diff options
Diffstat (limited to 'drivers/leds/trigger/ledtrig-gpio.c')
| -rw-r--r-- | drivers/leds/trigger/ledtrig-gpio.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/drivers/leds/trigger/ledtrig-gpio.c b/drivers/leds/trigger/ledtrig-gpio.c new file mode 100644 index 000000000..3b3e6869e --- /dev/null +++ b/drivers/leds/trigger/ledtrig-gpio.c @@ -0,0 +1,142 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * ledtrig-gio.c - LED Trigger Based on GPIO events + * + * Copyright 2009 Felipe Balbi <me@felipebalbi.com> + * Copyright 2023 Linus Walleij <linus.walleij@linaro.org> + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/gpio/consumer.h> +#include <linux/interrupt.h> +#include <linux/leds.h> +#include <linux/slab.h> +#include "../leds.h" + +struct gpio_trig_data { + struct led_classdev *led; + unsigned desired_brightness; /* desired brightness when led is on */ + struct gpio_desc *gpiod; /* gpio that triggers the led */ +}; + +static irqreturn_t gpio_trig_irq(int irq, void *_led) +{ + struct led_classdev *led = _led; + struct gpio_trig_data *gpio_data = led_get_trigger_data(led); + int tmp; + + tmp = gpiod_get_value_cansleep(gpio_data->gpiod); + if (tmp) { + if (gpio_data->desired_brightness) + led_set_brightness_nosleep(gpio_data->led, + gpio_data->desired_brightness); + else + led_set_brightness_nosleep(gpio_data->led, LED_FULL); + } else { + led_set_brightness_nosleep(gpio_data->led, LED_OFF); + } + + return IRQ_HANDLED; +} + +static ssize_t desired_brightness_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev); + + return sysfs_emit(buf, "%u\n", gpio_data->desired_brightness); +} + +static ssize_t desired_brightness_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t n) +{ + struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev); + u8 desired_brightness; + int ret; + + ret = kstrtou8(buf, 10, &desired_brightness); + if (ret) + return ret; + + gpio_data->desired_brightness = desired_brightness; + + return n; +} +static DEVICE_ATTR_RW(desired_brightness); + +static struct attribute *gpio_trig_attrs[] = { + &dev_attr_desired_brightness.attr, + NULL +}; +ATTRIBUTE_GROUPS(gpio_trig); + +static int gpio_trig_activate(struct led_classdev *led) +{ + struct gpio_trig_data *gpio_data; + struct device *dev = led->dev; + int ret; + + gpio_data = kzalloc_obj(*gpio_data); + if (!gpio_data) + return -ENOMEM; + + /* + * The generic property "trigger-sources" is followed, + * and we hope that this is a GPIO. + */ + gpio_data->gpiod = gpiod_get_optional(dev, "trigger-sources", + GPIOD_IN | GPIOD_FLAGS_BIT_NONEXCLUSIVE); + if (IS_ERR(gpio_data->gpiod)) { + ret = PTR_ERR(gpio_data->gpiod); + kfree(gpio_data); + return ret; + } + if (!gpio_data->gpiod) { + dev_err(dev, "no valid GPIO for the trigger\n"); + kfree(gpio_data); + return -EINVAL; + } + + gpiod_set_consumer_name(gpio_data->gpiod, "led-trigger"); + + gpio_data->led = led; + led_set_trigger_data(led, gpio_data); + + ret = request_threaded_irq(gpiod_to_irq(gpio_data->gpiod), NULL, gpio_trig_irq, + IRQF_ONESHOT | IRQF_SHARED | IRQF_TRIGGER_RISING + | IRQF_TRIGGER_FALLING, "ledtrig-gpio", led); + if (ret) { + dev_err(dev, "request_irq failed with error %d\n", ret); + gpiod_put(gpio_data->gpiod); + kfree(gpio_data); + return ret; + } + + /* Finally update the LED to initial status */ + gpio_trig_irq(0, led); + + return 0; +} + +static void gpio_trig_deactivate(struct led_classdev *led) +{ + struct gpio_trig_data *gpio_data = led_get_trigger_data(led); + + free_irq(gpiod_to_irq(gpio_data->gpiod), led); + gpiod_put(gpio_data->gpiod); + kfree(gpio_data); +} + +static struct led_trigger gpio_led_trigger = { + .name = "gpio", + .activate = gpio_trig_activate, + .deactivate = gpio_trig_deactivate, + .groups = gpio_trig_groups, +}; +module_led_trigger(gpio_led_trigger); + +MODULE_AUTHOR("Felipe Balbi <me@felipebalbi.com>"); +MODULE_DESCRIPTION("GPIO LED trigger"); +MODULE_LICENSE("GPL v2"); |