1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Copyright (c) 2021 Richtek Technology Corp. 4 * 5 * Author: ChiYuan Huang <cy_huang@richtek.com> 6 */ 7 8 #include <linux/gpio/consumer.h> 9 #include <linux/i2c.h> 10 #include <linux/kernel.h> 11 #include <linux/mfd/core.h> 12 #include <linux/module.h> 13 #include <linux/regmap.h> 14 15 #define RT4831_REG_REVISION 0x01 16 #define RT4831_REG_ENABLE 0x08 17 #define RT4831_REG_I2CPROT 0x15 18 19 #define RICHTEK_VENDOR_ID 0x03 20 #define RT4831_VID_MASK GENMASK(1, 0) 21 #define RT4831_RESET_MASK BIT(7) 22 #define RT4831_I2CSAFETMR_MASK BIT(0) 23 24 static const struct mfd_cell rt4831_subdevs[] = { 25 MFD_CELL_OF("rt4831-backlight", NULL, NULL, 0, 0, "richtek,rt4831-backlight"), 26 MFD_CELL_NAME("rt4831-regulator") 27 }; 28 29 static bool rt4831_is_accessible_reg(struct device *dev, unsigned int reg) 30 { 31 if (reg >= RT4831_REG_REVISION && reg <= RT4831_REG_I2CPROT) 32 return true; 33 return false; 34 } 35 36 static const struct regmap_config rt4831_regmap_config = { 37 .reg_bits = 8, 38 .val_bits = 8, 39 .max_register = RT4831_REG_I2CPROT, 40 41 .readable_reg = rt4831_is_accessible_reg, 42 .writeable_reg = rt4831_is_accessible_reg, 43 }; 44 45 static int rt4831_probe(struct i2c_client *client) 46 { 47 struct gpio_desc *enable_gpio; 48 struct regmap *regmap; 49 unsigned int chip_id; 50 int ret; 51 52 enable_gpio = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_HIGH); 53 if (IS_ERR(enable_gpio)) { 54 dev_err(&client->dev, "Failed to get 'enable' GPIO\n"); 55 return PTR_ERR(enable_gpio); 56 } 57 58 regmap = devm_regmap_init_i2c(client, &rt4831_regmap_config); 59 if (IS_ERR(regmap)) { 60 dev_err(&client->dev, "Failed to initialize regmap\n"); 61 return PTR_ERR(regmap); 62 } 63 64 ret = regmap_read(regmap, RT4831_REG_REVISION, &chip_id); 65 if (ret) { 66 dev_err(&client->dev, "Failed to get H/W revision\n"); 67 return ret; 68 } 69 70 if ((chip_id & RT4831_VID_MASK) != RICHTEK_VENDOR_ID) { 71 dev_err(&client->dev, "Chip vendor ID 0x%02x not matched\n", chip_id); 72 return -ENODEV; 73 } 74 75 /* 76 * Used to prevent the abnormal shutdown. 77 * If SCL/SDA both keep low for one second to reset HW. 78 */ 79 ret = regmap_update_bits(regmap, RT4831_REG_I2CPROT, RT4831_I2CSAFETMR_MASK, 80 RT4831_I2CSAFETMR_MASK); 81 if (ret) { 82 dev_err(&client->dev, "Failed to enable I2C safety timer\n"); 83 return ret; 84 } 85 86 return devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_AUTO, rt4831_subdevs, 87 ARRAY_SIZE(rt4831_subdevs), NULL, 0, NULL); 88 } 89 90 static int rt4831_remove(struct i2c_client *client) 91 { 92 struct regmap *regmap = dev_get_regmap(&client->dev, NULL); 93 94 /* Disable WLED and DSV outputs */ 95 return regmap_update_bits(regmap, RT4831_REG_ENABLE, RT4831_RESET_MASK, RT4831_RESET_MASK); 96 } 97 98 static const struct of_device_id __maybe_unused rt4831_of_match[] = { 99 { .compatible = "richtek,rt4831", }, 100 {} 101 }; 102 MODULE_DEVICE_TABLE(of, rt4831_of_match); 103 104 static struct i2c_driver rt4831_driver = { 105 .driver = { 106 .name = "rt4831", 107 .of_match_table = rt4831_of_match, 108 }, 109 .probe_new = rt4831_probe, 110 .remove = rt4831_remove, 111 }; 112 module_i2c_driver(rt4831_driver); 113 114 MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>"); 115 MODULE_LICENSE("GPL v2"); 116