1c310074ad
As the chip can't be queried for it's current state, the "keep" option doesn't make sense. The only option in DT should be turn the LED on or off at probe time. Also 'flags' is never used since introduction. Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
141 lines
3.5 KiB
C
141 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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// Copyright (c) 2009,2018 Daniel Mack <daniel@zonque.org>
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#include <linux/kernel.h>
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#include <linux/platform_device.h>
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#include <linux/leds.h>
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#include <linux/delay.h>
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#include <linux/gpio.h>
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#include <linux/gpio/consumer.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <uapi/linux/uleds.h>
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struct lt3593_led_data {
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char name[LED_MAX_NAME_SIZE];
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struct led_classdev cdev;
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struct gpio_desc *gpiod;
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};
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static int lt3593_led_set(struct led_classdev *led_cdev,
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enum led_brightness value)
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{
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struct lt3593_led_data *led_dat =
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container_of(led_cdev, struct lt3593_led_data, cdev);
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int pulses;
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/*
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* The LT3593 resets its internal current level register to the maximum
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* level on the first falling edge on the control pin. Each following
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* falling edge decreases the current level by 625uA. Up to 32 pulses
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* can be sent, so the maximum power reduction is 20mA.
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* After a timeout of 128us, the value is taken from the register and
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* applied is to the output driver.
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*/
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if (value == 0) {
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gpiod_set_value_cansleep(led_dat->gpiod, 0);
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return 0;
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}
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pulses = 32 - (value * 32) / 255;
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if (pulses == 0) {
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gpiod_set_value_cansleep(led_dat->gpiod, 0);
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mdelay(1);
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gpiod_set_value_cansleep(led_dat->gpiod, 1);
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return 0;
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}
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gpiod_set_value_cansleep(led_dat->gpiod, 1);
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while (pulses--) {
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gpiod_set_value_cansleep(led_dat->gpiod, 0);
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udelay(1);
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gpiod_set_value_cansleep(led_dat->gpiod, 1);
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udelay(1);
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}
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return 0;
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}
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static int lt3593_led_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct lt3593_led_data *led_data;
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struct fwnode_handle *child;
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int ret, state = LEDS_GPIO_DEFSTATE_OFF;
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const char *tmp;
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if (!dev->of_node)
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return -ENODEV;
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led_data = devm_kzalloc(dev, sizeof(*led_data), GFP_KERNEL);
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if (!led_data)
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return -ENOMEM;
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if (device_get_child_node_count(dev) != 1) {
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dev_err(dev, "Device must have exactly one LED sub-node.");
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return -EINVAL;
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}
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led_data->gpiod = devm_gpiod_get(dev, "lltc,ctrl", 0);
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if (IS_ERR(led_data->gpiod))
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return PTR_ERR(led_data->gpiod);
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child = device_get_next_child_node(dev, NULL);
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ret = fwnode_property_read_string(child, "label", &tmp);
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if (ret < 0)
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snprintf(led_data->name, sizeof(led_data->name),
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"lt3593::");
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else
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snprintf(led_data->name, sizeof(led_data->name),
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"lt3593:%s", tmp);
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fwnode_property_read_string(child, "linux,default-trigger",
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&led_data->cdev.default_trigger);
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if (!fwnode_property_read_string(child, "default-state", &tmp)) {
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if (!strcmp(tmp, "on"))
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state = LEDS_GPIO_DEFSTATE_ON;
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}
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led_data->cdev.name = led_data->name;
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led_data->cdev.brightness_set_blocking = lt3593_led_set;
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led_data->cdev.brightness = state ? LED_FULL : LED_OFF;
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ret = devm_led_classdev_register(dev, &led_data->cdev);
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if (ret < 0) {
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fwnode_handle_put(child);
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return ret;
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}
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led_data->cdev.dev->of_node = dev->of_node;
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platform_set_drvdata(pdev, led_data);
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return 0;
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}
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static const struct of_device_id of_lt3593_leds_match[] = {
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{ .compatible = "lltc,lt3593", },
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{},
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};
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MODULE_DEVICE_TABLE(of, of_lt3593_leds_match);
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static struct platform_driver lt3593_led_driver = {
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.probe = lt3593_led_probe,
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.driver = {
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.name = "leds-lt3593",
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.of_match_table = of_match_ptr(of_lt3593_leds_match),
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},
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};
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module_platform_driver(lt3593_led_driver);
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MODULE_AUTHOR("Daniel Mack <daniel@zonque.org>");
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MODULE_DESCRIPTION("LED driver for LT3593 controllers");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:leds-lt3593");
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