diff options
Diffstat (limited to 'drivers/leds/leds-regulator.c')
| -rw-r--r-- | drivers/leds/leds-regulator.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/drivers/leds/leds-regulator.c b/drivers/leds/leds-regulator.c new file mode 100644 index 000000000..208c98918 --- /dev/null +++ b/drivers/leds/leds-regulator.c @@ -0,0 +1,200 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * leds-regulator.c - LED class driver for regulator driven LEDs. + * + * Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it> + * + * Inspired by leds-wm8350 driver. + */ + +#include <linux/module.h> +#include <linux/err.h> +#include <linux/slab.h> +#include <linux/leds.h> +#include <linux/leds-regulator.h> +#include <linux/platform_device.h> +#include <linux/regulator/consumer.h> + +#define to_regulator_led(led_cdev) \ + container_of(led_cdev, struct regulator_led, cdev) + +struct regulator_led { + struct led_classdev cdev; + int enabled; + struct mutex mutex; + + struct regulator *vcc; +}; + +static inline int led_regulator_get_max_brightness(struct regulator *supply) +{ + int ret; + int voltage = regulator_list_voltage(supply, 0); + + if (voltage <= 0) + return 1; + + /* even if regulator can't change voltages, + * we still assume it can change status + * and the LED can be turned on and off. + */ + ret = regulator_set_voltage(supply, voltage, voltage); + if (ret < 0) + return 1; + + return regulator_count_voltages(supply); +} + +static int led_regulator_get_voltage(struct regulator *supply, + enum led_brightness brightness) +{ + if (brightness == 0) + return -EINVAL; + + return regulator_list_voltage(supply, brightness - 1); +} + + +static void regulator_led_enable(struct regulator_led *led) +{ + int ret; + + if (led->enabled) + return; + + ret = regulator_enable(led->vcc); + if (ret != 0) { + dev_err(led->cdev.dev, "Failed to enable vcc: %d\n", ret); + return; + } + + led->enabled = 1; +} + +static void regulator_led_disable(struct regulator_led *led) +{ + int ret; + + if (!led->enabled) + return; + + ret = regulator_disable(led->vcc); + if (ret != 0) { + dev_err(led->cdev.dev, "Failed to disable vcc: %d\n", ret); + return; + } + + led->enabled = 0; +} + +static int regulator_led_brightness_set(struct led_classdev *led_cdev, + enum led_brightness value) +{ + struct regulator_led *led = to_regulator_led(led_cdev); + int voltage; + int ret = 0; + + mutex_lock(&led->mutex); + + if (value == LED_OFF) { + regulator_led_disable(led); + goto out; + } + + if (led->cdev.max_brightness > 1) { + voltage = led_regulator_get_voltage(led->vcc, value); + dev_dbg(led->cdev.dev, "brightness: %d voltage: %d\n", + value, voltage); + + ret = regulator_set_voltage(led->vcc, voltage, voltage); + if (ret != 0) + dev_err(led->cdev.dev, "Failed to set voltage %d: %d\n", + voltage, ret); + } + + regulator_led_enable(led); + +out: + mutex_unlock(&led->mutex); + return ret; +} + +static int regulator_led_probe(struct platform_device *pdev) +{ + struct led_regulator_platform_data *pdata = + dev_get_platdata(&pdev->dev); + struct regulator_led *led; + struct regulator *vcc; + int ret = 0; + + if (pdata == NULL) { + dev_err(&pdev->dev, "no platform data\n"); + return -ENODEV; + } + + vcc = devm_regulator_get_exclusive(&pdev->dev, "vled"); + if (IS_ERR(vcc)) { + dev_err(&pdev->dev, "Cannot get vcc for %s\n", pdata->name); + return PTR_ERR(vcc); + } + + led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL); + if (led == NULL) + return -ENOMEM; + + led->cdev.max_brightness = led_regulator_get_max_brightness(vcc); + if (pdata->brightness > led->cdev.max_brightness) { + dev_err(&pdev->dev, "Invalid default brightness %d\n", + pdata->brightness); + return -EINVAL; + } + + led->cdev.brightness_set_blocking = regulator_led_brightness_set; + led->cdev.name = pdata->name; + led->cdev.flags |= LED_CORE_SUSPENDRESUME; + led->vcc = vcc; + + /* to handle correctly an already enabled regulator */ + if (regulator_is_enabled(led->vcc)) + led->enabled = 1; + + mutex_init(&led->mutex); + + platform_set_drvdata(pdev, led); + + ret = led_classdev_register(&pdev->dev, &led->cdev); + if (ret < 0) + return ret; + + /* to expose the default value to userspace */ + led->cdev.brightness = pdata->brightness; + + /* Set the default led status */ + regulator_led_brightness_set(&led->cdev, led->cdev.brightness); + + return 0; +} + +static int regulator_led_remove(struct platform_device *pdev) +{ + struct regulator_led *led = platform_get_drvdata(pdev); + + led_classdev_unregister(&led->cdev); + regulator_led_disable(led); + return 0; +} + +static struct platform_driver regulator_led_driver = { + .driver = { + .name = "leds-regulator", + }, + .probe = regulator_led_probe, + .remove = regulator_led_remove, +}; + +module_platform_driver(regulator_led_driver); + +MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>"); +MODULE_DESCRIPTION("Regulator driven LED driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:leds-regulator"); |