/*
  handle cx231xx IR remotes via linux kernel input layer.

  Copyright (C) 2008 <srinivasa.deevi at conexant dot com>
                Based on em28xx driver

                < This is a place holder for IR now.>

  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/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/usb.h>

#include "cx231xx.h"

static unsigned int ir_debug;
module_param(ir_debug, int, 0644);
MODULE_PARM_DESC(ir_debug, "enable debug messages [IR]");

#define i2cdprintk(fmt, arg...) \
        if (ir_debug) { \
                printk(KERN_DEBUG "%s/ir: " fmt, ir->name , ## arg); \
        }

#define dprintk(fmt, arg...) \
        if (ir_debug) { \
                printk(KERN_DEBUG "%s/ir: " fmt, ir->name , ## arg); \
        }

/**********************************************************
 Polling structure used by cx231xx IR's
 **********************************************************/

struct cx231xx_ir_poll_result {
        unsigned int toggle_bit:1;
        unsigned int read_count:7;
        u8 rc_address;
        u8 rc_data[4];
};

struct cx231xx_IR {
        struct cx231xx *dev;
        struct input_dev *input;
        struct ir_input_state ir;
        char name[32];
        char phys[32];

        /* poll external decoder */
        int polling;
        struct work_struct work;
        struct timer_list timer;
        unsigned int last_toggle:1;
        unsigned int last_readcount;
        unsigned int repeat_interval;

        int (*get_key) (struct cx231xx_IR *, struct cx231xx_ir_poll_result *);
};

/**********************************************************
 Polling code for cx231xx
 **********************************************************/

static void cx231xx_ir_handle_key(struct cx231xx_IR *ir)
{
        int result;
        int do_sendkey = 0;
        struct cx231xx_ir_poll_result poll_result;

        /* read the registers containing the IR status */
        result = ir->get_key(ir, &poll_result);
        if (result < 0) {
                dprintk("ir->get_key() failed %d\n", result);
                return;
        }

        dprintk("ir->get_key result tb=%02x rc=%02x lr=%02x data=%02x\n",
                poll_result.toggle_bit, poll_result.read_count,
                ir->last_readcount, poll_result.rc_data[0]);

        if (ir->dev->chip_id == CHIP_ID_EM2874) {
                /* The em2874 clears the readcount field every time the
                   register is read.  The em2860/2880 datasheet says that it
                   is supposed to clear the readcount, but it doesn't.  So with
                   the em2874, we are looking for a non-zero read count as
                   opposed to a readcount that is incrementing */
                ir->last_readcount = 0;
        }

        if (poll_result.read_count == 0) {
                /* The button has not been pressed since the last read */
        } else if (ir->last_toggle != poll_result.toggle_bit) {
                /* A button has been pressed */
                dprintk("button has been pressed\n");
                ir->last_toggle = poll_result.toggle_bit;
                ir->repeat_interval = 0;
                do_sendkey = 1;
        } else if (poll_result.toggle_bit == ir->last_toggle &&
                   poll_result.read_count > 0 &&
                   poll_result.read_count != ir->last_readcount) {
                /* The button is still being held down */
                dprintk("button being held down\n");

                /* Debouncer for first keypress */
                if (ir->repeat_interval++ > 9) {
                        /* Start repeating after 1 second */
                        do_sendkey = 1;
                }
        }

        if (do_sendkey) {
                dprintk("sending keypress\n");
                ir_input_keydown(ir->input, &ir->ir, poll_result.rc_data[0],
                                 poll_result.rc_data[0]);
                ir_input_nokey(ir->input, &ir->ir);
        }

        ir->last_readcount = poll_result.read_count;
        return;
}

static void ir_timer(unsigned long data)
{
        struct cx231xx_IR *ir = (struct cx231xx_IR *)data;

        schedule_work(&ir->work);
}

static void cx231xx_ir_work(struct work_struct *work)
{
        struct cx231xx_IR *ir = container_of(work, struct cx231xx_IR, work);

        cx231xx_ir_handle_key(ir);
        mod_timer(&ir->timer, jiffies + msecs_to_jiffies(ir->polling));
}

void cx231xx_ir_start(struct cx231xx_IR *ir)
{
        setup_timer(&ir->timer, ir_timer, (unsigned long)ir);
        INIT_WORK(&ir->work, cx231xx_ir_work);
        schedule_work(&ir->work);
}

static void cx231xx_ir_stop(struct cx231xx_IR *ir)
{
        del_timer_sync(&ir->timer);
        flush_scheduled_work();
}

int cx231xx_ir_init(struct cx231xx *dev)
{
        struct cx231xx_IR *ir;
        struct input_dev *input_dev;
        u8 ir_config;
        int err = -ENOMEM;

        if (dev->board.ir_codes == NULL) {
                /* No remote control support */
                return 0;
        }

        ir = kzalloc(sizeof(*ir), GFP_KERNEL);
        input_dev = input_allocate_device();
        if (!ir || !input_dev)
                goto err_out_free;

        ir->input = input_dev;

        /* Setup the proper handler based on the chip */
        switch (dev->chip_id) {
        default:
                printk("Unrecognized cx231xx chip id: IR not supported\n");
                goto err_out_free;
        }

        /* This is how often we ask the chip for IR information */
        ir->polling = 100;      /* ms */

        /* init input device */
        snprintf(ir->name, sizeof(ir->name), "cx231xx IR (%s)", dev->name);

        usb_make_path(dev->udev, ir->phys, sizeof(ir->phys));
        strlcat(ir->phys, "/input0", sizeof(ir->phys));

        ir_input_init(input_dev, &ir->ir, IR_TYPE_OTHER, dev->board.ir_codes);
        input_dev->name = ir->name;
        input_dev->phys = ir->phys;
        input_dev->id.bustype = BUS_USB;
        input_dev->id.version = 1;
        input_dev->id.vendor = le16_to_cpu(dev->udev->descriptor.idVendor);
        input_dev->id.product = le16_to_cpu(dev->udev->descriptor.idProduct);

        input_dev->dev.parent = &dev->udev->dev;
        /* record handles to ourself */
        ir->dev = dev;
        dev->ir = ir;

        cx231xx_ir_start(ir);

        /* all done */
        err = input_register_device(ir->input);
        if (err)
                goto err_out_stop;

        return 0;
err_out_stop:
        cx231xx_ir_stop(ir);
        dev->ir = NULL;
err_out_free:
        input_free_device(input_dev);
        kfree(ir);
        return err;
}

int cx231xx_ir_fini(struct cx231xx *dev)
{
        struct cx231xx_IR *ir = dev->ir;

        /* skip detach on non attached boards */
        if (!ir)
                return 0;

        cx231xx_ir_stop(ir);
        input_unregister_device(ir->input);
        kfree(ir);

        /* done */
        dev->ir = NULL;
        return 0;
}