n411.c

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/*
 * 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;

    platform_device_add_data(n411_device, &n411_board, sizeof(n411_board));

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

    if (ret)
        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(dio_addr, ulong, 0);
MODULE_PARM_DESC(dio_addr, "IO address for data, eg: 0x480");
module_param(cio_addr, ulong, 0);
MODULE_PARM_DESC(cio_addr, "IO address for control, eg: 0x400");
module_param(c2io_addr, ulong, 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");