1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2021, The Linux Foundation. All rights reserved.
4  * Copyright (c) 2022, Linaro Ltd.
5  */
6 
7 #include <linux/bitfield.h>
8 #include <linux/gpio/consumer.h>
9 #include <linux/i2c.h>
10 #include <linux/module.h>
11 #include <linux/of_platform.h>
12 #include <linux/regmap.h>
13 #include <linux/regulator/driver.h>
14 #include <linux/regulator/machine.h>
15 #include <linux/regulator/of_regulator.h>
16 
17 #define MAX20411_UV_STEP		6250
18 #define MAX20411_BASE_UV		243750
19 #define MAX20411_MIN_SEL		41 /* 0.5V */
20 #define MAX20411_MAX_SEL		165 /* 1.275V */
21 #define MAX20411_VID_OFFSET		0x7
22 #define MAX20411_VID_MASK		0xff
23 #define MAX20411_SLEW_OFFSET		0x6
24 #define MAX20411_SLEW_DVS_MASK		0xc
25 #define MAX20411_SLEW_SR_MASK		0x3
26 
27 struct max20411 {
28 	struct device *dev;
29 	struct device_node *of_node;
30 	struct regulator_desc desc;
31 	struct regulator_dev *rdev;
32 	struct regmap *regmap;
33 };
34 
35 static const unsigned int max20411_slew_rates[] = { 13100, 6600, 3300, 1600 };
36 
37 static int max20411_enable_time(struct regulator_dev *rdev)
38 {
39 	int voltage, rate, ret;
40 	unsigned int val;
41 
42 	/* get voltage */
43 	ret = regmap_read(rdev->regmap, rdev->desc->vsel_reg, &val);
44 	if (ret)
45 		return ret;
46 
47 	val &= rdev->desc->vsel_mask;
48 	voltage = regulator_list_voltage_linear(rdev, val);
49 
50 	/* get rate */
51 	ret = regmap_read(rdev->regmap, MAX20411_SLEW_OFFSET, &val);
52 	if (ret)
53 		return ret;
54 
55 	val = FIELD_GET(MAX20411_SLEW_SR_MASK, val);
56 	rate = max20411_slew_rates[val];
57 
58 	return DIV_ROUND_UP(voltage, rate);
59 }
60 
61 static const struct regmap_config max20411_regmap_config = {
62 	.reg_bits		= 8,
63 	.val_bits		= 8,
64 	.max_register		= 0xe,
65 };
66 
67 static const struct regulator_ops max20411_ops = {
68 	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
69 	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
70 	.list_voltage		= regulator_list_voltage_linear,
71 	.enable_time		= max20411_enable_time,
72 };
73 
74 static const struct regulator_desc max20411_desc = {
75 	.ops = &max20411_ops,
76 	.owner = THIS_MODULE,
77 	.type = REGULATOR_VOLTAGE,
78 	.supply_name = "vin",
79 	.name = "max20411",
80 
81 	/*
82 	 * voltage = 0.24375V + selector * 6.25mV
83 	 * with valid selector between 41 to 165 (0.5V to 1.275V)
84 	 */
85 	.min_uV = MAX20411_BASE_UV,
86 	.uV_step = MAX20411_UV_STEP,
87 	.linear_min_sel = MAX20411_MIN_SEL,
88 	.n_voltages = MAX20411_MAX_SEL + 1,
89 
90 	.vsel_reg = MAX20411_VID_OFFSET,
91 	.vsel_mask = MAX20411_VID_MASK,
92 
93 	.ramp_reg = MAX20411_SLEW_OFFSET,
94 	.ramp_mask = MAX20411_SLEW_DVS_MASK,
95 	.ramp_delay_table = max20411_slew_rates,
96 	.n_ramp_values = ARRAY_SIZE(max20411_slew_rates),
97 };
98 
99 static int max20411_probe(struct i2c_client *client)
100 {
101 	struct regulator_init_data *init_data;
102 	struct device *dev = &client->dev;
103 	struct regulator_config cfg = {};
104 	struct max20411 *max20411;
105 
106 	max20411 = devm_kzalloc(dev, sizeof(*max20411), GFP_KERNEL);
107 	if (!max20411)
108 		return -ENOMEM;
109 
110 	max20411->regmap = devm_regmap_init_i2c(client, &max20411_regmap_config);
111 	if (IS_ERR(max20411->regmap)) {
112 		dev_err(dev, "Failed to allocate regmap!\n");
113 		return PTR_ERR(max20411->regmap);
114 	}
115 
116 	max20411->dev = dev;
117 	max20411->of_node = dev->of_node;
118 
119 	max20411->desc = max20411_desc;
120 	init_data = of_get_regulator_init_data(max20411->dev, max20411->of_node, &max20411->desc);
121 	if (!init_data)
122 		return -ENODATA;
123 
124 	cfg.dev = max20411->dev;
125 	cfg.init_data = init_data;
126 	cfg.of_node = max20411->of_node;
127 	cfg.driver_data = max20411;
128 
129 	cfg.ena_gpiod = gpiod_get(max20411->dev, "enable", GPIOD_ASIS);
130 	if (IS_ERR(cfg.ena_gpiod))
131 		return dev_err_probe(dev, PTR_ERR(cfg.ena_gpiod),
132 				     "unable to acquire enable gpio\n");
133 
134 	max20411->rdev = devm_regulator_register(max20411->dev, &max20411->desc, &cfg);
135 	if (IS_ERR(max20411->rdev))
136 		dev_err(max20411->dev, "Failed to register regulator\n");
137 
138 	return PTR_ERR_OR_ZERO(max20411->rdev);
139 }
140 
141 static const struct of_device_id of_max20411_match_tbl[] = {
142 	{ .compatible = "maxim,max20411", },
143 	{ },
144 };
145 MODULE_DEVICE_TABLE(of, of_max20411_match_tbl);
146 
147 static const struct i2c_device_id max20411_id[] = {
148 	{ "max20411", 0 },
149 	{ },
150 };
151 MODULE_DEVICE_TABLE(i2c, max20411_id);
152 
153 static struct i2c_driver max20411_i2c_driver = {
154 	.driver	= {
155 		.name = "max20411",
156 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
157 		.of_match_table	= of_max20411_match_tbl,
158 	},
159 	.probe = max20411_probe,
160 	.id_table = max20411_id,
161 };
162 module_i2c_driver(max20411_i2c_driver);
163 
164 MODULE_LICENSE("GPL");
165