--- /dev/null
+/*
+ * Maxim MAX14656 / AL32 USB Charger Detector driver
+ *
+ * Copyright (C) 2014 LG Electronics, Inc
+ * Copyright (C) 2016 Alexander Kurz <akurz@blala.de>
+ *
+ * Components from Maxim AL32 Charger detection Driver for MX50 Yoshi Board
+ * Copyright (C) Amazon Technologies Inc. All rights reserved.
+ * Manish Lachwani (lachwani@lab126.com)
+ *
+ * This package is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
+#include <linux/of_device.h>
+#include <linux/workqueue.h>
+#include <linux/power_supply.h>
+
+#define MAX14656_MANUFACTURER "Maxim Integrated"
+#define MAX14656_NAME "max14656"
+
+#define MAX14656_DEVICE_ID 0x00
+#define MAX14656_INTERRUPT_1 0x01
+#define MAX14656_INTERRUPT_2 0x02
+#define MAX14656_STATUS_1 0x03
+#define MAX14656_STATUS_2 0x04
+#define MAX14656_INTMASK_1 0x05
+#define MAX14656_INTMASK_2 0x06
+#define MAX14656_CONTROL_1 0x07
+#define MAX14656_CONTROL_2 0x08
+#define MAX14656_CONTROL_3 0x09
+
+#define DEVICE_VENDOR_MASK 0xf0
+#define DEVICE_REV_MASK 0x0f
+#define INT_EN_REG_MASK BIT(4)
+#define CHG_TYPE_INT_MASK BIT(0)
+#define STATUS1_VB_VALID_MASK BIT(4)
+#define STATUS1_CHG_TYPE_MASK 0xf
+#define INT1_DCD_TIMEOUT_MASK BIT(7)
+#define CONTROL1_DEFAULT 0x0d
+#define CONTROL1_INT_EN BIT(4)
+#define CONTROL1_INT_ACTIVE_HIGH BIT(5)
+#define CONTROL1_EDGE BIT(7)
+#define CONTROL2_DEFAULT 0x8e
+#define CONTROL2_ADC_EN BIT(0)
+#define CONTROL3_DEFAULT 0x8d
+
+enum max14656_chg_type {
+ MAX14656_NO_CHARGER = 0,
+ MAX14656_SDP_CHARGER,
+ MAX14656_CDP_CHARGER,
+ MAX14656_DCP_CHARGER,
+ MAX14656_APPLE_500MA_CHARGER,
+ MAX14656_APPLE_1A_CHARGER,
+ MAX14656_APPLE_2A_CHARGER,
+ MAX14656_SPECIAL_500MA_CHARGER,
+ MAX14656_APPLE_12W,
+ MAX14656_CHARGER_LAST
+};
+
+static const struct max14656_chg_type_props {
+ enum power_supply_type type;
+} chg_type_props[] = {
+ { POWER_SUPPLY_TYPE_UNKNOWN },
+ { POWER_SUPPLY_TYPE_USB },
+ { POWER_SUPPLY_TYPE_USB_CDP },
+ { POWER_SUPPLY_TYPE_USB_DCP },
+ { POWER_SUPPLY_TYPE_USB_DCP },
+ { POWER_SUPPLY_TYPE_USB_DCP },
+ { POWER_SUPPLY_TYPE_USB_DCP },
+ { POWER_SUPPLY_TYPE_USB_DCP },
+ { POWER_SUPPLY_TYPE_USB },
+};
+
+struct max14656_chip {
+ struct i2c_client *client;
+ struct power_supply *detect_psy;
+ struct power_supply_desc psy_desc;
+ struct delayed_work irq_work;
+
+ int irq;
+ int online;
+};
+
+static int max14656_read_reg(struct i2c_client *client, int reg, u8 *val)
+{
+ s32 ret;
+
+ ret = i2c_smbus_read_byte_data(client, reg);
+ if (ret < 0) {
+ dev_err(&client->dev,
+ "i2c read fail: can't read from %02x: %d\n",
+ reg, ret);
+ return ret;
+ }
+ *val = ret;
+ return 0;
+}
+
+static int max14656_write_reg(struct i2c_client *client, int reg, u8 val)
+{
+ s32 ret;
+
+ ret = i2c_smbus_write_byte_data(client, reg, val);
+ if (ret < 0) {
+ dev_err(&client->dev,
+ "i2c write fail: can't write %02x to %02x: %d\n",
+ val, reg, ret);
+ return ret;
+ }
+ return 0;
+}
+
+static int max14656_read_block_reg(struct i2c_client *client, u8 reg,
+ u8 length, u8 *val)
+{
+ int ret;
+
+ ret = i2c_smbus_read_i2c_block_data(client, reg, length, val);
+ if (ret < 0) {
+ dev_err(&client->dev, "failed to block read reg 0x%x: %d\n",
+ reg, ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+#define REG_TOTAL_NUM 5
+static void max14656_irq_worker(struct work_struct *work)
+{
+ struct max14656_chip *chip =
+ container_of(work, struct max14656_chip, irq_work.work);
+
+ u8 buf[REG_TOTAL_NUM];
+ u8 chg_type;
+ int ret = 0;
+
+ ret = max14656_read_block_reg(chip->client, MAX14656_DEVICE_ID,
+ REG_TOTAL_NUM, buf);
+
+ if ((buf[MAX14656_STATUS_1] & STATUS1_VB_VALID_MASK) &&
+ (buf[MAX14656_STATUS_1] & STATUS1_CHG_TYPE_MASK)) {
+ chg_type = buf[MAX14656_STATUS_1] & STATUS1_CHG_TYPE_MASK;
+ if (chg_type < MAX14656_CHARGER_LAST)
+ chip->psy_desc.type = chg_type_props[chg_type].type;
+ else
+ chip->psy_desc.type = POWER_SUPPLY_TYPE_UNKNOWN;
+ chip->online = 1;
+ } else {
+ chip->online = 0;
+ chip->psy_desc.type = POWER_SUPPLY_TYPE_UNKNOWN;
+ }
+
+ power_supply_changed(chip->detect_psy);
+}
+
+static irqreturn_t max14656_irq(int irq, void *dev_id)
+{
+ struct max14656_chip *chip = dev_id;
+
+ schedule_delayed_work(&chip->irq_work, msecs_to_jiffies(100));
+
+ return IRQ_HANDLED;
+}
+
+static int max14656_hw_init(struct max14656_chip *chip)
+{
+ uint8_t val = 0;
+ uint8_t rev;
+ struct i2c_client *client = chip->client;
+
+ if (max14656_read_reg(client, MAX14656_DEVICE_ID, &val))
+ return -ENODEV;
+
+ if ((val & DEVICE_VENDOR_MASK) != 0x20) {
+ dev_err(&client->dev, "wrong vendor ID %d\n",
+ ((val & DEVICE_VENDOR_MASK) >> 4));
+ return -ENODEV;
+ }
+ rev = val & DEVICE_REV_MASK;
+
+ /* Turn on ADC_EN */
+ if (max14656_write_reg(client, MAX14656_CONTROL_2, CONTROL2_ADC_EN))
+ return -EINVAL;
+
+ /* turn on interrupts and low power mode */
+ if (max14656_write_reg(client, MAX14656_CONTROL_1,
+ CONTROL1_DEFAULT |
+ CONTROL1_INT_EN |
+ CONTROL1_INT_ACTIVE_HIGH |
+ CONTROL1_EDGE))
+ return -EINVAL;
+
+ if (max14656_write_reg(client, MAX14656_INTMASK_1, 0x3))
+ return -EINVAL;
+
+ if (max14656_write_reg(client, MAX14656_INTMASK_2, 0x1))
+ return -EINVAL;
+
+ dev_info(&client->dev, "detected revision %d\n", rev);
+ return 0;
+}
+
+static int max14656_get_property(struct power_supply *psy,
+ enum power_supply_property psp,
+ union power_supply_propval *val)
+{
+ struct max14656_chip *chip = power_supply_get_drvdata(psy);
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_ONLINE:
+ val->intval = chip->online;
+ break;
+ case POWER_SUPPLY_PROP_MODEL_NAME:
+ val->strval = MAX14656_NAME;
+ break;
+ case POWER_SUPPLY_PROP_MANUFACTURER:
+ val->strval = MAX14656_MANUFACTURER;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static enum power_supply_property max14656_battery_props[] = {
+ POWER_SUPPLY_PROP_ONLINE,
+ POWER_SUPPLY_PROP_MODEL_NAME,
+ POWER_SUPPLY_PROP_MANUFACTURER,
+};
+
+static int max14656_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
+ struct device *dev = &client->dev;
+ struct power_supply_config psy_cfg = {};
+ struct max14656_chip *chip;
+ int irq = client->irq;
+ int ret = 0;
+
+ if (irq <= 0) {
+ dev_err(dev, "invalid irq number: %d\n", irq);
+ return -ENODEV;
+ }
+
+ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
+ dev_err(dev, "No support for SMBUS_BYTE_DATA\n");
+ return -ENODEV;
+ }
+
+ chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
+
+ psy_cfg.drv_data = chip;
+ chip->client = client;
+ chip->online = 0;
+ chip->psy_desc.name = MAX14656_NAME;
+ chip->psy_desc.type = POWER_SUPPLY_TYPE_UNKNOWN;
+ chip->psy_desc.properties = max14656_battery_props;
+ chip->psy_desc.num_properties = ARRAY_SIZE(max14656_battery_props);
+ chip->psy_desc.get_property = max14656_get_property;
+ chip->irq = irq;
+
+ ret = max14656_hw_init(chip);
+ if (ret)
+ return -ENODEV;
+
+ INIT_DELAYED_WORK(&chip->irq_work, max14656_irq_worker);
+
+ ret = devm_request_irq(dev, chip->irq, max14656_irq,
+ IRQF_TRIGGER_FALLING,
+ MAX14656_NAME, chip);
+ if (ret) {
+ dev_err(dev, "request_irq %d failed\n", chip->irq);
+ return -EINVAL;
+ }
+ enable_irq_wake(chip->irq);
+
+ chip->detect_psy = devm_power_supply_register(dev,
+ &chip->psy_desc, &psy_cfg);
+ if (IS_ERR(chip->detect_psy)) {
+ dev_err(dev, "power_supply_register failed\n");
+ return -EINVAL;
+ }
+
+ schedule_delayed_work(&chip->irq_work, msecs_to_jiffies(2000));
+
+ return 0;
+}
+
+static const struct i2c_device_id max14656_id[] = {
+ { "max14656", 0 },
+ {}
+};
+
+static const struct of_device_id max14656_match_table[] = {
+ { .compatible = "maxim,max14656", },
+ {}
+};
+
+static struct i2c_driver max14656_i2c_driver = {
+ .driver = {
+ .name = "max14656",
+ .owner = THIS_MODULE,
+ .of_match_table = max14656_match_table,
+ },
+ .probe = max14656_probe,
+ .id_table = max14656_id,
+};
+module_i2c_driver(max14656_i2c_driver);
+
+MODULE_DESCRIPTION("MAX14656 USB charger detector");
+MODULE_LICENSE("GPL v2");
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