linux/drivers/leds/leds-lt3593.c
Daniel Mack dd08ac2e5f leds: lt3593: update email address and switch to SPDX license header
Update the email address in the module information and in the comments
and in the module information, and drop the existing boilerplate in
favor of a SPDX header.

Also sync the module license information with the header.

Signed-off-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
2018-07-03 22:12:41 +02:00

203 lines
5.1 KiB
C

// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2009,2018 Daniel Mack <daniel@zonque.org>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/leds.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/of.h>
#include <uapi/linux/uleds.h>
struct lt3593_led_data {
char name[LED_MAX_NAME_SIZE];
struct led_classdev cdev;
struct gpio_desc *gpiod;
};
static int lt3593_led_set(struct led_classdev *led_cdev,
enum led_brightness value)
{
struct lt3593_led_data *led_dat =
container_of(led_cdev, struct lt3593_led_data, cdev);
int pulses;
/*
* The LT3593 resets its internal current level register to the maximum
* level on the first falling edge on the control pin. Each following
* falling edge decreases the current level by 625uA. Up to 32 pulses
* can be sent, so the maximum power reduction is 20mA.
* After a timeout of 128us, the value is taken from the register and
* applied is to the output driver.
*/
if (value == 0) {
gpiod_set_value_cansleep(led_dat->gpiod, 0);
return 0;
}
pulses = 32 - (value * 32) / 255;
if (pulses == 0) {
gpiod_set_value_cansleep(led_dat->gpiod, 0);
mdelay(1);
gpiod_set_value_cansleep(led_dat->gpiod, 1);
return 0;
}
gpiod_set_value_cansleep(led_dat->gpiod, 1);
while (pulses--) {
gpiod_set_value_cansleep(led_dat->gpiod, 0);
udelay(1);
gpiod_set_value_cansleep(led_dat->gpiod, 1);
udelay(1);
}
return 0;
}
static struct lt3593_led_data *lt3593_led_probe_pdata(struct device *dev)
{
struct gpio_led_platform_data *pdata = dev_get_platdata(dev);
const struct gpio_led *template = &pdata->leds[0];
struct lt3593_led_data *led_data;
int ret, state;
if (pdata->num_leds != 1)
return ERR_PTR(-EINVAL);
led_data = devm_kzalloc(dev, sizeof(*led_data), GFP_KERNEL);
if (!led_data)
return ERR_PTR(-ENOMEM);
led_data->cdev.name = template->name;
led_data->cdev.default_trigger = template->default_trigger;
led_data->cdev.brightness_set_blocking = lt3593_led_set;
state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
led_data->cdev.brightness = state ? LED_FULL : LED_OFF;
if (!template->retain_state_suspended)
led_data->cdev.flags |= LED_CORE_SUSPENDRESUME;
ret = devm_gpio_request_one(dev, template->gpio, state ?
GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW,
template->name);
if (ret < 0)
return ERR_PTR(ret);
led_data->gpiod = gpio_to_desc(template->gpio);
if (!led_data->gpiod)
return ERR_PTR(-EPROBE_DEFER);
ret = devm_led_classdev_register(dev, &led_data->cdev);
if (ret < 0)
return ERR_PTR(ret);
dev_info(dev, "registered LT3593 LED '%s' at GPIO %d\n",
template->name, template->gpio);
return led_data;
}
static int lt3593_led_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct lt3593_led_data *led_data;
struct fwnode_handle *child;
int ret, state = LEDS_GPIO_DEFSTATE_OFF;
enum gpiod_flags flags = GPIOD_OUT_LOW;
const char *tmp;
if (dev_get_platdata(dev)) {
led_data = lt3593_led_probe_pdata(dev);
if (IS_ERR(led_data))
return PTR_ERR(led_data);
goto out;
}
if (!dev->of_node)
return -ENODEV;
led_data = devm_kzalloc(dev, sizeof(*led_data), GFP_KERNEL);
if (!led_data)
return -ENOMEM;
if (device_get_child_node_count(dev) != 1) {
dev_err(dev, "Device must have exactly one LED sub-node.");
return -EINVAL;
}
led_data->gpiod = devm_gpiod_get(dev, "lltc,ctrl", 0);
if (IS_ERR(led_data->gpiod))
return PTR_ERR(led_data->gpiod);
child = device_get_next_child_node(dev, NULL);
ret = fwnode_property_read_string(child, "label", &tmp);
if (ret < 0)
snprintf(led_data->name, sizeof(led_data->name),
"lt3593::");
else
snprintf(led_data->name, sizeof(led_data->name),
"lt3593:%s", tmp);
fwnode_property_read_string(child, "linux,default-trigger",
&led_data->cdev.default_trigger);
if (!fwnode_property_read_string(child, "default-state", &tmp)) {
if (!strcmp(tmp, "keep")) {
state = LEDS_GPIO_DEFSTATE_KEEP;
flags = GPIOD_ASIS;
} else if (!strcmp(tmp, "on")) {
state = LEDS_GPIO_DEFSTATE_ON;
flags = GPIOD_OUT_HIGH;
}
}
led_data->cdev.name = led_data->name;
led_data->cdev.brightness_set_blocking = lt3593_led_set;
led_data->cdev.brightness = state ? LED_FULL : LED_OFF;
ret = devm_led_classdev_register(dev, &led_data->cdev);
if (ret < 0) {
fwnode_handle_put(child);
return ret;
}
led_data->cdev.dev->of_node = dev->of_node;
out:
platform_set_drvdata(pdev, led_data);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id of_lt3593_leds_match[] = {
{ .compatible = "lltc,lt3593", },
{},
};
MODULE_DEVICE_TABLE(of, of_lt3593_leds_match);
#endif
static struct platform_driver lt3593_led_driver = {
.probe = lt3593_led_probe,
.driver = {
.name = "leds-lt3593",
.of_match_table = of_match_ptr(of_lt3593_leds_match),
},
};
module_platform_driver(lt3593_led_driver);
MODULE_AUTHOR("Daniel Mack <daniel@zonque.org>");
MODULE_DESCRIPTION("LED driver for LT3593 controllers");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:leds-lt3593");