/*
 * Touch Screen driver for Renesas MIGO-R Platform
 *
 * Copyright (c) 2008 Magnus Damm
 * Copyright (c) 2007 Ujjwal Pande <ujjwal@kenati.com>,
 *  Kenati Technologies Pvt Ltd.
 *
 * This file 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 file 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 library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <asm/io.h>
#include <linux/i2c.h>
#include <linux/timer.h>

#define EVENT_PENDOWN 1
#define EVENT_REPEAT  2
#define EVENT_PENUP   3

struct migor_ts_priv {
        struct i2c_client *client;
        struct input_dev *input;
        struct delayed_work work;
        int irq;
};

static const u_int8_t migor_ts_ena_seq[17] = { 0x33, 0x22, 0x11,
                                               0x01, 0x06, 0x07, };
static const u_int8_t migor_ts_dis_seq[17] = { };

static void migor_ts_poscheck(struct work_struct *work)
{
        struct migor_ts_priv *priv = container_of(work,
                                                  struct migor_ts_priv,
                                                  work.work);
        unsigned short xpos, ypos;
        unsigned char event;
        u_int8_t buf[16];

        memset(buf, 0, sizeof(buf));

        /* Set Index 0 */
        buf[0] = 0;
        if (i2c_master_send(priv->client, buf, 1) != 1) {
                dev_err(&priv->client->dev, "Unable to write i2c index\n");
                goto out;
        }

        /* Now do Page Read */
        if (i2c_master_recv(priv->client, buf, sizeof(buf)) != sizeof(buf)) {
                dev_err(&priv->client->dev, "Unable to read i2c page\n");
                goto out;
        }

        ypos = ((buf[9] & 0x03) << 8 | buf[8]);
        xpos = ((buf[11] & 0x03) << 8 | buf[10]);
        event = buf[12];

        if (event == EVENT_PENDOWN || event == EVENT_REPEAT) {
                input_report_key(priv->input, BTN_TOUCH, 1);
                input_report_abs(priv->input, ABS_X, ypos); /*X-Y swap*/
                input_report_abs(priv->input, ABS_Y, xpos);
                input_sync(priv->input);
        } else if (event == EVENT_PENUP) {
                input_report_key(priv->input, BTN_TOUCH, 0);
                input_sync(priv->input);
        }
 out:
        enable_irq(priv->irq);
}

static irqreturn_t migor_ts_isr(int irq, void *dev_id)
{
        struct migor_ts_priv *priv = dev_id;

        /* the touch screen controller chip is hooked up to the cpu
         * using i2c and a single interrupt line. the interrupt line
         * is pulled low whenever someone taps the screen. to deassert
         * the interrupt line we need to acknowledge the interrupt by
         * communicating with the controller over the slow i2c bus.
         *
         * we can't acknowledge from interrupt context since the i2c
         * bus controller may sleep, so we just disable the interrupt
         * here and handle the acknowledge using delayed work.
         */

        disable_irq_nosync(irq);
        schedule_delayed_work(&priv->work, HZ / 20);

        return IRQ_HANDLED;
}


static int migor_ts_open(struct input_dev *dev)
{
        struct migor_ts_priv *priv = input_get_drvdata(dev);
        struct i2c_client *client = priv->client;
        int count;

        /* enable controller */
        count = i2c_master_send(client, migor_ts_ena_seq,
                                sizeof(migor_ts_ena_seq));
        if (count != sizeof(migor_ts_ena_seq)) {
                dev_err(&client->dev, "Unable to enable touchscreen.\n");
                return -ENXIO;
        }

        return 0;
}

static void migor_ts_close(struct input_dev *dev)
{
        struct migor_ts_priv *priv = input_get_drvdata(dev);
        struct i2c_client *client = priv->client;

        disable_irq(priv->irq);

        /* cancel pending work and wait for migor_ts_poscheck() to finish */
        if (cancel_delayed_work_sync(&priv->work)) {
                /*
                 * if migor_ts_poscheck was canceled we need to enable IRQ
                 * here to balance disable done in migor_ts_isr.
                 */
                enable_irq(priv->irq);
        }

        /* disable controller */
        i2c_master_send(client, migor_ts_dis_seq, sizeof(migor_ts_dis_seq));

        enable_irq(priv->irq);
}

static int migor_ts_probe(struct i2c_client *client,
                          const struct i2c_device_id *idp)
{
        struct migor_ts_priv *priv;
        struct input_dev *input;
        int error;

        priv = kzalloc(sizeof(*priv), GFP_KERNEL);
        if (!priv) {
                dev_err(&client->dev, "failed to allocate driver data\n");
                error = -ENOMEM;
                goto err0;
        }

        dev_set_drvdata(&client->dev, priv);

        input = input_allocate_device();
        if (!input) {
                dev_err(&client->dev, "Failed to allocate input device.\n");
                error = -ENOMEM;
                goto err1;
        }

        input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
        input->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);

        input_set_abs_params(input, ABS_X, 95, 955, 0, 0);
        input_set_abs_params(input, ABS_Y, 85, 935, 0, 0);

        input->name = client->name;
        input->id.bustype = BUS_I2C;
        input->dev.parent = &client->dev;

        input->open = migor_ts_open;
        input->close = migor_ts_close;

        input_set_drvdata(input, priv);

        priv->client = client;
        priv->input = input;
        INIT_DELAYED_WORK(&priv->work, migor_ts_poscheck);
        priv->irq = client->irq;

        error = input_register_device(input);
        if (error)
                goto err1;

        error = request_irq(priv->irq, migor_ts_isr, IRQF_TRIGGER_LOW,
                            client->name, priv);
        if (error) {
                dev_err(&client->dev, "Unable to request touchscreen IRQ.\n");
                goto err2;
        }

        device_init_wakeup(&client->dev, 1);
        return 0;

 err2:
        input_unregister_device(input);
        input = NULL; /* so we dont try to free it below */
 err1:
        input_free_device(input);
        kfree(priv);
 err0:
        dev_set_drvdata(&client->dev, NULL);
        return error;
}

static int migor_ts_remove(struct i2c_client *client)
{
        struct migor_ts_priv *priv = dev_get_drvdata(&client->dev);

        free_irq(priv->irq, priv);
        input_unregister_device(priv->input);
        kfree(priv);

        dev_set_drvdata(&client->dev, NULL);

        return 0;
}

static int migor_ts_suspend(struct i2c_client *client, pm_message_t mesg)
{
        struct migor_ts_priv *priv = dev_get_drvdata(&client->dev);

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

        return 0;
}

static int migor_ts_resume(struct i2c_client *client)
{
        struct migor_ts_priv *priv = dev_get_drvdata(&client->dev);

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

        return 0;
}

static const struct i2c_device_id migor_ts_id[] = {
        { "migor_ts", 0 },
        { }
};
MODULE_DEVICE_TABLE(i2c, migor_ts);

static struct i2c_driver migor_ts_driver = {
        .driver = {
                .name = "migor_ts",
        },
        .probe = migor_ts_probe,
        .remove = migor_ts_remove,
        .suspend = migor_ts_suspend,
        .resume = migor_ts_resume,
        .id_table = migor_ts_id,
};

static int __init migor_ts_init(void)
{
        return i2c_add_driver(&migor_ts_driver);
}

static void __exit migor_ts_exit(void)
{
        i2c_del_driver(&migor_ts_driver);
}

MODULE_DESCRIPTION("MigoR Touchscreen driver");
MODULE_AUTHOR("Magnus Damm <damm@opensource.se>");
MODULE_LICENSE("GPL");

module_init(migor_ts_init);
module_exit(migor_ts_exit);