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/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
  19 struct sy7636a_data {
  20         struct regmap *regmap;
  21         struct gpio_desc *pgood_gpio;
  22 };
  23
  24 static 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
  42 static 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
  54 static 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
  62 static 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
  74 static 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
 121 static const struct platform_device_id sy7636a_regulator_id_table[] = {
 122         { "sy7636a-regulator", },
 123         { }
 124 };
 125 MODULE_DEVICE_TABLE(platform, sy7636a_regulator_id_table);
 126
 127 static 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 };
 135 module_platform_driver(sy7636a_regulator_driver);
 136
 137 MODULE_AUTHOR("Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>");
 138 MODULE_DESCRIPTION("SY7636A voltage regulator driver");
 139 MODULE_LICENSE("GPL v2");