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/consumer.h> 16 #include <linux/regulator/driver.h> 17 #include <linux/regulator/machine.h> 18 #include <linux/regmap.h> 19 20 struct sy7636a_data { 21 struct regmap *regmap; 22 struct gpio_desc *pgood_gpio; 23 struct gpio_desc *en_gpio; 24 struct gpio_desc *vcom_en_gpio; 25 }; 26 27 static int sy7636a_get_vcom_voltage_op(struct regulator_dev *rdev) 28 { 29 int ret; 30 unsigned int val, val_h; 31 32 ret = regmap_read(rdev->regmap, SY7636A_REG_VCOM_ADJUST_CTRL_L, &val); 33 if (ret) 34 return ret; 35 36 ret = regmap_read(rdev->regmap, SY7636A_REG_VCOM_ADJUST_CTRL_H, &val_h); 37 if (ret) 38 return ret; 39 40 val |= (val_h << VCOM_ADJUST_CTRL_SHIFT); 41 42 return (val & VCOM_ADJUST_CTRL_MASK) * VCOM_ADJUST_CTRL_SCAL; 43 } 44 45 static int sy7636a_get_status(struct regulator_dev *rdev) 46 { 47 struct sy7636a_data *data = dev_get_drvdata(rdev->dev.parent); 48 int ret = 0; 49 50 ret = gpiod_get_value_cansleep(data->pgood_gpio); 51 if (ret < 0) 52 dev_err(&rdev->dev, "Failed to read pgood gpio: %d\n", ret); 53 54 return ret; 55 } 56 57 static const struct regulator_ops sy7636a_vcom_volt_ops = { 58 .get_voltage = sy7636a_get_vcom_voltage_op, 59 .enable = regulator_enable_regmap, 60 .disable = regulator_disable_regmap, 61 .is_enabled = regulator_is_enabled_regmap, 62 .get_status = sy7636a_get_status, 63 }; 64 65 static const struct regulator_desc desc = { 66 .name = "vcom", 67 .id = 0, 68 .ops = &sy7636a_vcom_volt_ops, 69 .type = REGULATOR_VOLTAGE, 70 .owner = THIS_MODULE, 71 .enable_reg = SY7636A_REG_OPERATION_MODE_CRL, 72 .enable_mask = SY7636A_OPERATION_MODE_CRL_ONOFF, 73 .regulators_node = of_match_ptr("regulators"), 74 .of_match = of_match_ptr("vcom"), 75 }; 76 77 static int sy7636a_regulator_probe(struct platform_device *pdev) 78 { 79 struct regmap *regmap = dev_get_regmap(pdev->dev.parent, NULL); 80 struct regulator_config config = { }; 81 struct regulator_dev *rdev; 82 struct gpio_desc *gdp; 83 struct sy7636a_data *data; 84 int ret; 85 86 if (!regmap) 87 return -EPROBE_DEFER; 88 89 device_set_of_node_from_dev(&pdev->dev, pdev->dev.parent); 90 91 gdp = devm_gpiod_get(&pdev->dev, "epd-pwr-good", GPIOD_IN); 92 if (IS_ERR(gdp)) { 93 dev_err(&pdev->dev, "Power good GPIO fault %ld\n", PTR_ERR(gdp)); 94 return PTR_ERR(gdp); 95 } 96 97 data = devm_kzalloc(&pdev->dev, sizeof(struct sy7636a_data), GFP_KERNEL); 98 if (!data) 99 return -ENOMEM; 100 101 data->regmap = regmap; 102 data->pgood_gpio = gdp; 103 104 ret = devm_regulator_get_enable_optional(&pdev->dev, "vin"); 105 if (ret) 106 return dev_err_probe(&pdev->dev, ret, 107 "failed to get vin regulator\n"); 108 109 data->en_gpio = devm_gpiod_get_optional(&pdev->dev, "enable", 110 GPIOD_OUT_HIGH); 111 if (IS_ERR(data->en_gpio)) 112 return dev_err_probe(&pdev->dev, 113 PTR_ERR(data->en_gpio), 114 "failed to get en gpio\n"); 115 116 /* Let VCOM just follow the default power on sequence */ 117 data->vcom_en_gpio = devm_gpiod_get_optional(&pdev->dev, 118 "vcom-en", GPIOD_OUT_LOW); 119 if (IS_ERR(data->vcom_en_gpio)) 120 return dev_err_probe(&pdev->dev, 121 PTR_ERR(data->vcom_en_gpio), 122 "failed to get vcom-en gpio\n"); 123 124 /* if chip was not enabled, give it time to wake up */ 125 if (data->en_gpio) 126 usleep_range(2500, 4000); 127 128 platform_set_drvdata(pdev, data); 129 130 ret = regmap_write(regmap, SY7636A_REG_POWER_ON_DELAY_TIME, 0x0); 131 if (ret) { 132 dev_err(pdev->dev.parent, "Failed to initialize regulator: %d\n", ret); 133 return ret; 134 } 135 136 config.dev = &pdev->dev; 137 config.regmap = regmap; 138 139 rdev = devm_regulator_register(&pdev->dev, &desc, &config); 140 if (IS_ERR(rdev)) { 141 dev_err(pdev->dev.parent, "Failed to register %s regulator\n", 142 pdev->name); 143 return PTR_ERR(rdev); 144 } 145 146 return 0; 147 } 148 149 static const struct platform_device_id sy7636a_regulator_id_table[] = { 150 { "sy7636a-regulator", }, 151 { } 152 }; 153 MODULE_DEVICE_TABLE(platform, sy7636a_regulator_id_table); 154 155 static struct platform_driver sy7636a_regulator_driver = { 156 .driver = { 157 .name = "sy7636a-regulator", 158 .probe_type = PROBE_PREFER_ASYNCHRONOUS, 159 }, 160 .probe = sy7636a_regulator_probe, 161 .id_table = sy7636a_regulator_id_table, 162 }; 163 module_platform_driver(sy7636a_regulator_driver); 164 165 MODULE_AUTHOR("Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>"); 166 MODULE_DESCRIPTION("SY7636A voltage regulator driver"); 167 MODULE_LICENSE("GPL v2"); 168