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 struct sy8106a {
26 struct regulator_dev *rdev;
27 struct regmap *regmap;
28 u32 fixed_voltage;
29 };
30
31 static const struct regmap_config sy8106a_regmap_config = {
32 .reg_bits = 8,
33 .val_bits = 8,
34 };
35
36 static const struct regulator_ops sy8106a_ops = {
37 .set_voltage_sel = regulator_set_voltage_sel_regmap,
38 .set_voltage_time_sel = regulator_set_voltage_time_sel,
39 .get_voltage_sel = regulator_get_voltage_sel_regmap,
40 .list_voltage = regulator_list_voltage_linear,
41 /* Enabling/disabling the regulator is not yet implemented */
42 };
43
44 /* Default limits measured in millivolts */
45 #define SY8106A_MIN_MV 680
46 #define SY8106A_MAX_MV 1950
47 #define SY8106A_STEP_MV 10
48
49 static const struct regulator_desc sy8106a_reg = {
50 .name = "SY8106A",
51 .id = 0,
52 .ops = &sy8106a_ops,
53 .type = REGULATOR_VOLTAGE,
54 .n_voltages = ((SY8106A_MAX_MV - SY8106A_MIN_MV) / SY8106A_STEP_MV) + 1,
55 .min_uV = (SY8106A_MIN_MV * 1000),
56 .uV_step = (SY8106A_STEP_MV * 1000),
57 .vsel_reg = SY8106A_REG_VOUT1_SEL,
58 .vsel_mask = SY8106A_REG_VOUT1_SEL_MASK,
59 /*
60 * This ramp_delay is a conservative default value which works on
61 * H3/H5 boards VDD-CPUX situations.
62 */
63 .ramp_delay = 200,
64 .owner = THIS_MODULE,
65 };
66
67 /*
68 * I2C driver interface functions
69 */
sy8106a_i2c_probe(struct i2c_client * i2c,const struct i2c_device_id * id)70 static int sy8106a_i2c_probe(struct i2c_client *i2c,
71 const struct i2c_device_id *id)
72 {
73 struct sy8106a *chip;
74 struct device *dev = &i2c->dev;
75 struct regulator_dev *rdev = NULL;
76 struct regulator_config config = { };
77 unsigned int reg, vsel;
78 int error;
79
80 chip = devm_kzalloc(&i2c->dev, sizeof(struct sy8106a), GFP_KERNEL);
81 if (!chip)
82 return -ENOMEM;
83
84 error = of_property_read_u32(dev->of_node, "silergy,fixed-microvolt",
85 &chip->fixed_voltage);
86 if (error)
87 return error;
88
89 if (chip->fixed_voltage < SY8106A_MIN_MV * 1000 ||
90 chip->fixed_voltage > SY8106A_MAX_MV * 1000)
91 return -EINVAL;
92
93 chip->regmap = devm_regmap_init_i2c(i2c, &sy8106a_regmap_config);
94 if (IS_ERR(chip->regmap)) {
95 error = PTR_ERR(chip->regmap);
96 dev_err(dev, "Failed to allocate register map: %d\n", error);
97 return error;
98 }
99
100 config.dev = &i2c->dev;
101 config.regmap = chip->regmap;
102 config.driver_data = chip;
103
104 config.of_node = dev->of_node;
105 config.init_data = of_get_regulator_init_data(dev, dev->of_node,
106 &sy8106a_reg);
107
108 if (!config.init_data)
109 return -ENOMEM;
110
111 /* Ensure GO_BIT is enabled when probing */
112 error = regmap_read(chip->regmap, SY8106A_REG_VOUT1_SEL, ®);
113 if (error)
114 return error;
115
116 if (!(reg & SY8106A_GO_BIT)) {
117 vsel = (chip->fixed_voltage / 1000 - SY8106A_MIN_MV) /
118 SY8106A_STEP_MV;
119
120 error = regmap_write(chip->regmap, SY8106A_REG_VOUT1_SEL,
121 vsel | SY8106A_GO_BIT);
122 if (error)
123 return error;
124 }
125
126 /* Probe regulator */
127 rdev = devm_regulator_register(&i2c->dev, &sy8106a_reg, &config);
128 if (IS_ERR(rdev)) {
129 error = PTR_ERR(rdev);
130 dev_err(&i2c->dev, "Failed to register SY8106A regulator: %d\n", error);
131 return error;
132 }
133
134 chip->rdev = rdev;
135
136 i2c_set_clientdata(i2c, chip);
137
138 return 0;
139 }
140
141 static const struct of_device_id sy8106a_i2c_of_match[] = {
142 { .compatible = "silergy,sy8106a" },
143 { },
144 };
145 MODULE_DEVICE_TABLE(of, sy8106a_i2c_of_match);
146
147 static const struct i2c_device_id sy8106a_i2c_id[] = {
148 { "sy8106a", 0 },
149 { },
150 };
151 MODULE_DEVICE_TABLE(i2c, sy8106a_i2c_id);
152
153 static struct i2c_driver sy8106a_regulator_driver = {
154 .driver = {
155 .name = "sy8106a",
156 .of_match_table = of_match_ptr(sy8106a_i2c_of_match),
157 },
158 .probe = sy8106a_i2c_probe,
159 .id_table = sy8106a_i2c_id,
160 };
161
162 module_i2c_driver(sy8106a_regulator_driver);
163
164 MODULE_AUTHOR("Ondřej Jirman <megous@megous.com>");
165 MODULE_AUTHOR("Icenowy Zheng <icenowy@aosc.io>");
166 MODULE_DESCRIPTION("Regulator device driver for Silergy SY8106A");
167 MODULE_LICENSE("GPL");
168