1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun // Copyright (c) 2009,2018 Daniel Mack <daniel@zonque.org>
3*4882a593Smuzhiyun
4*4882a593Smuzhiyun #include <linux/kernel.h>
5*4882a593Smuzhiyun #include <linux/platform_device.h>
6*4882a593Smuzhiyun #include <linux/leds.h>
7*4882a593Smuzhiyun #include <linux/delay.h>
8*4882a593Smuzhiyun #include <linux/gpio/consumer.h>
9*4882a593Smuzhiyun #include <linux/slab.h>
10*4882a593Smuzhiyun #include <linux/module.h>
11*4882a593Smuzhiyun #include <linux/of.h>
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun #define LED_LT3593_NAME "lt3593"
14*4882a593Smuzhiyun
15*4882a593Smuzhiyun struct lt3593_led_data {
16*4882a593Smuzhiyun struct led_classdev cdev;
17*4882a593Smuzhiyun struct gpio_desc *gpiod;
18*4882a593Smuzhiyun };
19*4882a593Smuzhiyun
lt3593_led_set(struct led_classdev * led_cdev,enum led_brightness value)20*4882a593Smuzhiyun static int lt3593_led_set(struct led_classdev *led_cdev,
21*4882a593Smuzhiyun enum led_brightness value)
22*4882a593Smuzhiyun {
23*4882a593Smuzhiyun struct lt3593_led_data *led_dat =
24*4882a593Smuzhiyun container_of(led_cdev, struct lt3593_led_data, cdev);
25*4882a593Smuzhiyun int pulses;
26*4882a593Smuzhiyun
27*4882a593Smuzhiyun /*
28*4882a593Smuzhiyun * The LT3593 resets its internal current level register to the maximum
29*4882a593Smuzhiyun * level on the first falling edge on the control pin. Each following
30*4882a593Smuzhiyun * falling edge decreases the current level by 625uA. Up to 32 pulses
31*4882a593Smuzhiyun * can be sent, so the maximum power reduction is 20mA.
32*4882a593Smuzhiyun * After a timeout of 128us, the value is taken from the register and
33*4882a593Smuzhiyun * applied is to the output driver.
34*4882a593Smuzhiyun */
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun if (value == 0) {
37*4882a593Smuzhiyun gpiod_set_value_cansleep(led_dat->gpiod, 0);
38*4882a593Smuzhiyun return 0;
39*4882a593Smuzhiyun }
40*4882a593Smuzhiyun
41*4882a593Smuzhiyun pulses = 32 - (value * 32) / 255;
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun if (pulses == 0) {
44*4882a593Smuzhiyun gpiod_set_value_cansleep(led_dat->gpiod, 0);
45*4882a593Smuzhiyun mdelay(1);
46*4882a593Smuzhiyun gpiod_set_value_cansleep(led_dat->gpiod, 1);
47*4882a593Smuzhiyun return 0;
48*4882a593Smuzhiyun }
49*4882a593Smuzhiyun
50*4882a593Smuzhiyun gpiod_set_value_cansleep(led_dat->gpiod, 1);
51*4882a593Smuzhiyun
52*4882a593Smuzhiyun while (pulses--) {
53*4882a593Smuzhiyun gpiod_set_value_cansleep(led_dat->gpiod, 0);
54*4882a593Smuzhiyun udelay(1);
55*4882a593Smuzhiyun gpiod_set_value_cansleep(led_dat->gpiod, 1);
56*4882a593Smuzhiyun udelay(1);
57*4882a593Smuzhiyun }
58*4882a593Smuzhiyun
59*4882a593Smuzhiyun return 0;
60*4882a593Smuzhiyun }
61*4882a593Smuzhiyun
lt3593_led_probe(struct platform_device * pdev)62*4882a593Smuzhiyun static int lt3593_led_probe(struct platform_device *pdev)
63*4882a593Smuzhiyun {
64*4882a593Smuzhiyun struct device *dev = &pdev->dev;
65*4882a593Smuzhiyun struct lt3593_led_data *led_data;
66*4882a593Smuzhiyun struct fwnode_handle *child;
67*4882a593Smuzhiyun int ret, state = LEDS_GPIO_DEFSTATE_OFF;
68*4882a593Smuzhiyun struct led_init_data init_data = {};
69*4882a593Smuzhiyun const char *tmp;
70*4882a593Smuzhiyun
71*4882a593Smuzhiyun if (!dev_of_node(dev))
72*4882a593Smuzhiyun return -ENODEV;
73*4882a593Smuzhiyun
74*4882a593Smuzhiyun led_data = devm_kzalloc(dev, sizeof(*led_data), GFP_KERNEL);
75*4882a593Smuzhiyun if (!led_data)
76*4882a593Smuzhiyun return -ENOMEM;
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun if (device_get_child_node_count(dev) != 1) {
79*4882a593Smuzhiyun dev_err(dev, "Device must have exactly one LED sub-node.");
80*4882a593Smuzhiyun return -EINVAL;
81*4882a593Smuzhiyun }
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun led_data->gpiod = devm_gpiod_get(dev, "lltc,ctrl", 0);
84*4882a593Smuzhiyun if (IS_ERR(led_data->gpiod))
85*4882a593Smuzhiyun return PTR_ERR(led_data->gpiod);
86*4882a593Smuzhiyun
87*4882a593Smuzhiyun child = device_get_next_child_node(dev, NULL);
88*4882a593Smuzhiyun
89*4882a593Smuzhiyun if (!fwnode_property_read_string(child, "default-state", &tmp)) {
90*4882a593Smuzhiyun if (!strcmp(tmp, "on"))
91*4882a593Smuzhiyun state = LEDS_GPIO_DEFSTATE_ON;
92*4882a593Smuzhiyun }
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun led_data->cdev.brightness_set_blocking = lt3593_led_set;
95*4882a593Smuzhiyun led_data->cdev.brightness = state ? LED_FULL : LED_OFF;
96*4882a593Smuzhiyun
97*4882a593Smuzhiyun init_data.fwnode = child;
98*4882a593Smuzhiyun init_data.devicename = LED_LT3593_NAME;
99*4882a593Smuzhiyun init_data.default_label = ":";
100*4882a593Smuzhiyun
101*4882a593Smuzhiyun ret = devm_led_classdev_register_ext(dev, &led_data->cdev, &init_data);
102*4882a593Smuzhiyun fwnode_handle_put(child);
103*4882a593Smuzhiyun if (ret < 0)
104*4882a593Smuzhiyun return ret;
105*4882a593Smuzhiyun
106*4882a593Smuzhiyun platform_set_drvdata(pdev, led_data);
107*4882a593Smuzhiyun
108*4882a593Smuzhiyun return 0;
109*4882a593Smuzhiyun }
110*4882a593Smuzhiyun
111*4882a593Smuzhiyun static const struct of_device_id of_lt3593_leds_match[] = {
112*4882a593Smuzhiyun { .compatible = "lltc,lt3593", },
113*4882a593Smuzhiyun {},
114*4882a593Smuzhiyun };
115*4882a593Smuzhiyun MODULE_DEVICE_TABLE(of, of_lt3593_leds_match);
116*4882a593Smuzhiyun
117*4882a593Smuzhiyun static struct platform_driver lt3593_led_driver = {
118*4882a593Smuzhiyun .probe = lt3593_led_probe,
119*4882a593Smuzhiyun .driver = {
120*4882a593Smuzhiyun .name = "leds-lt3593",
121*4882a593Smuzhiyun .of_match_table = of_match_ptr(of_lt3593_leds_match),
122*4882a593Smuzhiyun },
123*4882a593Smuzhiyun };
124*4882a593Smuzhiyun
125*4882a593Smuzhiyun module_platform_driver(lt3593_led_driver);
126*4882a593Smuzhiyun
127*4882a593Smuzhiyun MODULE_AUTHOR("Daniel Mack <daniel@zonque.org>");
128*4882a593Smuzhiyun MODULE_DESCRIPTION("LED driver for LT3593 controllers");
129*4882a593Smuzhiyun MODULE_LICENSE("GPL v2");
130*4882a593Smuzhiyun MODULE_ALIAS("platform:leds-lt3593");
131