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
 19struct sy7636a_data {
 20	struct regmap *regmap;
 21	struct gpio_desc *pgood_gpio;
 22};
 23
 24static 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
 42static 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
 54static 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
 62static 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
 74static 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
121static const struct platform_device_id sy7636a_regulator_id_table[] = {
122	{ "sy7636a-regulator", },
123	{ }
124};
125MODULE_DEVICE_TABLE(platform, sy7636a_regulator_id_table);
126
127static 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};
135module_platform_driver(sy7636a_regulator_driver);
136
137MODULE_AUTHOR("Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>");
138MODULE_DESCRIPTION("SY7636A voltage regulator driver");
139MODULE_LICENSE("GPL v2");