1// SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0-or-later
2/*
3 * Dell Wyse 3020 a.k.a. "Ariel" Embedded Controller LED Driver
4 *
5 * Copyright (C) 2020 Lubomir Rintel
6 */
7
8#include <linux/module.h>
9#include <linux/leds.h>
10#include <linux/platform_device.h>
11#include <linux/regmap.h>
12
13enum ec_index {
14	EC_BLUE_LED	= 0x01,
15	EC_AMBER_LED	= 0x02,
16	EC_GREEN_LED	= 0x03,
17};
18
19enum {
20	EC_LED_OFF	= 0x00,
21	EC_LED_STILL	= 0x01,
22	EC_LED_FADE	= 0x02,
23	EC_LED_BLINK	= 0x03,
24};
25
26struct ariel_led {
27	struct regmap *ec_ram;
28	enum ec_index ec_index;
29	struct led_classdev led_cdev;
30};
31
32#define led_cdev_to_ariel_led(c) container_of(c, struct ariel_led, led_cdev)
33
34static enum led_brightness ariel_led_get(struct led_classdev *led_cdev)
35{
36	struct ariel_led *led = led_cdev_to_ariel_led(led_cdev);
37	unsigned int led_status = 0;
38
39	if (regmap_read(led->ec_ram, led->ec_index, &led_status))
40		return LED_OFF;
41
42	if (led_status == EC_LED_STILL)
43		return LED_FULL;
44	else
45		return LED_OFF;
46}
47
48static void ariel_led_set(struct led_classdev *led_cdev,
49			  enum led_brightness brightness)
50{
51	struct ariel_led *led = led_cdev_to_ariel_led(led_cdev);
52
53	if (brightness == LED_OFF)
54		regmap_write(led->ec_ram, led->ec_index, EC_LED_OFF);
55	else
56		regmap_write(led->ec_ram, led->ec_index, EC_LED_STILL);
57}
58
59static int ariel_blink_set(struct led_classdev *led_cdev,
60			   unsigned long *delay_on, unsigned long *delay_off)
61{
62	struct ariel_led *led = led_cdev_to_ariel_led(led_cdev);
63
64	if (*delay_on == 0 && *delay_off == 0)
65		return -EINVAL;
66
67	if (*delay_on == 0) {
68		regmap_write(led->ec_ram, led->ec_index, EC_LED_OFF);
69	} else if (*delay_off == 0) {
70		regmap_write(led->ec_ram, led->ec_index, EC_LED_STILL);
71	} else {
72		*delay_on = 500;
73		*delay_off = 500;
74		regmap_write(led->ec_ram, led->ec_index, EC_LED_BLINK);
75	}
76
77	return 0;
78}
79
80#define NLEDS 3
81
82static int ariel_led_probe(struct platform_device *pdev)
83{
84	struct device *dev = &pdev->dev;
85	struct ariel_led *leds;
86	struct regmap *ec_ram;
87	int ret;
88	int i;
89
90	ec_ram = dev_get_regmap(dev->parent, "ec_ram");
91	if (!ec_ram)
92		return -ENODEV;
93
94	leds = devm_kcalloc(dev, NLEDS, sizeof(*leds), GFP_KERNEL);
95	if (!leds)
96		return -ENOMEM;
97
98	leds[0].ec_index = EC_BLUE_LED;
99	leds[0].led_cdev.name = "blue:power";
100	leds[0].led_cdev.default_trigger = "default-on";
101
102	leds[1].ec_index = EC_AMBER_LED;
103	leds[1].led_cdev.name = "amber:status";
104
105	leds[2].ec_index = EC_GREEN_LED;
106	leds[2].led_cdev.name = "green:status";
107	leds[2].led_cdev.default_trigger = "default-on";
108
109	for (i = 0; i < NLEDS; i++) {
110		leds[i].ec_ram = ec_ram;
111		leds[i].led_cdev.brightness_get = ariel_led_get;
112		leds[i].led_cdev.brightness_set = ariel_led_set;
113		leds[i].led_cdev.blink_set = ariel_blink_set;
114
115		ret = devm_led_classdev_register(dev, &leds[i].led_cdev);
116		if (ret)
117			return ret;
118	}
119
120	return 0;
121}
122
123static struct platform_driver ariel_led_driver = {
124	.probe = ariel_led_probe,
125	.driver = {
126		.name = "dell-wyse-ariel-led",
127	},
128};
129module_platform_driver(ariel_led_driver);
130
131MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
132MODULE_DESCRIPTION("Dell Wyse 3020 Status LEDs Driver");
133MODULE_LICENSE("Dual BSD/GPL");
134