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