/*
 * linux/drivers/video/n411.c -- Platform device for N411 EPD kit
 *
 * Copyright (C) 2008, Jaya Kumar
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License. See the file COPYING in the main directory of this archive for
 * more details.
 *
 * Layout is based on skeletonfb.c by James Simmons and Geert Uytterhoeven.
 *
 * This driver is written to be used with the Hecuba display controller
 * board, and tested with the EInk 800x600 display in 1 bit mode.
 * The interface between Hecuba and the host is TTL based GPIO. The
 * GPIO requirements are 8 writable data lines and 6 lines for control.
 * Only 4 of the controls are actually used here but 6 for future use.
 * The driver requires the IO addresses for data and control GPIO at
 * load time. It is also possible to use this display with a standard
 * PC parallel port.
 *
 * General notes:
 * - User must set dio_addr=0xIOADDR cio_addr=0xIOADDR c2io_addr=0xIOADDR
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/list.h>
#include <linux/uaccess.h>
#include <linux/irq.h>

#include <video/hecubafb.h>

static unsigned long dio_addr;
static unsigned long cio_addr;
static unsigned long c2io_addr;
static unsigned long splashval;
static unsigned int nosplash;
static unsigned char ctl;

static void n411_set_ctl(struct hecubafb_par *par, unsigned char bit, unsigned
                                                        char state)
{
        switch (bit) {
        case HCB_CD_BIT:
                if (state)
                        ctl &= ~(HCB_CD_BIT);
                else
                        ctl |= HCB_CD_BIT;
                break;
        case HCB_DS_BIT:
                if (state)
                        ctl &= ~(HCB_DS_BIT);
                else
                        ctl |= HCB_DS_BIT;
                break;
        }
        outb(ctl, cio_addr);
}

static unsigned char n411_get_ctl(struct hecubafb_par *par)
{
        return inb(c2io_addr);
}

static void n411_set_data(struct hecubafb_par *par, unsigned char value)
{
        outb(value, dio_addr);
}

static void n411_wait_for_ack(struct hecubafb_par *par, int clear)
{
        int timeout;
        unsigned char tmp;

        timeout = 500;
        do {
                tmp = n411_get_ctl(par);
                if ((tmp & HCB_ACK_BIT) && (!clear))
                        return;
                else if (!(tmp & HCB_ACK_BIT) && (clear))
                        return;
                udelay(1);
        } while (timeout--);
        printk(KERN_ERR "timed out waiting for ack\n");
}

static int n411_init_control(struct hecubafb_par *par)
{
        unsigned char tmp;
        /* for init, we want the following setup to be set:
        WUP = lo
        ACK = hi
        DS = hi
        RW = hi
        CD = lo
        */

        /* write WUP to lo, DS to hi, RW to hi, CD to lo */
        ctl = HCB_WUP_BIT | HCB_RW_BIT | HCB_CD_BIT ;
        n411_set_ctl(par, HCB_DS_BIT, 1);

        /* check ACK is not lo */
        tmp = n411_get_ctl(par);
        if (tmp & HCB_ACK_BIT) {
                printk(KERN_ERR "Fail because ACK is already low\n");
                return -ENXIO;
        }

        return 0;
}


static int n411_init_board(struct hecubafb_par *par)
{
        int retval;

        retval = n411_init_control(par);
        if (retval)
                return retval;

        par->send_command(par, APOLLO_INIT_DISPLAY);
        par->send_data(par, 0x81);

        /* have to wait while display resets */
        udelay(1000);

        /* if we were told to splash the screen, we just clear it */
        if (!nosplash) {
                par->send_command(par, APOLLO_ERASE_DISPLAY);
                par->send_data(par, splashval);
        }

        return 0;
}

static struct hecuba_board n411_board = {
        .owner                  = THIS_MODULE,
        .init                   = n411_init_board,
        .set_ctl                = n411_set_ctl,
        .set_data               = n411_set_data,
        .wait_for_ack           = n411_wait_for_ack,
};

static struct platform_device *n411_device;
static int __init n411_init(void)
{
        int ret;
        if (!dio_addr || !cio_addr || !c2io_addr) {
                printk(KERN_WARNING "no IO addresses supplied\n");
                return -EINVAL;
        }

        /* request our platform independent driver */
        request_module("hecubafb");

        n411_device = platform_device_alloc("hecubafb", -1);
        if (!n411_device)
                return -ENOMEM;

        ret = platform_device_add_data(n411_device, &n411_board,
                                       sizeof(n411_board));
        if (ret)
                goto put_plat_device;

        /* this _add binds hecubafb to n411. hecubafb refcounts n411 */
        ret = platform_device_add(n411_device);

        if (ret)
                goto put_plat_device;

        return 0;

put_plat_device:
        platform_device_put(n411_device);
        return ret;
}

static void __exit n411_exit(void)
{
        platform_device_unregister(n411_device);
}

module_init(n411_init);
module_exit(n411_exit);

module_param(nosplash, uint, 0);
MODULE_PARM_DESC(nosplash, "Disable doing the splash screen");
module_param_hw(dio_addr, ulong, ioport, 0);
MODULE_PARM_DESC(dio_addr, "IO address for data, eg: 0x480");
module_param_hw(cio_addr, ulong, ioport, 0);
MODULE_PARM_DESC(cio_addr, "IO address for control, eg: 0x400");
module_param_hw(c2io_addr, ulong, ioport, 0);
MODULE_PARM_DESC(c2io_addr, "IO address for secondary control, eg: 0x408");
module_param(splashval, ulong, 0);
MODULE_PARM_DESC(splashval, "Splash pattern: 0x00 is black, 0x01 is white");

MODULE_DESCRIPTION("board driver for n411 hecuba/apollo epd kit");
MODULE_AUTHOR("Jaya Kumar");
MODULE_LICENSE("GPL");