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
22 struct regulator_led {
23 struct led_classdev cdev;
24 int enabled;
25 struct mutex mutex;
26
27 struct regulator *vcc;
28 };
29
led_regulator_get_max_brightness(struct regulator * supply)30 static 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
led_regulator_get_voltage(struct regulator * supply,enum led_brightness brightness)49 static 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
regulator_led_enable(struct regulator_led * led)59 static 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
regulator_led_disable(struct regulator_led * led)75 static 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
regulator_led_brightness_set(struct led_classdev * led_cdev,enum led_brightness value)91 static 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
118 out:
119 mutex_unlock(&led->mutex);
120 return ret;
121 }
122
regulator_led_probe(struct platform_device * pdev)123 static 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
regulator_led_remove(struct platform_device * pdev)176 static 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
184 static const struct of_device_id regulator_led_of_match[] = {
185 { .compatible = "regulator-led", },
186 {}
187 };
188 MODULE_DEVICE_TABLE(of, regulator_led_of_match);
189
190 static 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
199 module_platform_driver(regulator_led_driver);
200
201 MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>");
202 MODULE_DESCRIPTION("Regulator driven LED driver");
203 MODULE_LICENSE("GPL");
204 MODULE_ALIAS("platform:leds-regulator");
205