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 | |
24 | static 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 | |
29 | static 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 | |
36 | static 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 | |
45 | static 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(dev: &client->dev, con_id: "enable" , flags: GPIOD_OUT_HIGH); |
53 | if (IS_ERR(ptr: enable_gpio)) { |
54 | dev_err(&client->dev, "Failed to get 'enable' GPIO\n" ); |
55 | return PTR_ERR(ptr: enable_gpio); |
56 | } |
57 | |
58 | regmap = devm_regmap_init_i2c(client, &rt4831_regmap_config); |
59 | if (IS_ERR(ptr: regmap)) { |
60 | dev_err(&client->dev, "Failed to initialize regmap\n" ); |
61 | return PTR_ERR(ptr: regmap); |
62 | } |
63 | |
64 | ret = regmap_read(map: regmap, RT4831_REG_REVISION, val: &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(map: 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(dev: &client->dev, PLATFORM_DEVID_AUTO, cells: rt4831_subdevs, |
87 | ARRAY_SIZE(rt4831_subdevs), NULL, irq_base: 0, NULL); |
88 | } |
89 | |
90 | static void rt4831_remove(struct i2c_client *client) |
91 | { |
92 | struct regmap *regmap = dev_get_regmap(dev: &client->dev, NULL); |
93 | int ret; |
94 | |
95 | /* Disable WLED and DSV outputs */ |
96 | ret = regmap_update_bits(map: 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 | |
101 | static const struct of_device_id __maybe_unused rt4831_of_match[] = { |
102 | { .compatible = "richtek,rt4831" , }, |
103 | {} |
104 | }; |
105 | MODULE_DEVICE_TABLE(of, rt4831_of_match); |
106 | |
107 | static 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 | }; |
115 | module_i2c_driver(rt4831_driver); |
116 | |
117 | MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>" ); |
118 | MODULE_LICENSE("GPL v2" ); |
119 | |