1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2023 Andreas Kemnade
4 *
5 * Datasheet:
6 * https://fscdn.rohm.com/en/products/databook/datasheet/ic/power/led_driver/bd2606mvv_1-e.pdf
7 *
8 * If LED brightness cannot be controlled independently due to shared
9 * brightness registers, max_brightness is set to 1 and only on/off
10 * is possible for the affected LED pair.
11 */
12
13#include <linux/i2c.h>
14#include <linux/leds.h>
15#include <linux/module.h>
16#include <linux/mod_devicetable.h>
17#include <linux/property.h>
18#include <linux/regmap.h>
19#include <linux/slab.h>
20
21#define BD2606_MAX_LEDS 6
22#define BD2606_MAX_BRIGHTNESS 63
23#define BD2606_REG_PWRCNT 3
24#define ldev_to_led(c)	container_of(c, struct bd2606mvv_led, ldev)
25
26struct bd2606mvv_led {
27	unsigned int led_no;
28	struct led_classdev ldev;
29	struct bd2606mvv_priv *priv;
30};
31
32struct bd2606mvv_priv {
33	struct bd2606mvv_led leds[BD2606_MAX_LEDS];
34	struct regmap *regmap;
35};
36
37static int
38bd2606mvv_brightness_set(struct led_classdev *led_cdev,
39		      enum led_brightness brightness)
40{
41	struct bd2606mvv_led *led = ldev_to_led(led_cdev);
42	struct bd2606mvv_priv *priv = led->priv;
43	int err;
44
45	if (brightness == 0)
46		return regmap_update_bits(priv->regmap,
47					  BD2606_REG_PWRCNT,
48					  1 << led->led_no,
49					  0);
50
51	/* shared brightness register */
52	err = regmap_write(priv->regmap, led->led_no / 2,
53			   led_cdev->max_brightness == 1 ?
54			   BD2606_MAX_BRIGHTNESS : brightness);
55	if (err)
56		return err;
57
58	return regmap_update_bits(priv->regmap,
59				  BD2606_REG_PWRCNT,
60				  1 << led->led_no,
61				  1 << led->led_no);
62}
63
64static const struct regmap_config bd2606mvv_regmap = {
65	.reg_bits = 8,
66	.val_bits = 8,
67	.max_register = 0x3,
68};
69
70static int bd2606mvv_probe(struct i2c_client *client)
71{
72	struct fwnode_handle *np, *child;
73	struct device *dev = &client->dev;
74	struct bd2606mvv_priv *priv;
75	struct fwnode_handle *led_fwnodes[BD2606_MAX_LEDS] = { 0 };
76	int active_pairs[BD2606_MAX_LEDS / 2] = { 0 };
77	int err, reg;
78	int i;
79
80	np = dev_fwnode(dev);
81	if (!np)
82		return -ENODEV;
83
84	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
85	if (!priv)
86		return -ENOMEM;
87
88	priv->regmap = devm_regmap_init_i2c(client, &bd2606mvv_regmap);
89	if (IS_ERR(priv->regmap)) {
90		err = PTR_ERR(priv->regmap);
91		dev_err(dev, "Failed to allocate register map: %d\n", err);
92		return err;
93	}
94
95	i2c_set_clientdata(client, priv);
96
97	fwnode_for_each_available_child_node(np, child) {
98		struct bd2606mvv_led *led;
99
100		err = fwnode_property_read_u32(child, "reg", &reg);
101		if (err) {
102			fwnode_handle_put(child);
103			return err;
104		}
105		if (reg < 0 || reg >= BD2606_MAX_LEDS || led_fwnodes[reg]) {
106			fwnode_handle_put(child);
107			return -EINVAL;
108		}
109		led = &priv->leds[reg];
110		led_fwnodes[reg] = child;
111		active_pairs[reg / 2]++;
112		led->priv = priv;
113		led->led_no = reg;
114		led->ldev.brightness_set_blocking = bd2606mvv_brightness_set;
115		led->ldev.max_brightness = BD2606_MAX_BRIGHTNESS;
116	}
117
118	for (i = 0; i < BD2606_MAX_LEDS; i++) {
119		struct led_init_data init_data = {};
120
121		if (!led_fwnodes[i])
122			continue;
123
124		init_data.fwnode = led_fwnodes[i];
125		/* Check whether brightness can be independently adjusted. */
126		if (active_pairs[i / 2] == 2)
127			priv->leds[i].ldev.max_brightness = 1;
128
129		err = devm_led_classdev_register_ext(dev,
130						     &priv->leds[i].ldev,
131						     &init_data);
132		if (err < 0) {
133			fwnode_handle_put(child);
134			return dev_err_probe(dev, err,
135					     "couldn't register LED %s\n",
136					     priv->leds[i].ldev.name);
137		}
138	}
139	return 0;
140}
141
142static const struct of_device_id __maybe_unused of_bd2606mvv_leds_match[] = {
143	{ .compatible = "rohm,bd2606mvv", },
144	{},
145};
146MODULE_DEVICE_TABLE(of, of_bd2606mvv_leds_match);
147
148static struct i2c_driver bd2606mvv_driver = {
149	.driver   = {
150		.name    = "leds-bd2606mvv",
151		.of_match_table = of_match_ptr(of_bd2606mvv_leds_match),
152	},
153	.probe = bd2606mvv_probe,
154};
155
156module_i2c_driver(bd2606mvv_driver);
157
158MODULE_AUTHOR("Andreas Kemnade <andreas@kemnade.info>");
159MODULE_DESCRIPTION("BD2606 LED driver");
160MODULE_LICENSE("GPL");
161