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
sy7636a_get_vcom_voltage_op(struct regulator_dev * rdev)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
sy7636a_get_status(struct regulator_dev * rdev)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
sy7636a_regulator_probe(struct platform_device * pdev)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 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
131 },
132 .probe = sy7636a_regulator_probe,
133 .id_table = sy7636a_regulator_id_table,
134 };
135 module_platform_driver(sy7636a_regulator_driver);
136
137 MODULE_AUTHOR("Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>");
138 MODULE_DESCRIPTION("SY7636A voltage regulator driver");
139 MODULE_LICENSE("GPL v2");
140