LXR linux/drivers/regulator/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/module.h>
  11#include <linux/platform_device.h>
  12#include <linux/regmap.h>
  13#include <linux/gpio/consumer.h>
  14#include <linux/mfd/sy7636a.h>
  15
  16struct sy7636a_data {
  17        struct regmap *regmap;
  18        struct gpio_desc *pgood_gpio;
  19};
  20
  21static int sy7636a_get_vcom_voltage_op(struct regulator_dev *rdev)
  22{
  23        int ret;
  24        unsigned int val, val_h;
  25
  26        ret = regmap_read(rdev->regmap, SY7636A_REG_VCOM_ADJUST_CTRL_L, &val);
  27        if (ret)
  28                return ret;
  29
  30        ret = regmap_read(rdev->regmap, SY7636A_REG_VCOM_ADJUST_CTRL_H, &val_h);
  31        if (ret)
  32                return ret;
  33
  34        val |= (val_h << VCOM_ADJUST_CTRL_SHIFT);
  35
  36        return (val & VCOM_ADJUST_CTRL_MASK) * VCOM_ADJUST_CTRL_SCAL;
  37}
  38
  39static int sy7636a_get_status(struct regulator_dev *rdev)
  40{
  41        struct sy7636a_data *data = dev_get_drvdata(rdev->dev.parent);
  42        int ret = 0;
  43
  44        ret = gpiod_get_value_cansleep(data->pgood_gpio);
  45        if (ret < 0)
  46                dev_err(&rdev->dev, "Failed to read pgood gpio: %d\n", ret);
  47
  48        return ret;
  49}
  50
  51static const struct regulator_ops sy7636a_vcom_volt_ops = {
  52        .get_voltage = sy7636a_get_vcom_voltage_op,
  53        .enable = regulator_enable_regmap,
  54        .disable = regulator_disable_regmap,
  55        .is_enabled = regulator_is_enabled_regmap,
  56        .get_status = sy7636a_get_status,
  57};
  58
  59static const struct regulator_desc desc = {
  60        .name = "vcom",
  61        .id = 0,
  62        .ops = &sy7636a_vcom_volt_ops,
  63        .type = REGULATOR_VOLTAGE,
  64        .owner = THIS_MODULE,
  65        .enable_reg = SY7636A_REG_OPERATION_MODE_CRL,
  66        .enable_mask = SY7636A_OPERATION_MODE_CRL_ONOFF,
  67        .regulators_node = of_match_ptr("regulators"),
  68        .of_match = of_match_ptr("vcom"),
  69};
  70
  71static int sy7636a_regulator_probe(struct platform_device *pdev)
  72{
  73        struct regmap *regmap = dev_get_drvdata(pdev->dev.parent);
  74        struct regulator_config config = { };
  75        struct regulator_dev *rdev;
  76        struct gpio_desc *gdp;
  77        struct sy7636a_data *data;
  78        int ret;
  79
  80        if (!regmap)
  81                return -EPROBE_DEFER;
  82
  83        gdp = devm_gpiod_get(pdev->dev.parent, "epd-pwr-good", GPIOD_IN);
  84        if (IS_ERR(gdp)) {
  85                dev_err(pdev->dev.parent, "Power good GPIO fault %ld\n", PTR_ERR(gdp));
  86                return PTR_ERR(gdp);
  87        }
  88
  89        data = devm_kzalloc(&pdev->dev, sizeof(struct sy7636a_data), GFP_KERNEL);
  90        if (!data)
  91                return -ENOMEM;
  92
  93        data->regmap = regmap;
  94        data->pgood_gpio = gdp;
  95
  96        platform_set_drvdata(pdev, data);
  97
  98        ret = regmap_write(regmap, SY7636A_REG_POWER_ON_DELAY_TIME, 0x0);
  99        if (ret) {
 100                dev_err(pdev->dev.parent, "Failed to initialize regulator: %d\n", ret);
 101                return ret;
 102        }
 103
 104        config.dev = &pdev->dev;
 105        config.dev->of_node = pdev->dev.parent->of_node;
 106        config.regmap = regmap;
 107
 108        rdev = devm_regulator_register(&pdev->dev, &desc, &config);
 109        if (IS_ERR(rdev)) {
 110                dev_err(pdev->dev.parent, "Failed to register %s regulator\n",
 111                        pdev->name);
 112                return PTR_ERR(rdev);
 113        }
 114
 115        return 0;
 116}
 117
 118static const struct platform_device_id sy7636a_regulator_id_table[] = {
 119        { "sy7636a-regulator", },
 120        { }
 121};
 122MODULE_DEVICE_TABLE(platform, sy7636a_regulator_id_table);
 123
 124static struct platform_driver sy7636a_regulator_driver = {
 125        .driver = {
 126                .name = "sy7636a-regulator",
 127        },
 128        .probe = sy7636a_regulator_probe,
 129        .id_table = sy7636a_regulator_id_table,
 130};
 131module_platform_driver(sy7636a_regulator_driver);
 132
 133MODULE_AUTHOR("Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>");
 134MODULE_DESCRIPTION("SY7636A voltage regulator driver");
 135MODULE_LICENSE("GPL v2");
 136