205 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*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 status40 * 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