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(supply, 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(supply, voltage, voltage);
43	if (ret < 0)
44		return 1;
45
46	return regulator_count_voltages(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(supply, 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(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(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(led->vcc, value);
107		dev_dbg(led->cdev.dev, "brightness: %d voltage: %d\n",
108				value, voltage);
109
110		ret = regulator_set_voltage(led->vcc, voltage, 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(&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(&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, "vled");
134	if (IS_ERR(vcc)) {
135		dev_err(dev, "Cannot get vcc\n");
136		return PTR_ERR(vcc);
137	}
138
139	led = devm_kzalloc(dev, 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(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(led->vcc))
163		led->enabled = 1;
164
165	mutex_init(&led->mutex);
166
167	platform_set_drvdata(pdev, led);
168
169	ret = led_classdev_register_ext(dev, &led->cdev, &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);
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