1 // SPDX-License-Identifier: GPL-2.0+
2 //
3 // Functions to access SY3686A power management chip voltages
4 //
5 // Copyright (C) 2019 reMarkable AS - http://www.remarkable.com/
6 //
7 // Authors: Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>
8 //          Alistair Francis <alistair@alistair23.me>
9 
10 #include <linux/gpio/consumer.h>
11 #include <linux/i2c.h>
12 #include <linux/mfd/sy7636a.h>
13 #include <linux/module.h>
14 #include <linux/platform_device.h>
15 #include <linux/regulator/driver.h>
16 #include <linux/regulator/machine.h>
17 #include <linux/regmap.h>
18 
19 struct sy7636a_data {
20 	struct regmap *regmap;
21 	struct gpio_desc *pgood_gpio;
22 };
23 
24 static int sy7636a_get_vcom_voltage_op(struct regulator_dev *rdev)
25 {
26 	int ret;
27 	unsigned int val, val_h;
28 
29 	ret = regmap_read(rdev->regmap, SY7636A_REG_VCOM_ADJUST_CTRL_L, &val);
30 	if (ret)
31 		return ret;
32 
33 	ret = regmap_read(rdev->regmap, SY7636A_REG_VCOM_ADJUST_CTRL_H, &val_h);
34 	if (ret)
35 		return ret;
36 
37 	val |= (val_h << VCOM_ADJUST_CTRL_SHIFT);
38 
39 	return (val & VCOM_ADJUST_CTRL_MASK) * VCOM_ADJUST_CTRL_SCAL;
40 }
41 
42 static int sy7636a_get_status(struct regulator_dev *rdev)
43 {
44 	struct sy7636a_data *data = dev_get_drvdata(rdev->dev.parent);
45 	int ret = 0;
46 
47 	ret = gpiod_get_value_cansleep(data->pgood_gpio);
48 	if (ret < 0)
49 		dev_err(&rdev->dev, "Failed to read pgood gpio: %d\n", ret);
50 
51 	return ret;
52 }
53 
54 static const struct regulator_ops sy7636a_vcom_volt_ops = {
55 	.get_voltage = sy7636a_get_vcom_voltage_op,
56 	.enable = regulator_enable_regmap,
57 	.disable = regulator_disable_regmap,
58 	.is_enabled = regulator_is_enabled_regmap,
59 	.get_status = sy7636a_get_status,
60 };
61 
62 static const struct regulator_desc desc = {
63 	.name = "vcom",
64 	.id = 0,
65 	.ops = &sy7636a_vcom_volt_ops,
66 	.type = REGULATOR_VOLTAGE,
67 	.owner = THIS_MODULE,
68 	.enable_reg = SY7636A_REG_OPERATION_MODE_CRL,
69 	.enable_mask = SY7636A_OPERATION_MODE_CRL_ONOFF,
70 	.regulators_node = of_match_ptr("regulators"),
71 	.of_match = of_match_ptr("vcom"),
72 };
73 
74 static int sy7636a_regulator_probe(struct platform_device *pdev)
75 {
76 	struct regmap *regmap = dev_get_regmap(pdev->dev.parent, NULL);
77 	struct regulator_config config = { };
78 	struct regulator_dev *rdev;
79 	struct gpio_desc *gdp;
80 	struct sy7636a_data *data;
81 	int ret;
82 
83 	if (!regmap)
84 		return -EPROBE_DEFER;
85 
86 	gdp = devm_gpiod_get(pdev->dev.parent, "epd-pwr-good", GPIOD_IN);
87 	if (IS_ERR(gdp)) {
88 		dev_err(pdev->dev.parent, "Power good GPIO fault %ld\n", PTR_ERR(gdp));
89 		return PTR_ERR(gdp);
90 	}
91 
92 	data = devm_kzalloc(&pdev->dev, sizeof(struct sy7636a_data), GFP_KERNEL);
93 	if (!data)
94 		return -ENOMEM;
95 
96 	data->regmap = regmap;
97 	data->pgood_gpio = gdp;
98 
99 	platform_set_drvdata(pdev, data);
100 
101 	ret = regmap_write(regmap, SY7636A_REG_POWER_ON_DELAY_TIME, 0x0);
102 	if (ret) {
103 		dev_err(pdev->dev.parent, "Failed to initialize regulator: %d\n", ret);
104 		return ret;
105 	}
106 
107 	config.dev = &pdev->dev;
108 	config.dev->of_node = pdev->dev.parent->of_node;
109 	config.regmap = regmap;
110 
111 	rdev = devm_regulator_register(&pdev->dev, &desc, &config);
112 	if (IS_ERR(rdev)) {
113 		dev_err(pdev->dev.parent, "Failed to register %s regulator\n",
114 			pdev->name);
115 		return PTR_ERR(rdev);
116 	}
117 
118 	return 0;
119 }
120 
121 static const struct platform_device_id sy7636a_regulator_id_table[] = {
122 	{ "sy7636a-regulator", },
123 	{ }
124 };
125 MODULE_DEVICE_TABLE(platform, sy7636a_regulator_id_table);
126 
127 static struct platform_driver sy7636a_regulator_driver = {
128 	.driver = {
129 		.name = "sy7636a-regulator",
130 	},
131 	.probe = sy7636a_regulator_probe,
132 	.id_table = sy7636a_regulator_id_table,
133 };
134 module_platform_driver(sy7636a_regulator_driver);
135 
136 MODULE_AUTHOR("Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>");
137 MODULE_DESCRIPTION("SY7636A voltage regulator driver");
138 MODULE_LICENSE("GPL v2");
139