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
  16 struct sy7636a_data {
  17         struct regmap *regmap;
  18         struct gpio_desc *pgood_gpio;
  19 };
  20
  21 static 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
  39 static 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
  51 static 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
  59 static 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
  71 static 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
 118 static const struct platform_device_id sy7636a_regulator_id_table[] = {
 119         { "sy7636a-regulator", },
 120         { }
 121 };
 122 MODULE_DEVICE_TABLE(platform, sy7636a_regulator_id_table);
 123
 124 static 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 };
 131 module_platform_driver(sy7636a_regulator_driver);
 132
 133 MODULE_AUTHOR("Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>");
 134 MODULE_DESCRIPTION("SY7636A voltage regulator driver");
 135 MODULE_LICENSE("GPL v2");