/*
 * File: drivers/input/keyboard/adp5588_keys.c
 * Description:  keypad driver for ADP5588 I2C QWERTY Keypad and IO Expander
 * Bugs: Enter bugs at http://blackfin.uclinux.org/
 *
 * Copyright (C) 2008-2009 Analog Devices Inc.
 * Licensed under the GPL-2 or later.
 */

#include <linux/module.h>
#include <linux/version.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/workqueue.h>
#include <linux/errno.h>
#include <linux/pm.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/i2c.h>

#include <linux/i2c/adp5588.h>

 /* Configuration Register1 */
#define AUTO_INC	(1 << 7)
#define GPIEM_CFG	(1 << 6)
#define OVR_FLOW_M	(1 << 5)
#define INT_CFG		(1 << 4)
#define OVR_FLOW_IEN	(1 << 3)
#define K_LCK_IM	(1 << 2)
#define GPI_IEN		(1 << 1)
#define KE_IEN		(1 << 0)

/* Interrupt Status Register */
#define CMP2_INT	(1 << 5)
#define CMP1_INT	(1 << 4)
#define OVR_FLOW_INT	(1 << 3)
#define K_LCK_INT	(1 << 2)
#define GPI_INT		(1 << 1)
#define KE_INT		(1 << 0)

/* Key Lock and Event Counter Register */
#define K_LCK_EN	(1 << 6)
#define LCK21		0x30
#define KEC		0xF

/* Key Event Register xy */
#define KEY_EV_PRESSED		(1 << 7)
#define KEY_EV_MASK		(0x7F)

#define KP_SEL(x)		(0xFFFF >> (16 - x))	/* 2^x-1 */

#define KEYP_MAX_EVENT		10

/*
 * Early pre 4.0 Silicon required to delay readout by at least 25ms,
 * since the Event Counter Register updated 25ms after the interrupt
 * asserted.
 */
#define WA_DELAYED_READOUT_REVID(rev)		((rev) < 4)

struct adp5588_kpad {
	struct i2c_client *client;
	struct input_dev *input;
	struct delayed_work work;
	unsigned long delay;
	unsigned short keycode[ADP5588_KEYMAPSIZE];
};

static int adp5588_read(struct i2c_client *client, u8 reg)
{
	int ret = i2c_smbus_read_byte_data(client, reg);

	if (ret < 0)
		dev_err(&client->dev, "Read Error\n");

	return ret;
}

static int adp5588_write(struct i2c_client *client, u8 reg, u8 val)
{
	return i2c_smbus_write_byte_data(client, reg, val);
}

static void adp5588_work(struct work_struct *work)
{
	struct adp5588_kpad *kpad = container_of(work,
						struct adp5588_kpad, work.work);
	struct i2c_client *client = kpad->client;
	int i, key, status, ev_cnt;

	status = adp5588_read(client, INT_STAT);

	if (status & OVR_FLOW_INT)	/* Unlikely and should never happen */
		dev_err(&client->dev, "Event Overflow Error\n");

	if (status & KE_INT) {
		ev_cnt = adp5588_read(client, KEY_LCK_EC_STAT) & KEC;
		if (ev_cnt) {
			for (i = 0; i < ev_cnt; i++) {
				key = adp5588_read(client, Key_EVENTA + i);
				input_report_key(kpad->input,
					kpad->keycode[(key & KEY_EV_MASK) - 1],
					key & KEY_EV_PRESSED);
			}
			input_sync(kpad->input);
		}
	}
	adp5588_write(client, INT_STAT, status); /* Status is W1C */
}

static irqreturn_t adp5588_irq(int irq, void *handle)
{
	struct adp5588_kpad *kpad = handle;

	/*
	 * use keventd context to read the event fifo registers
	 * Schedule readout at least 25ms after notification for
	 * REVID < 4
	 */

	schedule_delayed_work(&kpad->work, kpad->delay);

	return IRQ_HANDLED;
}

static int __devinit adp5588_setup(struct i2c_client *client)
{
	struct adp5588_kpad_platform_data *pdata = client->dev.platform_data;
	int i, ret;

	ret = adp5588_write(client, KP_GPIO1, KP_SEL(pdata->rows));
	ret |= adp5588_write(client, KP_GPIO2, KP_SEL(pdata->cols) & 0xFF);
	ret |= adp5588_write(client, KP_GPIO3, KP_SEL(pdata->cols) >> 8);

	if (pdata->en_keylock) {
		ret |= adp5588_write(client, UNLOCK1, pdata->unlock_key1);
		ret |= adp5588_write(client, UNLOCK2, pdata->unlock_key2);
		ret |= adp5588_write(client, KEY_LCK_EC_STAT, K_LCK_EN);
	}

	for (i = 0; i < KEYP_MAX_EVENT; i++)
		ret |= adp5588_read(client, Key_EVENTA);

	ret |= adp5588_write(client, INT_STAT, CMP2_INT | CMP1_INT |
					OVR_FLOW_INT | K_LCK_INT |
					GPI_INT | KE_INT); /* Status is W1C */

	ret |= adp5588_write(client, CFG, INT_CFG | OVR_FLOW_IEN | KE_IEN);

	if (ret < 0) {
		dev_err(&client->dev, "Write Error\n");
		return ret;
	}

	return 0;
}

static int __devinit adp5588_probe(struct i2c_client *client,
					const struct i2c_device_id *id)
{
	struct adp5588_kpad *kpad;
	struct adp5588_kpad_platform_data *pdata = client->dev.platform_data;
	struct input_dev *input;
	unsigned int revid;
	int ret, i;
	int error;

	if (!i2c_check_functionality(client->adapter,
					I2C_FUNC_SMBUS_BYTE_DATA)) {
		dev_err(&client->dev, "SMBUS Byte Data not Supported\n");
		return -EIO;
	}

	if (!pdata) {
		dev_err(&client->dev, "no platform data?\n");
		return -EINVAL;
	}

	if (!pdata->rows || !pdata->cols || !pdata->keymap) {
		dev_err(&client->dev, "no rows, cols or keymap from pdata\n");
		return -EINVAL;
	}

	if (pdata->keymapsize != ADP5588_KEYMAPSIZE) {
		dev_err(&client->dev, "invalid keymapsize\n");
		return -EINVAL;
	}

	if (!client->irq) {
		dev_err(&client->dev, "no IRQ?\n");
		return -EINVAL;
	}

	kpad = kzalloc(sizeof(*kpad), GFP_KERNEL);
	input = input_allocate_device();
	if (!kpad || !input) {
		error = -ENOMEM;
		goto err_free_mem;
	}

	kpad->client = client;
	kpad->input = input;
	INIT_DELAYED_WORK(&kpad->work, adp5588_work);

	ret = adp5588_read(client, DEV_ID);
	if (ret < 0) {
		error = ret;
		goto err_free_mem;
	}

	revid = (u8) ret & ADP5588_DEVICE_ID_MASK;
	if (WA_DELAYED_READOUT_REVID(revid))
		kpad->delay = msecs_to_jiffies(30);

	input->name = client->name;
	input->phys = "adp5588-keys/input0";
	input->dev.parent = &client->dev;

	input_set_drvdata(input, kpad);

	input->id.bustype = BUS_I2C;
	input->id.vendor = 0x0001;
	input->id.product = 0x0001;
	input->id.version = revid;

	input->keycodesize = sizeof(kpad->keycode[0]);
	input->keycodemax = pdata->keymapsize;
	input->keycode = kpad->keycode;

	memcpy(kpad->keycode, pdata->keymap,
		pdata->keymapsize * input->keycodesize);

	/* setup input device */
	__set_bit(EV_KEY, input->evbit);

	if (pdata->repeat)
		__set_bit(EV_REP, input->evbit);

	for (i = 0; i < input->keycodemax; i++)
		__set_bit(kpad->keycode[i] & KEY_MAX, input->keybit);
	__clear_bit(KEY_RESERVED, input->keybit);

	error = input_register_device(input);
	if (error) {
		dev_err(&client->dev, "unable to register input device\n");
		goto err_free_mem;
	}

	error = request_irq(client->irq, adp5588_irq,
			    IRQF_TRIGGER_FALLING | IRQF_DISABLED,
			    client->dev.driver->name, kpad);
	if (error) {
		dev_err(&client->dev, "irq %d busy?\n", client->irq);
		goto err_unreg_dev;
	}

	error = adp5588_setup(client);
	if (error)
		goto err_free_irq;

	device_init_wakeup(&client->dev, 1);
	i2c_set_clientdata(client, kpad);

	dev_info(&client->dev, "Rev.%d keypad, irq %d\n", revid, client->irq);
	return 0;

 err_free_irq:
	free_irq(client->irq, kpad);
 err_unreg_dev:
	input_unregister_device(input);
	input = NULL;
 err_free_mem:
	input_free_device(input);
	kfree(kpad);

	return error;
}

static int __devexit adp5588_remove(struct i2c_client *client)
{
	struct adp5588_kpad *kpad = i2c_get_clientdata(client);

	adp5588_write(client, CFG, 0);
	free_irq(client->irq, kpad);
	cancel_delayed_work_sync(&kpad->work);
	input_unregister_device(kpad->input);
	i2c_set_clientdata(client, NULL);
	kfree(kpad);

	return 0;
}

#ifdef CONFIG_PM
static int adp5588_suspend(struct device *dev)
{
	struct adp5588_kpad *kpad = dev_get_drvdata(dev);
	struct i2c_client *client = kpad->client;

	disable_irq(client->irq);
	cancel_delayed_work_sync(&kpad->work);

	if (device_may_wakeup(&client->dev))
		enable_irq_wake(client->irq);

	return 0;
}

static int adp5588_resume(struct device *dev)
{
	struct adp5588_kpad *kpad = dev_get_drvdata(dev);
	struct i2c_client *client = kpad->client;

	if (device_may_wakeup(&client->dev))
		disable_irq_wake(client->irq);

	enable_irq(client->irq);

	return 0;
}

static const struct dev_pm_ops adp5588_dev_pm_ops = {
	.suspend = adp5588_suspend,
	.resume  = adp5588_resume,
};
#endif

static const struct i2c_device_id adp5588_id[] = {
	{ KBUILD_MODNAME, 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, adp5588_id);

static struct i2c_driver adp5588_driver = {
	.driver = {
		.name = KBUILD_MODNAME,
#ifdef CONFIG_PM
		.pm   = &adp5588_dev_pm_ops,
#endif
	},
	.probe    = adp5588_probe,
	.remove   = __devexit_p(adp5588_remove),
	.id_table = adp5588_id,
};

static int __init adp5588_init(void)
{
	return i2c_add_driver(&adp5588_driver);
}
module_init(adp5588_init);

static void __exit adp5588_exit(void)
{
	i2c_del_driver(&adp5588_driver);
}
module_exit(adp5588_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
MODULE_DESCRIPTION("ADP5588 Keypad driver");
MODULE_ALIAS("platform:adp5588-keys");