sy7636a-regulator.c

  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(rdev->regmap, SY7636A_REG_VCOM_ADJUST_CTRL_L, &val);
 33	if (ret)
 34		return ret;
 35
 36	ret = regmap_read(rdev->regmap, SY7636A_REG_VCOM_ADJUST_CTRL_H, &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(rdev->dev.parent);
 48	int ret = 0;
 49
 50	ret = gpiod_get_value_cansleep(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(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(&pdev->dev, pdev->dev.parent);
 90
 91	gdp = devm_gpiod_get(&pdev->dev, "epd-pwr-good", GPIOD_IN);
 92	if (IS_ERR(gdp)) {
 93		dev_err(&pdev->dev, "Power good GPIO fault %ld\n", PTR_ERR(gdp));
 94		return PTR_ERR(gdp);
 95	}
 96
 97	data = devm_kzalloc(&pdev->dev, 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(&pdev->dev, "vin");
105	if (ret)
106		return dev_err_probe(&pdev->dev, ret,
107				     "failed to get vin regulator\n");
108
109	data->en_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
110						GPIOD_OUT_HIGH);
111	if (IS_ERR(data->en_gpio))
112		return dev_err_probe(&pdev->dev,
113				     PTR_ERR(data->en_gpio),
114				     "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(&pdev->dev,
118						     "vcom-en", GPIOD_OUT_LOW);
119	if (IS_ERR(data->vcom_en_gpio))
120		return dev_err_probe(&pdev->dev,
121				     PTR_ERR(data->vcom_en_gpio),
122				     "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(2500, 4000);
127
128	platform_set_drvdata(pdev, data);
129
130	ret = regmap_write(regmap, SY7636A_REG_POWER_ON_DELAY_TIME, 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(&pdev->dev, &desc, &config);
140	if (IS_ERR(rdev)) {
141		dev_err(pdev->dev.parent, "Failed to register %s regulator\n",
142			pdev->name);
143		return PTR_ERR(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");