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