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_regmap(pdev->dev.parent, NULL); 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"); 136