/* Copyright (c) 2009-2011, Code Aurora Forum. 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 version 2 and
 * only version 2 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.
 */

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/regmap.h>
#include <linux/of.h>
#include <linux/input/matrix_keypad.h>

#define PM8XXX_MAX_ROWS		18
#define PM8XXX_MAX_COLS		8
#define PM8XXX_ROW_SHIFT	3
#define PM8XXX_MATRIX_MAX_SIZE	(PM8XXX_MAX_ROWS * PM8XXX_MAX_COLS)

#define PM8XXX_MIN_ROWS		5
#define PM8XXX_MIN_COLS		5

#define MAX_SCAN_DELAY		128
#define MIN_SCAN_DELAY		1

/* in nanoseconds */
#define MAX_ROW_HOLD_DELAY	122000
#define MIN_ROW_HOLD_DELAY	30500

#define MAX_DEBOUNCE_TIME	20
#define MIN_DEBOUNCE_TIME	5

#define KEYP_CTRL			0x148

#define KEYP_CTRL_EVNTS			BIT(0)
#define KEYP_CTRL_EVNTS_MASK		0x3

#define KEYP_CTRL_SCAN_COLS_SHIFT	5
#define KEYP_CTRL_SCAN_COLS_MIN		5
#define KEYP_CTRL_SCAN_COLS_BITS	0x3

#define KEYP_CTRL_SCAN_ROWS_SHIFT	2
#define KEYP_CTRL_SCAN_ROWS_MIN		5
#define KEYP_CTRL_SCAN_ROWS_BITS	0x7

#define KEYP_CTRL_KEYP_EN		BIT(7)

#define KEYP_SCAN			0x149

#define KEYP_SCAN_READ_STATE		BIT(0)
#define KEYP_SCAN_DBOUNCE_SHIFT		1
#define KEYP_SCAN_PAUSE_SHIFT		3
#define KEYP_SCAN_ROW_HOLD_SHIFT	6

#define KEYP_TEST			0x14A

#define KEYP_TEST_CLEAR_RECENT_SCAN	BIT(6)
#define KEYP_TEST_CLEAR_OLD_SCAN	BIT(5)
#define KEYP_TEST_READ_RESET		BIT(4)
#define KEYP_TEST_DTEST_EN		BIT(3)
#define KEYP_TEST_ABORT_READ		BIT(0)

#define KEYP_TEST_DBG_SELECT_SHIFT	1

/* bits of these registers represent
 * '0' for key press
 * '1' for key release
 */
#define KEYP_RECENT_DATA		0x14B
#define KEYP_OLD_DATA			0x14C

#define KEYP_CLOCK_FREQ			32768

/**
 * struct pmic8xxx_kp - internal keypad data structure
 * @num_cols - number of columns of keypad
 * @num_rows - number of row of keypad
 * @input - input device pointer for keypad
 * @regmap - regmap handle
 * @key_sense_irq - key press/release irq number
 * @key_stuck_irq - key stuck notification irq number
 * @keycodes - array to hold the key codes
 * @dev - parent device pointer
 * @keystate - present key press/release state
 * @stuckstate - present state when key stuck irq
 * @ctrl_reg - control register value
 */
struct pmic8xxx_kp {
	unsigned int num_rows;
	unsigned int num_cols;
	struct input_dev *input;
	struct regmap *regmap;
	int key_sense_irq;
	int key_stuck_irq;

	unsigned short keycodes[PM8XXX_MATRIX_MAX_SIZE];

	struct device *dev;
	u16 keystate[PM8XXX_MAX_ROWS];
	u16 stuckstate[PM8XXX_MAX_ROWS];

	u8 ctrl_reg;
};

static u8 pmic8xxx_col_state(struct pmic8xxx_kp *kp, u8 col)
{
	/* all keys pressed on that particular row? */
	if (col == 0x00)
		return 1 << kp->num_cols;
	else
		return col & ((1 << kp->num_cols) - 1);
}

/*
 * Synchronous read protocol for RevB0 onwards:
 *
 * 1. Write '1' to ReadState bit in KEYP_SCAN register
 * 2. Wait 2*32KHz clocks, so that HW can successfully enter read mode
 *    synchronously
 * 3. Read rows in old array first if events are more than one
 * 4. Read rows in recent array
 * 5. Wait 4*32KHz clocks
 * 6. Write '0' to ReadState bit of KEYP_SCAN register so that hw can
 *    synchronously exit read mode.
 */
static int pmic8xxx_chk_sync_read(struct pmic8xxx_kp *kp)
{
	int rc;
	unsigned int scan_val;

	rc = regmap_read(kp->regmap, KEYP_SCAN, &scan_val);
	if (rc < 0) {
		dev_err(kp->dev, "Error reading KEYP_SCAN reg, rc=%d\n", rc);
		return rc;
	}

	scan_val |= 0x1;

	rc = regmap_write(kp->regmap, KEYP_SCAN, scan_val);
	if (rc < 0) {
		dev_err(kp->dev, "Error writing KEYP_SCAN reg, rc=%d\n", rc);
		return rc;
	}

	/* 2 * 32KHz clocks */
	udelay((2 * DIV_ROUND_UP(USEC_PER_SEC, KEYP_CLOCK_FREQ)) + 1);

	return rc;
}

static int pmic8xxx_kp_read_data(struct pmic8xxx_kp *kp, u16 *state,
					u16 data_reg, int read_rows)
{
	int rc, row;
	unsigned int val;

	for (row = 0; row < read_rows; row++) {
		rc = regmap_read(kp->regmap, data_reg, &val);
		if (rc)
			return rc;
		dev_dbg(kp->dev, "%d = %d\n", row, val);
		state[row] = pmic8xxx_col_state(kp, val);
	}

	return 0;
}

static int pmic8xxx_kp_read_matrix(struct pmic8xxx_kp *kp, u16 *new_state,
					 u16 *old_state)
{
	int rc, read_rows;
	unsigned int scan_val;

	if (kp->num_rows < PM8XXX_MIN_ROWS)
		read_rows = PM8XXX_MIN_ROWS;
	else
		read_rows = kp->num_rows;

	pmic8xxx_chk_sync_read(kp);

	if (old_state) {
		rc = pmic8xxx_kp_read_data(kp, old_state, KEYP_OLD_DATA,
						read_rows);
		if (rc < 0) {
			dev_err(kp->dev,
				"Error reading KEYP_OLD_DATA, rc=%d\n", rc);
			return rc;
		}
	}

	rc = pmic8xxx_kp_read_data(kp, new_state, KEYP_RECENT_DATA,
					 read_rows);
	if (rc < 0) {
		dev_err(kp->dev,
			"Error reading KEYP_RECENT_DATA, rc=%d\n", rc);
		return rc;
	}

	/* 4 * 32KHz clocks */
	udelay((4 * DIV_ROUND_UP(USEC_PER_SEC, KEYP_CLOCK_FREQ)) + 1);

	rc = regmap_read(kp->regmap, KEYP_SCAN, &scan_val);
	if (rc < 0) {
		dev_err(kp->dev, "Error reading KEYP_SCAN reg, rc=%d\n", rc);
		return rc;
	}

	scan_val &= 0xFE;
	rc = regmap_write(kp->regmap, KEYP_SCAN, scan_val);
	if (rc < 0)
		dev_err(kp->dev, "Error writing KEYP_SCAN reg, rc=%d\n", rc);

	return rc;
}

static void __pmic8xxx_kp_scan_matrix(struct pmic8xxx_kp *kp, u16 *new_state,
					 u16 *old_state)
{
	int row, col, code;

	for (row = 0; row < kp->num_rows; row++) {
		int bits_changed = new_state[row] ^ old_state[row];

		if (!bits_changed)
			continue;

		for (col = 0; col < kp->num_cols; col++) {
			if (!(bits_changed & (1 << col)))
				continue;

			dev_dbg(kp->dev, "key [%d:%d] %s\n", row, col,
					!(new_state[row] & (1 << col)) ?
					"pressed" : "released");

			code = MATRIX_SCAN_CODE(row, col, PM8XXX_ROW_SHIFT);

			input_event(kp->input, EV_MSC, MSC_SCAN, code);
			input_report_key(kp->input,
					kp->keycodes[code],
					!(new_state[row] & (1 << col)));

			input_sync(kp->input);
		}
	}
}

static bool pmic8xxx_detect_ghost_keys(struct pmic8xxx_kp *kp, u16 *new_state)
{
	int row, found_first = -1;
	u16 check, row_state;

	check = 0;
	for (row = 0; row < kp->num_rows; row++) {
		row_state = (~new_state[row]) &
				 ((1 << kp->num_cols) - 1);

		if (hweight16(row_state) > 1) {
			if (found_first == -1)
				found_first = row;
			if (check & row_state) {
				dev_dbg(kp->dev, "detected ghost key on row[%d]"
					 " and row[%d]\n", found_first, row);
				return true;
			}
		}
		check |= row_state;
	}
	return false;
}

static int pmic8xxx_kp_scan_matrix(struct pmic8xxx_kp *kp, unsigned int events)
{
	u16 new_state[PM8XXX_MAX_ROWS];
	u16 old_state[PM8XXX_MAX_ROWS];
	int rc;

	switch (events) {
	case 0x1:
		rc = pmic8xxx_kp_read_matrix(kp, new_state, NULL);
		if (rc < 0)
			return rc;

		/* detecting ghost key is not an error */
		if (pmic8xxx_detect_ghost_keys(kp, new_state))
			return 0;
		__pmic8xxx_kp_scan_matrix(kp, new_state, kp->keystate);
		memcpy(kp->keystate, new_state, sizeof(new_state));
	break;
	case 0x3: /* two events - eventcounter is gray-coded */
		rc = pmic8xxx_kp_read_matrix(kp, new_state, old_state);
		if (rc < 0)
			return rc;

		__pmic8xxx_kp_scan_matrix(kp, old_state, kp->keystate);
		__pmic8xxx_kp_scan_matrix(kp, new_state, old_state);
		memcpy(kp->keystate, new_state, sizeof(new_state));
	break;
	case 0x2:
		dev_dbg(kp->dev, "Some key events were lost\n");
		rc = pmic8xxx_kp_read_matrix(kp, new_state, old_state);
		if (rc < 0)
			return rc;
		__pmic8xxx_kp_scan_matrix(kp, old_state, kp->keystate);
		__pmic8xxx_kp_scan_matrix(kp, new_state, old_state);
		memcpy(kp->keystate, new_state, sizeof(new_state));
	break;
	default:
		rc = -EINVAL;
	}
	return rc;
}

/*
 * NOTE: We are reading recent and old data registers blindly
 * whenever key-stuck interrupt happens, because events counter doesn't
 * get updated when this interrupt happens due to key stuck doesn't get
 * considered as key state change.
 *
 * We are not using old data register contents after they are being read
 * because it might report the key which was pressed before the key being stuck
 * as stuck key because it's pressed status is stored in the old data
 * register.
 */
static irqreturn_t pmic8xxx_kp_stuck_irq(int irq, void *data)
{
	u16 new_state[PM8XXX_MAX_ROWS];
	u16 old_state[PM8XXX_MAX_ROWS];
	int rc;
	struct pmic8xxx_kp *kp = data;

	rc = pmic8xxx_kp_read_matrix(kp, new_state, old_state);
	if (rc < 0) {
		dev_err(kp->dev, "failed to read keypad matrix\n");
		return IRQ_HANDLED;
	}

	__pmic8xxx_kp_scan_matrix(kp, new_state, kp->stuckstate);

	return IRQ_HANDLED;
}

static irqreturn_t pmic8xxx_kp_irq(int irq, void *data)
{
	struct pmic8xxx_kp *kp = data;
	unsigned int ctrl_val, events;
	int rc;

	rc = regmap_read(kp->regmap, KEYP_CTRL, &ctrl_val);
	if (rc < 0) {
		dev_err(kp->dev, "failed to read keyp_ctrl register\n");
		return IRQ_HANDLED;
	}

	events = ctrl_val & KEYP_CTRL_EVNTS_MASK;

	rc = pmic8xxx_kp_scan_matrix(kp, events);
	if (rc < 0)
		dev_err(kp->dev, "failed to scan matrix\n");

	return IRQ_HANDLED;
}

static int pmic8xxx_kpd_init(struct pmic8xxx_kp *kp,
			     struct platform_device *pdev)
{
	const struct device_node *of_node = pdev->dev.of_node;
	unsigned int scan_delay_ms;
	unsigned int row_hold_ns;
	unsigned int debounce_ms;
	int bits, rc, cycles;
	u8 scan_val = 0, ctrl_val = 0;
	static const u8 row_bits[] = {
		0, 1, 2, 3, 4, 4, 5, 5, 6, 6, 6, 7, 7, 7,
	};

	/* Find column bits */
	if (kp->num_cols < KEYP_CTRL_SCAN_COLS_MIN)
		bits = 0;
	else
		bits = kp->num_cols - KEYP_CTRL_SCAN_COLS_MIN;
	ctrl_val = (bits & KEYP_CTRL_SCAN_COLS_BITS) <<
		KEYP_CTRL_SCAN_COLS_SHIFT;

	/* Find row bits */
	if (kp->num_rows < KEYP_CTRL_SCAN_ROWS_MIN)
		bits = 0;
	else
		bits = row_bits[kp->num_rows - KEYP_CTRL_SCAN_ROWS_MIN];

	ctrl_val |= (bits << KEYP_CTRL_SCAN_ROWS_SHIFT);

	rc = regmap_write(kp->regmap, KEYP_CTRL, ctrl_val);
	if (rc < 0) {
		dev_err(kp->dev, "Error writing KEYP_CTRL reg, rc=%d\n", rc);
		return rc;
	}

	if (of_property_read_u32(of_node, "scan-delay", &scan_delay_ms))
		scan_delay_ms = MIN_SCAN_DELAY;

	if (scan_delay_ms > MAX_SCAN_DELAY || scan_delay_ms < MIN_SCAN_DELAY ||
	    !is_power_of_2(scan_delay_ms)) {
		dev_err(&pdev->dev, "invalid keypad scan time supplied\n");
		return -EINVAL;
	}

	if (of_property_read_u32(of_node, "row-hold", &row_hold_ns))
		row_hold_ns = MIN_ROW_HOLD_DELAY;

	if (row_hold_ns > MAX_ROW_HOLD_DELAY ||
	    row_hold_ns < MIN_ROW_HOLD_DELAY ||
	    ((row_hold_ns % MIN_ROW_HOLD_DELAY) != 0)) {
		dev_err(&pdev->dev, "invalid keypad row hold time supplied\n");
		return -EINVAL;
	}

	if (of_property_read_u32(of_node, "debounce", &debounce_ms))
		debounce_ms = MIN_DEBOUNCE_TIME;

	if (((debounce_ms % 5) != 0) ||
	    debounce_ms > MAX_DEBOUNCE_TIME ||
	    debounce_ms < MIN_DEBOUNCE_TIME) {
		dev_err(&pdev->dev, "invalid debounce time supplied\n");
		return -EINVAL;
	}

	bits = (debounce_ms / 5) - 1;

	scan_val |= (bits << KEYP_SCAN_DBOUNCE_SHIFT);

	bits = fls(scan_delay_ms) - 1;
	scan_val |= (bits << KEYP_SCAN_PAUSE_SHIFT);

	/* Row hold time is a multiple of 32KHz cycles. */
	cycles = (row_hold_ns * KEYP_CLOCK_FREQ) / NSEC_PER_SEC;

	scan_val |= (cycles << KEYP_SCAN_ROW_HOLD_SHIFT);

	rc = regmap_write(kp->regmap, KEYP_SCAN, scan_val);
	if (rc)
		dev_err(kp->dev, "Error writing KEYP_SCAN reg, rc=%d\n", rc);

	return rc;

}

static int pmic8xxx_kp_enable(struct pmic8xxx_kp *kp)
{
	int rc;

	kp->ctrl_reg |= KEYP_CTRL_KEYP_EN;

	rc = regmap_write(kp->regmap, KEYP_CTRL, kp->ctrl_reg);
	if (rc < 0)
		dev_err(kp->dev, "Error writing KEYP_CTRL reg, rc=%d\n", rc);

	return rc;
}

static int pmic8xxx_kp_disable(struct pmic8xxx_kp *kp)
{
	int rc;

	kp->ctrl_reg &= ~KEYP_CTRL_KEYP_EN;

	rc = regmap_write(kp->regmap, KEYP_CTRL, kp->ctrl_reg);
	if (rc < 0)
		return rc;

	return rc;
}

static int pmic8xxx_kp_open(struct input_dev *dev)
{
	struct pmic8xxx_kp *kp = input_get_drvdata(dev);

	return pmic8xxx_kp_enable(kp);
}

static void pmic8xxx_kp_close(struct input_dev *dev)
{
	struct pmic8xxx_kp *kp = input_get_drvdata(dev);

	pmic8xxx_kp_disable(kp);
}

/*
 * keypad controller should be initialized in the following sequence
 * only, otherwise it might get into FSM stuck state.
 *
 * - Initialize keypad control parameters, like no. of rows, columns,
 *   timing values etc.,
 * - configure rows and column gpios pull up/down.
 * - set irq edge type.
 * - enable the keypad controller.
 */
static int pmic8xxx_kp_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	unsigned int rows, cols;
	bool repeat;
	bool wakeup;
	struct pmic8xxx_kp *kp;
	int rc;
	unsigned int ctrl_val;

	rc = matrix_keypad_parse_properties(&pdev->dev, &rows, &cols);
	if (rc)
		return rc;

	if (cols > PM8XXX_MAX_COLS || rows > PM8XXX_MAX_ROWS ||
	    cols < PM8XXX_MIN_COLS) {
		dev_err(&pdev->dev, "invalid platform data\n");
		return -EINVAL;
	}

	repeat = !of_property_read_bool(np, "linux,input-no-autorepeat");

	wakeup = of_property_read_bool(np, "wakeup-source") ||
		 /* legacy name */
		 of_property_read_bool(np, "linux,keypad-wakeup");

	kp = devm_kzalloc(&pdev->dev, sizeof(*kp), GFP_KERNEL);
	if (!kp)
		return -ENOMEM;

	kp->regmap = dev_get_regmap(pdev->dev.parent, NULL);
	if (!kp->regmap)
		return -ENODEV;

	platform_set_drvdata(pdev, kp);

	kp->num_rows	= rows;
	kp->num_cols	= cols;
	kp->dev		= &pdev->dev;

	kp->input = devm_input_allocate_device(&pdev->dev);
	if (!kp->input) {
		dev_err(&pdev->dev, "unable to allocate input device\n");
		return -ENOMEM;
	}

	kp->key_sense_irq = platform_get_irq(pdev, 0);
	if (kp->key_sense_irq < 0) {
		dev_err(&pdev->dev, "unable to get keypad sense irq\n");
		return kp->key_sense_irq;
	}

	kp->key_stuck_irq = platform_get_irq(pdev, 1);
	if (kp->key_stuck_irq < 0) {
		dev_err(&pdev->dev, "unable to get keypad stuck irq\n");
		return kp->key_stuck_irq;
	}

	kp->input->name = "PMIC8XXX keypad";
	kp->input->phys = "pmic8xxx_keypad/input0";

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

	kp->input->open		= pmic8xxx_kp_open;
	kp->input->close	= pmic8xxx_kp_close;

	rc = matrix_keypad_build_keymap(NULL, NULL,
					PM8XXX_MAX_ROWS, PM8XXX_MAX_COLS,
					kp->keycodes, kp->input);
	if (rc) {
		dev_err(&pdev->dev, "failed to build keymap\n");
		return rc;
	}

	if (repeat)
		__set_bit(EV_REP, kp->input->evbit);
	input_set_capability(kp->input, EV_MSC, MSC_SCAN);

	input_set_drvdata(kp->input, kp);

	/* initialize keypad state */
	memset(kp->keystate, 0xff, sizeof(kp->keystate));
	memset(kp->stuckstate, 0xff, sizeof(kp->stuckstate));

	rc = pmic8xxx_kpd_init(kp, pdev);
	if (rc < 0) {
		dev_err(&pdev->dev, "unable to initialize keypad controller\n");
		return rc;
	}

	rc = devm_request_any_context_irq(&pdev->dev, kp->key_sense_irq,
			pmic8xxx_kp_irq, IRQF_TRIGGER_RISING, "pmic-keypad",
			kp);
	if (rc < 0) {
		dev_err(&pdev->dev, "failed to request keypad sense irq\n");
		return rc;
	}

	rc = devm_request_any_context_irq(&pdev->dev, kp->key_stuck_irq,
			pmic8xxx_kp_stuck_irq, IRQF_TRIGGER_RISING,
			"pmic-keypad-stuck", kp);
	if (rc < 0) {
		dev_err(&pdev->dev, "failed to request keypad stuck irq\n");
		return rc;
	}

	rc = regmap_read(kp->regmap, KEYP_CTRL, &ctrl_val);
	if (rc < 0) {
		dev_err(&pdev->dev, "failed to read KEYP_CTRL register\n");
		return rc;
	}

	kp->ctrl_reg = ctrl_val;

	rc = input_register_device(kp->input);
	if (rc < 0) {
		dev_err(&pdev->dev, "unable to register keypad input device\n");
		return rc;
	}

	device_init_wakeup(&pdev->dev, wakeup);

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int pmic8xxx_kp_suspend(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct pmic8xxx_kp *kp = platform_get_drvdata(pdev);
	struct input_dev *input_dev = kp->input;

	if (device_may_wakeup(dev)) {
		enable_irq_wake(kp->key_sense_irq);
	} else {
		mutex_lock(&input_dev->mutex);

		if (input_dev->users)
			pmic8xxx_kp_disable(kp);

		mutex_unlock(&input_dev->mutex);
	}

	return 0;
}

static int pmic8xxx_kp_resume(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct pmic8xxx_kp *kp = platform_get_drvdata(pdev);
	struct input_dev *input_dev = kp->input;

	if (device_may_wakeup(dev)) {
		disable_irq_wake(kp->key_sense_irq);
	} else {
		mutex_lock(&input_dev->mutex);

		if (input_dev->users)
			pmic8xxx_kp_enable(kp);

		mutex_unlock(&input_dev->mutex);
	}

	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(pm8xxx_kp_pm_ops,
			 pmic8xxx_kp_suspend, pmic8xxx_kp_resume);

static const struct of_device_id pm8xxx_match_table[] = {
	{ .compatible = "qcom,pm8058-keypad" },
	{ .compatible = "qcom,pm8921-keypad" },
	{ }
};
MODULE_DEVICE_TABLE(of, pm8xxx_match_table);

static struct platform_driver pmic8xxx_kp_driver = {
	.probe		= pmic8xxx_kp_probe,
	.driver		= {
		.name = "pm8xxx-keypad",
		.pm = &pm8xxx_kp_pm_ops,
		.of_match_table = pm8xxx_match_table,
	},
};
module_platform_driver(pmic8xxx_kp_driver);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("PMIC8XXX keypad driver");
MODULE_ALIAS("platform:pmic8xxx_keypad");
MODULE_AUTHOR("Trilok Soni <tsoni@codeaurora.org>");