/*
 * clearpad_tm1217.c - Touch Screen driver for Synaptics Clearpad
 * TM1217 controller
 *
 * Copyright (C) 2008 Intel Corp
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * 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; version 2 of the License.
 *
 * 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; ifnot, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * Questions/Comments/Bug fixes to Ramesh Agarwal (ramesh.agarwal@intel.com)
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/i2c.h>
#include <linux/timer.h>
#include <linux/gpio.h>
#include <linux/hrtimer.h>
#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include "cp_tm1217.h"

#define CPTM1217_DEVICE_NAME            "cptm1217"
#define CPTM1217_DRIVER_NAME            CPTM1217_DEVICE_NAME

#define MAX_TOUCH_SUPPORTED             2
#define TOUCH_SUPPORTED                 1
#define SAMPLING_FREQ                   80      /* Frequency in HZ */
#define DELAY_BTWIN_SAMPLE              (1000 / SAMPLING_FREQ)
#define WAIT_FOR_RESPONSE               5       /* 5msec just works */
#define MAX_RETRIES                     5       /* As above */
#define INCREMENTAL_DELAY               5       /* As above */

/* Regster Definitions */
#define TMA1217_DEV_STATUS              0x13    /* Device Status */
#define TMA1217_INT_STATUS              0x14    /* Interrupt Status */

/* Controller can detect up to 2 possible finger touches.
 * Each finger touch provides  12 bit X Y co-ordinates, the values are split
 * across 2 registers, and an 8 bit  Z value */
#define TMA1217_FINGER_STATE            0x18 /* Finger State */
#define TMA1217_FINGER1_X_HIGHER8       0x19 /* Higher 8 bit of X coordinate */
#define TMA1217_FINGER1_Y_HIGHER8       0x1A /* Higher 8 bit of Y coordinate */
#define TMA1217_FINGER1_XY_LOWER4       0x1B /* Lower 4 bits of X and Y */
#define TMA1217_FINGER1_Z_VALUE         0x1D /* 8 bit Z value for finger 1 */
#define TMA1217_FINGER2_X_HIGHER8       0x1E /* Higher 8 bit of X coordinate */
#define TMA1217_FINGER2_Y_HIGHER8       0x1F /* Higher 8 bit of Y coordinate */
#define TMA1217_FINGER2_XY_LOWER4       0x20 /* Lower 4 bits of X and Y */
#define TMA1217_FINGER2_Z_VALUE         0x22 /* 8 bit Z value for finger 2 */
#define TMA1217_DEVICE_CTRL             0x23 /* Device Control */
#define TMA1217_INTERRUPT_ENABLE        0x24 /* Interrupt Enable */
#define TMA1217_REPORT_MODE             0x2B /* Reporting Mode */
#define TMA1217_MAX_X_LOWER8            0x31 /* Bit 0-7 for Max X */
#define TMA1217_MAX_X_HIGHER4           0x32 /* Bit 8-11 for Max X */
#define TMA1217_MAX_Y_LOWER8            0x33 /* Bit 0-7 for Max Y */
#define TMA1217_MAX_Y_HIGHER4           0x34 /* Bit 8-11 for Max Y */
#define TMA1217_DEVICE_CMD_RESET        0x67 /* Device CMD reg for reset */
#define TMA1217_DEVICE_CMD_REZERO       0x69 /* Device CMD reg for rezero */

#define TMA1217_MANUFACTURER_ID         0x73 /* Manufacturer Id */
#define TMA1217_PRODUCT_FAMILY          0x75 /* Product Family */
#define TMA1217_FIRMWARE_REVISION       0x76 /* Firmware Revision */
#define TMA1217_SERIAL_NO_HIGH          0x7C /* Bit 8-15 of device serial no. */
#define TMA1217_SERIAL_NO_LOW           0x7D /* Bit 0-7 of device serial no. */
#define TMA1217_PRODUCT_ID_START        0x7E /* Start address for 10 byte ID */
#define TMA1217_DEVICE_CAPABILITY       0x8B /* Reporting capability */


/*
 * The touch position structure.
 */
struct touch_state {
        int     x;
        int     y;
        bool button;
};

/* Device Specific info given by the controller */
struct cp_dev_info {
        u16     maxX;
        u16     maxY;
};

/* Vendor related info given by the controller */
struct cp_vendor_info {
        u8      vendor_id;
        u8      product_family;
        u8      firmware_rev;
        u16     serial_no;
};

/*
 * Private structure to store the device details
 */
struct cp_tm1217_device {
        struct i2c_client       *client;
        struct device           *dev;
        struct cp_vendor_info   vinfo;
        struct cp_dev_info      dinfo;
        struct input_dev_info {
                char                    phys[32];
                char                    name[128];
                struct input_dev        *input;
                struct touch_state      touch;
        } cp_input_info[MAX_TOUCH_SUPPORTED];

        int     thread_running;
        struct mutex    thread_mutex;

        int gpio;
};


/* The following functions are used to read/write registers on the device
 * as per the RMI prorocol. Technically, a page select should be written
 * before doing read/write but since the register offsets are below 0xFF
 * we can use the default value of page which is 0x00
 */
static int cp_tm1217_read(struct cp_tm1217_device *ts,
                                u8 *req, int size)
{
        int i, retval;

        /* Send the address */
        retval = i2c_master_send(ts->client, &req[0], 1);
        if (retval != 1) {
                dev_err(ts->dev, "cp_tm1217: I2C send failed\n");
                return retval;
        }
        msleep(WAIT_FOR_RESPONSE);
        for (i = 0; i < MAX_RETRIES; i++) {
                retval = i2c_master_recv(ts->client, &req[1], size);
                if (retval == size) {
                        break;
                } else {
                        msleep(INCREMENTAL_DELAY);
                        dev_dbg(ts->dev, "cp_tm1217: Retry count is %d\n", i);
                }
        }
        if (retval != size)
                dev_err(ts->dev, "cp_tm1217: Read from device failed\n");

        return retval;
}

static int cp_tm1217_write(struct cp_tm1217_device *ts,
                                u8 *req, int size)
{
        int retval;

        /* Send the address and the data to be written */
        retval = i2c_master_send(ts->client, &req[0], size + 1);
        if (retval != size + 1) {
                dev_err(ts->dev, "cp_tm1217: I2C write  failed: %d\n", retval);
                return retval;
        }
        /* Wait for the write to complete. TBD why this is required */
        msleep(WAIT_FOR_RESPONSE);

        return size;
}

static int cp_tm1217_mask_interrupt(struct cp_tm1217_device *ts)
{
        u8 req[2];
        int retval;

        req[0] = TMA1217_INTERRUPT_ENABLE;
        req[1] = 0x0;
        retval = cp_tm1217_write(ts, req, 1);
        if (retval != 1)
                return -EIO;

        return 0;
}

static int cp_tm1217_unmask_interrupt(struct cp_tm1217_device *ts)
{
        u8 req[2];
        int retval;

        req[0] = TMA1217_INTERRUPT_ENABLE;
        req[1] = 0xa;
        retval = cp_tm1217_write(ts, req, 1);
        if (retval != 1)
                return -EIO;

        return 0;
}

static void process_touch(struct cp_tm1217_device *ts, int index)
{
        int retval;
        struct input_dev_info *input_info =
                (struct input_dev_info *)&ts->cp_input_info[index];
        u8 xy_data[6];

        if (index == 0)
                xy_data[0] = TMA1217_FINGER1_X_HIGHER8;
        else
                xy_data[0] = TMA1217_FINGER2_X_HIGHER8;

        retval = cp_tm1217_read(ts, xy_data, 5);
        if (retval < 5) {
                dev_err(ts->dev, "cp_tm1217: XY read from device failed\n");
                return;
        }

        /* Note: Currently not using the Z values but may be requried in
           the future. */
        input_info->touch.x = (xy_data[1] << 4)
                                        | (xy_data[3] & 0x0F);
        input_info->touch.y = (xy_data[2] << 4)
                                        | ((xy_data[3] & 0xF0) >> 4);
        input_report_abs(input_info->input, ABS_X, input_info->touch.x);
        input_report_abs(input_info->input, ABS_Y, input_info->touch.y);
        input_sync(input_info->input);
}

static void cp_tm1217_get_data(struct cp_tm1217_device *ts)
{
        u8 req[2];
        int retval, i, finger_touched = 0;

        do {
                req[0] = TMA1217_FINGER_STATE;
                retval = cp_tm1217_read(ts, req, 1);
                if (retval != 1) {
                        dev_err(ts->dev,
                                "cp_tm1217: Read from device failed\n");
                        continue;
                }
                finger_touched = 0;
                /* Start sampling until the pressure is below
                  threshold */
                for (i = 0; i < TOUCH_SUPPORTED; i++) {
                        if (req[1] & 0x3) {
                                finger_touched++;
                                if (ts->cp_input_info[i].touch.button == 0) {
                                        /* send the button touch event */
                                        input_report_key(
                                                ts->cp_input_info[i].input,
                                                BTN_TOUCH, 1);
                                        ts->cp_input_info[i].touch.button = 1;
                                }
                                process_touch(ts, i);
                        } else {
                                if (ts->cp_input_info[i].touch.button == 1) {
                                        /* send the button release event */
                                        input_report_key(
                                                ts->cp_input_info[i].input,
                                                BTN_TOUCH, 0);
                                        input_sync(ts->cp_input_info[i].input);
                                        ts->cp_input_info[i].touch.button = 0;
                                }
                        }
                        req[1] = req[1] >> 2;
                }
                msleep(DELAY_BTWIN_SAMPLE);
        } while (finger_touched > 0);
}

static irqreturn_t cp_tm1217_sample_thread(int irq, void *handle)
{
        struct cp_tm1217_device *ts = (struct cp_tm1217_device *) handle;
        u8 req[2];
        int retval;

        /* Chedk if another thread is already running */
        mutex_lock(&ts->thread_mutex);
        if (ts->thread_running == 1) {
                mutex_unlock(&ts->thread_mutex);
                return IRQ_HANDLED;
        } else {
                ts->thread_running = 1;
                mutex_unlock(&ts->thread_mutex);
        }

        /* Mask the interrupts */
        retval = cp_tm1217_mask_interrupt(ts);

        /* Read the Interrupt Status register to find the cause of the
           Interrupt */
        req[0] = TMA1217_INT_STATUS;
        retval = cp_tm1217_read(ts, req, 1);
        if (retval != 1)
                goto exit_thread;

        if (!(req[1] & 0x8))
                goto exit_thread;

        cp_tm1217_get_data(ts);

exit_thread:
        /* Unmask the interrupts before going to sleep */
        retval = cp_tm1217_unmask_interrupt(ts);

        mutex_lock(&ts->thread_mutex);
        ts->thread_running = 0;
        mutex_unlock(&ts->thread_mutex);

        return IRQ_HANDLED;
}

static int cp_tm1217_init_data(struct cp_tm1217_device *ts)
{
        int retval;
        u8      req[2];

        /* Read the vendor id/ fw revision etc. Ignoring return check as this
           is non critical info  */
        req[0] = TMA1217_MANUFACTURER_ID;
        retval = cp_tm1217_read(ts, req, 1);
        ts->vinfo.vendor_id = req[1];

        req[0] = TMA1217_PRODUCT_FAMILY;
        retval = cp_tm1217_read(ts, req, 1);
        ts->vinfo.product_family = req[1];

        req[0] = TMA1217_FIRMWARE_REVISION;
        retval = cp_tm1217_read(ts, req, 1);
        ts->vinfo.firmware_rev = req[1];

        req[0] = TMA1217_SERIAL_NO_HIGH;
        retval = cp_tm1217_read(ts, req, 1);
        ts->vinfo.serial_no = (req[1] << 8);

        req[0] = TMA1217_SERIAL_NO_LOW;
        retval = cp_tm1217_read(ts, req, 1);
        ts->vinfo.serial_no = ts->vinfo.serial_no | req[1];

        req[0] = TMA1217_MAX_X_HIGHER4;
        retval = cp_tm1217_read(ts, req, 1);
        ts->dinfo.maxX = (req[1] & 0xF) << 8;

        req[0] = TMA1217_MAX_X_LOWER8;
        retval = cp_tm1217_read(ts, req, 1);
        ts->dinfo.maxX = ts->dinfo.maxX | req[1];

        req[0] = TMA1217_MAX_Y_HIGHER4;
        retval = cp_tm1217_read(ts, req, 1);
        ts->dinfo.maxY = (req[1] & 0xF) << 8;

        req[0] = TMA1217_MAX_Y_LOWER8;
        retval = cp_tm1217_read(ts, req, 1);
        ts->dinfo.maxY = ts->dinfo.maxY | req[1];

        return 0;

}

/*
 *      Set up a GPIO for use as the interrupt. We can't simply do this at
 *      boot time because the GPIO drivers themselves may not be around at
 *      boot/firmware set up time to do the work. Instead defer it to driver
 *      detection.
 */

static int cp_tm1217_setup_gpio_irq(struct cp_tm1217_device *ts)
{
        int retval;

        /* Hook up the irq handler */
        retval = gpio_request(ts->gpio, "cp_tm1217_touch");
        if (retval < 0) {
                dev_err(ts->dev, "cp_tm1217: GPIO request failed error %d\n",
                                                                retval);
                return retval;
        }

        retval = gpio_direction_input(ts->gpio);
        if (retval < 0) {
                dev_err(ts->dev,
                "cp_tm1217: GPIO direction configuration failed, error %d\n",
                                                                retval);
                gpio_free(ts->gpio);
                return retval;
        }

        retval = gpio_to_irq(ts->gpio);
        if (retval < 0) {
                dev_err(ts->dev, "cp_tm1217: GPIO to IRQ failedi,"
                " error %d\n", retval);
                gpio_free(ts->gpio);
        }
        dev_dbg(ts->dev,
                "cp_tm1217: Got IRQ number is %d for GPIO %d\n",
                retval, ts->gpio);
        return retval;
}

static int cp_tm1217_probe(struct i2c_client *client,
                        const struct i2c_device_id *id)
{
        struct cp_tm1217_device *ts;
        struct input_dev *input_dev;
        struct input_dev_info   *input_info;
        struct cp_tm1217_platform_data *pdata;
        u8 req[2];
        int i, retval;

        /* No pdata is fine - we then use "normal" IRQ mode */

        pdata = client->dev.platform_data;

        ts = kzalloc(sizeof(struct cp_tm1217_device), GFP_KERNEL);
        if (!ts) {
                dev_err(&client->dev,
                        "cp_tm1217: Private Device Struct alloc failed\n");
                return -ENOMEM;
        }

        ts->client = client;
        ts->dev = &client->dev;
        i2c_set_clientdata(client, ts);

        ts->thread_running = 0;
        mutex_init(&ts->thread_mutex);

        /* Reset the Controller */
        req[0] = TMA1217_DEVICE_CMD_RESET;
        req[1] = 0x1;
        retval = cp_tm1217_write(ts, req, 1);
        if (retval != 1) {
                dev_err(ts->dev, "cp_tm1217: Controller reset failed\n");
                kfree(ts);
                return -EIO;
        }

        /* Clear up the interrupt status from reset. */
        req[0] = TMA1217_INT_STATUS;
        retval = cp_tm1217_read(ts, req, 1);

        /* Mask all the interrupts */
        retval = cp_tm1217_mask_interrupt(ts);

        /* Read the controller information */
        cp_tm1217_init_data(ts);

        /* The following code will register multiple event devices when
           multi-pointer is enabled, the code has not been tested
           with MPX */
        for (i = 0; i < TOUCH_SUPPORTED; i++) {
                input_dev = input_allocate_device();
                if (input_dev == NULL) {
                        dev_err(ts->dev,
                                "cp_tm1217:Input Device Struct alloc failed\n");
                        retval = -ENOMEM;
                        goto fail;
                }
                input_info = &ts->cp_input_info[i];
                snprintf(input_info->name, sizeof(input_info->name),
                        "cp_tm1217_touchscreen_%d", i);
                input_dev->name = input_info->name;
                snprintf(input_info->phys, sizeof(input_info->phys),
                        "%s/input%d", dev_name(&client->dev), i);

                input_dev->phys = input_info->phys;
                input_dev->id.bustype = BUS_I2C;

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

                input_set_abs_params(input_dev, ABS_X, 0, ts->dinfo.maxX, 0, 0);
                input_set_abs_params(input_dev, ABS_Y, 0, ts->dinfo.maxY, 0, 0);

                retval = input_register_device(input_dev);
                if (retval) {
                        dev_err(ts->dev,
                                "Input dev registration failed for %s\n",
                                        input_dev->name);
                        input_free_device(input_dev);
                        goto fail;
                }
                input_info->input = input_dev;
        }

        /* Setup the reporting mode to send an interrupt only when
           finger arrives or departs. */
        req[0] = TMA1217_REPORT_MODE;
        req[1] = 0x02;
        retval = cp_tm1217_write(ts, req, 1);

        /* Setup the device to no sleep mode for now and make it configured */
        req[0] = TMA1217_DEVICE_CTRL;
        req[1] = 0x84;
        retval = cp_tm1217_write(ts, req, 1);

        /* Check for the status of the device */
        req[0] = TMA1217_DEV_STATUS;
        retval = cp_tm1217_read(ts, req, 1);
        if (req[1] != 0) {
                dev_err(ts->dev,
                        "cp_tm1217: Device Status 0x%x != 0: config failed\n",
                        req[1]);

                retval = -EIO;
                goto fail;
        }

        if (pdata && pdata->gpio) {
                ts->gpio = pdata->gpio;
                retval = cp_tm1217_setup_gpio_irq(ts);
        } else
                retval = client->irq;

        if (retval < 0) {
                dev_err(ts->dev, "cp_tm1217: GPIO request failed error %d\n",
                                                                retval);
                goto fail;
        }

        client->irq = retval;


        retval = request_threaded_irq(client->irq,
                NULL, cp_tm1217_sample_thread,
                IRQF_TRIGGER_FALLING, "cp_tm1217_touch", ts);
        if (retval < 0) {
                dev_err(ts->dev, "cp_tm1217: Request IRQ error %d\n", retval);
                goto fail_gpio;
        }

        /* Unmask the interrupts */
        retval = cp_tm1217_unmask_interrupt(ts);
        if (retval == 0)
                return 0;

        free_irq(client->irq, ts);
fail_gpio:
        if (ts->gpio)
                gpio_free(ts->gpio);
fail:
        /* Clean up before returning failure */
        for (i = 0; i < TOUCH_SUPPORTED; i++) {
                if (ts->cp_input_info[i].input) {
                        input_unregister_device(ts->cp_input_info[i].input);
                        input_free_device(ts->cp_input_info[i].input);
                }
        }
        kfree(ts);
        return retval;

}

/*
 * cp_tm1217 suspend
 *
 */
static int cp_tm1217_suspend(struct i2c_client *client, pm_message_t mesg)
{
        struct cp_tm1217_device *ts = i2c_get_clientdata(client);
        u8 req[2];
        int retval;

        /* Put the controller to sleep */
        req[0] = TMA1217_DEVICE_CTRL;
        retval = cp_tm1217_read(ts, req, 1);
        req[1] = (req[1] & 0xF8) | 0x1;
        retval = cp_tm1217_write(ts, req, 1);

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

        return 0;
}

/*
 * cp_tm1217_resume
 *
 */
static int cp_tm1217_resume(struct i2c_client *client)
{
        struct cp_tm1217_device *ts = i2c_get_clientdata(client);
        u8 req[2];
        int retval;

        /* Take the controller out of sleep */
        req[0] = TMA1217_DEVICE_CTRL;
        retval = cp_tm1217_read(ts, req, 1);
        req[1] = (req[1] & 0xF8) | 0x4;
        retval = cp_tm1217_write(ts, req, 1);

        /* Restore the register settings sinc the power to the
           could have been cut off */

        /* Setup the reporting mode to send an interrupt only when
           finger arrives or departs. */
        req[0] = TMA1217_REPORT_MODE;
        req[1] = 0x02;
        retval = cp_tm1217_write(ts, req, 1);

        /* Setup the device to no sleep mode for now and make it configured */
        req[0] = TMA1217_DEVICE_CTRL;
        req[1] = 0x84;
        retval = cp_tm1217_write(ts, req, 1);

        /* Setup the interrupt mask */
        retval = cp_tm1217_unmask_interrupt(ts);

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

        return 0;
}

/*
 * cp_tm1217_remove
 *
 */
static int cp_tm1217_remove(struct i2c_client *client)
{
        struct cp_tm1217_device *ts = i2c_get_clientdata(client);
        int i;

        free_irq(client->irq, ts);
        if (ts->gpio)
                gpio_free(ts->gpio);
        for (i = 0; i < TOUCH_SUPPORTED; i++)
                input_unregister_device(ts->cp_input_info[i].input);
        kfree(ts);
        return 0;
}

static struct i2c_device_id cp_tm1217_idtable[] = {
        { CPTM1217_DEVICE_NAME, 0 },
        { }
};

MODULE_DEVICE_TABLE(i2c, cp_tm1217_idtable);

static struct i2c_driver cp_tm1217_driver = {
        .driver = {
                .owner  = THIS_MODULE,
                .name   = CPTM1217_DRIVER_NAME,
        },
        .id_table       = cp_tm1217_idtable,
        .probe          = cp_tm1217_probe,
        .remove         = cp_tm1217_remove,
        .suspend    = cp_tm1217_suspend,
        .resume     = cp_tm1217_resume,
};

static int __init clearpad_tm1217_init(void)
{
        return i2c_add_driver(&cp_tm1217_driver);
}

static void __exit clearpad_tm1217_exit(void)
{
        i2c_del_driver(&cp_tm1217_driver);
}

module_init(clearpad_tm1217_init);
module_exit(clearpad_tm1217_exit);

MODULE_AUTHOR("Ramesh Agarwal <ramesh.agarwal@intel.com>");
MODULE_DESCRIPTION("Synaptics TM1217 TouchScreen Driver");
MODULE_LICENSE("GPL v2");