1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * leds-regulator.c - LED class driver for regulator driven LEDs.
4 *
5 * Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it>
6 *
7 * Inspired by leds-wm8350 driver.
8 */
9
10#include <linux/module.h>
11#include <linux/mod_devicetable.h>
12#include <linux/err.h>
13#include <linux/slab.h>
14#include <linux/leds.h>
15#include <linux/leds-regulator.h>
16#include <linux/platform_device.h>
17#include <linux/regulator/consumer.h>
18
19#define to_regulator_led(led_cdev) \
20 container_of(led_cdev, struct regulator_led, cdev)
21
22struct regulator_led {
23 struct led_classdev cdev;
24 int enabled;
25 struct mutex mutex;
26
27 struct regulator *vcc;
28};
29
30static inline int led_regulator_get_max_brightness(struct regulator *supply)
31{
32 int ret;
33 int voltage = regulator_list_voltage(regulator: supply, selector: 0);
34
35 if (voltage <= 0)
36 return 1;
37
38 /* even if regulator can't change voltages,
39 * we still assume it can change status
40 * and the LED can be turned on and off.
41 */
42 ret = regulator_set_voltage(regulator: supply, min_uV: voltage, max_uV: voltage);
43 if (ret < 0)
44 return 1;
45
46 return regulator_count_voltages(regulator: supply);
47}
48
49static int led_regulator_get_voltage(struct regulator *supply,
50 enum led_brightness brightness)
51{
52 if (brightness == 0)
53 return -EINVAL;
54
55 return regulator_list_voltage(regulator: supply, selector: brightness - 1);
56}
57
58
59static void regulator_led_enable(struct regulator_led *led)
60{
61 int ret;
62
63 if (led->enabled)
64 return;
65
66 ret = regulator_enable(regulator: led->vcc);
67 if (ret != 0) {
68 dev_err(led->cdev.dev, "Failed to enable vcc: %d\n", ret);
69 return;
70 }
71
72 led->enabled = 1;
73}
74
75static void regulator_led_disable(struct regulator_led *led)
76{
77 int ret;
78
79 if (!led->enabled)
80 return;
81
82 ret = regulator_disable(regulator: led->vcc);
83 if (ret != 0) {
84 dev_err(led->cdev.dev, "Failed to disable vcc: %d\n", ret);
85 return;
86 }
87
88 led->enabled = 0;
89}
90
91static int regulator_led_brightness_set(struct led_classdev *led_cdev,
92 enum led_brightness value)
93{
94 struct regulator_led *led = to_regulator_led(led_cdev);
95 int voltage;
96 int ret = 0;
97
98 mutex_lock(&led->mutex);
99
100 if (value == LED_OFF) {
101 regulator_led_disable(led);
102 goto out;
103 }
104
105 if (led->cdev.max_brightness > 1) {
106 voltage = led_regulator_get_voltage(supply: led->vcc, brightness: value);
107 dev_dbg(led->cdev.dev, "brightness: %d voltage: %d\n",
108 value, voltage);
109
110 ret = regulator_set_voltage(regulator: led->vcc, min_uV: voltage, max_uV: voltage);
111 if (ret != 0)
112 dev_err(led->cdev.dev, "Failed to set voltage %d: %d\n",
113 voltage, ret);
114 }
115
116 regulator_led_enable(led);
117
118out:
119 mutex_unlock(lock: &led->mutex);
120 return ret;
121}
122
123static int regulator_led_probe(struct platform_device *pdev)
124{
125 struct led_regulator_platform_data *pdata =
126 dev_get_platdata(dev: &pdev->dev);
127 struct device *dev = &pdev->dev;
128 struct led_init_data init_data = {};
129 struct regulator_led *led;
130 struct regulator *vcc;
131 int ret = 0;
132
133 vcc = devm_regulator_get_exclusive(dev, id: "vled");
134 if (IS_ERR(ptr: vcc)) {
135 dev_err(dev, "Cannot get vcc\n");
136 return PTR_ERR(ptr: vcc);
137 }
138
139 led = devm_kzalloc(dev, size: sizeof(*led), GFP_KERNEL);
140 if (led == NULL)
141 return -ENOMEM;
142
143 init_data.fwnode = dev->fwnode;
144
145 led->cdev.max_brightness = led_regulator_get_max_brightness(supply: vcc);
146 /* Legacy platform data label assignment */
147 if (pdata) {
148 if (pdata->brightness > led->cdev.max_brightness) {
149 dev_err(dev, "Invalid default brightness %d\n",
150 pdata->brightness);
151 return -EINVAL;
152 }
153 led->cdev.brightness = pdata->brightness;
154 init_data.default_label = pdata->name;
155 }
156
157 led->cdev.brightness_set_blocking = regulator_led_brightness_set;
158 led->cdev.flags |= LED_CORE_SUSPENDRESUME;
159 led->vcc = vcc;
160
161 /* to handle correctly an already enabled regulator */
162 if (regulator_is_enabled(regulator: led->vcc))
163 led->enabled = 1;
164
165 mutex_init(&led->mutex);
166
167 platform_set_drvdata(pdev, data: led);
168
169 ret = led_classdev_register_ext(parent: dev, led_cdev: &led->cdev, init_data: &init_data);
170 if (ret < 0)
171 return ret;
172
173 return 0;
174}
175
176static void regulator_led_remove(struct platform_device *pdev)
177{
178 struct regulator_led *led = platform_get_drvdata(pdev);
179
180 led_classdev_unregister(led_cdev: &led->cdev);
181 regulator_led_disable(led);
182}
183
184static const struct of_device_id regulator_led_of_match[] = {
185 { .compatible = "regulator-led", },
186 {}
187};
188MODULE_DEVICE_TABLE(of, regulator_led_of_match);
189
190static struct platform_driver regulator_led_driver = {
191 .driver = {
192 .name = "leds-regulator",
193 .of_match_table = regulator_led_of_match,
194 },
195 .probe = regulator_led_probe,
196 .remove_new = regulator_led_remove,
197};
198
199module_platform_driver(regulator_led_driver);
200
201MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>");
202MODULE_DESCRIPTION("Regulator driven LED driver");
203MODULE_LICENSE("GPL");
204MODULE_ALIAS("platform:leds-regulator");
205

source code of linux/drivers/leds/leds-regulator.c