watchdog: pic32-dmt: Remove .owner field for driver

[linux/fpc-iii.git] / drivers / input / keyboard / cros_ec_keyb.c

/*
 * ChromeOS EC keyboard driver
 *
 * Copyright (C) 2012 Google, Inc
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 *
 * This driver uses the Chrome OS EC byte-level message-based protocol for
 * communicating the keyboard state (which keys are pressed) from a keyboard EC
 * to the AP over some bus (such as i2c, lpc, spi).  The EC does debouncing,
 * but everything else (including deghosting) is done here.  The main
 * motivation for this is to keep the EC firmware as simple as possible, since
 * it cannot be easily upgraded and EC flash/IRAM space is relatively
 * expensive.
 */

#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/input/matrix_keypad.h>
#include <linux/mfd/cros_ec.h>
#include <linux/mfd/cros_ec_commands.h>

/*
 * @rows: Number of rows in the keypad
 * @cols: Number of columns in the keypad
 * @row_shift: log2 or number of rows, rounded up
 * @keymap_data: Matrix keymap data used to convert to keyscan values
 * @ghost_filter: true to enable the matrix key-ghosting filter
 * @valid_keys: bitmap of existing keys for each matrix column
 * @old_kb_state: bitmap of keys pressed last scan
 * @dev: Device pointer
 * @idev: Input device
 * @ec: Top level ChromeOS device to use to talk to EC
 */
struct cros_ec_keyb {
        unsigned int rows;
        unsigned int cols;
        int row_shift;
        const struct matrix_keymap_data *keymap_data;
        bool ghost_filter;
        uint8_t *valid_keys;
        uint8_t *old_kb_state;

        struct device *dev;
        struct input_dev *idev;
        struct cros_ec_device *ec;
};


/*
 * Returns true when there is at least one combination of pressed keys that
 * results in ghosting.
 */
static bool cros_ec_keyb_has_ghosting(struct cros_ec_keyb *ckdev, uint8_t *buf)
{
        int col1, col2, buf1, buf2;
        struct device *dev = ckdev->dev;
        uint8_t *valid_keys = ckdev->valid_keys;

        /*
         * Ghosting happens if for any pressed key X there are other keys
         * pressed both in the same row and column of X as, for instance,
         * in the following diagram:
         *
         * . . Y . g .
         * . . . . . .
         * . . . . . .
         * . . X . Z .
         *
         * In this case only X, Y, and Z are pressed, but g appears to be
         * pressed too (see Wikipedia).
         */
        for (col1 = 0; col1 < ckdev->cols; col1++) {
                buf1 = buf[col1] & valid_keys[col1];
                for (col2 = col1 + 1; col2 < ckdev->cols; col2++) {
                        buf2 = buf[col2] & valid_keys[col2];
                        if (hweight8(buf1 & buf2) > 1) {
                                dev_dbg(dev, "ghost found at: B[%02d]:0x%02x & B[%02d]:0x%02x",
                                        col1, buf1, col2, buf2);
                                return true;
                        }
                }
        }

        return false;
}


/*
 * Compares the new keyboard state to the old one and produces key
 * press/release events accordingly.  The keyboard state is 13 bytes (one byte
 * per column)
 */
static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
                         uint8_t *kb_state, int len)
{
        struct input_dev *idev = ckdev->idev;
        int col, row;
        int new_state;
        int old_state;
        int num_cols;

        num_cols = len;

        if (ckdev->ghost_filter && cros_ec_keyb_has_ghosting(ckdev, kb_state)) {
                /*
                 * Simple-minded solution: ignore this state. The obvious
                 * improvement is to only ignore changes to keys involved in
                 * the ghosting, but process the other changes.
                 */
                dev_dbg(ckdev->dev, "ghosting found\n");
                return;
        }

        for (col = 0; col < ckdev->cols; col++) {
                for (row = 0; row < ckdev->rows; row++) {
                        int pos = MATRIX_SCAN_CODE(row, col, ckdev->row_shift);
                        const unsigned short *keycodes = idev->keycode;

                        new_state = kb_state[col] & (1 << row);
                        old_state = ckdev->old_kb_state[col] & (1 << row);
                        if (new_state != old_state) {
                                dev_dbg(ckdev->dev,
                                        "changed: [r%d c%d]: byte %02x\n",
                                        row, col, new_state);

                                input_report_key(idev, keycodes[pos],
                                                 new_state);
                        }
                }
                ckdev->old_kb_state[col] = kb_state[col];
        }
        input_sync(ckdev->idev);
}

static int cros_ec_keyb_get_state(struct cros_ec_keyb *ckdev, uint8_t *kb_state)
{
        int ret = 0;
        struct cros_ec_command *msg;

        msg = kmalloc(sizeof(*msg) + ckdev->cols, GFP_KERNEL);
        if (!msg)
                return -ENOMEM;

        msg->version = 0;
        msg->command = EC_CMD_MKBP_STATE;
        msg->insize = ckdev->cols;
        msg->outsize = 0;

        ret = cros_ec_cmd_xfer(ckdev->ec, msg);
        if (ret < 0) {
                dev_err(ckdev->dev, "Error transferring EC message %d\n", ret);
                goto exit;
        }

        memcpy(kb_state, msg->data, ckdev->cols);
exit:
        kfree(msg);
        return ret;
}

static irqreturn_t cros_ec_keyb_irq(int irq, void *data)
{
        struct cros_ec_keyb *ckdev = data;
        struct cros_ec_device *ec = ckdev->ec;
        int ret;
        uint8_t kb_state[ckdev->cols];

        if (device_may_wakeup(ec->dev))
                pm_wakeup_event(ec->dev, 0);

        ret = cros_ec_keyb_get_state(ckdev, kb_state);
        if (ret >= 0)
                cros_ec_keyb_process(ckdev, kb_state, ret);
        else
                dev_err(ec->dev, "failed to get keyboard state: %d\n", ret);

        return IRQ_HANDLED;
}

static int cros_ec_keyb_open(struct input_dev *dev)
{
        struct cros_ec_keyb *ckdev = input_get_drvdata(dev);
        struct cros_ec_device *ec = ckdev->ec;

        return request_threaded_irq(ec->irq, NULL, cros_ec_keyb_irq,
                                        IRQF_TRIGGER_LOW | IRQF_ONESHOT,
                                        "cros_ec_keyb", ckdev);
}

static void cros_ec_keyb_close(struct input_dev *dev)
{
        struct cros_ec_keyb *ckdev = input_get_drvdata(dev);
        struct cros_ec_device *ec = ckdev->ec;

        free_irq(ec->irq, ckdev);
}

/*
 * Walks keycodes flipping bit in buffer COLUMNS deep where bit is ROW.  Used by
 * ghosting logic to ignore NULL or virtual keys.
 */
static void cros_ec_keyb_compute_valid_keys(struct cros_ec_keyb *ckdev)
{
        int row, col;
        int row_shift = ckdev->row_shift;
        unsigned short *keymap = ckdev->idev->keycode;
        unsigned short code;

        BUG_ON(ckdev->idev->keycodesize != sizeof(*keymap));

        for (col = 0; col < ckdev->cols; col++) {
                for (row = 0; row < ckdev->rows; row++) {
                        code = keymap[MATRIX_SCAN_CODE(row, col, row_shift)];
                        if (code && (code != KEY_BATTERY))
                                ckdev->valid_keys[col] |= 1 << row;
                }
                dev_dbg(ckdev->dev, "valid_keys[%02d] = 0x%02x\n",
                        col, ckdev->valid_keys[col]);
        }
}

static int cros_ec_keyb_probe(struct platform_device *pdev)
{
        struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
        struct device *dev = ec->dev;
        struct cros_ec_keyb *ckdev;
        struct input_dev *idev;
        struct device_node *np;
        int err;

        np = pdev->dev.of_node;
        if (!np)
                return -ENODEV;

        ckdev = devm_kzalloc(&pdev->dev, sizeof(*ckdev), GFP_KERNEL);
        if (!ckdev)
                return -ENOMEM;
        err = matrix_keypad_parse_of_params(&pdev->dev, &ckdev->rows,
                                            &ckdev->cols);
        if (err)
                return err;

        ckdev->valid_keys = devm_kzalloc(&pdev->dev, ckdev->cols, GFP_KERNEL);
        if (!ckdev->valid_keys)
                return -ENOMEM;

        ckdev->old_kb_state = devm_kzalloc(&pdev->dev, ckdev->cols, GFP_KERNEL);
        if (!ckdev->old_kb_state)
                return -ENOMEM;

        idev = devm_input_allocate_device(&pdev->dev);
        if (!idev)
                return -ENOMEM;

        if (!ec->irq) {
                dev_err(dev, "no EC IRQ specified\n");
                return -EINVAL;
        }

        ckdev->ec = ec;
        ckdev->dev = dev;
        dev_set_drvdata(&pdev->dev, ckdev);

        idev->name = CROS_EC_DEV_NAME;
        idev->phys = ec->phys_name;
        __set_bit(EV_REP, idev->evbit);

        idev->id.bustype = BUS_VIRTUAL;
        idev->id.version = 1;
        idev->id.product = 0;
        idev->dev.parent = &pdev->dev;
        idev->open = cros_ec_keyb_open;
        idev->close = cros_ec_keyb_close;

        ckdev->ghost_filter = of_property_read_bool(np,
                                        "google,needs-ghost-filter");

        err = matrix_keypad_build_keymap(NULL, NULL, ckdev->rows, ckdev->cols,
                                         NULL, idev);
        if (err) {
                dev_err(dev, "cannot build key matrix\n");
                return err;
        }

        ckdev->row_shift = get_count_order(ckdev->cols);

        input_set_capability(idev, EV_MSC, MSC_SCAN);
        input_set_drvdata(idev, ckdev);
        ckdev->idev = idev;
        cros_ec_keyb_compute_valid_keys(ckdev);

        err = input_register_device(ckdev->idev);
        if (err) {
                dev_err(dev, "cannot register input device\n");
                return err;
        }

        return 0;
}

#ifdef CONFIG_PM_SLEEP
/* Clear any keys in the buffer */
static void cros_ec_keyb_clear_keyboard(struct cros_ec_keyb *ckdev)
{
        uint8_t old_state[ckdev->cols];
        uint8_t new_state[ckdev->cols];
        unsigned long duration;
        int i, ret;

        /*
         * Keep reading until we see that the scan state does not change.
         * That indicates that we are done.
         *
         * Assume that the EC keyscan buffer is at most 32 deep.
         */
        duration = jiffies;
        ret = cros_ec_keyb_get_state(ckdev, new_state);
        for (i = 1; !ret && i < 32; i++) {
                memcpy(old_state, new_state, sizeof(old_state));
                ret = cros_ec_keyb_get_state(ckdev, new_state);
                if (0 == memcmp(old_state, new_state, sizeof(old_state)))
                        break;
        }
        duration = jiffies - duration;
        dev_info(ckdev->dev, "Discarded %d keyscan(s) in %dus\n", i,
                jiffies_to_usecs(duration));
}

static int cros_ec_keyb_resume(struct device *dev)
{
        struct cros_ec_keyb *ckdev = dev_get_drvdata(dev);

        /*
         * When the EC is not a wake source, then it could not have caused the
         * resume, so we clear the EC's key scan buffer. If the EC was a
         * wake source (e.g. the lid is open and the user might press a key to
         * wake) then the key scan buffer should be preserved.
         */
        if (!ckdev->ec->was_wake_device)
                cros_ec_keyb_clear_keyboard(ckdev);

        return 0;
}

#endif

static SIMPLE_DEV_PM_OPS(cros_ec_keyb_pm_ops, NULL, cros_ec_keyb_resume);

#ifdef CONFIG_OF
static const struct of_device_id cros_ec_keyb_of_match[] = {
        { .compatible = "google,cros-ec-keyb" },
        {},
};
MODULE_DEVICE_TABLE(of, cros_ec_keyb_of_match);
#endif

static struct platform_driver cros_ec_keyb_driver = {
        .probe = cros_ec_keyb_probe,
        .driver = {
                .name = "cros-ec-keyb",
                .of_match_table = of_match_ptr(cros_ec_keyb_of_match),
                .pm     = &cros_ec_keyb_pm_ops,
        },
};

module_platform_driver(cros_ec_keyb_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ChromeOS EC keyboard driver");
MODULE_ALIAS("platform:cros-ec-keyb");