1 // SPDX-License-Identifier: GPL-2.0+
2 //
3 // sy8106a-regulator.c - Regulator device driver for SY8106A
4 //
5 // Copyright (C) 2016 Ondřej Jirman <megous@megous.com>
6 // Copyright (c) 2017-2018 Icenowy Zheng <icenowy@aosc.io>
7 
8 #include <linux/err.h>
9 #include <linux/i2c.h>
10 #include <linux/module.h>
11 #include <linux/regmap.h>
12 #include <linux/regulator/driver.h>
13 #include <linux/regulator/of_regulator.h>
14 
15 #define SY8106A_REG_VOUT1_SEL		0x01
16 #define SY8106A_REG_VOUT_COM		0x02
17 #define SY8106A_REG_VOUT1_SEL_MASK	0x7f
18 #define SY8106A_DISABLE_REG		BIT(0)
19 /*
20  * The I2C controlled voltage will only work when this bit is set; otherwise
21  * it will behave like a fixed regulator.
22  */
23 #define SY8106A_GO_BIT			BIT(7)
24 
25 static const struct regmap_config sy8106a_regmap_config = {
26 	.reg_bits = 8,
27 	.val_bits = 8,
28 };
29 
30 static const struct regulator_ops sy8106a_ops = {
31 	.set_voltage_sel = regulator_set_voltage_sel_regmap,
32 	.set_voltage_time_sel = regulator_set_voltage_time_sel,
33 	.get_voltage_sel = regulator_get_voltage_sel_regmap,
34 	.list_voltage = regulator_list_voltage_linear,
35 	/* Enabling/disabling the regulator is not yet implemented */
36 };
37 
38 /* Default limits measured in millivolts */
39 #define SY8106A_MIN_MV		680
40 #define SY8106A_MAX_MV		1950
41 #define SY8106A_STEP_MV		10
42 
43 static const struct regulator_desc sy8106a_reg = {
44 	.name = "SY8106A",
45 	.id = 0,
46 	.ops = &sy8106a_ops,
47 	.type = REGULATOR_VOLTAGE,
48 	.n_voltages = ((SY8106A_MAX_MV - SY8106A_MIN_MV) / SY8106A_STEP_MV) + 1,
49 	.min_uV = (SY8106A_MIN_MV * 1000),
50 	.uV_step = (SY8106A_STEP_MV * 1000),
51 	.vsel_reg = SY8106A_REG_VOUT1_SEL,
52 	.vsel_mask = SY8106A_REG_VOUT1_SEL_MASK,
53 	/*
54 	 * This ramp_delay is a conservative default value which works on
55 	 * H3/H5 boards VDD-CPUX situations.
56 	 */
57 	.ramp_delay = 200,
58 	.owner = THIS_MODULE,
59 };
60 
61 /*
62  * I2C driver interface functions
63  */
64 static int sy8106a_i2c_probe(struct i2c_client *i2c)
65 {
66 	struct device *dev = &i2c->dev;
67 	struct regulator_dev *rdev;
68 	struct regulator_config config = { };
69 	struct regmap *regmap;
70 	unsigned int reg, vsel;
71 	u32 fixed_voltage;
72 	int error;
73 
74 	error = of_property_read_u32(dev->of_node, "silergy,fixed-microvolt",
75 				     &fixed_voltage);
76 	if (error)
77 		return error;
78 
79 	if (fixed_voltage < SY8106A_MIN_MV * 1000 ||
80 	    fixed_voltage > SY8106A_MAX_MV * 1000)
81 		return -EINVAL;
82 
83 	regmap = devm_regmap_init_i2c(i2c, &sy8106a_regmap_config);
84 	if (IS_ERR(regmap)) {
85 		error = PTR_ERR(regmap);
86 		dev_err(dev, "Failed to allocate register map: %d\n", error);
87 		return error;
88 	}
89 
90 	config.dev = &i2c->dev;
91 	config.regmap = regmap;
92 
93 	config.of_node = dev->of_node;
94 	config.init_data = of_get_regulator_init_data(dev, dev->of_node,
95 						      &sy8106a_reg);
96 
97 	if (!config.init_data)
98 		return -ENOMEM;
99 
100 	/* Ensure GO_BIT is enabled when probing */
101 	error = regmap_read(regmap, SY8106A_REG_VOUT1_SEL, &reg);
102 	if (error)
103 		return error;
104 
105 	if (!(reg & SY8106A_GO_BIT)) {
106 		vsel = (fixed_voltage / 1000 - SY8106A_MIN_MV) /
107 		       SY8106A_STEP_MV;
108 
109 		error = regmap_write(regmap, SY8106A_REG_VOUT1_SEL,
110 				     vsel | SY8106A_GO_BIT);
111 		if (error)
112 			return error;
113 	}
114 
115 	/* Probe regulator */
116 	rdev = devm_regulator_register(&i2c->dev, &sy8106a_reg, &config);
117 	if (IS_ERR(rdev)) {
118 		error = PTR_ERR(rdev);
119 		dev_err(&i2c->dev, "Failed to register SY8106A regulator: %d\n", error);
120 		return error;
121 	}
122 
123 	return 0;
124 }
125 
126 static const struct of_device_id sy8106a_i2c_of_match[] = {
127 	{ .compatible = "silergy,sy8106a" },
128 	{ },
129 };
130 MODULE_DEVICE_TABLE(of, sy8106a_i2c_of_match);
131 
132 static const struct i2c_device_id sy8106a_i2c_id[] = {
133 	{ "sy8106a", 0 },
134 	{ },
135 };
136 MODULE_DEVICE_TABLE(i2c, sy8106a_i2c_id);
137 
138 static struct i2c_driver sy8106a_regulator_driver = {
139 	.driver = {
140 		.name = "sy8106a",
141 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
142 		.of_match_table	= sy8106a_i2c_of_match,
143 	},
144 	.probe = sy8106a_i2c_probe,
145 	.id_table = sy8106a_i2c_id,
146 };
147 
148 module_i2c_driver(sy8106a_regulator_driver);
149 
150 MODULE_AUTHOR("Ondřej Jirman <megous@megous.com>");
151 MODULE_AUTHOR("Icenowy Zheng <icenowy@aosc.io>");
152 MODULE_DESCRIPTION("Regulator device driver for Silergy SY8106A");
153 MODULE_LICENSE("GPL");
154