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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 0x0116#define RT4831_REG_ENABLE 0x0817#define RT4831_REG_I2CPROT 0x1518 19#define RICHTEK_VENDOR_ID 0x0320#define RT4831_VID_MASK GENMASK(1, 0)21#define RT4831_RESET_MASK BIT(7)22#define RT4831_I2CSAFETMR_MASK BIT(0)23 24static 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 29static 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 36static 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 45static 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 90static void rt4831_remove(struct i2c_client *client)91{92 struct regmap *regmap = dev_get_regmap(&client->dev, NULL);93 int ret;94 95 /* Disable WLED and DSV outputs */96 ret = regmap_update_bits(regmap, RT4831_REG_ENABLE, RT4831_RESET_MASK, RT4831_RESET_MASK);97 if (ret)98 dev_warn(&client->dev, "Failed to disable outputs (%pe)\n", ERR_PTR(ret));99}100 101static const struct of_device_id __maybe_unused rt4831_of_match[] = {102 { .compatible = "richtek,rt4831", },103 {}104};105MODULE_DEVICE_TABLE(of, rt4831_of_match);106 107static struct i2c_driver rt4831_driver = {108 .driver = {109 .name = "rt4831",110 .of_match_table = rt4831_of_match,111 },112 .probe = rt4831_probe,113 .remove = rt4831_remove,114};115module_i2c_driver(rt4831_driver);116 117MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");118MODULE_DESCRIPTION("Richtek RT4831 core driver");119MODULE_LICENSE("GPL v2");120