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 #define SY7636A_POLL_ENABLED_TIME 500
  17
  18 static int sy7636a_get_vcom_voltage_op(struct regulator_dev *rdev)
  19 {
  20         int ret;
  21         unsigned int val, val_h;
  22
  23         ret = regmap_read(rdev->regmap, SY7636A_REG_VCOM_ADJUST_CTRL_L, &val);
  24         if (ret)
  25                 return ret;
  26
  27         ret = regmap_read(rdev->regmap, SY7636A_REG_VCOM_ADJUST_CTRL_H, &val_h);
  28         if (ret)
  29                 return ret;
  30
  31         val |= (val_h << VCOM_ADJUST_CTRL_SHIFT);
  32
  33         return (val & VCOM_ADJUST_CTRL_MASK) * VCOM_ADJUST_CTRL_SCAL;
  34 }
  35
  36 static int sy7636a_get_status(struct regulator_dev *rdev)
  37 {
  38         struct sy7636a *sy7636a = rdev_get_drvdata(rdev);
  39         int ret = 0;
  40
  41         ret = gpiod_get_value_cansleep(sy7636a->pgood_gpio);
  42         if (ret < 0)
  43                 dev_err(&rdev->dev, "Failed to read pgood gpio: %d\n", ret);
  44
  45         return ret;
  46 }
  47
  48 static const struct regulator_ops sy7636a_vcom_volt_ops = {
  49         .get_voltage = sy7636a_get_vcom_voltage_op,
  50         .enable = regulator_enable_regmap,
  51         .disable = regulator_disable_regmap,
  52         .is_enabled = regulator_is_enabled_regmap,
  53         .get_status = sy7636a_get_status,
  54 };
  55
  56 static const struct regulator_desc desc = {
  57         .name = "vcom",
  58         .id = 0,
  59         .ops = &sy7636a_vcom_volt_ops,
  60         .type = REGULATOR_VOLTAGE,
  61         .owner = THIS_MODULE,
  62         .enable_reg = SY7636A_REG_OPERATION_MODE_CRL,
  63         .enable_mask = SY7636A_OPERATION_MODE_CRL_ONOFF,
  64         .poll_enabled_time = SY7636A_POLL_ENABLED_TIME,
  65         .regulators_node = of_match_ptr("regulators"),
  66         .of_match = of_match_ptr("vcom"),
  67 };
  68
  69 static int sy7636a_regulator_probe(struct platform_device *pdev)
  70 {
  71         struct sy7636a *sy7636a = dev_get_drvdata(pdev->dev.parent);
  72         struct regulator_config config = { };
  73         struct regulator_dev *rdev;
  74         struct gpio_desc *gdp;
  75         int ret;
  76
  77         if (!sy7636a)
  78                 return -EPROBE_DEFER;
  79
  80         platform_set_drvdata(pdev, sy7636a);
  81
  82         gdp = devm_gpiod_get(sy7636a->dev, "epd-pwr-good", GPIOD_IN);
  83         if (IS_ERR(gdp)) {
  84                 dev_err(sy7636a->dev, "Power good GPIO fault %ld\n", PTR_ERR(gdp));
  85                 return PTR_ERR(gdp);
  86         }
  87
  88         sy7636a->pgood_gpio = gdp;
  89
  90         ret = regmap_write(sy7636a->regmap, SY7636A_REG_POWER_ON_DELAY_TIME, 0x0);
  91         if (ret) {
  92                 dev_err(sy7636a->dev, "Failed to initialize regulator: %d\n", ret);
  93                 return ret;
  94         }
  95
  96         config.dev = &pdev->dev;
  97         config.dev->of_node = sy7636a->dev->of_node;
  98         config.driver_data = sy7636a;
  99         config.regmap = sy7636a->regmap;
 100
 101         rdev = devm_regulator_register(&pdev->dev, &desc, &config);
 102         if (IS_ERR(rdev)) {
 103                 dev_err(sy7636a->dev, "Failed to register %s regulator\n",
 104                         pdev->name);
 105                 return PTR_ERR(rdev);
 106         }
 107
 108         return 0;
 109 }
 110
 111 static const struct platform_device_id sy7636a_regulator_id_table[] = {
 112         { "sy7636a-regulator", },
 113         { }
 114 };
 115 MODULE_DEVICE_TABLE(platform, sy7636a_regulator_id_table);
 116
 117 static struct platform_driver sy7636a_regulator_driver = {
 118         .driver = {
 119                 .name = "sy7636a-regulator",
 120         },
 121         .probe = sy7636a_regulator_probe,
 122         .id_table = sy7636a_regulator_id_table,
 123 };
 124 module_platform_driver(sy7636a_regulator_driver);
 125
 126 MODULE_AUTHOR("Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>");
 127 MODULE_DESCRIPTION("SY7636A voltage regulator driver");
 128 MODULE_LICENSE("GPL v2");