xref: /kernel/linux/linux-6.6/drivers/mfd/rt4831.c (revision 62306a36) 
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (c) 2021 Richtek Technology Corp.
4 *
5 * Author: ChiYuan Huang <cy_huang@richtek.com>
6 */
7
8#include <linux/gpio/consumer.h>
9#include <linux/i2c.h>
10#include <linux/kernel.h>
11#include <linux/mfd/core.h>
12#include <linux/module.h>
13#include <linux/regmap.h>
14
15#define RT4831_REG_REVISION	0x01
16#define RT4831_REG_ENABLE	0x08
17#define RT4831_REG_I2CPROT	0x15
18
19#define RICHTEK_VENDOR_ID	0x03
20#define RT4831_VID_MASK		GENMASK(1, 0)
21#define RT4831_RESET_MASK	BIT(7)
22#define RT4831_I2CSAFETMR_MASK	BIT(0)
23
24static const struct mfd_cell rt4831_subdevs[] = {
25	MFD_CELL_OF("rt4831-backlight", NULL, NULL, 0, 0, "richtek,rt4831-backlight"),
26	MFD_CELL_NAME("rt4831-regulator")
27};
28
29static bool rt4831_is_accessible_reg(struct device *dev, unsigned int reg)
30{
31	if (reg >= RT4831_REG_REVISION && reg <= RT4831_REG_I2CPROT)
32		return true;
33	return false;
34}
35
36static const struct regmap_config rt4831_regmap_config = {
37	.reg_bits = 8,
38	.val_bits = 8,
39	.max_register = RT4831_REG_I2CPROT,
40
41	.readable_reg = rt4831_is_accessible_reg,
42	.writeable_reg = rt4831_is_accessible_reg,
43};
44
45static int rt4831_probe(struct i2c_client *client)
46{
47	struct gpio_desc *enable_gpio;
48	struct regmap *regmap;
49	unsigned int chip_id;
50	int ret;
51
52	enable_gpio = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_HIGH);
53	if (IS_ERR(enable_gpio)) {
54		dev_err(&client->dev, "Failed to get 'enable' GPIO\n");
55		return PTR_ERR(enable_gpio);
56	}
57
58	regmap = devm_regmap_init_i2c(client, &rt4831_regmap_config);
59	if (IS_ERR(regmap)) {
60		dev_err(&client->dev, "Failed to initialize regmap\n");
61		return PTR_ERR(regmap);
62	}
63
64	ret = regmap_read(regmap, RT4831_REG_REVISION, &chip_id);
65	if (ret) {
66		dev_err(&client->dev, "Failed to get H/W revision\n");
67		return ret;
68	}
69
70	if ((chip_id & RT4831_VID_MASK) != RICHTEK_VENDOR_ID) {
71		dev_err(&client->dev, "Chip vendor ID 0x%02x not matched\n", chip_id);
72		return -ENODEV;
73	}
74
75	/*
76	 * Used to prevent the abnormal shutdown.
77	 * If SCL/SDA both keep low for one second to reset HW.
78	 */
79	ret = regmap_update_bits(regmap, RT4831_REG_I2CPROT, RT4831_I2CSAFETMR_MASK,
80				 RT4831_I2CSAFETMR_MASK);
81	if (ret) {
82		dev_err(&client->dev, "Failed to enable I2C safety timer\n");
83		return ret;
84	}
85
86	return devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_AUTO, rt4831_subdevs,
87				    ARRAY_SIZE(rt4831_subdevs), NULL, 0, NULL);
88}
89
90static void rt4831_remove(struct i2c_client *client)
91{
92	struct regmap *regmap = dev_get_regmap(&client->dev, NULL);
93	int ret;
94
95	/* Disable WLED and DSV outputs */
96	ret = regmap_update_bits(regmap, RT4831_REG_ENABLE, RT4831_RESET_MASK, RT4831_RESET_MASK);
97	if (ret)
98		dev_warn(&client->dev, "Failed to disable outputs (%pe)\n", ERR_PTR(ret));
99}
100
101static const struct of_device_id __maybe_unused rt4831_of_match[] = {
102	{ .compatible = "richtek,rt4831", },
103	{}
104};
105MODULE_DEVICE_TABLE(of, rt4831_of_match);
106
107static struct i2c_driver rt4831_driver = {
108	.driver = {
109		.name = "rt4831",
110		.of_match_table = rt4831_of_match,
111	},
112	.probe = rt4831_probe,
113	.remove = rt4831_remove,
114};
115module_i2c_driver(rt4831_driver);
116
117MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
118MODULE_LICENSE("GPL v2");
119