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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.h>
16#include <linux/leds.h>
17#include <linux/err.h>
18#include <linux/pwm.h>
19#include <linux/slab.h>
20
21struct led_pwm {
22 const char *name;
23 u8 active_low;
24 u8 default_state;
25 unsigned int max_brightness;
26};
27
28struct led_pwm_data {
29 struct led_classdev cdev;
30 struct pwm_device *pwm;
31 struct pwm_state pwmstate;
32 unsigned int active_low;
33};
34
35struct led_pwm_priv {
36 int num_leds;
37 struct led_pwm_data leds[];
38};
39
40static int led_pwm_set(struct led_classdev *led_cdev,
41 enum led_brightness brightness)
42{
43 struct led_pwm_data *led_dat =
44 container_of(led_cdev, struct led_pwm_data, cdev);
45 unsigned int max = led_dat->cdev.max_brightness;
46 unsigned long long duty = led_dat->pwmstate.period;
47
48 duty *= brightness;
49 do_div(duty, max);
50
51 if (led_dat->active_low)
52 duty = led_dat->pwmstate.period - duty;
53
54 led_dat->pwmstate.duty_cycle = duty;
55 /*
56 * Disabling a PWM doesn't guarantee that it emits the inactive level.
57 * So keep it on. Only for suspending the PWM should be disabled because
58 * otherwise it refuses to suspend. The possible downside is that the
59 * LED might stay (or even go) on.
60 */
61 led_dat->pwmstate.enabled = !(led_cdev->flags & LED_SUSPENDED);
62 return pwm_apply_might_sleep(led_dat->pwm, &led_dat->pwmstate);
63}
64
65static int led_pwm_default_brightness_get(struct fwnode_handle *fwnode,
66 int max_brightness)
67{
68 unsigned int default_brightness;
69 int ret;
70
71 ret = fwnode_property_read_u32(fwnode, "default-brightness",
72 &default_brightness);
73 if (ret < 0 || default_brightness > max_brightness)
74 default_brightness = max_brightness;
75
76 return default_brightness;
77}
78
79__attribute__((nonnull))
80static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
81 struct led_pwm *led, struct fwnode_handle *fwnode)
82{
83 struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
84 struct led_init_data init_data = { .fwnode = fwnode };
85 int ret;
86
87 led_data->active_low = led->active_low;
88 led_data->cdev.name = led->name;
89 led_data->cdev.brightness = LED_OFF;
90 led_data->cdev.max_brightness = led->max_brightness;
91 led_data->cdev.flags = LED_CORE_SUSPENDRESUME;
92
93 led_data->pwm = devm_fwnode_pwm_get(dev, fwnode, NULL);
94 if (IS_ERR(led_data->pwm))
95 return dev_err_probe(dev, PTR_ERR(led_data->pwm),
96 "unable to request PWM for %s\n",
97 led->name);
98
99 led_data->cdev.brightness_set_blocking = led_pwm_set;
100
101 /* init PWM state */
102 switch (led->default_state) {
103 case LEDS_DEFSTATE_KEEP:
104 pwm_get_state(led_data->pwm, &led_data->pwmstate);
105 if (led_data->pwmstate.period)
106 break;
107 led->default_state = LEDS_DEFSTATE_OFF;
108 dev_warn(dev,
109 "failed to read period for %s, default to off",
110 led->name);
111 fallthrough;
112 default:
113 pwm_init_state(led_data->pwm, &led_data->pwmstate);
114 break;
115 }
116
117 /* set brightness */
118 switch (led->default_state) {
119 case LEDS_DEFSTATE_ON:
120 led_data->cdev.brightness =
121 led_pwm_default_brightness_get(fwnode, led->max_brightness);
122 break;
123 case LEDS_DEFSTATE_KEEP:
124 {
125 uint64_t brightness;
126
127 brightness = led->max_brightness;
128 brightness *= led_data->pwmstate.duty_cycle;
129 do_div(brightness, led_data->pwmstate.period);
130 led_data->cdev.brightness = brightness;
131 }
132 break;
133 }
134
135 ret = devm_led_classdev_register_ext(dev, &led_data->cdev, &init_data);
136 if (ret) {
137 dev_err(dev, "failed to register PWM led for %s: %d\n",
138 led->name, ret);
139 return ret;
140 }
141
142 if (led->default_state != LEDS_DEFSTATE_KEEP) {
143 ret = led_pwm_set(&led_data->cdev, led_data->cdev.brightness);
144 if (ret) {
145 dev_err(dev, "failed to set led PWM value for %s: %d",
146 led->name, ret);
147 return ret;
148 }
149 }
150
151 priv->num_leds++;
152 return 0;
153}
154
155static int led_pwm_create_fwnode(struct device *dev, struct led_pwm_priv *priv)
156{
157 struct led_pwm led;
158 int ret;
159
160 device_for_each_child_node_scoped(dev, fwnode) {
161 memset(&led, 0, sizeof(led));
162
163 ret = fwnode_property_read_string(fwnode, "label", &led.name);
164 if (ret && is_of_node(fwnode))
165 led.name = to_of_node(fwnode)->name;
166
167 if (!led.name)
168 return -EINVAL;
169
170 led.active_low = fwnode_property_read_bool(fwnode,
171 "active-low");
172 fwnode_property_read_u32(fwnode, "max-brightness",
173 &led.max_brightness);
174
175 led.default_state = led_init_default_state_get(fwnode);
176
177 ret = led_pwm_add(dev, priv, &led, fwnode);
178 if (ret)
179 return ret;
180 }
181
182 return 0;
183}
184
185static int led_pwm_probe(struct platform_device *pdev)
186{
187 struct led_pwm_priv *priv;
188 int ret = 0;
189 int count;
190
191 count = device_get_child_node_count(&pdev->dev);
192
193 if (!count)
194 return -EINVAL;
195
196 priv = devm_kzalloc(&pdev->dev, struct_size(priv, leds, count),
197 GFP_KERNEL);
198 if (!priv)
199 return -ENOMEM;
200
201 ret = led_pwm_create_fwnode(&pdev->dev, priv);
202
203 if (ret)
204 return ret;
205
206 platform_set_drvdata(pdev, priv);
207
208 return 0;
209}
210
211static const struct of_device_id of_pwm_leds_match[] = {
212 { .compatible = "pwm-leds", },
213 {},
214};
215MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
216
217static struct platform_driver led_pwm_driver = {
218 .probe = led_pwm_probe,
219 .driver = {
220 .name = "leds_pwm",
221 .of_match_table = of_pwm_leds_match,
222 },
223};
224
225module_platform_driver(led_pwm_driver);
226
227MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
228MODULE_DESCRIPTION("generic PWM LED driver");
229MODULE_LICENSE("GPL v2");
230MODULE_ALIAS("platform:leds-pwm");