/* 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_of_params(&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_VERSION("1.0");
MODULE_ALIAS("platform:pmic8xxx_keypad");
MODULE_AUTHOR("Trilok Soni <tsoni@codeaurora.org>");