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// 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 int rt4831_remove(struct i2c_client *client)
{
struct regmap *regmap = dev_get_regmap(&client->dev, NULL);
/* Disable WLED and DSV outputs */
return regmap_update_bits(regmap, RT4831_REG_ENABLE, RT4831_RESET_MASK, RT4831_RESET_MASK);
}
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_new = rt4831_probe,
.remove = rt4831_remove,
};
module_i2c_driver(rt4831_driver);
MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
MODULE_LICENSE("GPL v2");
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