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1// SPDX-License-Identifier: GPL-2.0+2//3// Functions to access SY3686A power management chip voltages4//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");140