/*
 * drivers/power/smb349-charger.c
 *
 * Battery charger driver for smb349 from summit microelectronics
 *
 * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation;
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/power_supply.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/smb349-charger.h>
#include <linux/slab.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/usb/otg.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>

#define SMB349_CHARGE		0x00
#define SMB349_CHRG_CRNTS	0x01
#define SMB349_VRS_FUNC		0x02
#define SMB349_FLOAT_VLTG	0x03
#define SMB349_CHRG_CTRL	0x04
#define SMB349_STAT_TIME_CTRL	0x05
#define SMB349_PIN_CTRL		0x06
#define SMB349_THERM_CTRL	0x07
#define SMB349_CTRL_REG		0x09

#define SMB349_OTG_TLIM_REG	0x0A
#define SMB349_HRD_SFT_TEMP	0x0B
#define SMB349_FAULT_INTR	0x0C
#define SMB349_STS_INTR_1	0x0D
#define SMB349_SYSOK_USB3	0x0E
#define SMB349_IN_CLTG_DET	0x10
#define SMB349_STS_INTR_2	0x11

#define SMB349_CMD_REG		0x30
#define SMB349_CMD_REG_B	0x31
#define SMB349_CMD_REG_c	0x33

#define SMB349_INTR_STS_A	0x35
#define SMB349_INTR_STS_B	0x36
#define SMB349_INTR_STS_C	0x37
#define SMB349_INTR_STS_D	0x38
#define SMB349_INTR_STS_E	0x39
#define SMB349_INTR_STS_F	0x3A

#define SMB349_STS_REG_A	0x3B
#define SMB349_STS_REG_B	0x3C
#define SMB349_STS_REG_C	0x3D
#define SMB349_STS_REG_D	0x3E
#define SMB349_STS_REG_E	0x3F

#define SMB349_ENABLE_WRITE	1
#define SMB349_DISABLE_WRITE	0
#define ENABLE_WRT_ACCESS	0x80
#define THERM_CTRL		0x10
#define BATTERY_MISSING		0x10
#define CHARGING		0x06
#define DEDICATED_CHARGER	0x04
#define CHRG_DOWNSTRM_PORT	0x08
#define ENABLE_CHARGE		0x02

static struct smb349_charger *charger;
static int smb349_configure_charger(struct i2c_client *client, int value);

static int smb349_read(struct i2c_client *client, int reg)
{
	int ret;

	ret = i2c_smbus_read_byte_data(client, reg);

	if (ret < 0)
		dev_err(&client->dev, "%s: err %d\n", __func__, ret);

	return ret;
}

static int smb349_write(struct i2c_client *client, int reg, u8 value)
{
	int ret;

	ret = i2c_smbus_write_byte_data(client, reg, value);

	if (ret < 0)
		dev_err(&client->dev, "%s: err %d\n", __func__, ret);

	return ret;
}

static int smb349_update_reg(struct i2c_client *client, int reg, u8 value)
{
	int ret, retval;

	retval = smb349_read(client, reg);
	if (retval < 0) {
		dev_err(&client->dev, "%s: err %d\n", __func__, retval);
		return retval;
	}

	ret = smb349_write(client, reg, retval | value);
	if (ret < 0) {
		dev_err(&client->dev, "%s: err %d\n", __func__, ret);
		return ret;
	}

	return ret;
}

int smb349_volatile_writes(struct i2c_client *client, uint8_t value)
{
	int ret = 0;

	if (value == SMB349_ENABLE_WRITE) {
		/* Enable volatile write to config registers */
		ret = smb349_update_reg(client, SMB349_CMD_REG,
						ENABLE_WRT_ACCESS);
		if (ret < 0) {
			dev_err(&client->dev, "%s(): Failed in writing"
				"register 0x%02x\n", __func__, SMB349_CMD_REG);
			return ret;
		}
	} else {
		ret = smb349_read(client, SMB349_CMD_REG);
		if (ret < 0) {
			dev_err(&client->dev, "%s: err %d\n", __func__, ret);
			return ret;
		}

		ret = smb349_write(client, SMB349_CMD_REG, ret & (~(1<<7)));
		if (ret < 0) {
			dev_err(&client->dev, "%s: err %d\n", __func__, ret);
			return ret;
		}
	}
	return ret;
}

static int smb349_configure_otg(struct i2c_client *client, int enable)
{
	int ret = 0;

	/*Enable volatile writes to registers*/
	ret = smb349_volatile_writes(client, SMB349_ENABLE_WRITE);
	if (ret < 0) {
		dev_err(&client->dev, "%s error in configuring otg..\n",
								__func__);
		goto error;
	}

	if (enable) {
		/* Configure PGOOD to be active low if no 5V on VBUS */
		ret = smb349_read(client, SMB349_STS_REG_C);
		if (ret < 0) {
			dev_err(&client->dev, "%s: err %d\n", __func__, ret);
			goto error;
		}

		if (!(ret & 0x01)) {
			ret = smb349_read(client, SMB349_SYSOK_USB3);
			if (ret < 0) {
				dev_err(&client->dev, "%s: err %d\n",
					__func__, ret);
				goto error;
			}

			ret = smb349_write(client, SMB349_SYSOK_USB3,
						(ret & (~(1))));
			if (ret < 0) {
				dev_err(&client->dev, "%s: err %d\n",
					__func__, ret);
				goto error;
			}
		}

		/* Enable OTG */
		ret = smb349_update_reg(client, SMB349_CMD_REG, 0x10);
		if (ret < 0) {
			dev_err(&client->dev, "%s: Failed in writing register"
				"0x%02x\n", __func__, SMB349_CMD_REG);
			goto error;
		}
	} else {
		/* Disable OTG */
		ret = smb349_read(client, SMB349_CMD_REG);
		if (ret < 0) {
			dev_err(&client->dev, "%s: err %d\n", __func__, ret);
			goto error;
		}

		ret = smb349_write(client, SMB349_CMD_REG, (ret & (~(1<<4))));
		if (ret < 0) {
			dev_err(&client->dev, "%s: err %d\n", __func__, ret);
			goto error;
		}

		/* Configure PGOOD to be active high */
		ret = smb349_update_reg(client, SMB349_SYSOK_USB3, 0x01);
		if (ret < 0) {
			dev_err(&client->dev, "%s: err %d\n", __func__, ret);
			goto error;
		}
	}

	/* Disable volatile writes to registers */
	ret = smb349_volatile_writes(client, SMB349_DISABLE_WRITE);
	if (ret < 0)
		dev_err(&client->dev, "%s error in configuring OTG..\n",
								__func__);
error:
	return ret;
}

static int smb349_configure_charger(struct i2c_client *client, int value)
{
	int ret = 0;

	/* Enable volatile writes to registers */
	ret = smb349_volatile_writes(client, SMB349_ENABLE_WRITE);
	if (ret < 0) {
		dev_err(&client->dev, "%s() error in configuring charger..\n",
								__func__);
		goto error;
	}

	if (value) {
		 /* Enable charging */
		ret = smb349_update_reg(client, SMB349_CMD_REG, ENABLE_CHARGE);
		if (ret < 0) {
			dev_err(&client->dev, "%s(): Failed in writing register"
					"0x%02x\n", __func__, SMB349_CMD_REG);
			goto error;
		}

		/* Configure THERM ctrl */
		ret = smb349_update_reg(client, SMB349_THERM_CTRL, THERM_CTRL);
		if (ret < 0) {
			dev_err(&client->dev, "%s: err %d\n", __func__, ret);
			goto error;
		}
	} else {
		ret = smb349_read(client, SMB349_CMD_REG);
		if (ret < 0) {
			dev_err(&client->dev, "%s: err %d\n", __func__, ret);
			goto error;
		}

		ret = smb349_write(client, SMB349_CMD_REG, (ret & (~(1<<1))));
		if (ret < 0) {
			dev_err(&client->dev, "%s: err %d\n", __func__, ret);
			goto error;
		}
	}
	/* Disable volatile writes to registers */
	ret = smb349_volatile_writes(client, SMB349_DISABLE_WRITE);
	if (ret < 0) {
		dev_err(&client->dev, "%s() error in configuring charger..\n",
								__func__);
		goto error;
	}
error:
	return ret;
}

int update_charger_status(void)
{
	struct i2c_client *client;
	int val;

	if (!charger)
		return -ENODEV;
	else
		client = charger->client;

	val =  smb349_read(client, SMB349_STS_REG_D);
	if (val < 0) {
		dev_err(&client->dev, "%s(): Failed in reading register"
			"0x%02x\n", __func__, SMB349_STS_REG_D);
		goto val_error;
	} else if (val != 0) {
		if (val & DEDICATED_CHARGER)
			charger->chrg_type = AC;
		else
			charger->chrg_type = USB;

		charger->state = progress;
	} else {
		charger->state = stopped;
	}

	if (charger->charger_cb)
		charger->charger_cb(charger->state, charger->chrg_type,
						charger->charger_cb_data);
	return 0;
val_error:
	return val;
}
EXPORT_SYMBOL_GPL(update_charger_status);

int register_callback(charging_callback_t cb, void *args)
{
	struct smb349_charger *charger_data = charger;
	if (!charger_data)
		return -ENODEV;

	charger_data->charger_cb = cb;
	charger_data->charger_cb_data = args;
	return 0;
}
EXPORT_SYMBOL_GPL(register_callback);

int smb349_battery_online(void)
{
	int val;
	struct i2c_client *client = charger->client;

	val = smb349_read(charger->client, SMB349_INTR_STS_B);
	if (val < 0) {
		dev_err(&client->dev, "%s(): Failed in reading register"
				"0x%02x\n", __func__, SMB349_INTR_STS_B);
		return val;
	}
	if (val & BATTERY_MISSING)
		return 0;
	else
		return 1;
}

static int smb349_enable_otg(struct regulator_dev *otg_rdev)
{
	struct i2c_client *client = charger->client;
	int ret;

	/* configure charger */
	ret = smb349_configure_charger(client, 0);
	if (ret < 0)
		goto error;
	/* ENABLE OTG */
	ret = smb349_configure_otg(client, 1);
	if (ret < 0)
		goto error;

	charger->is_otg_enabled = 1;
	return 0;
error:
	dev_err(&client->dev, "%s() error in enabling"
			"otg..\n", __func__);
	return ret;
}

static int smb349_disable_otg(struct regulator_dev *otg_rdev)
{
	struct i2c_client *client = charger->client;
	int ret;

	/* Disable OTG */
	ret = smb349_configure_otg(client, 0);
	if (ret < 0)
		goto error;
	/* configure charger */
	ret = smb349_configure_charger(client, 1);
	if (ret < 0)
		goto error;

	charger->is_otg_enabled = 0;
	return 0;
error:
	dev_err(&client->dev, "%s() error in disabling"
			"otg..\n", __func__);
	return ret;
}

static int smb349_is_otg_enabled(struct regulator_dev *otg_rdev)
{
	return charger->is_otg_enabled;
}

static int smb349_enable_charging(struct regulator_dev *rdev,
					int min_uA, int max_uA)
{
	struct i2c_client *client = charger->client;
	int ret;

	if (!max_uA) {
		/* Wait for SMB349 to debounce and get reset to POR when cable is unpluged */
		msleep(50);

		ret =  smb349_read(client, SMB349_STS_REG_C);
		if (ret < 0) {
			dev_err(&client->dev, "%s(): Failed in reading register"
				"0x%02x\n", __func__, SMB349_STS_REG_C);
			return ret;
		}

		if (ret & CHARGING)
			return 0;

		charger->state = stopped;
		charger->chrg_type = NONE;
	} else {
		/* Wait for SMB349 to reload OTP setting and detect type*/
		msleep(500);

		ret =  smb349_read(client, SMB349_STS_REG_D);
		if (ret < 0) {
			dev_err(&client->dev, "%s(): Failed in reading register"
					"0x%02x\n", __func__, SMB349_STS_REG_D);
			return ret;
		} else if (ret != 0) {
			if (ret & DEDICATED_CHARGER)
				charger->chrg_type = AC;
			else
				charger->chrg_type = USB;

			/* configure charger */
			ret = smb349_configure_charger(client, 1);
			if (ret < 0) {
				dev_err(&client->dev, "%s() error in"
					"configuring charger..\n", __func__);
				return ret;
			}
			charger->state = progress;
		}
	}
	if (charger->charger_cb)
		charger->charger_cb(charger->state, charger->chrg_type,
						charger->charger_cb_data);
	return 0;
}

static struct regulator_ops smb349_tegra_regulator_ops = {
	.set_current_limit = smb349_enable_charging,
};

static struct regulator_ops smb349_tegra_otg_regulator_ops = {
	.enable = smb349_enable_otg,
	.disable = smb349_disable_otg,
	.is_enabled = smb349_is_otg_enabled,
};

#if defined(CONFIG_DEBUG_FS)
static struct dentry *smb349_dentry_regs;

static int smb349_dump_regs(struct i2c_client *client, u8 *addrs, int num_addrs,
		char *buf, ssize_t *len)
{
	ssize_t count = *len;
	int ret = 0;
	int i;

	if (count >= PAGE_SIZE - 1)
		return -ERANGE;

	for (i = 0; i < num_addrs; i++) {
		count += sprintf(buf + count, "0x%02x: ", addrs[i]);
		if (count >= PAGE_SIZE - 1)
			return -ERANGE;

		ret = smb349_read(client, addrs[i]);
		if (ret < 0)
			count += sprintf(buf + count, "<read fail: %d\n", ret);
		else
			count += sprintf(buf + count, "0x%02x\n", ret);

		if (count >= PAGE_SIZE - 1)
			return -ERANGE;
	}
	*len = count;

	return 0;
}

static ssize_t smb349_debugfs_open(struct inode *inode, struct file *file)
{
	file->private_data = inode->i_private;
	return 0;
}

static u8 regs[] = {
	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x09, 0x0A, 0x0B,
	0x0C, 0x0D, 0x0E, 0x10, 0x11, 0x12, 0x30, 0x31, 0x33, 0x35, 0x36,
	0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F
};
static ssize_t smb349_debugfs_read(struct file *file, char __user *user_buf,
				size_t count, loff_t *ppos)
{
	ssize_t ret;
	struct i2c_client *client = file->private_data;
	char *buf;
	size_t len = 0;

	buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	len += sprintf(buf + len, "SMB349 Registers\n");
	smb349_dump_regs(client, regs, ARRAY_SIZE(regs), buf, &len);

	ret = simple_read_from_buffer(user_buf, count, ppos, buf, len);
	kfree(buf);
	return ret;
}

static const struct file_operations smb349_debugfs_fops = {
	.open = smb349_debugfs_open,
	.read = smb349_debugfs_read,
};

static void smb349_debugfs_init(struct i2c_client *client)
{
	smb349_dentry_regs = debugfs_create_file(client->name,
						0444, 0, client,
						&smb349_debugfs_fops);
}

static void smb349_debugfs_exit(struct i2c_client *client)
{
	debugfs_remove(smb349_dentry_regs);
}
#else
static void smb349_debugfs_init(struct i2c_client *client){}
static void smb349_debugfs_exit(struct i2c_client *client){}
#endif /* CONFIG_DEBUG_FS */

static int smb349_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
	struct smb349_charger_platform_data *pdata;
	struct regulator_config config = { };
	struct regulator_config config_otg = { };
	int ret;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
		return -EIO;

	charger = kzalloc(sizeof(*charger), GFP_KERNEL);
	if (!charger)
		return -ENOMEM;

	charger->client = client;
	charger->dev = &client->dev;
	pdata = client->dev.platform_data;
	i2c_set_clientdata(client, charger);

	/* Check battery presence */
	if (!smb349_battery_online()) {
		dev_err(&client->dev, "%s() No Battery present, exiting..\n",
					__func__);
		ret = -ENODEV;
		goto regulator_error;
	}

	charger->is_otg_enabled = 0;

	charger->reg_desc.name  = "vbus_charger";
	charger->reg_desc.ops   = &smb349_tegra_regulator_ops;
	charger->reg_desc.type  = REGULATOR_CURRENT;
	charger->reg_desc.id    = pdata->regulator_id;
	charger->reg_desc.type  = REGULATOR_CURRENT;
	charger->reg_desc.owner = THIS_MODULE;

	charger->reg_init_data.supply_regulator         = NULL;
	charger->reg_init_data.num_consumer_supplies    =
				       pdata->num_consumer_supplies;
	charger->reg_init_data.regulator_init           = NULL;
	charger->reg_init_data.consumer_supplies        =
				       pdata->consumer_supplies;
	charger->reg_init_data.driver_data              = charger;
	charger->reg_init_data.constraints.name         = "vbus_charger";
	charger->reg_init_data.constraints.min_uA       = 0;
	charger->reg_init_data.constraints.max_uA       =
					pdata->max_charge_current_mA * 1000;

	charger->reg_init_data.constraints.valid_modes_mask =
					REGULATOR_MODE_NORMAL |
					REGULATOR_MODE_STANDBY;

	charger->reg_init_data.constraints.valid_ops_mask =
					REGULATOR_CHANGE_MODE |
					REGULATOR_CHANGE_STATUS |
					REGULATOR_CHANGE_CURRENT;

	config.dev = charger->dev;
	config.init_data = &charger->reg_init_data;
	config.driver_data = charger;
	config.of_node = NULL;

	charger->rdev = regulator_register(&charger->reg_desc, &config);

	smb349_debugfs_init(client);

	if (IS_ERR(charger->rdev)) {
		dev_err(&client->dev, "failed to register %s\n",
				charger->reg_desc.name);
		ret = PTR_ERR(charger->rdev);
		goto regulator_error;
	}

	charger->otg_reg_desc.name  = "vbus_otg";
	charger->otg_reg_desc.ops   = &smb349_tegra_otg_regulator_ops;
	charger->otg_reg_desc.type  = REGULATOR_CURRENT;
	charger->otg_reg_desc.id    = pdata->otg_regulator_id;
	charger->otg_reg_desc.type  = REGULATOR_CURRENT;
	charger->otg_reg_desc.owner = THIS_MODULE;

	charger->otg_reg_init_data.supply_regulator         = NULL;
	charger->otg_reg_init_data.num_consumer_supplies    =
				       pdata->num_otg_consumer_supplies;
	charger->otg_reg_init_data.regulator_init           = NULL;
	charger->otg_reg_init_data.consumer_supplies        =
				       pdata->otg_consumer_supplies;
	charger->otg_reg_init_data.driver_data              = charger;
	charger->otg_reg_init_data.constraints.name         = "vbus_otg";
	charger->otg_reg_init_data.constraints.min_uA       = 0;
	charger->otg_reg_init_data.constraints.max_uA       = 500000;

	charger->otg_reg_init_data.constraints.valid_modes_mask =
					REGULATOR_MODE_NORMAL |
					REGULATOR_MODE_STANDBY;

	charger->otg_reg_init_data.constraints.valid_ops_mask =
					REGULATOR_CHANGE_MODE |
					REGULATOR_CHANGE_STATUS |
					REGULATOR_CHANGE_CURRENT;

	config.dev = charger->dev;
	config.init_data = &charger->otg_reg_init_data;
	config.driver_data = charger;
	config.of_node = NULL;

	charger->otg_rdev = regulator_register(&charger->otg_reg_desc, &config);
	if (IS_ERR(charger->otg_rdev)) {
		dev_err(&client->dev, "failed to register %s\n",
				charger->otg_reg_desc.name);
		ret = PTR_ERR(charger->otg_rdev);
		goto otg_regulator_error;
	}

	/* disable OTG */
	ret = smb349_configure_otg(client, 0);
	if (ret < 0) {
		dev_err(&client->dev, "%s() error in configuring"
			"charger..\n", __func__);
		goto error;
	}

	ret =  smb349_read(client, SMB349_STS_REG_D);
	if (ret < 0) {
		dev_err(&client->dev, "%s(): Failed in reading register"
			"0x%02x\n", __func__, SMB349_STS_REG_D);
		goto error;
	} else if (ret != 0) {
		/* configure charger */
		ret = smb349_configure_charger(client, 1);
		if (ret < 0) {
			dev_err(&client->dev, "%s() error in configuring"
				"charger..\n", __func__);
			goto error;
		}
	} else {
		/* disable charger */
		ret = smb349_configure_charger(client, 0);
		if (ret < 0) {
			dev_err(&client->dev, "%s() error in configuring"
				"charger..\n", __func__);
			goto error;
		}
	}

	return 0;
error:
	smb349_debugfs_exit(client);
	regulator_unregister(charger->otg_rdev);
otg_regulator_error:
	regulator_unregister(charger->rdev);
regulator_error:
	kfree(charger);
	charger = NULL;
	return ret;
}

static int smb349_remove(struct i2c_client *client)
{
	struct smb349_charger *charger = i2c_get_clientdata(client);

	smb349_debugfs_exit(client);
	regulator_unregister(charger->rdev);
	regulator_unregister(charger->otg_rdev);
	kfree(charger);

	return 0;
}

static const struct i2c_device_id smb349_id[] = {
	{ "smb349", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, smb349_id);

static struct i2c_driver smb349_i2c_driver = {
	.driver	= {
		.name	= "smb349",
	},
	.probe		= smb349_probe,
	.remove		= smb349_remove,
	.id_table	= smb349_id,
};

static int __init smb349_init(void)
{
	return i2c_add_driver(&smb349_i2c_driver);
}
subsys_initcall(smb349_init);

static void __exit smb349_exit(void)
{
	i2c_del_driver(&smb349_i2c_driver);
}
module_exit(smb349_exit);

MODULE_AUTHOR("Syed Rafiuddin <srafiuddin@nvidia.com>");
MODULE_DESCRIPTION("SMB349 Battery-Charger");
MODULE_LICENSE("GPL");