Merge tag 'ovl-fixes-6.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/overla...
[platform/kernel/linux-rpi.git] / drivers / leds / leds-pwm.c
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 #include "leds.h"
21
22 struct led_pwm {
23         const char      *name;
24         u8              active_low;
25         u8              default_state;
26         unsigned int    max_brightness;
27 };
28
29 struct 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
36 struct led_pwm_priv {
37         int num_leds;
38         struct led_pwm_data leds[];
39 };
40
41 static 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))
61 static 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
135 static 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         device_for_each_child_node(dev, fwnode) {
142                 memset(&led, 0, sizeof(led));
143
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
167 err_child_out:
168         fwnode_handle_put(fwnode);
169         return ret;
170 }
171
172 static 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
198 static const struct of_device_id of_pwm_leds_match[] = {
199         { .compatible = "pwm-leds", },
200         {},
201 };
202 MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
203
204 static 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
212 module_platform_driver(led_pwm_driver);
213
214 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
215 MODULE_DESCRIPTION("generic PWM LED driver");
216 MODULE_LICENSE("GPL v2");
217 MODULE_ALIAS("platform:leds-pwm");