drivers/mfd/rt4831.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 /*
0003  * Copyright (c) 2021 Richtek Technology Corp.
0004  *
0005  * Author: ChiYuan Huang <cy_huang@richtek.com>
0006  */
0007
0008 #include <linux/gpio/consumer.h>
0009 #include <linux/i2c.h>
0010 #include <linux/kernel.h>
0011 #include <linux/mfd/core.h>
0012 #include <linux/module.h>
0013 #include <linux/regmap.h>
0014
0015 #define RT4831_REG_REVISION 0x01
0016 #define RT4831_REG_ENABLE   0x08
0017 #define RT4831_REG_I2CPROT  0x15
0018
0019 #define RICHTEK_VENDOR_ID   0x03
0020 #define RT4831_VID_MASK     GENMASK(1, 0)
0021 #define RT4831_RESET_MASK   BIT(7)
0022 #define RT4831_I2CSAFETMR_MASK  BIT(0)
0023
0024 static const struct mfd_cell rt4831_subdevs[] = {
0025     MFD_CELL_OF("rt4831-backlight", NULL, NULL, 0, 0, "richtek,rt4831-backlight"),
0026     MFD_CELL_NAME("rt4831-regulator")
0027 };
0028
0029 static bool rt4831_is_accessible_reg(struct device *dev, unsigned int reg)
0030 {
0031     if (reg >= RT4831_REG_REVISION && reg <= RT4831_REG_I2CPROT)
0032         return true;
0033     return false;
0034 }
0035
0036 static const struct regmap_config rt4831_regmap_config = {
0037     .reg_bits = 8,
0038     .val_bits = 8,
0039     .max_register = RT4831_REG_I2CPROT,
0040
0041     .readable_reg = rt4831_is_accessible_reg,
0042     .writeable_reg = rt4831_is_accessible_reg,
0043 };
0044
0045 static int rt4831_probe(struct i2c_client *client)
0046 {
0047     struct gpio_desc *enable_gpio;
0048     struct regmap *regmap;
0049     unsigned int chip_id;
0050     int ret;
0051
0052     enable_gpio = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_HIGH);
0053     if (IS_ERR(enable_gpio)) {
0054         dev_err(&client->dev, "Failed to get 'enable' GPIO\n");
0055         return PTR_ERR(enable_gpio);
0056     }
0057
0058     regmap = devm_regmap_init_i2c(client, &rt4831_regmap_config);
0059     if (IS_ERR(regmap)) {
0060         dev_err(&client->dev, "Failed to initialize regmap\n");
0061         return PTR_ERR(regmap);
0062     }
0063
0064     ret = regmap_read(regmap, RT4831_REG_REVISION, &chip_id);
0065     if (ret) {
0066         dev_err(&client->dev, "Failed to get H/W revision\n");
0067         return ret;
0068     }
0069
0070     if ((chip_id & RT4831_VID_MASK) != RICHTEK_VENDOR_ID) {
0071         dev_err(&client->dev, "Chip vendor ID 0x%02x not matched\n", chip_id);
0072         return -ENODEV;
0073     }
0074
0075     /*
0076      * Used to prevent the abnormal shutdown.
0077      * If SCL/SDA both keep low for one second to reset HW.
0078      */
0079     ret = regmap_update_bits(regmap, RT4831_REG_I2CPROT, RT4831_I2CSAFETMR_MASK,
0080                  RT4831_I2CSAFETMR_MASK);
0081     if (ret) {
0082         dev_err(&client->dev, "Failed to enable I2C safety timer\n");
0083         return ret;
0084     }
0085
0086     return devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_AUTO, rt4831_subdevs,
0087                     ARRAY_SIZE(rt4831_subdevs), NULL, 0, NULL);
0088 }
0089
0090 static int rt4831_remove(struct i2c_client *client)
0091 {
0092     struct regmap *regmap = dev_get_regmap(&client->dev, NULL);
0093     int ret;
0094
0095     /* Disable WLED and DSV outputs */
0096     ret = regmap_update_bits(regmap, RT4831_REG_ENABLE, RT4831_RESET_MASK, RT4831_RESET_MASK);
0097     if (ret)
0098         dev_warn(&client->dev, "Failed to disable outputs (%pe)\n", ERR_PTR(ret));
0099
0100     return 0;
0101 }
0102
0103 static const struct of_device_id __maybe_unused rt4831_of_match[] = {
0104     { .compatible = "richtek,rt4831", },
0105     {}
0106 };
0107 MODULE_DEVICE_TABLE(of, rt4831_of_match);
0108
0109 static struct i2c_driver rt4831_driver = {
0110     .driver = {
0111         .name = "rt4831",
0112         .of_match_table = rt4831_of_match,
0113     },
0114     .probe_new = rt4831_probe,
0115     .remove = rt4831_remove,
0116 };
0117 module_i2c_driver(rt4831_driver);
0118
0119 MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
0120 MODULE_LICENSE("GPL v2");