>
18#include <linux/pwm.h>
19#include <linux/leds_pwm.h>
20#include <linux/slab.h>
21
22struct led_pwm_data {
23 struct led_classdev cdev;
24 struct pwm_device *pwm;
25 unsigned int active_low;
26 unsigned int period;
27 int duty;
28};
29
30struct led_pwm_priv {
31 int num_leds;
32 struct led_pwm_data leds[0];
33};
34
35static void __led_pwm_set(struct led_pwm_data *led_dat)
36{
37 int new_duty = led_dat->duty;
38
39 pwm_config(led_dat->pwm, new_duty, led_dat->period);
40
41 if (new_duty == 0)
42 pwm_disable(led_dat->pwm);
43 else
44 pwm_enable(led_dat->pwm);
45}
46
47static int led_pwm_set(struct led_classdev *led_cdev,
48 enum led_brightness brightness)
49{
50 struct led_pwm_data *led_dat =
51 container_of(led_cdev, struct led_pwm_data, cdev);
52 unsigned int max = led_dat->cdev.max_brightness;
53 unsigned long long duty = led_dat->period;
54
55 duty *= brightness;
56 do_div(duty, max);
57
58 if (led_dat->active_low)
59 duty = led_dat->period - duty;
60
61 led_dat->duty = duty;
62
63 __led_pwm_set(led_dat);
64
65 return 0;
66}
67
68static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
69 struct led_pwm *led, struct fwnode_handle *fwnode)
70{
71 struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
72 struct pwm_args pargs;
73 int ret;
74
75 led_data->active_low = led->active_low;
76 led_data->cdev.name = led->name;
77 led_data->cdev.default_trigger = led->default_trigger;
78 led_data->cdev.brightness = LED_OFF;
79 led_data->cdev.max_brightness = led->max_brightness;
80 led_data->cdev.flags = LED_CORE_SUSPENDRESUME;
81
82 if (fwnode)
83 led_data->pwm = devm_fwnode_pwm_get(dev, fwnode, NULL);
84 else
85 led_data->pwm = devm_pwm_get(dev, led->name);
86 if (IS_ERR(led_data->pwm)) {
87 ret = PTR_ERR(led_data->pwm);
88 if (ret != -EPROBE_DEFER)
89 dev_err(dev, "unable to request PWM for %s: %d\n",
90 led->name, ret);
91 return ret;
92 }
93
94 led_data->cdev.brightness_set_blocking = led_pwm_set;
95
96 /*
97 * FIXME: pwm_apply_args() should be removed when switching to the
98 * atomic PWM API.
99 */
100 pwm_apply_args(led_data->pwm);
101
102 pwm_get_args(led_data->pwm, &pargs);
103
104 led_data->period = pargs.period;
105 if (!led_data->period && (led->pwm_period_ns > 0))
106 led_data->period = led->pwm_period_ns;
107
108 ret = devm_led_classdev_register(dev, &led_data->cdev);
109 if (ret == 0) {
110 priv->num_leds++;
111 led_pwm_set(&led_data->cdev, led_data->cdev.brightness);
112 } else {
113 dev_err(dev, "failed to register PWM led for %s: %d\n",
114 led->name, ret);
115 }
116
117 return ret;
118}
119
120static int led_pwm_create_fwnode(struct device *dev, struct led_pwm_priv *priv)
121{
122 struct fwnode_handle *fwnode;
123 struct led_pwm led;
124 int ret = 0;
125
126 memset(&led, 0, sizeof(led));
127
128 device_for_each_child_node(dev, fwnode) {
129 ret = fwnode_property_read_string(fwnode, "label", &led.name);
130 if (ret && is_of_node(fwnode))
131 led.name = to_of_node(fwnode)->name;
132
133 if (!led.name) {
134 fwnode_handle_put(fwnode);
135 return -EINVAL;
136 }
137
138 fwnode_property_read_string(fwnode, "linux,default-trigger",
139 &led.default_trigger);
140
141 led.active_low = fwnode_property_read_bool(fwnode,
142 "active-low");
143 fwnode_property_read_u32(fwnode, "max-brightness",
144 &led.max_brightness);
145
146 ret = led_pwm_add(dev, priv, &led, fwnode);
147 if (ret) {
148 fwnode_handle_put(fwnode);
149 break;
150 }
151 }
152
153 return ret;
154}
155
156static int led_pwm_probe(struct platform_device *pdev)
157{
158 struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
159 struct led_pwm_priv *priv;
160 int count, i;
161 int ret = 0;
162
163 if (pdata)
164 count = pdata->num_leds;
165 else
166 count = device_get_child_node_count(&pdev->dev);
167
168 if (!count)
169 return -EINVAL;
170
171 priv = devm_kzalloc(&pdev->dev, struct_size(priv, leds, count),
172 GFP_KERNEL);
173 if (!priv)
174 return -ENOMEM;
175
176 if (pdata) {
177 for (i = 0; i < count; i++) {
178 ret = led_pwm_add(&pdev->dev, priv, &pdata->leds[i],
179 NULL);
180 if (ret)
181 break;
182 }
183 } else {
184 ret = led_pwm_create_fwnode(&pdev->dev, priv);
185 }
186
187 if (ret)
188 return ret;
189
190 platform_set_drvdata(pdev, priv);
191
192 return 0;
193}
194
195static const struct of_device_id of_pwm_leds_match[] = {
196 { .compatible = "pwm-leds", },
197 {},
198};
199MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
200
201static struct platform_driver led_pwm_driver = {
202 .probe = led_pwm_probe,
203 .driver = {
204 .name = "leds_pwm",
205 .of_match_table = of_pwm_leds_match,
206 },
207};
208
209module_platform_driver(led_pwm_driver);
210
211MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
212MODULE_DESCRIPTION("generic PWM LED driver");
213MODULE_LICENSE("GPL v2");
214MODULE_ALIAS("platform:leds-pwm");