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/consumer.h>
16#include <linux/regulator/driver.h>
17#include <linux/regulator/machine.h>
18#include <linux/regmap.h>
19
20struct sy7636a_data {
21 struct regmap *regmap;
22 struct gpio_desc *pgood_gpio;
23 struct gpio_desc *en_gpio;
24 struct gpio_desc *vcom_en_gpio;
25};
26
27static int sy7636a_get_vcom_voltage_op(struct regulator_dev *rdev)
28{
29 int ret;
30 unsigned int val, val_h;
31
32 ret = regmap_read(map: rdev->regmap, SY7636A_REG_VCOM_ADJUST_CTRL_L, val: &val);
33 if (ret)
34 return ret;
35
36 ret = regmap_read(map: rdev->regmap, SY7636A_REG_VCOM_ADJUST_CTRL_H, val: &val_h);
37 if (ret)
38 return ret;
39
40 val |= (val_h << VCOM_ADJUST_CTRL_SHIFT);
41
42 return (val & VCOM_ADJUST_CTRL_MASK) * VCOM_ADJUST_CTRL_SCAL;
43}
44
45static int sy7636a_get_status(struct regulator_dev *rdev)
46{
47 struct sy7636a_data *data = dev_get_drvdata(dev: rdev->dev.parent);
48 int ret = 0;
49
50 ret = gpiod_get_value_cansleep(desc: data->pgood_gpio);
51 if (ret < 0)
52 dev_err(&rdev->dev, "Failed to read pgood gpio: %d\n", ret);
53
54 return ret;
55}
56
57static const struct regulator_ops sy7636a_vcom_volt_ops = {
58 .get_voltage = sy7636a_get_vcom_voltage_op,
59 .enable = regulator_enable_regmap,
60 .disable = regulator_disable_regmap,
61 .is_enabled = regulator_is_enabled_regmap,
62 .get_status = sy7636a_get_status,
63};
64
65static const struct regulator_desc desc = {
66 .name = "vcom",
67 .id = 0,
68 .ops = &sy7636a_vcom_volt_ops,
69 .type = REGULATOR_VOLTAGE,
70 .owner = THIS_MODULE,
71 .enable_reg = SY7636A_REG_OPERATION_MODE_CRL,
72 .enable_mask = SY7636A_OPERATION_MODE_CRL_ONOFF,
73 .regulators_node = of_match_ptr("regulators"),
74 .of_match = of_match_ptr("vcom"),
75};
76
77static int sy7636a_regulator_probe(struct platform_device *pdev)
78{
79 struct regmap *regmap = dev_get_regmap(dev: pdev->dev.parent, NULL);
80 struct regulator_config config = { };
81 struct regulator_dev *rdev;
82 struct gpio_desc *gdp;
83 struct sy7636a_data *data;
84 int ret;
85
86 if (!regmap)
87 return -EPROBE_DEFER;
88
89 device_set_of_node_from_dev(dev: &pdev->dev, dev2: pdev->dev.parent);
90
91 gdp = devm_gpiod_get(dev: &pdev->dev, con_id: "epd-pwr-good", flags: GPIOD_IN);
92 if (IS_ERR(ptr: gdp)) {
93 dev_err(&pdev->dev, "Power good GPIO fault %ld\n", PTR_ERR(gdp));
94 return PTR_ERR(ptr: gdp);
95 }
96
97 data = devm_kzalloc(dev: &pdev->dev, size: sizeof(struct sy7636a_data), GFP_KERNEL);
98 if (!data)
99 return -ENOMEM;
100
101 data->regmap = regmap;
102 data->pgood_gpio = gdp;
103
104 ret = devm_regulator_get_enable_optional(dev: &pdev->dev, id: "vin");
105 if (ret)
106 return dev_err_probe(dev: &pdev->dev, err: ret,
107 fmt: "failed to get vin regulator\n");
108
109 data->en_gpio = devm_gpiod_get_optional(dev: &pdev->dev, con_id: "enable",
110 flags: GPIOD_OUT_HIGH);
111 if (IS_ERR(ptr: data->en_gpio))
112 return dev_err_probe(dev: &pdev->dev,
113 err: PTR_ERR(ptr: data->en_gpio),
114 fmt: "failed to get en gpio\n");
115
116 /* Let VCOM just follow the default power on sequence */
117 data->vcom_en_gpio = devm_gpiod_get_optional(dev: &pdev->dev,
118 con_id: "vcom-en", flags: GPIOD_OUT_LOW);
119 if (IS_ERR(ptr: data->vcom_en_gpio))
120 return dev_err_probe(dev: &pdev->dev,
121 err: PTR_ERR(ptr: data->vcom_en_gpio),
122 fmt: "failed to get vcom-en gpio\n");
123
124 /* if chip was not enabled, give it time to wake up */
125 if (data->en_gpio)
126 usleep_range(min: 2500, max: 4000);
127
128 platform_set_drvdata(pdev, data);
129
130 ret = regmap_write(map: regmap, SY7636A_REG_POWER_ON_DELAY_TIME, val: 0x0);
131 if (ret) {
132 dev_err(pdev->dev.parent, "Failed to initialize regulator: %d\n", ret);
133 return ret;
134 }
135
136 config.dev = &pdev->dev;
137 config.regmap = regmap;
138
139 rdev = devm_regulator_register(dev: &pdev->dev, regulator_desc: &desc, config: &config);
140 if (IS_ERR(ptr: rdev)) {
141 dev_err(pdev->dev.parent, "Failed to register %s regulator\n",
142 pdev->name);
143 return PTR_ERR(ptr: rdev);
144 }
145
146 return 0;
147}
148
149static const struct platform_device_id sy7636a_regulator_id_table[] = {
150 { "sy7636a-regulator", },
151 { }
152};
153MODULE_DEVICE_TABLE(platform, sy7636a_regulator_id_table);
154
155static struct platform_driver sy7636a_regulator_driver = {
156 .driver = {
157 .name = "sy7636a-regulator",
158 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
159 },
160 .probe = sy7636a_regulator_probe,
161 .id_table = sy7636a_regulator_id_table,
162};
163module_platform_driver(sy7636a_regulator_driver);
164
165MODULE_AUTHOR("Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>");
166MODULE_DESCRIPTION("SY7636A voltage regulator driver");
167MODULE_LICENSE("GPL v2");
168

source code of linux/drivers/regulator/sy7636a-regulator.c