twl4030_keypad.c

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/*
 * twl4030_keypad.c - driver for 8x8 keypad controller in twl4030 chips
 *
 * Copyright (C) 2007 Texas Instruments, Inc.
 * Copyright (C) 2008 Nokia Corporation
 *
 * Code re-written for 2430SDP by:
 * Syed Mohammed Khasim <[email protected]>
 *
 * Initial Code:
 * Manjunatha G K <[email protected]>
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/platform_device.h>
#include <linux/i2c/twl.h>
#include <linux/slab.h>

/*
 * The TWL4030 family chips include a keypad controller that supports
 * up to an 8x8 switch matrix.  The controller can issue system wakeup
 * events, since it uses only the always-on 32KiHz oscillator, and has
 * an internal state machine that decodes pressed keys, including
 * multi-key combinations.
 *
 * This driver lets boards define what keycodes they wish to report for
 * which scancodes, as part of the "struct twl4030_keypad_data" used in
 * the probe() routine.
 *
 * See the TPS65950 documentation; that's the general availability
 * version of the TWL5030 second generation part.
 */
#define TWL4030_MAX_ROWS    8   /* TWL4030 hard limit */
#define TWL4030_MAX_COLS    8
/*
 * Note that we add space for an extra column so that we can handle
 * row lines connected to the gnd (see twl4030_col_xlate()).
 */
#define TWL4030_ROW_SHIFT   4
#define TWL4030_KEYMAP_SIZE (TWL4030_MAX_ROWS << TWL4030_ROW_SHIFT)

struct twl4030_keypad {
    unsigned short  keymap[TWL4030_KEYMAP_SIZE];
    u16     kp_state[TWL4030_MAX_ROWS];
    unsigned    n_rows;
    unsigned    n_cols;
    unsigned    irq;

    struct device *dbg_dev;
    struct input_dev *input;
};

/*----------------------------------------------------------------------*/

/* arbitrary prescaler value 0..7 */
#define PTV_PRESCALER           4

/* Register Offsets */
#define KEYP_CTRL           0x00
#define KEYP_DEB            0x01
#define KEYP_LONG_KEY           0x02
#define KEYP_LK_PTV         0x03
#define KEYP_TIMEOUT_L          0x04
#define KEYP_TIMEOUT_H          0x05
#define KEYP_KBC            0x06
#define KEYP_KBR            0x07
#define KEYP_SMS            0x08
#define KEYP_FULL_CODE_7_0      0x09    /* row 0 column status */
#define KEYP_FULL_CODE_15_8     0x0a    /* ... row 1 ... */
#define KEYP_FULL_CODE_23_16        0x0b
#define KEYP_FULL_CODE_31_24        0x0c
#define KEYP_FULL_CODE_39_32        0x0d
#define KEYP_FULL_CODE_47_40        0x0e
#define KEYP_FULL_CODE_55_48        0x0f
#define KEYP_FULL_CODE_63_56        0x10
#define KEYP_ISR1           0x11
#define KEYP_IMR1           0x12
#define KEYP_ISR2           0x13
#define KEYP_IMR2           0x14
#define KEYP_SIR            0x15
#define KEYP_EDR            0x16    /* edge triggers */
#define KEYP_SIH_CTRL           0x17

/* KEYP_CTRL_REG Fields */
#define KEYP_CTRL_SOFT_NRST     BIT(0)
#define KEYP_CTRL_SOFTMODEN     BIT(1)
#define KEYP_CTRL_LK_EN         BIT(2)
#define KEYP_CTRL_TOE_EN        BIT(3)
#define KEYP_CTRL_TOLE_EN       BIT(4)
#define KEYP_CTRL_RP_EN         BIT(5)
#define KEYP_CTRL_KBD_ON        BIT(6)

/* KEYP_DEB, KEYP_LONG_KEY, KEYP_TIMEOUT_x*/
#define KEYP_PERIOD_US(t, prescale) ((t) / (31 << (prescale + 1)) - 1)

/* KEYP_LK_PTV_REG Fields */
#define KEYP_LK_PTV_PTV_SHIFT       5

/* KEYP_{IMR,ISR,SIR} Fields */
#define KEYP_IMR1_MIS           BIT(3)
#define KEYP_IMR1_TO            BIT(2)
#define KEYP_IMR1_LK            BIT(1)
#define KEYP_IMR1_KP            BIT(0)

/* KEYP_EDR Fields */
#define KEYP_EDR_KP_FALLING     0x01
#define KEYP_EDR_KP_RISING      0x02
#define KEYP_EDR_KP_BOTH        0x03
#define KEYP_EDR_LK_FALLING     0x04
#define KEYP_EDR_LK_RISING      0x08
#define KEYP_EDR_TO_FALLING     0x10
#define KEYP_EDR_TO_RISING      0x20
#define KEYP_EDR_MIS_FALLING        0x40
#define KEYP_EDR_MIS_RISING     0x80


/*----------------------------------------------------------------------*/

static int twl4030_kpread(struct twl4030_keypad *kp,
        u8 *data, u32 reg, u8 num_bytes)
{
    int ret = twl_i2c_read(TWL4030_MODULE_KEYPAD, data, reg, num_bytes);

    if (ret < 0)
        dev_warn(kp->dbg_dev,
            "Couldn't read TWL4030: %X - ret %d[%x]\n",
             reg, ret, ret);

    return ret;
}

static int twl4030_kpwrite_u8(struct twl4030_keypad *kp, u8 data, u32 reg)
{
    int ret = twl_i2c_write_u8(TWL4030_MODULE_KEYPAD, data, reg);

    if (ret < 0)
        dev_warn(kp->dbg_dev,
            "Could not write TWL4030: %X - ret %d[%x]\n",
             reg, ret, ret);

    return ret;
}

static inline u16 twl4030_col_xlate(struct twl4030_keypad *kp, u8 col)
{
    /* If all bits in a row are active for all coloumns then
     * we have that row line connected to gnd. Mark this
     * key on as if it was on matrix position n_cols (ie
     * one higher than the size of the matrix).
     */
    if (col == 0xFF)
        return 1 << kp->n_cols;
    else
        return col & ((1 << kp->n_cols) - 1);
}

static int twl4030_read_kp_matrix_state(struct twl4030_keypad *kp, u16 *state)
{
    u8 new_state[TWL4030_MAX_ROWS];
    int row;
    int ret = twl4030_kpread(kp, new_state,
                 KEYP_FULL_CODE_7_0, kp->n_rows);
    if (ret >= 0)
        for (row = 0; row < kp->n_rows; row++)
            state[row] = twl4030_col_xlate(kp, new_state[row]);

    return ret;
}

static bool twl4030_is_in_ghost_state(struct twl4030_keypad *kp, u16 *key_state)
{
    int i;
    u16 check = 0;

    for (i = 0; i < kp->n_rows; i++) {
        u16 col = key_state[i];

        if ((col & check) && hweight16(col) > 1)
            return true;

        check |= col;
    }

    return false;
}

static void twl4030_kp_scan(struct twl4030_keypad *kp, bool release_all)
{
    struct input_dev *input = kp->input;
    u16 new_state[TWL4030_MAX_ROWS];
    int col, row;

    if (release_all)
        memset(new_state, 0, sizeof(new_state));
    else {
        /* check for any changes */
        int ret = twl4030_read_kp_matrix_state(kp, new_state);

        if (ret < 0)    /* panic ... */
            return;

        if (twl4030_is_in_ghost_state(kp, new_state))
            return;
    }

    /* check for changes and print those */
    for (row = 0; row < kp->n_rows; row++) {
        int changed = new_state[row] ^ kp->kp_state[row];

        if (!changed)
            continue;

        /* Extra column handles "all gnd" rows */
        for (col = 0; col < kp->n_cols + 1; col++) {
            int code;

            if (!(changed & (1 << col)))
                continue;

            dev_dbg(kp->dbg_dev, "key [%d:%d] %s\n", row, col,
                (new_state[row] & (1 << col)) ?
                "press" : "release");

            code = MATRIX_SCAN_CODE(row, col, TWL4030_ROW_SHIFT);
            input_event(input, EV_MSC, MSC_SCAN, code);
            input_report_key(input, kp->keymap[code],
                     new_state[row] & (1 << col));
        }
        kp->kp_state[row] = new_state[row];
    }
    input_sync(input);
}

/*
 * Keypad interrupt handler
 */
static irqreturn_t do_kp_irq(int irq, void *_kp)
{
    struct twl4030_keypad *kp = _kp;
    u8 reg;
    int ret;

    /* Read & Clear TWL4030 pending interrupt */
    ret = twl4030_kpread(kp, &reg, KEYP_ISR1, 1);

    /* Release all keys if I2C has gone bad or
     * the KEYP has gone to idle state */
    if (ret >= 0 && (reg & KEYP_IMR1_KP))
        twl4030_kp_scan(kp, false);
    else
        twl4030_kp_scan(kp, true);

    return IRQ_HANDLED;
}

static int __devinit twl4030_kp_program(struct twl4030_keypad *kp)
{
    u8 reg;
    int i;

    /* Enable controller, with hardware decoding but not autorepeat */
    reg = KEYP_CTRL_SOFT_NRST | KEYP_CTRL_SOFTMODEN
        | KEYP_CTRL_TOE_EN | KEYP_CTRL_KBD_ON;
    if (twl4030_kpwrite_u8(kp, reg, KEYP_CTRL) < 0)
        return -EIO;

    /* NOTE:  we could use sih_setup() here to package keypad
     * event sources as four different IRQs ... but we don't.
     */

    /* Enable TO rising and KP rising and falling edge detection */
    reg = KEYP_EDR_KP_BOTH | KEYP_EDR_TO_RISING;
    if (twl4030_kpwrite_u8(kp, reg, KEYP_EDR) < 0)
        return -EIO;

    /* Set PTV prescaler Field */
    reg = (PTV_PRESCALER << KEYP_LK_PTV_PTV_SHIFT);
    if (twl4030_kpwrite_u8(kp, reg, KEYP_LK_PTV) < 0)
        return -EIO;

    /* Set key debounce time to 20 ms */
    i = KEYP_PERIOD_US(20000, PTV_PRESCALER);
    if (twl4030_kpwrite_u8(kp, i, KEYP_DEB) < 0)
        return -EIO;

    /* Set timeout period to 200 ms */
    i = KEYP_PERIOD_US(200000, PTV_PRESCALER);
    if (twl4030_kpwrite_u8(kp, (i & 0xFF), KEYP_TIMEOUT_L) < 0)
        return -EIO;

    if (twl4030_kpwrite_u8(kp, (i >> 8), KEYP_TIMEOUT_H) < 0)
        return -EIO;

    /*
     * Enable Clear-on-Read; disable remembering events that fire
     * after the IRQ but before our handler acks (reads) them,
     */
    reg = TWL4030_SIH_CTRL_COR_MASK | TWL4030_SIH_CTRL_PENDDIS_MASK;
    if (twl4030_kpwrite_u8(kp, reg, KEYP_SIH_CTRL) < 0)
        return -EIO;

    /* initialize key state; irqs update it from here on */
    if (twl4030_read_kp_matrix_state(kp, kp->kp_state) < 0)
        return -EIO;

    return 0;
}

/*
 * Registers keypad device with input subsystem
 * and configures TWL4030 keypad registers
 */
static int __devinit twl4030_kp_probe(struct platform_device *pdev)
{
    struct twl4030_keypad_data *pdata = pdev->dev.platform_data;
    const struct matrix_keymap_data *keymap_data;
    struct twl4030_keypad *kp;
    struct input_dev *input;
    u8 reg;
    int error;

    if (!pdata || !pdata->rows || !pdata->cols || !pdata->keymap_data ||
        pdata->rows > TWL4030_MAX_ROWS || pdata->cols > TWL4030_MAX_COLS) {
        dev_err(&pdev->dev, "Invalid platform_data\n");
        return -EINVAL;
    }

    keymap_data = pdata->keymap_data;

    kp = kzalloc(sizeof(*kp), GFP_KERNEL);
    input = input_allocate_device();
    if (!kp || !input) {
        error = -ENOMEM;
        goto err1;
    }

    /* Get the debug Device */
    kp->dbg_dev = &pdev->dev;
    kp->input = input;

    kp->n_rows = pdata->rows;
    kp->n_cols = pdata->cols;
    kp->irq = platform_get_irq(pdev, 0);

    /* setup input device */
    input->name     = "TWL4030 Keypad";
    input->phys     = "twl4030_keypad/input0";
    input->dev.parent   = &pdev->dev;

    input->id.bustype   = BUS_HOST;
    input->id.vendor    = 0x0001;
    input->id.product   = 0x0001;
    input->id.version   = 0x0003;

    error = matrix_keypad_build_keymap(keymap_data, NULL,
                       TWL4030_MAX_ROWS,
                       1 << TWL4030_ROW_SHIFT,
                       kp->keymap, input);
    if (error) {
        dev_err(kp->dbg_dev, "Failed to build keymap\n");
        goto err1;
    }

    input_set_capability(input, EV_MSC, MSC_SCAN);
    /* Enable auto repeat feature of Linux input subsystem */
    if (pdata->rep)
        __set_bit(EV_REP, input->evbit);

    error = input_register_device(input);
    if (error) {
        dev_err(kp->dbg_dev,
            "Unable to register twl4030 keypad device\n");
        goto err1;
    }

    error = twl4030_kp_program(kp);
    if (error)
        goto err2;

    /*
     * This ISR will always execute in kernel thread context because of
     * the need to access the TWL4030 over the I2C bus.
     *
     * NOTE:  we assume this host is wired to TWL4040 INT1, not INT2 ...
     */
    error = request_threaded_irq(kp->irq, NULL, do_kp_irq,
            0, pdev->name, kp);
    if (error) {
        dev_info(kp->dbg_dev, "request_irq failed for irq no=%d\n",
            kp->irq);
        goto err2;
    }

    /* Enable KP and TO interrupts now. */
    reg = (u8) ~(KEYP_IMR1_KP | KEYP_IMR1_TO);
    if (twl4030_kpwrite_u8(kp, reg, KEYP_IMR1)) {
        error = -EIO;
        goto err3;
    }

    platform_set_drvdata(pdev, kp);
    return 0;

err3:
    /* mask all events - we don't care about the result */
    (void) twl4030_kpwrite_u8(kp, 0xff, KEYP_IMR1);
    free_irq(kp->irq, NULL);
err2:
    input_unregister_device(input);
    input = NULL;
err1:
    input_free_device(input);
    kfree(kp);
    return error;
}

static int __devexit twl4030_kp_remove(struct platform_device *pdev)
{
    struct twl4030_keypad *kp = platform_get_drvdata(pdev);

    free_irq(kp->irq, kp);
    input_unregister_device(kp->input);
    platform_set_drvdata(pdev, NULL);
    kfree(kp);

    return 0;
}

/*
 * NOTE: twl4030 are multi-function devices connected via I2C.
 * So this device is a child of an I2C parent, thus it needs to
 * support unplug/replug (which most platform devices don't).
 */

static struct platform_driver twl4030_kp_driver = {
    .probe      = twl4030_kp_probe,
    .remove     = __devexit_p(twl4030_kp_remove),
    .driver     = {
        .name   = "twl4030_keypad",
        .owner  = THIS_MODULE,
    },
};
module_platform_driver(twl4030_kp_driver);

MODULE_AUTHOR("Texas Instruments");
MODULE_DESCRIPTION("TWL4030 Keypad Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:twl4030_keypad");