cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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sy7636a-regulator.c (3643B)

      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	},
    131	.probe = sy7636a_regulator_probe,
    132	.id_table = sy7636a_regulator_id_table,
    133};
    134module_platform_driver(sy7636a_regulator_driver);
    135
    136MODULE_AUTHOR("Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>");
    137MODULE_DESCRIPTION("SY7636A voltage regulator driver");
    138MODULE_LICENSE("GPL v2");