// SPDX-License-Identifier: GPL-2.0+/* * Copyright (c) 2021 Richtek Technology Corp. * * Author: ChiYuan Huang <cy_huang@richtek.com> */ #include <linux/gpio/consumer.h>#include <linux/i2c.h>#include <linux/kernel.h>#include <linux/mfd/core.h>#include <linux/module.h>#include <linux/regmap.h> #define RT4831_REG_REVISION	0x01#define RT4831_REG_ENABLE	0x08#define RT4831_REG_I2CPROT	0x15 #define RICHTEK_VENDOR_ID	0x03#define RT4831_VID_MASK		GENMASK(1, 0)#define RT4831_RESET_MASK	BIT(7)#define RT4831_I2CSAFETMR_MASK	BIT(0) static const struct mfd_cell rt4831_subdevs[] = {	MFD_CELL_OF("rt4831-backlight", NULL, NULL, 0, 0, "richtek,rt4831-backlight"),	MFD_CELL_NAME("rt4831-regulator")}; static bool rt4831_is_accessible_reg(struct device *dev, unsigned int reg){	if (reg >= RT4831_REG_REVISION && reg <= RT4831_REG_I2CPROT)		return true;	return false;} static const struct regmap_config rt4831_regmap_config = {	.reg_bits = 8,	.val_bits = 8,	.max_register = RT4831_REG_I2CPROT, 	.readable_reg = rt4831_is_accessible_reg,	.writeable_reg = rt4831_is_accessible_reg,}; static int rt4831_probe(struct i2c_client *client){	struct gpio_desc *enable_gpio;	struct regmap *regmap;	unsigned int chip_id;	int ret; 	enable_gpio = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_HIGH);	if (IS_ERR(enable_gpio)) {		dev_err(&client->dev, "Failed to get 'enable' GPIO\n");		return PTR_ERR(enable_gpio);	} 	regmap = devm_regmap_init_i2c(client, &rt4831_regmap_config);	if (IS_ERR(regmap)) {		dev_err(&client->dev, "Failed to initialize regmap\n");		return PTR_ERR(regmap);	} 	ret = regmap_read(regmap, RT4831_REG_REVISION, &chip_id);	if (ret) {		dev_err(&client->dev, "Failed to get H/W revision\n");		return ret;	} 	if ((chip_id & RT4831_VID_MASK) != RICHTEK_VENDOR_ID) {		dev_err(&client->dev, "Chip vendor ID 0x%02x not matched\n", chip_id);		return -ENODEV;	} 	/*	 * Used to prevent the abnormal shutdown.	 * If SCL/SDA both keep low for one second to reset HW.	 */	ret = regmap_update_bits(regmap, RT4831_REG_I2CPROT, RT4831_I2CSAFETMR_MASK,				 RT4831_I2CSAFETMR_MASK);	if (ret) {		dev_err(&client->dev, "Failed to enable I2C safety timer\n");		return ret;	} 	return devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_AUTO, rt4831_subdevs,				    ARRAY_SIZE(rt4831_subdevs), NULL, 0, NULL);} static void rt4831_remove(struct i2c_client *client){	struct regmap *regmap = dev_get_regmap(&client->dev, NULL);	int ret; 	/* Disable WLED and DSV outputs */	ret = regmap_update_bits(regmap, RT4831_REG_ENABLE, RT4831_RESET_MASK, RT4831_RESET_MASK);	if (ret)		dev_warn(&client->dev, "Failed to disable outputs (%pe)\n", ERR_PTR(ret));} static const struct of_device_id __maybe_unused rt4831_of_match[] = {	{ .compatible = "richtek,rt4831", },	{}};MODULE_DEVICE_TABLE(of, rt4831_of_match); static struct i2c_driver rt4831_driver = {	.driver = {		.name = "rt4831",		.of_match_table = rt4831_of_match,	},	.probe = rt4831_probe,	.remove = rt4831_remove,};module_i2c_driver(rt4831_driver); MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");MODULE_DESCRIPTION("Richtek RT4831 core driver");MODULE_LICENSE("GPL v2");