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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/slab.h>
20#include "leds.h"
21
22struct led_pwm {
23 const char *name;
24 u8 active_low;
25 u8 default_state;
26 unsigned int max_brightness;
27};
28
29struct led_pwm_data {
30 struct led_classdev cdev;
31 struct pwm_device *pwm;
32 struct pwm_state pwmstate;
33 unsigned int active_low;
34};
35
36struct led_pwm_priv {
37 int num_leds;
38 struct led_pwm_data leds[];
39};
40
41static int led_pwm_set(struct led_classdev *led_cdev,
42 enum led_brightness brightness)
43{
44 struct led_pwm_data *led_dat =
45 container_of(led_cdev, struct led_pwm_data, cdev);
46 unsigned int max = led_dat->cdev.max_brightness;
47 unsigned long long duty = led_dat->pwmstate.period;
48
49 duty *= brightness;
50 do_div(duty, max);
51
52 if (led_dat->active_low)
53 duty = led_dat->pwmstate.period - duty;
54
55 led_dat->pwmstate.duty_cycle = duty;
56 led_dat->pwmstate.enabled = duty > 0;
57 return pwm_apply_state(led_dat->pwm, &led_dat->pwmstate);
58}
59
60__attribute__((nonnull))
61static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
62 struct led_pwm *led, struct fwnode_handle *fwnode)
63{
64 struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
65 struct led_init_data init_data = { .fwnode = fwnode };
66 int ret;
67
68 led_data->active_low = led->active_low;
69 led_data->cdev.name = led->name;
70 led_data->cdev.brightness = LED_OFF;
71 led_data->cdev.max_brightness = led->max_brightness;
72 led_data->cdev.flags = LED_CORE_SUSPENDRESUME;
73
74 led_data->pwm = devm_fwnode_pwm_get(dev, fwnode, NULL);
75 if (IS_ERR(led_data->pwm))
76 return dev_err_probe(dev, PTR_ERR(led_data->pwm),
77 "unable to request PWM for %s\n",
78 led->name);
79
80 led_data->cdev.brightness_set_blocking = led_pwm_set;
81
82 /* init PWM state */
83 switch (led->default_state) {
84 case LEDS_DEFSTATE_KEEP:
85 pwm_get_state(led_data->pwm, &led_data->pwmstate);
86 if (led_data->pwmstate.period)
87 break;
88 led->default_state = LEDS_DEFSTATE_OFF;
89 dev_warn(dev,
90 "failed to read period for %s, default to off",
91 led->name);
92 fallthrough;
93 default:
94 pwm_init_state(led_data->pwm, &led_data->pwmstate);
95 break;
96 }
97
98 /* set brightness */
99 switch (led->default_state) {
100 case LEDS_DEFSTATE_ON:
101 led_data->cdev.brightness = led->max_brightness;
102 break;
103 case LEDS_DEFSTATE_KEEP:
104 {
105 uint64_t brightness;
106
107 brightness = led->max_brightness;
108 brightness *= led_data->pwmstate.duty_cycle;
109 do_div(brightness, led_data->pwmstate.period);
110 led_data->cdev.brightness = brightness;
111 }
112 break;
113 }
114
115 ret = devm_led_classdev_register_ext(dev, &led_data->cdev, &init_data);
116 if (ret) {
117 dev_err(dev, "failed to register PWM led for %s: %d\n",
118 led->name, ret);
119 return ret;
120 }
121
122 if (led->default_state != LEDS_DEFSTATE_KEEP) {
123 ret = led_pwm_set(&led_data->cdev, led_data->cdev.brightness);
124 if (ret) {
125 dev_err(dev, "failed to set led PWM value for %s: %d",
126 led->name, ret);
127 return ret;
128 }
129 }
130
131 priv->num_leds++;
132 return 0;
133}
134
135static int led_pwm_create_fwnode(struct device *dev, struct led_pwm_priv *priv)
136{
137 struct fwnode_handle *fwnode;
138 struct led_pwm led;
139 int ret;
140
141 memset(&led, 0, sizeof(led));
142
143 device_for_each_child_node(dev, fwnode) {
144 ret = fwnode_property_read_string(fwnode, "label", &led.name);
145 if (ret && is_of_node(fwnode))
146 led.name = to_of_node(fwnode)->name;
147
148 if (!led.name) {
149 ret = EINVAL;
150 goto err_child_out;
151 }
152
153 led.active_low = fwnode_property_read_bool(fwnode,
154 "active-low");
155 fwnode_property_read_u32(fwnode, "max-brightness",
156 &led.max_brightness);
157
158 led.default_state = led_init_default_state_get(fwnode);
159
160 ret = led_pwm_add(dev, priv, &led, fwnode);
161 if (ret)
162 goto err_child_out;
163 }
164
165 return 0;
166
167err_child_out:
168 fwnode_handle_put(fwnode);
169 return ret;
170}
171
172static int led_pwm_probe(struct platform_device *pdev)
173{
174 struct led_pwm_priv *priv;
175 int ret = 0;
176 int count;
177
178 count = device_get_child_node_count(&pdev->dev);
179
180 if (!count)
181 return -EINVAL;
182
183 priv = devm_kzalloc(&pdev->dev, struct_size(priv, leds, count),
184 GFP_KERNEL);
185 if (!priv)
186 return -ENOMEM;
187
188 ret = led_pwm_create_fwnode(&pdev->dev, priv);
189
190 if (ret)
191 return ret;
192
193 platform_set_drvdata(pdev, priv);
194
195 return 0;
196}
197
198static const struct of_device_id of_pwm_leds_match[] = {
199 { .compatible = "pwm-leds", },
200 {},
201};
202MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
203
204static struct platform_driver led_pwm_driver = {
205 .probe = led_pwm_probe,
206 .driver = {
207 .name = "leds_pwm",
208 .of_match_table = of_pwm_leds_match,
209 },
210};
211
212module_platform_driver(led_pwm_driver);
213
214MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
215MODULE_DESCRIPTION("generic PWM LED driver");
216MODULE_LICENSE("GPL v2");
217MODULE_ALIAS("platform:leds-pwm");
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
26struct 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
35struct led_pwm_priv {
36 int num_leds;
37 struct led_pwm_data leds[0];
38};
39
40static 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
52static 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
71static 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
78static 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
84static 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
90static 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 int ret;
95
96 led_data->active_low = led->active_low;
97 led_data->cdev.name = led->name;
98 led_data->cdev.default_trigger = led->default_trigger;
99 led_data->cdev.brightness = LED_OFF;
100 led_data->cdev.max_brightness = led->max_brightness;
101 led_data->cdev.flags = LED_CORE_SUSPENDRESUME;
102
103 if (child)
104 led_data->pwm = devm_of_pwm_get(dev, child, NULL);
105 else
106 led_data->pwm = devm_pwm_get(dev, led->name);
107 if (IS_ERR(led_data->pwm)) {
108 ret = PTR_ERR(led_data->pwm);
109 dev_err(dev, "unable to request PWM for %s: %d\n",
110 led->name, ret);
111 return ret;
112 }
113
114 led_data->can_sleep = pwm_can_sleep(led_data->pwm);
115 if (!led_data->can_sleep)
116 led_data->cdev.brightness_set = led_pwm_set;
117 else
118 led_data->cdev.brightness_set_blocking = led_pwm_set_blocking;
119
120 led_data->period = pwm_get_period(led_data->pwm);
121 if (!led_data->period && (led->pwm_period_ns > 0))
122 led_data->period = led->pwm_period_ns;
123
124 ret = led_classdev_register(dev, &led_data->cdev);
125 if (ret == 0) {
126 priv->num_leds++;
127 led_pwm_set(&led_data->cdev, led_data->cdev.brightness);
128 } else {
129 dev_err(dev, "failed to register PWM led for %s: %d\n",
130 led->name, ret);
131 }
132
133 return ret;
134}
135
136static int led_pwm_create_of(struct device *dev, struct led_pwm_priv *priv)
137{
138 struct device_node *child;
139 struct led_pwm led;
140 int ret = 0;
141
142 memset(&led, 0, sizeof(led));
143
144 for_each_child_of_node(dev->of_node, child) {
145 led.name = of_get_property(child, "label", NULL) ? :
146 child->name;
147
148 led.default_trigger = of_get_property(child,
149 "linux,default-trigger", NULL);
150 led.active_low = of_property_read_bool(child, "active-low");
151 of_property_read_u32(child, "max-brightness",
152 &led.max_brightness);
153
154 ret = led_pwm_add(dev, priv, &led, child);
155 if (ret) {
156 of_node_put(child);
157 break;
158 }
159 }
160
161 return ret;
162}
163
164static int led_pwm_probe(struct platform_device *pdev)
165{
166 struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
167 struct led_pwm_priv *priv;
168 int count, i;
169 int ret = 0;
170
171 if (pdata)
172 count = pdata->num_leds;
173 else
174 count = of_get_child_count(pdev->dev.of_node);
175
176 if (!count)
177 return -EINVAL;
178
179 priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
180 GFP_KERNEL);
181 if (!priv)
182 return -ENOMEM;
183
184 if (pdata) {
185 for (i = 0; i < count; i++) {
186 ret = led_pwm_add(&pdev->dev, priv, &pdata->leds[i],
187 NULL);
188 if (ret)
189 break;
190 }
191 } else {
192 ret = led_pwm_create_of(&pdev->dev, priv);
193 }
194
195 if (ret) {
196 led_pwm_cleanup(priv);
197 return ret;
198 }
199
200 platform_set_drvdata(pdev, priv);
201
202 return 0;
203}
204
205static int led_pwm_remove(struct platform_device *pdev)
206{
207 struct led_pwm_priv *priv = platform_get_drvdata(pdev);
208
209 led_pwm_cleanup(priv);
210
211 return 0;
212}
213
214static const struct of_device_id of_pwm_leds_match[] = {
215 { .compatible = "pwm-leds", },
216 {},
217};
218MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
219
220static struct platform_driver led_pwm_driver = {
221 .probe = led_pwm_probe,
222 .remove = led_pwm_remove,
223 .driver = {
224 .name = "leds_pwm",
225 .of_match_table = of_pwm_leds_match,
226 },
227};
228
229module_platform_driver(led_pwm_driver);
230
231MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
232MODULE_DESCRIPTION("generic PWM LED driver");
233MODULE_LICENSE("GPL v2");
234MODULE_ALIAS("platform:leds-pwm");